Hair Science Thread [Archive] - The Long Hair Community Discussion Boards

meteor

March 12th, 2016, 07:14 PM

INDEX - PART 1

Hair Basics and Relevant Studies:

1. Hair Damage:

1.1 Photo-damage (UV damage): (post # 5 - studies (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187913&viewfull=1#post3187913)) UVB: morphological damage, protein loss; UVA: biochemical damage, color changes

1.2 Chemical damage:

Bleaching: (post # 127 - studies Part I (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3192945&viewfull=1#post3192945))
Dyeing: (post # 127 - studies Part I (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3192945&viewfull=1#post3192945))
Perming and Relaxing: (post # 128 - studies Part II (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3192947&viewfull=1#post3192947))
Keratin Straightening (Brazilian, Japanese straightening): (post # 128 - studies Part II (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3192947&viewfull=1#post3192947))
1.3 Mechanical damage: (post # 166 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3196068&viewfull=1#post3196068) - studies Part I, post # 167 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3196069&viewfull=1#post3196069) - studies Part II)

1.4 Thermal / heat damage: Blow-drying and direct heat (post # 92 - studies (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3191167&viewfull=1#post3191167))

2. Hair Structure: (Studies on overall structure, keratin, 18-MEA, ceramides, etc: post # 130 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3193005&viewfull=1#post3193005)), (Studies on CMC and cuticle: post # 153 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3194611&viewfull=1#post3194611))

3. Sebum and Hair Oils:

3.1 Sebum Composition: (post # 36 - natural and artificial sebum (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188414&viewfull=1#post3188414))
http://www.dermnetnz.org/acne/sebum.html

Sebum and acne: (post # 77 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3190215&viewfull=1#post3190215))

3.2 Details on intercellular lipids: (post # 130 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3193005&viewfull=1#post3193005))

Hair Pigmentation:

- The cell biology of human hair follicle pigmentation: http://www.ncbi.nlm.nih.gov/pubmed/21070612

- Aging of the Hair Follicle Pigmentation System: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2938584/

- Graying: gerontobiology of the hair follicle pigmentary unit: http://www.ncbi.nlm.nih.gov/pubmed/11162910

- Hair cycle and hair pigmentation: dynamic interactions and changes associated with aging: http://www.ncbi.nlm.nih.gov/pubmed/15036274

- Hair Follicle Pigmentation: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1201498/

4. Hair Growth:

Downloadable Excel Table for Managing Your Hair Growth Data: http://forums.longhaircommunity.com/showthread.php?t=36275

- Melanogenesis during the anagen-catagen-telogen transformation of the murine hair cycle: http://ac.els-cdn.com/S0022202X94946205/1-s2.0-S0022202X94946205-main.pdf?_tid=8cca3ea2-fdb5-11e5-b9ed-00000aab0f6c&acdnat=1460139369_ea576faba55e11154d71f70570611601

- Peppermint Oil Promotes Hair Growth without Toxic Signs: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4289931/

- Action Mechanism of Chamaecyparis obtusa Oil on Hair Growth: http://www.ncbi.nlm.nih.gov/pubmed/24578794

- The essential oils of Chamaecyparis obtusa promote hair growth through the induction of vascular endothelial growth factor gene: http://www.ncbi.nlm.nih.gov/pubmed/19576968

- Effectiveness of the combinational treatment of Laminaria japonica and Cistanche tubulosa extracts in hair growth: http://www.ncbi.nlm.nih.gov/pubmed/25806080

- Hair growth-promoting effect of Carthamus tinctorius floret extract: http://www.ncbi.nlm.nih.gov/pubmed/24338940

- The hair growth promoting effect of Asiasari radix extract and its molecular regulation: http://www.ncbi.nlm.nih.gov/pubmed/15862941

- The hair growth promoting effect of Sophora flavescens extract and its molecular regulation: http://www.ncbi.nlm.nih.gov/pubmed/12354419

- Relationships between hair growth rate and morphological parameters of human straight hair: a same law above ethnical origins? http://www.ncbi.nlm.nih.gov/pubmed/21951315 (Discussion: post # 154 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3194642&viewfull=1#post3194642))

- Changes in Chinese hair growth along a full year: http://www.ncbi.nlm.nih.gov/pubmed/25065943 (Discussion: post # 165 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3196037&viewfull=1#post3196037))

5. Hair Thickness/Density:
"120,000 to 150,000 - the number of individual hairs in a full head of hair.
250 - the number of hairs per square centimetre of scalp. This figure varies between 200 and 300 according to the area of scalp in question."(L'Oreal Hair Science (http://www.hair-science.com/_int/_en/topic/topic_sousrub.aspx?tc=ROOT-HAIR-SCIENCE^PORTRAIT-OF-AN-UNKNOWN-ELEMENT^WHAT-WE-DO-SEE&cur=WHAT-WE-DO-SEE))

LHC stats on correlations between strand thickness, ponytail circumference and length: (post # 144 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3193684&viewfull=1#post3193684))

How to calculate your density from strand thickness and ponytail circumference: (post # 183 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3203951&viewfull=1#post3203951) and 3rd (last) point in "Terminal Length Calculations" Tab on spreadsheet here: http://forums.longhaircommunity.com/showthread.php?t=36275)

6. Hair Strand Thickness (Fineness – Coarseness): 17 - 181 microns Diameter of a Human Hair: http://hypertextbook.com/facts/1999/BrianLey.shtml or 58 - 100 microns (L'Oreal Hair Science (http://www.hair-science.com/_int/_en/topic/topic_sousrub.aspx?tc=ROOT-HAIR-SCIENCE^PORTRAIT-OF-AN-UNKNOWN-ELEMENT^WHAT-WE-DO-SEE&cur=WHAT-WE-DO-SEE))
< 40 microns - very fine
40 - 60 microns - fine
60 - 80 microns - medium
> 80 microns - coarse (80 - 95 - slightly coarse, 95 - 110 - moderately coarse, > 110 - very coarse)
(http://science-yhairblog.blogspot.com/2012/06/is-your-hair-fine-medium-or-coarse-how.html)

Hair strand thickness and age: (post # 124 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3192887&viewfull=1#post3192887))

A method for measuring hair strand thickness: http://forums.longhaircommunity.com/showthread.php?t=136858

7. Hair Porosity:
Damaged hair can absorb 45% of its weight in water; undamaged hair in good condition can absorb 30% (L'Oreal Hair Science (http://www.hair-science.com/_int/_en/topic/topic_sousrub.aspx?tc=ROOT-HAIR-SCIENCE^PORTRAIT-OF-AN-UNKNOWN-ELEMENT^WHAT-WE-DO-SEE&cur=WHAT-WE-DO-SEE))

- True porosity measurement of hair: a new way to study hair damage mechanisms: http://www.ncbi.nlm.nih.gov/pubmed/18818850

On the importance of oiling high-porosity hair:

- The effects of lipid penetration and removal from subsurface microcavities and cracks at the human cuticle sheath: http://www.ncbi.nlm.nih.gov/pubmed/19450411
"The presence of exogenous lipids in these cavities was found to be critical in maintaining the mechanical integrity of the cuticle cells."

- Managing elasticity and porosity in hair (blog): http://science-yhairblog.blogspot.ca/2014/03/managing-elasticity-and-porosity-in-hair.html

8. Hair Texture: (post # 132 - studies (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3193068&viewfull=1#post3193068))

9. Pictures - Hair and Scalp under Microscope: (post # 69 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3189819&viewfull=1#post3189819), post # 70 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3189844&viewfull=1#post3189844))

10. Hair Loss (Alopecia):

10.1. Androgenetic Alopecia: Studies on Androgenetic Alopecia: (Part I: post # 118 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3192491&viewfull=1#post3192491), Part II: post # 119 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3192503&viewfull=1#post3192503))
(post # 76 - studies on AGA and Ketoconazole, DHT and oiliness connection discussed (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3190148&viewfull=1#post3190148))
(post # 103 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3192034&viewfull=1#post3192034) - summary of study on 1% ketoconazole, 1% piroctone olamine and 1% zinc pyrithione for hair loss, post # 104 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3192073&viewfull=1#post3192073))

10.2. Alopecia Areata: (post # 45 - studies on Alopecia Areata (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188561&viewfull=1#post3188561))

meteor

March 12th, 2016, 07:14 PM

INDEX - PART 2

I. Hair Care Ingredients:

Surfactants:

- Surfactant structure effects on swelling of isolated human stratum corneum:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.541.7442&rep=rep1&type=pdf

Oils:

- Penetrating oils: post # 14 (http://forums.longhaircommunity.com/showthread.php?t=136845&page=2&p=3188071&viewfull=1#post3188071), post # 25 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188288&viewfull=1#post3188288), oil rinses - post # 34 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188362&viewfull=1#post3188362), pre-wash (blog) - http://science-yhairblog.blogspot.com/2014/03/oil-pre-shampoo-or-pre-wash.html)
(post # 170 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3196584&viewfull=1#post3196584) - Brazilian oils and butters for gloss, split ends, combability, strength; coconut oil absorption rates),
(post # 172 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3196991&viewfull=1#post3196991) - Argan oil and Cupuassu butter reduce protein loss after hair dye)

- Anti-bacterial and anti-fungal oils: (post # 57 - studies 1 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188920&viewfull=1#post3188920), post # 58 - studies 2 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188921&viewfull=1#post3188921))

- Drying capacity of oils: (post # 173 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3196993&viewfull=1#post3196993))

Silicones:

- Nanotribological effects of silicone type, silicone deposition level, and surfactant type on human hair using atomic force microscopy: http://www.ncbi.nlm.nih.gov/pubmed/16676122

Silicone Solubility List: http://science-yhairblog.blogspot.com/2014/04/silicone-ingredient-solubility-list.html

Hydrolyzed Proteins:

- http://science-yhairblog.blogspot.ca/2012/02/how-hot-is-too-hot-for-healthy-hair.html "The protein polymer, hydrolyzed wheat protein polysiloxane copolymer was found to prevent cuticle cracking. Other proteins and conditioners were not tested. Other testing has demonstrated that P/DMAPA Acrylates Copolymer and Polyquaternium-55 have good heat-protecting qualities."

Amino Acids:
- Hair and amino acids: the interactions and the effects: http://www.ncbi.nlm.nih.gov/pubmed/17728935

Basics on hydrolyzed proteins: http://science-yhairblog.blogspot.com/2015/10/protein-101-lots-of-basic-information.html and http://science-yhairblog.blogspot.com/2013/09/more-about-protein.html

Protein size - http://www.thenaturalhavenbloom.com/2009/06/size-matters-protein-conditioning-part.html)

Humectants:

Film-forming humectants: (blog) http://science-yhairblog.blogspot.com/2014/07/film-forming-humectants-what-they-are.html

Glycerin

Honey

Polymers:

- Conditioning polymers in today's shampoo formulations - efficacy, mechanism and test methods: http://www.ncbi.nlm.nih.gov/pubmed/18503458

- Quantitative methods for evaluating optical and frictional properties of cationic polymers: http://www.ncbi.nlm.nih.gov/pubmed/11382843

- Surfactants, polymers and their nanoparticles for personal care applications: http://www.ncbi.nlm.nih.gov/pubmed/15645085

- Polymer/surfactant interactions and nanostructures: current development for cleansing, release, and deposition of actives: http://www.ncbi.nlm.nih.gov/pubmed/21635852

- Effects of low-level hydrophobic substitution on conditioning properties of cationic cellulosic polymers in shampoo systems: http://www.ncbi.nlm.nih.gov/pubmed/15645097

- Evaluation of novel synthetic conditioning polymers for shampoos: http://www.ncbi.nlm.nih.gov/pubmed/19450423

- New high-charge density hydrophobically modified cationic HEC polymers for improved co-deposition of benefit agents and serious conditioning for problem hair: http://www.ncbi.nlm.nih.gov/pubmed/17728943

Basic Hair Care Practices and Products:

- Hair: its structure and response to cosmetic preparations: http://www.ncbi.nlm.nih.gov/pubmed/8901408

- The biology of hair care: http://www.ncbi.nlm.nih.gov/pubmed/11059373

- Biology of human hair: know your hair to control it: http://www.ncbi.nlm.nih.gov/pubmed/21072698

- Hair cosmetics: http://www.ncbi.nlm.nih.gov/pubmed/2022094

- Hair shaft effects from cosmetics and styling: http://www.ncbi.nlm.nih.gov/pubmed/10439246

Cleansing Methods:

Microscope photography and comparison of hair strands washed with:

- Conditioner (Co-Wash) vs. Shampoo vs. Water Only vs. Unwashed Hair : http://www.thenaturalhavenbloom.com/2014/02/does-co-washing-really-clean-your-hair.html

- Bentonite Clay vs. Rassoul Clay vs. Shampoo vs. Unwashed Hair: http://www.thenaturalhavenbloom.com/2014/02/can-you-really-wash-your-hair-with.html

- Baking Soda vs. ACV vs. Shampoo vs. Unwashed Hair: http://www.thenaturalhavenbloom.com/2014/07/can-you-wash-your-hair-with-baking-soda.html

- Shikakai vs. Bentonite Clay vs. Baking Soda vs. ACV vs. Shampoo vs. Conditioner (CO-Wash) vs. Water Only vs. Unwashed Hair: http://www.thenaturalhavenbloom.com/2014/11/caucasian-hair-cleansing-shikakai.html

- Compilation: Oat Water vs. Bentonite Clay vs. Rassoul Clay vs. Baking Soda vs. ACV vs. Shampoo Bar vs. Castile Soap vs. Shampoo vs. Conditioner (CO-Wash) vs. Unwashed Hair: http://www.thenaturalhavenbloom.com/2015/05/hair-science-how-well-do-mild-cleansers.html

- Matting of scalp hair during shampooing--a new look: http://www.ncbi.nlm.nih.gov/pubmed/2347105

- Matting of hair: what is the role of conditioners? http://www.ncbi.nlm.nih.gov/pubmed/16503900

Sodium Lauryl Sulfate vs. Sodium Coco Sulfate: (post # 115 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3192392&viewfull=1#post3192392))

Water Hardness, Mineral Build-Up, Chelating: (post # 180 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3202649&viewfull=1#post3202649), post # 181 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3202650&viewfull=1#post3202650))

Conventional Products:

Hair Cosmetics: An Overview: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4387693/

Shampoos - Studies:

- Selective removal of sebum components from hair by surfactants: http://journal.scconline.org/pdf/cc1989/cc040n06/p00309-p00320.pdf

- Shampoos: ingredients, efficacy and adverse effects: http://www.ncbi.nlm.nih.gov/pubmed/17451380

- Shampoos: composition and clinical applications: http://www.ncbi.nlm.nih.gov/pubmed/9914886

- The cross-modal effect of fragrance in shampoo: Modifying the perceived feel of both product and hair during and after washing: https://www.researchgate.net/publication/222519212_The_cross-modal_effect_of_fragrance_in_shampoo_Modifying_the _perceived_feel_of_both_product_and_hair_during_an d_after_washing

Anti-dandruff Shampoos: (post # 134 - studies (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3193101&viewfull=1#post3193101))

pH - Studies: Evaluation of pH of Bathing Soaps and Shampoos for Skin and Hair Care: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4171909/; The Shampoo pH can Affect the Hair: Myth or Reality? : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4158629/
pH and hair (blog): http://science-yhairblog.blogspot.com/2013/07/ph-and-your-hair-little-redox-to-make.html

2-in-1 Products:

- 2-in-1 shampoo technology: state-of-the-art shampoo and conditioner in one: http://www.ncbi.nlm.nih.gov/pubmed/8003328

Conditioners: (post # 168 - studies (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3196091&viewfull=1#post3196091))

Styling Products:

- The mechanics of fixatives as explained by polymer composite principles: http://www.ncbi.nlm.nih.gov/pubmed/19450424

- Hair spray:

- (blog) http://science-yhairblog.blogspot.com/2013/05/alcohol-in-hair-sprays.html

- Dynamic hairspray analysis. II. Effect of polymer, hair type, and solvent composition: http://www.ncbi.nlm.nih.gov/pubmed/11567208

- Gel:

- Polymer composite principles applied to hair styling gels: http://www.ncbi.nlm.nih.gov/pubmed/19156332

- Assessment of styling performance in hair gels and hair sprays by means of a new two-point stiffness test: http://www.ncbi.nlm.nih.gov/pubmed/20939974

Hair Shine: (post # 133 - studies (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3193079&viewfull=1#post3193079))

meteor

March 12th, 2016, 07:16 PM

INDEX - PART 3

Hair Experiments:

1. Weight of hair:
- Gossamer: https://youtu.be/YW7yZrmLWdg and http://forums.longhaircommunity.com/archive/index.php/t-137282.html (Dry braid ~350 g, ~12 oz, ~.77 lbs)
- Lucy's Corsetry: https://www.youtube.com/watch?v=XduqBu1s44Y&nohtml5=False (Dry braid (48'' of hair) ~ 225 g (0.5 lbs), and Wet braid (not dripping wet) ~ 350 g (0.75 lbs), so the hair absorbed about 55% of its dry weight in water)
- Wusel: http://forums.longhaircommunity.com/archive/index.php/t-137282.html (~70 g)
- JJJ / LadyLongLocks: ~ 255 g (9 oz) dry hair (60'') (http://forums.longhaircommunity.com/showthread.php?t=110471&p=2392236&viewfull=1#post2392236)
- Igor: ~ 250 g (thick, knee length hair) (http://igorsbelltower.blogspot.ca/2011/09/hair-weight-and-headaches.html);
An average inch of hair weighs about 50 µg.

Theories:

1. Is curly hair more/less tangle-prone? Study: Why does curly hair get less tangled than straight hair? by Jean-Baptiste Masson: http://scitation.aip.org/content/aapt/journal/ajp/75/8/10.1119/1.2733683 (quick article on it: http://www.scientificamerican.com/article/straight-hair-is-knottier-than-curly-hair/) (post # 29 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188311&viewfull=1#post3188311), post # 48 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188746&viewfull=1#post3188746), post # 49 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188825&viewfull=1#post3188825))

________________

Recently raised questions:

1. Do UV filters in haircare products work well to protect from UV damage? (post # 5 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187913&viewfull=1#post3187913))

2. Which oils can penetrate hair? Does olive oil penetrate hair? Are other fatty acids (other than lauric acid) possibly responsible for penetrating abilities of oils? (post # 14 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188071&viewfull=1#post3188071), post # 25 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188288&viewfull=1#post3188288))
- Coconut (both unrefined and refined, as long as it's not fractionated; ~ 49% lauric acid): "coconut oil, being a triglyceride of lauric acid (principal fatty acid), has a high affinity for hair proteins and, because of its low molecular weight and straight linear chain, is able to penetrate inside the hair shaft."(Effect of mineral oil, sunflower oil, and coconut oil on prevention of hair damage. - http://journal.scconline.org/pdf/cc2003/cc054n02/p00175-p00192.pdf)
Maybe also:
- Babassu oil (~ 50% lauric acid)
- Palm kernel oil (~ 48% lauric acid)

Oils without lauric acid may still penetrate, though the instances are less documented (see below).
Olive oil can penetrate (probably due to its saturated and monounsaturated fat content), according to studies reviewed by Science-y Hair Blog: http://science-yhairblog.blogspot.com/2013/06/oils-which-ones-soak-in-vs-coat-hair.html
According to this study (Investigation of penetration abilities of various oils into human hair fibers: http://journal.scconline.org/pdf/cc2005/cc056n05/p00283-p00295.pdf), "In general, saturated and monounsaturated oils penetrate into the hair because of a compact molecular structure and the polar head group of the triglyceride molecules that constitute these oils. In a dynamic mode these molecules can reptate and squeeze through the CMCs. On the other hand, polyunsaturated oils do not penetrate into hair, most likely because of the more open and spread-out structures of their triglyceride molecules and because of the presence of multiple double bond."

See fatty acid composition of oils: https://docs.google.com/spreadsheets/d/1-lDtdpjbJopUEvpk0vjNbDt_mE_prCCCZtOqfRnzIaw/edit?pref=2&pli=1#gid=3

3. Can oils penetrating hair cause brittleness?
(post # 7 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187923&viewfull=1#post3187923), post # 25 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188288&viewfull=1#post3188288)) Not likely. This study (Secondary ion mass spectrometric investigation of penetration of coconut and mineral oils into human hair fibers: Relevance to hair damage: http://journal.scconline.org/pdf/cc2001/cc052n03/p00169-p00184.pdf) showed that "reduction in moisturization of the fiber does not make the fiber rigid because of the plasticizating action of the absorbed coconut oil."

However, oils do build up on hair. According to this study (Effect of oil films on moisture vapor absorption on human hair: http://journal.scconline.org/pdf/cc2007/cc058n02/p00135-p00145.pdf), there is a reduction in moisture uptake and diffusion rates when oil film is formed on hair, and the thicker the film, the more pronounced the effect.

4. Do people who bathe less frequently have a healthier symbiotic community of bacteria on their skin? How is the population of bacteria on hair change depending on the type of hair care - shampooing, CO, WO, NW/SO, etc? What causes sebum to smell? (post # 37 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188431&viewfull=1#post3188431), post # 40, post # 48 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188746&viewfull=1#post3188746))

5. What is the evolution of hair strand thickness with ageing? (post # 47 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188631&viewfull=1#post3188631))

6. Is there a scientific study out there that deals with the question if the frequency of hair washes influences how quickly the scalp produces more sebum? (post # 63 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3189759&viewfull=1#post3189759), post # 66 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3189772&viewfull=1#post3189772), post # 67 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3189806&viewfull=1#post3189806))
The regulation of sebum excretion in man: http://link.springer.com/article/10.1007%2FBF00560397
"The refatting curve of 21 test persons shows that the sebum excretion is highest during the first hour and decreases continuously with every following refatting interval. Refatting after regular defatting every hour reveals a constant excretion rate over 7 hrs. Thus the conclusion can be drawn that sebum excretion is regulated by the excreted sebum itself."

7. Is hair steaming damaging, useless or beneficial? (post # 85 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3191005&viewfull=1#post3191005), post # 86 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3191051&viewfull=1#post3191051), post # 87 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3191068&viewfull=1#post3191068))

8. Is it less damaging to hair structure to cut hair when it's dry or wet? (post # 138 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3193306&viewfull=1#post3193306), post # 140 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3193454&viewfull=1#post3193454))

____________________

Additional Reading:
Chemical and Physical Behavior of Human Hair by By Clarence R. Robbins (2012) (post # 18 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3188107&viewfull=1#post3188107))

Some Hair Science Related Blogs:
http://science-yhairblog.blogspot.com/
http://www.thenaturalhavenbloom.com/

meteor

March 12th, 2016, 07:26 PM

Photo-Damage BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

Quick summary:

Photo-damage is a type of environmental damage and is sometimes referred to as "photo-aging".
UV rays damage hair keratin, deplete lipid layer and make natural and artificial colors fade, while making white hair develop a yellow tint.
"Damage to hair due to UV light occurs due to free radicals or cysteic acid, which forms after UV radiation and breaks disulfide bonds."(Pande CM, Jachowicz J. Hair photodamage-measurement and prevention. J Soc Cosmet Chem. 1993;44:109–122)
"Continuous UV-light exposure results in dryness, roughness, sun-bleaching and breakage due to photo-oxidation."(http://www.ncbi.nlm.nih.gov/pubmed/11382847)
"UVB radiation is responsible for hair protein loss and UVA radiation is responsible for color changes."(http://www.ncbi.nlm.nih.gov/pubmed/19138021)
"Morphological damage is significant in UVB-irradiated hairs, while biochemical changes are greater in UVA-irradiated hairs."(http://www.ncbi.nlm.nih.gov/pubmed/18408872)

According to some studies, different hair types can show different degrees of susceptibility to photo-damage: for example, "it has been found that gray hair undergoes more severe UV damage and needs more UV protection than dark brown hair" (http://www.ncbi.nlm.nih.gov/pubmed/11382847) and "after UV irradiation, European and African hair samples exhibited more damage because they have less integral hair lipids. However, Asian hair samples have less damage." (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3582929/)

UV rays make chemical dyes fade faster:
"The loss of dye hair color typically occurs because of color wash-out during the daily shampooing process or can be initiated by environmental circumstances such as exposure to UV radiation which can break down the color molecule. It was found that the washing process is the most signifi cant factor in the removal of hair color, while UV exposure has a significant impact only after 90 hours of intense irradiation." - Protection of oxidative hair color fading from shampoo washing by hydrophobically modified cationic polymers (http://journal.scconline.org/pdf/cc2009/cc060n02/p00217-p00238.pdf)

UV exposure increases hair's porosity:
"Chemical damage (oxidative bleach) nearly triples the hair surface area in the first minute of bleaching due to the increase in the number of pores, followed by a sudden drop after 10 min of bleaching from smaller pores breaking down into larger ones. In contrast, UV damage shows an immediate loss in surface area in the first 200 hr of exposure and a gradual increase as exposure time continues." (http://journal.scconline.org/pdf/cc2008/cc059n04/p00303-p00315.pdf)

This morphological study (http://journal.scconline.org/pdf/cc2008/cc059n02/p00151-p00156.pdf) shows that "UVA irradiation can penetrate deeply into the cortex, and so biochemical changes, including cuticles and cortex together, may appear greater after UVA irradiation. On the other hand, UVB cause severe morphological damage, confined to the hair cuticles because of its restricted depth of penetration." The study "shows relatively more destructive cuticular changes after UVB irradiation than after UVA, while disruptions of the intercellular lipid layer show similar results between UVA and UVB irradiation. However, in labile protein analysis, damaged labile hair proteins are much more observed after UVA irradiation than after UVB irradiation."

Photo-damage Studies:

- Photodegradation of human hair: a SEM study: http://journal.scconline.org/pdf/cc2000/cc051n02/p00103-p00125.pdf

- About photo-damage of human hair: http://www.ncbi.nlm.nih.gov/pubmed/16465301

- UV damage of the hair: http://www.ncbi.nlm.nih.gov/pubmed/19138021

- Hair color changes and protein damage caused by ultraviolet radiation: http://www.ncbi.nlm.nih.gov/pubmed/15157906

- Photoaggravation of Hair Aging: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2938585/, http://www.ijtrichology.com/article.asp?issn=0974-7753;year=2009;volume=1;issue=2;spage=94;epage=99; aulast=Lee

- Photo yellowing of human hair: http://www.ncbi.nlm.nih.gov/pubmed/17627835

- Comparison of hair shaft damage after UVA and UVB irradiation: http://www.ncbi.nlm.nih.gov/pubmed/18408872, http://journal.scconline.org/pdf/cc2008/cc059n02/p00151-p00156.pdf

- The ethnic differences of the damage of hair and integral hair lipid after ultra violet radiation: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3582929/

- Ultraviolet damage on natural gray hair and its photoprotection: http://www.ncbi.nlm.nih.gov/pubmed/11382847

- Protection of oxidative hair color fading from shampoo washing by hydrophobically modified cationic polymers: http://journal.scconline.org/pdf/cc2009/cc060n02/p00217-p00238.pdf

- True porosity measurement of hair: a new way to study hair damage mechanisms: http://journal.scconline.org/pdf/cc2008/cc059n04/p00303-p00315.pdf and seminar notes: http://journal.scconline.org/pdf/cc2007/cc058n05/p00579-p00580.pdf

- Impairment of hair mechanical properties by sun exposure and bleaching treatments: http://www.ncbi.nlm.nih.gov/pubmed/15645109

- Photoageing of hair fiber and photoprotection: http://www.ncbi.nlm.nih.gov/pubmed/8003327

- Measurement and prevention of hair photoaging: http://www.ncbi.nlm.nih.gov/pubmed/15645087

- UV radiation: aggressive agent to the hair--AFM, a new methodology of evaluation: http://www.ncbi.nlm.nih.gov/pubmed/12858226

Damage Prevention: compact protective styles and hats, buffs, scarves, etc made of UPF-rated materials.

What to do about white hair turning yellow (from the sun and other factors): http://science-yhairblog.blogspot.ca/2015/02/why-does-white-or-gray-light-blonde.html

____________

Open Question: Do UV filters in haircare products work well? :hmm:
There are some studies that suggest that they are somewhat protective, but they were done on separate tresses, and I'm not too sure that they can cover the whole surface area enough to protect from UV damage without making hair look soaked in product and unpresentable. :hmm: Also, how do they compare to things like simple oils and conditioners or hats?
Some studies (many aren't independent!) on UV filters and anti-oxidants for preventing hair damage from UV rays:

- UV Damage of the Hair: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0ahUKEwj96tKQ07zLAhUpvIMKHbVSCZAQFggyMAM&url=http%3A%2F%2Fhrcak.srce.hr%2Ffile%2F54884&usg=AFQjCNFoRp6DyW1G6AC3O8odejGEfsb1pw

- Detection of UV Induced Free Radicals in Hair and their Prevention by Hair Care Products: http://www.gematria-test-lab.com/pdf/detection%5B1%5D.pdf

- A Diester to Protect Hair from Color Fade and Sun Damage: http://www.alluredbooks.com/sample_pages/ca_ch35.pdf

- Influence of antioxidants on the sun protection properties of hair care products: http://www.ncbi.nlm.nih.gov/pubmed/15645086
"According to the HPDSC measurements the antioxidants showed a slight increase of the peak temperature and therewith a hint towards a protection effect when used in a pre-sun or after-sun product. In contrast thereto some of the antioxidants reduced the tensile strength of sun care products for hair when added. A slight reduction in the lightening of natural hair color could be observed when antioxidants were present in the sun care formulations. The effect of antioxidants in sun care formulations used on dyed hair was strongly dependent on the shade of hair. The addition of some antioxidants yielded significant improvements of the protection properties of the used sun care product in some measurement methods."

Igor ran an experiment on shed hair using a product with skin SPF and a product with hair UV filters. After 2 months (re-spraying product once a day), she found that the skin SPF patch was darker than the control patch, and the hair SPF patch was lighter than the control patch.
Is it possible that the darkening was caused by product meant for skin simply building up on hair; and the lightening could be caused by hair UV protection product being simply not effective enough?
http://igorsbelltower.blogspot.com/2014/05/the-sun-protection-experiment.html
http://igorsbelltower.blogspot.com/2014/07/the-sun-protection-experiment-2-months.html

school of fish

March 12th, 2016, 07:38 PM

What an excellent idea for a thread!!! Will be following this one keenly... :D

Darkhorse1

March 12th, 2016, 07:43 PM

Also for people to note about oils. As of now, the only 2 oils that have been scientifically proven to penetrate hair are coconut oil and olive oil. This is due to the size of the molecular structure. Be careful with coconut oil! Coconut oil is the smallest of the oils on a molecular level. Therefore, it can penetrate the hair shaft the best. HOWEVER, this can damage hair and make it very brittle (protein over load) and snap off. I almost did this to a test part of my hair (finally listening to my hair and it's loathe of proteins).
Coconut oil is known for strengthening hair, Olive oil, since it's molecular level is slightly larger, is known for moisturizing. Other oils, depending on their molecular structure, likely just sit on hair unless you allow overnight to absorb. :D

mermaid lullaby

March 12th, 2016, 08:35 PM

Thank you Artic!
This is a great idea! :joy:

gthlvrmx

March 12th, 2016, 08:55 PM

I am happy about this thread! I love hair science! :) I will be following this thread!

meteor

March 12th, 2016, 09:02 PM

That's great, guys! :cheer:

Darkhorse1, thank you! :) I didn't know that about olive oil. Do you know if there are any links on penetrating abilities of olive oil (or any other oil, for that matter)? :) Does anybody know? :)
I know for sure about coconut oil, :agree: and I think some other oils may fall into the category of penetrating oils (palm kernel, babassu), because they contain a lot of lauric acid (https://docs.google.com/spreadsheets/d/1-lDtdpjbJopUEvpk0vjNbDt_mE_prCCCZtOqfRnzIaw/edit?pref=2&pli=1#gid=3), as well, but I don't know if any other types of fatty acids can be responsible for penetrating abilities.... Maybe all the medium-chain tryglycerides (lauric, caprylic, capric, caproic acids) can penetrate hair? :hmm:

I thought coconut oil just reduces the hair's loss of its own protein, and this means that the hair doesn't become as damaged quickly. :) Protein loss in that study (http://journal.scconline.org/pdf/cc2003/cc054n02/p00175-p00192.pdf) was used as a measurement of damage: i.e. the more protein loss, the more damage was incurred; the less protein loss, the better the integrity of hair was preserved. Uncontaminated oil is 100% fat and 0% protein, so it can't really deposit protein. However, I know many people report getting "protein overload"-like symptoms from using coconut oil... hmm, I wonder, if it has something to do with simple build-up or the oil not agreeing well with that hair or maybe the fact that coconut oil solidifies at ambient temperatures (below 24°C) and feels a bit grabby/tacky compared to runny oils that don't solidify like that? :hmm:

languagenut

March 12th, 2016, 10:14 PM

I'm ready! :popcorn:

https://3.bp.blogspot.com/-qNeYnOyT7nU/VuTttviFfwI/AAAAAAAAAZ4/NfrrArUbnj4UgxJsayK79eB4jUcQYrWHg/s1600/IMG_2357.JPG

Arctic

March 13th, 2016, 05:19 AM

Wonderful!!! Thank you Meteor for starting this thread for us! I knew to whom to turn to with this idea! :flower: :cheer:

People, does anyone know what's the etiquette of quoting and sharing scientific articles/research from purchased licence databases?

I have access to many databases (but not to all) and I could help you all to find articles, especially if you already know an article/paper you'd like to see the abstract of. I don't have time currently to read and do the kind of research which would need lot of my time. And I don't think it's right to share whole articles, as much as I would love to do so.

I assume sharing abstracts is cool, and in general using those papers/articles like I would use them on my own scientific text: short quotes, summarys with my own words and elaborating about the central ideas, with correct references to the articles. Unfortunately I don't have time for reading articles and writing summaries right now (other than for my own research).

But sharing or copy/pasting lot of text and/or whole articles probably isn't good form, just like it wouldn't be in a scientific paper I would be writing.

Sucks that so much scientific information is restricted from the general public.

Arctic

March 13th, 2016, 05:20 AM

I'm ready! :popcorn:

https://3.bp.blogspot.com/-qNeYnOyT7nU/VuTttviFfwI/AAAAAAAAAZ4/NfrrArUbnj4UgxJsayK79eB4jUcQYrWHg/s1600/IMG_2357.JPG

OMG this is the best post ever! You rock! :rockerdud

Silverbleed

March 13th, 2016, 05:36 AM

*Subs*

This is going to be such an useful thread, I can feel it 8)

Thank you Meteor for starting one.

About the penetrating oils; I did find this one from the science-y blog; http://science-yhairblog.blogspot.nl/2013/06/oils-which-ones-soak-in-vs-coat-hair.html
I think this is what you're looking for?? That blog is so helpful I can't even.
One of the sources are; http://www.ncbi.nlm.nih.gov/pubmed/16258695
and; http://journal.scconline.org/pdf/cc2003/cc054n02/p00175-p00192.pdf
But tbh this is too much science-y for me, my English isn't that good :'D Hopefully it's of any use.

Wonderful!!! Thank you Meteor for starting this thread for us! I knew to whom to turn to with this idea! :flower: :cheer:

People, does anyone know what's the etiquette of quoting and sharing scientific articles/research from purchased licence databases?

I have access to many databases (but not to all) and I could help you all to find articles, especially if you already know an article/paper you'd like to see the abstract of. I don't have time currently to read and do that kind of research which would need lot of my time. And I don't think it's right to share whole articles, as much as I would love to do so.

I assume sharing abstracts is cool, and maybe some quotes, but sharing or copy/pasting lot of text and/or whole articles probably isn't. Summaries in own words probably are cool, but I don't have time for that right now. Sucks that so much scientific information is restricted from the big public.

I would like to know this too. I was already wondering if linking to these articles would be okay... I'm pretty sure the blog should be fine but I don't know about the last link I shared. I don't want to do anything wrong ;_;

Arctic

March 13th, 2016, 05:51 AM

I would like to know this too. I was already wondering if linking to these articles would be okay... I'm pretty sure the blog should be fine but I don't know about the last link I shared. I don't want to do anything wrong ;_;

Sharing Open Access and publicly available articles and papers should be fine, as long as your post shows clearly the accurate reference information (who made the research/wrote the article, the name of the article, where and when was it published and where you found it). :flower:

My question was mainly about the databases my university pays very high fees for the licence to use them. These type of databases are not usually open access, freely usable kinds.

Wusel

March 13th, 2016, 06:46 AM

http://science-yhairblog.blogspot.de/2012/03/how-fine-hair-is-different.html

I wanted to share this here because it explained me very understandably the difference between fine and medium hair and why conditioners weigh fine hair down.

I'd still like to know more about why/which hair needs protein and which hair doesn't and how to determine if your hair needs them or not. And which proteins penetrate the most and less and why. And the different kinds of proteins... For me it's still trial and error...

Great idea for a thread! :)

brickworld13

March 13th, 2016, 07:19 AM

Petulia

March 13th, 2016, 07:47 AM

MsPharaohMoan

March 13th, 2016, 09:38 AM

I'm ready! :popcorn:

https://3.bp.blogspot.com/-qNeYnOyT7nU/VuTttviFfwI/AAAAAAAAAZ4/NfrrArUbnj4UgxJsayK79eB4jUcQYrWHg/s1600/IMG_2357.JPG

-subscribes immediately- :rollin:

EdG

March 13th, 2016, 09:52 AM

This is a great thread. :thumbsup:
Ed

lapushka

March 13th, 2016, 10:35 AM

This is a great thread. :thumbsup:
Ed

Seconding that! :)

I'd love to see lots of info on clarifying the hair.

Arctic

March 13th, 2016, 11:54 AM

As a Biochemistry student, I'm very happy about this thread. This is the download link for a PDF of the Chemical and Physical Behavior of Human Hair - Clarence Robbins, 4th Edition. It's a very well known book in the Cosmetic Science industry and goes over just about everything from the structure of hair to the science behind chemical hair processes such as dyeing and perming. This is the book that actually taught me about the hair perming process and I've been using it for a few assignments too. Hope you find it useful!
http://www.cepigene.fr/component/phocadownload/category/22-cepigene-library.html?download=204:chemical-and-physical-behavior-on-human-hair

This is great, we need people who actually have studied these things. So you have actually done some hair-related studies yourself? Do tell more!

The book you linked to seems to be copyrighted material, and probably it's not ok to redistribute it online. That being said, it does seem interesting, as does the whole library where you linked to.

meteor

March 13th, 2016, 12:05 PM

I'm ready! :popcorn:

https://3.bp.blogspot.com/-qNeYnOyT7nU/VuTttviFfwI/AAAAAAAAAZ4/NfrrArUbnj4UgxJsayK79eB4jUcQYrWHg/s1600/IMG_2357.JPG

Ha-ha! That's awesome, languagenut! :rockerdud

Wonderful!!! Thank you Meteor for starting this thread for us! I knew to whom to turn to with this idea! :flower: :cheer:

People, does anyone know what's the etiquette of quoting and sharing scientific articles/research from purchased licence databases?

I have access to many databases (but not to all) and I could help you all to find articles, especially if you already know an article/paper you'd like to see the abstract of. I don't have time currently to read and do the kind of research which would need lot of my time. And I don't think it's right to share whole articles, as much as I would love to do so.

I assume sharing abstracts is cool, and in general using those papers/articles like I would use them on my own scientific text: short quotes, summarys with my own words and elaborating about the central ideas, with correct references to the articles. Unfortunately I don't have time for reading articles and writing summaries right now (other than for my own research).

But sharing or copy/pasting lot of text and/or whole articles probably isn't good form, just like it wouldn't be in a scientific paper I would be writing.

Sucks that so much scientific information is restricted from the general public.

Thanks a lot, Arctic! :flowers: I've been wondering about it, too - how to quote stuff from databases. With stuff that's open access, it's easy: just quote with links. With other research, I would err on the side of caution and just share knowledge based on the study. For example, one can probably still discuss/critique what they've read in very general ways or give a quick overview/impression (if it's not prohibited, of course)? I would imagine it's similar to discussing a book one bought and read, that isn't available in open access either. But I really don't know for sure, it might depend on whether or not there are specific rules and restrictions put in place...

The study I'd love to know more about (but can't access, unfortunately) is this one:

Why does curly hair get less tangled than straight hair? by Jean-Baptiste Masson - Article in American Journal of Physics, 75(8):701-706, July 2007 DOI: 10.1119/1.2733683
http://scitation.aip.org/content/aapt/journal/ajp/75/8/10.1119/1.2733683

It seems pretty intriguing and a bit counter-intuitive. I wonder how the model was built and what they considered a tangle (vs. just hair sticking together, for example).
Quick article about this study: http://www.scientificamerican.com/article/straight-hair-is-knottier-than-curly-hair/

http://science-yhairblog.blogspot.de/2012/03/how-fine-hair-is-different.html

I wanted to share this here because it explained me very understandably the difference between fine and medium hair and why conditioners weigh fine hair down.

I'd still like to know more about why/which hair needs protein and which hair doesn't and how to determine if your hair needs them or not. And which proteins penetrate the most and less and why. And the different kinds of proteins... For me it's still trial and error...

Great idea for a thread!

Cool! I love Science-y Hair Blog, too. :agree: I'll add it to the index, maybe I should add a section for recommended science-oriented hair blogs?
By the way, I hogged the first 3 posts (sorry! :oops:) for index and linking to interesting facts and studies, but please let me know if you want things changed/added there, guys. ;) It's going to be changed and updated continuously, as needed.

About protein, Science-y blog has quite a bit of information on it, and on who may need it when: http://science-yhairblog.blogspot.ca/2015/10/protein-101-lots-of-basic-information.html and http://science-yhairblog.blogspot.ca/2013/09/more-about-protein.html, including an excellent table on sizes (http://4.bp.blogspot.com/-6sUkULijJ1g/Un1uSLvjWzI/AAAAAAAAArI/mPnfHAo0N8g/s1600/amino_acids_table.jpg). Protein can patch-repair temporarily, and if it's hydrolyzed into small enough pieces, it can penetrate under the cuticle. It can also add extra rigidity, structure to fine or overly moisturized hair.
NaturalHavenBloom talks a bit about different sizes of proteins: http://www.thenaturalhavenbloom.com/2009/06/size-matters-protein-conditioning-part.html

As a Biochemistry student, I'm very happy about this thread. This is the download link for a PDF of the Chemical and Physical Behavior of Human Hair - Clarence Robbins, 4th Edition. It's a very well known book in the Cosmetic Science industry and goes over just about everything from the structure of hair to the science behind chemical hair processes such as dyeing and perming. This is the book that actually taught me about the hair perming process and I've been using it for a few assignments too. Hope you find it useful!
http://www.cepigene.fr/component/phocadownload/category/22-cepigene-library.html?download=204:chemical-and-physical-behavior-on-human-hair

^ I'd highly recommend it, too! Thanks so much for sharing! That's a *great* book - easily the best hair book I know. I only have this 2001 edition, but I know there are new editions out there (2012), with lots of updated information, but it's quite expensive.

Arctic

March 13th, 2016, 12:40 PM

Thanks a lot, Arctic! :flowers: I've been wondering about it, too - how to quote stuff from databases. With stuff that's open access, it's easy: just quote with links. With other research, I would err on the side of caution and just share knowledge based on the study. For example, one can probably still discuss/critique what they've read in very general ways or give a quick overview/impression (if it's not prohibited, of course)? I would imagine it's similar to discussing a book one bought and read, that isn't available in open access either. But I really don't know for sure, it might depend on whether or not there are specific rules and restrictions put in place...

The study I'd love to know more about (but can't access, unfortunately) is this one:

Why does curly hair get less tangled than straight hair? by Jean-Baptiste Masson - Article in American Journal of Physics, 75(8):701-706, July 2007 DOI: 10.1119/1.2733683
http://scitation.aip.org/content/aapt/journal/ajp/75/8/10.1119/1.2733683

It seems pretty intriguing and a bit counter-intuitive. I wonder how the model was built and what they considered a tangle (vs. just hair sticking together, for example).
Quick article about this study: http://www.scientificamerican.com/article/straight-hair-is-knottier-than-curly-hair/

I agree on you assessment on the material from the payment based databases.

It's very unfortunate, this restricts science from laypersons. I don't think science should be put in ivory towers, it should be where it can be used.

I have access to the article you mention (BTW it's in August issue) but unfortunately no time to read. From a glance it's full of mathematical formulas and calculations, hardly something I even would want to read, ha ha. From a glance, in other words, the article seem to be done mostly on theoretical level. In the end that say the subject needs more testing. I hope someone else with access could give a short summary.

meteor

March 13th, 2016, 12:55 PM

So happy to see so many join in! :cheer:

*Subs*

This is going to be such an useful thread, I can feel it 8)

Thank you Meteor for starting one.

About the penetrating oils; I did find this one from the science-y blog; http://science-yhairblog.blogspot.nl/2013/06/oils-which-ones-soak-in-vs-coat-hair.html
I think this is what you're looking for?? That blog is so helpful I can't even.
One of the sources are; http://www.ncbi.nlm.nih.gov/pubmed/16258695
and; http://journal.scconline.org/pdf/cc2003/cc054n02/p00175-p00192.pdf
But tbh this is too much science-y for me, my English isn't that good :'D Hopefully it's of any use.
Thanks so much, Silverbleed! And your English is great! :D
Those links are awesome! And that's such a great table, too. I'll be linking this helpful stuff to the index. :)

I just wanted to add this full text for the NCBI article summary you linked for those who want to dig into it in detail :) Investigation of penetration abilities of various oils into human hair fibers: http://journal.scconline.org/pdf/cc2005/cc056n05/p00283-p00295.pdf
"In general, saturated and monounsaturated oils penetrate into the hair because of a compact molecular structure and the polar head group of the triglyceride molecules that constitute these oils. In a dynamic mode these molecules can reptate and squeeze through the CMCs. On the other hand, polyunsaturated oils do not penetrate into hair, most likely because of the more open and spread-out structures of their triglyceride molecules and because of the presence of multiple double bond." (from p. 294)

And here's another interesting study on Coconut and Mineral oils:
Secondary ion mass spectrometric investigation of penetration of coconut and mineral oils into human hair fibers: Relevance to hair damage : http://journal.scconline.org/pdf/cc2001/cc052n03/p00169-p00184.pdf
"While both oil-treated categories show a significant decrease in swelling, it is slightly greater for the coconut-oil-treated fibers than the mineral-oil treated specimens. In coconut- and mineral-oil-treated specimens, swelling is reduced by 48% and 33%, respectively. This strongly suggests that the fiber is protected from damage by hygral fatigue (swelling and de-swelling).
It should be emphasized that the reduction in moisturization of the fiber does not make the fiber rigid because of the plasticizating action of the absorbed coconut oil.
[...]
Due to its polarity and affinity for the protein, coconut oil was found to penetrate into the hair cortex. Mineral oil, on the other hand, did not penetrate the fiber. The reason is likely to be its lack of affinity for the protein.
Penetration of oils seems to reduce the hydrophilicity of the protein, as indicated by the lower amount of swelling observed in hair fibers treated with coconut oil. Mineral oil also shows lower levels of swelling compared to the untreated fiber, suggesting that it may have penetrated into the cuticular regions, thereby preventing further penetration of water into the hair shaft during the swelling experiment." (from pp. 183 - 184)

Basically, it appears that even without penetrating ability, oil helps reduce swelling and de-swelling in water (hygral fatigue). Great news for those of us who aren't that into coconut oil. ;)
It also seems to answer the question raised on page 1 of this thread on whether penetrating oil can cause excessive rigidity of hair. According to this study, it doesn't appear so, thankfully.

Petulia

March 13th, 2016, 12:58 PM

This is great, we need people who actually have studied these things. So you have actually done some hair-related studies yourself? Do tell more!

The book you linked to seems to be copyrighted material, and probably it's not ok to redistribute it online. That being said, it does seem interesting, as does the whole library where you linked to.

Sorry I'm still a newbie so I wasn't aware of this :( I thought it was okay to share because this is available for free on Google Books, since it's not the most recent edition, but I've been using the PDF because it's a lot easier to read from. The 5th Edition isn't free online but it's more or less the same.

One thing I've noticed when it comes to Cosmetic Science discoveries is that some of the biggest innovations were actually made by hairdressers, not by chemists. First example: the first ever method of hair waving was invented by Karl Nessler, a German hairdresser who experimented on his wife's hair with heated rods, and burnt all of her hair off shudder: http://www.historychannel.com.au/classroom/day-in-history/863/first-permanent-wave-%20for-hair-is-demonstrated

meteor

March 13th, 2016, 12:59 PM

My life is a little nuts right now but I will be back in a couple months to actually read the thread and contribute from time to time. Why is life nuts? Oh I have to move on short notice because of new job.
Yay! Best of luck with the move and the new job, brickworld13! :cheer: Looking forward to seeing you back! :D

I have access to the article you mention (BTW it's in August issue) but unfortunately no time to read. From a glance it's full of mathematical formulas and calculations, hardly something I even would want to read, ha ha. From a glance, in other words the article seem to be done on theoretical level only. In the end that say the subject needs more testing. I hope someone else with access could give a short summary.

Thanks a lot! :) No pressure at all, of course, dear Arctic! And thanks a lot for checking it out! Hopefully, they'll test this subject more! ;)

Arctic

March 13th, 2016, 01:16 PM

MsPharaohMoan

March 13th, 2016, 01:28 PM

Silverbleed

March 13th, 2016, 01:58 PM

Maybe quoting would be okay like used in papers? With the source included in the post itself.

@meteor; Aw thanks. But it's really true. One year ago I didn't even know about words like humidity or porosity. So I've done a lot of reading to find out what the heck I'm doing haha. The good thing was I have found many useful articles to learn more about my hair. The sad part is I did not save any.

Arctic

March 13th, 2016, 02:11 PM

I think short quotes should be fine (few sentences), as well as summaries written in own words (maybe quite general and shortish). I also think abstracts are probably fine. They are often posted openly even if the articles themselves would not be open access.

The most important thing is to carefully mark reference information in each post where a reasearch has been used as a material.
(Who is author, what is the name of the paper, where and when it was published and where you found it [link]).

meteor

March 13th, 2016, 02:19 PM

Sorry I'm still a newbie so I wasn't aware of this :( I thought it was okay to share because this is available for free on Google Books, since it's not the most recent edition, but I've been using the PDF because it's a lot easier to read from. The 5th Edition isn't free online but it's more or less the same.

One thing I've noticed when it comes to Cosmetic Science discoveries is that some of the biggest innovations were actually made by hairdressers, not by chemists. First example: the first ever method of hair waving was invented by Karl Nessler, a German hairdresser who experimented on his wife's hair with heated rods, and burnt all of her hair off shudder: http://www.historychannel.com.au/classroom/day-in-history/863/first-permanent-wave-%20for-hair-is-demonstrated

No worries, I thought it was in open access, too (after all, that edition has been easily available for years on that website), and that edition is 15 years old. If somebody wants to check out a reading sample of the latest edition of the book, it's here: http://www.beck-shop.de/fachbuch/leseprobe/9783642256103_Excerpt_001.pdf

Oh that's pretty coo about the history permsl! I guess that initial waving experiment was a cautionary tale against chemical damage in one! ;)

Since I got to a university I have access to apparently all the articles, even hair articles! Initial talks of tangles in this study: "Tangles are one of the main subjects related to hair. The formation process, the destruction, the number, and the localization of tangles are still open questions." They link to a book called Knots: Mathematics with a Twist. Is it inappropriate for me to provide quotes off the studies btw? It's not against my own moral code (education for the masses!) but don't want to step on any toes in the forum.

Also, it's a bit tiring going through articles and summarizing them when I should really be doing research for my projects x3 If you provide me the title + author of the study you're interested in as well as what questions you'd like answered, I'd be glad to do some digging on my down time!

That's so awesome, MsPharaohMoan! :applause Thank you so very much! :flowers: And obviously, no pressure at all! :flower:
And maybe a mod can jump in and help us with this, since many of us are wondering about the same questions? :)

Maybe quoting would be okay like used in papers? With the source included in the post itself.

@meteor; Aw thanks. But it's really true. One year ago I didn't even know about words like humidity or porosity. So I've done a lot of reading to find out what the heck I'm doing haha. The good thing was I have found many useful articles to learn more about my hair. The sad part is I did not save any.

Oh no! :wail: I've searched through lots of articles, too, without saving! :doh:
Well, no worries! Now we can have a repository with links here! :D

lapushka

March 13th, 2016, 02:22 PM

And here's another interesting study on Coconut and Mineral oils:
Secondary ion mass spectrometric investigation of penetration of coconut and mineral oils into human hair fibers: Relevance to hair damage : http://journal.scconline.org/pdf/cc2001/cc052n03/p00169-p00184.pdf
"While both oil-treated categories show a significant decrease in swelling, it is slightly greater for the coconut-oil-treated fibers than the mineral-oil treated specimens. In coconut- and mineral-oil-treated specimens, swelling is reduced by 48% and 33%, respectively. This strongly suggests that the fiber is protected from damage by hygral fatigue (swelling and de-swelling).
It should be emphasized that the reduction in moisturization of the fiber does not make the fiber rigid because of the plasticizating action of the absorbed coconut oil.
[...]
Due to its polarity and affinity for the protein, coconut oil was found to penetrate into the hair cortex. Mineral oil, on the other hand, did not penetrate the fiber. The reason is likely to be its lack of affinity for the protein.
Penetration of oils seems to reduce the hydrophilicity of the protein, as indicated by the lower amount of swelling observed in hair fibers treated with coconut oil. Mineral oil also shows lower levels of swelling compared to the untreated fiber, suggesting that it may have penetrated into the cuticular regions, thereby preventing further penetration of water into the hair shaft during the swelling experiment." (from pp. 183 - 184)

Basically, it appears that even without penetrating ability, oil helps reduce swelling and de-swelling in water (hygral fatigue). Great news for those of us who aren't that into coconut oil. ;)
It also seems to answer the question raised on page 1 of this thread on whether penetrating oil can cause excessive rigidity of hair. According to this study, it doesn't appear so, thankfully.

I wonder if ROO/oil rinsing is so amazing (to those it works for) for that reason.

meteor

March 13th, 2016, 02:35 PM

I wonder if ROO/oil rinsing is so amazing (to those it works for) for that reason.

I think so! :) I also think that the same explains why pre-poo oiling works.

By the way, about oil rinses... I think, they may be successful because the conditioner helps spread out the oil more thoroughly and "sops up" extra oil and washes it off as well.
Also, maybe the relationship between negative and positive charges may have something to do with their success? :hmm:
Science-y blog explains:

The more porous the hair, the more easily dehydrated it is. And the more negative charges it has. Porous hair also has gaps in the cuticle "covering" that are temporarily patched in by this adhering of conditioner to negatively charged surfaces.
Dry (not wet) hair has more negative charges than positive charges. [...]
Conditioning ingredients have positive charges that allow them to interact with negatively charged hair. Like magnets, positive is attracted to negative. [...]
When lipids (oily ingredients) are present in a conditioner formula (or when you add them), you get even more conditioning goodness adhering to your hair - more cationic conditioning and more softness and flexibility from the lipid. It's an interesting mutual enhancement of conditioning ingredients for an even better end result. The presence of lipids in a formula makes it a better deep conditioner. Lipids themselves are great hair softeners and lubricants.
In most conditioners, the lipid is already present in the form of cetyl alcohol or cetaryl alcohol because this ingredient makes a nice creamy, thick conditioner with a soft after-feel. But other oils do the trick also, including plant oils or butters you might add to a conditioner. http://science-yhairblog.blogspot.ca/2014/01/deep-conditioning-part-i.html

lapushka

March 13th, 2016, 02:40 PM

Ooooh *very* interesting!!! Thanks, meteor! I'm even almost sad I didn't oil rinse today. Darn.

meteor

March 13th, 2016, 04:15 PM

Human Sebum BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

Since we seem to be on an oil kick ;), I figured I'll add on natural hair oils and composition of sebum. Fatty acids are present on scalp, on cuticle level, on cortex and CMC (cell-membrane-complex) level. The fatty acids include ceramides, 18-MEA, cholesterol (these ingredients can be found in hair products, too! ;). The composition is slightly different on different layers. The further away the hair is from scalp, the more the lipids tend to gets rubbed off, washed off, dissolved by chemicals, etc., which is why it is helpful to replenish length with topical application of oils, if needed.

Natural Sebum composition:
"Triglycerides and fatty acids, taken together, account for the predominant proportion (57.5%), followed by wax esters (26%) and squalene (12%). The least abundant lipid in sebum is cholesterol, which with its esters, accounts for the 4.5% of total lipids." (Sebaceous gland lipids: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2835893/; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2835893/table/T1/)

Artificial Sebum (mix that imitates human sebum) compositions:
Olive oil: 20%
Coconut oil: 15%
Palmitic acid: 10%
Stearic acid: 5%
Oleic acid: 15%
Paraffin wax: 10%
Squalene: 5%
Spermaceti: 15%
Cholesterol: 5%
Chemical and Physical Behavior of Human Hair: http://www.beck-shop.de/fachbuch/leseprobe/9783642256103_Excerpt_001.pdf (p. 141)

Palmitic Acid 10%
Stearic Acid 5%
Coconut Oil 15%
Paraffin Wax 10%
Synthetic Spermacetti 15%
Olive Oil 20%
Squalene 5%
Cholesterol 5%
Oleic Acid 10%
Linoleic Acid 5%
http://sciservsd.com/synthetic-sebum-datasheet.html

Fatty acids 17%
Triglyceride 44.7%
Wax monoester (jojoba oil) 25%
Squalene 12.4%
Human synthetic sebum formulation and stability under conditions of use and storage: http://www.ncbi.nlm.nih.gov/pubmed/19134124

Some of those ingredients are hard to get or need to be replaced, besides, natural sebum is quite complex and it varies quite a bit, but one can simplify things: e.g. jojoba oil ~ 20%, triglycerides (e.g. olive oil) ~ 50%, fatty acids (e.g. coconut oil) ~ 10%, squalene ~ 15%, cholesterol ~ 5%.

mary*rose

March 13th, 2016, 04:57 PM

I agree on you assessment on the material from the payment based databases.

It's very unfortunate, this restricts science from laypersons. I don't think science should be put in ivory towers, it should be where it can be used.

I have access to the article you mention (BTW it's in August issue) but unfortunately no time to read. From a glance it's full of mathematical formulas and calculations, hardly something I even would want to read, ha ha. From a glance, in other words, the article seem to be done mostly on theoretical level. In the end that say the subject needs more testing. I hope someone else with access could give a short summary.

This. THIS SO MUCH. This is partly the reason why anti-vaxxers and evolution denyers are a thing, because the scientific community is all high and mighty and instead of talking respectfully with people who disagree, there's this whole atmosphere of "better than thou" and it bothers me more than the fact that people don't believe scientific fact with years of hard work and evidence (although that bothers me, too). It's the same with doctors, sometimes, even though they have a responsibility (by law, I believe), to help their patients make informed decisions.

Considering citations, my first instinct was that as long as the study was fully cited MLA or APA style, I wouldn't see a problem quoting it. But on second thought, there's a difference between including quotes in a scientific paper for school and putting quotes on a public forum. What I think would be acceptable is saying "In John Smith's 1893 study..." and then summarizing some of the information. Libraries often have access to journals and other publications, so perhaps the people in LHC not part of an institution or otherwise doesn't have access to the article might be able to look it up.

~~~~

On a different note, one of the questions that has come to mind recently for me is the population of bacteria on hair depending on the type of hair care - like between shampooing, CO, WO, NW/SO, etc. Same for skin condition - do people who bathe less frequently have a healthier symbiotic community of bacteria on their skin? :hmm:

Petulia

March 13th, 2016, 05:52 PM

On a different note, one of the questions that has come to mind recently for me is the population of bacteria on hair depending on the type of hair care - like between shampooing, CO, WO, NW/SO, etc. Same for skin condition - do people who bathe less frequently have a healthier symbiotic community of bacteria on their skin? :hmm:

A few years ago some scientists in Japan actually discovered a species of bacteria living in common hairsprays, which they named Microbacterium hatanonis. https://www.sciencedaily.com/releases/2008/03/080307110337.htm and the original article can be found here http://ijs.microbiologyresearch.org/content/journal/ijsem/10.1099/ijs.0.65160-0#tab2 in the Journal of Systematic and Evolutionary Microbiology.
They're still doing research into whether the bacteria is a threat to humans, but I didn't actually realise that this is the reason why preservatives are so important in cosmetic products. It also makes me wonder how safe it is to use home-made products for more than one day at a time. e.g if we make something ourselves at home, like a hair-mask, and store it in a glass jar, how long is it safe to keep using that before it's infected by bacteria, yeast or mould? I would preserve things like that by storing them in the fridge, but without adding a chemical preservative, can we be sure that it hasn't become infected and that it won't damage our skin or scalp? It's made me more cautious about using DIY hair and face masks for more than one day :hmm:

cathair

March 13th, 2016, 06:02 PM

Great idea for a thread, subscribing :)

meteor

March 13th, 2016, 07:19 PM

Petulia, that's fascinating about new bacteria contaminating hair spray - I guess they are extremely good at adaptation! ;)

mary*rose, great question. I certainly don't know enough about microbiology to answer your question, and I don't want to spam this thread, but I just wanted to say that nowadays both new and established skincare companies are moving into this field of using microbes to cleanse and using milder, more "re-balancing" (rather than disinfecting) cleansers, and it's becoming popular really fast: http://www.nytimes.com/2014/05/25/magazine/my-no-soap-no-shampoo-bacteria-rich-hygiene-experiment.html?_r=0; http://thebeautybrains.com/2015/08/can-live-bacteria-cure-acne-episode-95/ After all, lots of bacterial and fungus-related issues (e.g. SD) are about an overgrowth, an imbalance (sometimes that happens after a period of taking antibiotics) - the colonies are already there, the idea is just to keep them from taking over and messing up the whole ecosystem.
I'd love to read up more on this issue, of course! :D

Some studies:
Acne vulgaris, probiotics and the gut-brain-skin axis - back to the future? - http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3038963/ (Under Section "Topical Probiotics")
Bifidobacterium longum lysate, a new ingredient for reactive skin. - http://www.ncbi.nlm.nih.gov/pubmed/19624730
Outside-in. Probiotic topical agents. - http://www.ncbi.nlm.nih.gov/pubmed/19655096

Impact of prebiotics and probiotics on skin health. - http://www.ncbi.nlm.nih.gov/pubmed/24583611 :
"Pre- and probiotic beneficial effects can be delivered topically or systemically (by ingestion). The pre- and probiotics have the capacity to optimise, maintain and restore the microbiota of the skin in different ways. Topical applications of probiotic bacteria have a direct effect at the site of application by enhancing the skin natural defence barriers. Probiotics as well as resident bacteria can produce antimicrobial peptides that benefit cutaneous immune responses and eliminate pathogens. In cosmetic formulations, prebiotics can be applied to the skin microbiota directly and increase selectively the activity and growth of beneficial 'normal' skin microbiota."

MsPharaohMoan

March 13th, 2016, 07:53 PM

lol @ "conditioning goodness" from science-y blog

Thanks for giving the titles to the studies, this is very helpful. I'll gladly put info into my own words and provide APA citation (my links to articles wouldn't work because of said 'special access'). Already this is an interesting thread!

pailin

March 13th, 2016, 08:17 PM

The issue of journal articles only being available with a charge or with a subscription to a journal service (ie through a university library) has come up recently at my work. Some of the regional journals in my field are free/open access, but those are all being published through a university, with the editorial work essentially being unpaid. It's a lot of work. The big journals are usually being published under one of the big publishing houses, and they all charge for access. They do have to make money somehow. The only way articles in those journals are open access is if the author pays a fee up front to make their article free/ open access. I don't know about the types of journals that we find hair science in, but it might be similar.

mary*rose

March 13th, 2016, 10:12 PM

meteor I don't think you're spamming, especially since you started the thread haha!

Those were some very interesting answers to my questions. AH! Human microbiome! That was the phrase I was looking for. I was wondering on the different microbiomes that form depending on hair care.

meteor

March 13th, 2016, 10:39 PM

^ Thank you so much, mary*rose! Yep, human microbiome is very interesting... :agree: Human body has 10 times as many bacteria as human cells (https://www.sciencedaily.com/releases/2008/06/080603085914.htm), and bacteria are critically important for our functioning.

... and I'll be periodically adding some study links (to be updated continuously), to start organizing them under topics...

meteor

March 13th, 2016, 10:42 PM

10. Hair Loss (Alopecia) BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

10.2. Alopecia Areata:

- Interventions for alopecia areata: http://www.ncbi.nlm.nih.gov/pubmed/18425901

- Randomized trial of aromatherapy. Successful treatment for alopecia areata: http://www.ncbi.nlm.nih.gov/pubmed/9828867

- Treatments for androgenetic alopecia and alopecia areata: current options and future prospects: http://www.ncbi.nlm.nih.gov/pubmed/11217871

- Topical minoxidil solution (1% and 5%) in the treatment of alopecia areata: http://www.ncbi.nlm.nih.gov/pubmed/3549811

- Topical minoxidil (3%) in extensive alopecia areata, including long-term efficacy: http://www.ncbi.nlm.nih.gov/pubmed/3549810

- Topical minoxidil. A preliminary review of its pharmacodynamic properties and therapeutic efficacy in alopecia areata and alopecia androgenetica: http://www.ncbi.nlm.nih.gov/pubmed/3552591

- Systemic steroids with or without 2% topical minoxidil in the treatment of alopecia areata: http://www.ncbi.nlm.nih.gov/pubmed/1444500

- 3 percent topical minoxidil compared with placebo for the treatment of chronic severe alopecia areata: http://www.ncbi.nlm.nih.gov/pubmed/3292159

- Topical minoxidil in the treatment of alopecia areata: http://www.ncbi.nlm.nih.gov/pubmed/6412929

- Double-blind, placebo-controlled evaluation of topical minoxidil in extensive alopecia areata: http://www.ncbi.nlm.nih.gov/pubmed/3549809

mary*rose

March 13th, 2016, 11:14 PM

Silverbleed

March 14th, 2016, 05:47 AM

mary*rose

March 14th, 2016, 10:37 AM

Perhaps some silver longhairs could comment on the difference in maintenance with growing age.

meteor, on post 36, the first link for the composition of sebum is broken. Also, did you mean to link post 45 (Alopecia) to the original post?

Concerning the physics article about curly hair and tangles, the theoretical math they were using was aligned with their experimental data. So the authors performed the experiment using hairdressers (I found it interesting that they relied on the hairdressers' definitions of "tangles" and "curly" - empowering, in a way), determining the amount of tangles in curly versus straight hair, and found that curly-haired people had significantly less tangles than straight haired people (straight-haired people most likely had 6 tangles; curly-haired, 3). Then they developed mathematical models using variables like the separation between hairs, their length, and the likelihood of the hairs crossing to explain why curly-haired people had less-tangly hair.

What is MOST interesting to me is that this is on the physics of hair! Not the biological or chemical behavior of hair, but the physical behavior. Fascinating :cool:

~~~

I have another question - what causes sebum to "smell"? I don't particularly smell mine, but I know other people can, because I've asked. Is it the composition of sebum, or the bacteria that live in it?

meteor

March 14th, 2016, 12:48 PM

meteor, thank you for all your hard work already c:

Looks like I'll need some peppermint oil.

About the diameter of the hair, in [this] (http://hypertextbook.com/facts/1999/BrianLey.shtml) article you shared, they mention baby hair is really fine and gets thicker when you become older. However nothing is mentioned when you are a senior. It's clear your hair looses melanin, but what about the thickness of your hair?
Personally I find this interesting because I'd like long hair when I get old. I don't mind silvery hair at all, I adore it. However I'd like to know how difficult it is to maintain that hair.

Thanks a lot! :flowers: Yes, that's an excellent question (I've added it to the index with open questions (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187907&viewfull=1#post3187907)). I would guess hair often grows coarser with age (from infancy to puberty, with increased melanin, etc, but later as well)... but I don't know the mechanism, it's likely controlled by hormones... I don't know, I hope we'll find answers soon! :D
I would guess if hair actually gets finer (and at the same time thinner) with ageing, I would wonder if maybe miniaturization of hair follicles could be setting in (it often goes hand in hand with androgenetic alopecia (male/female pattern baldness)? :hmm:
A bit on miniaturization as a symptom of AGA: http://practicaldermatology.com/2013/05/management-of-female-pattern-hair-loss/
Follicular miniaturization in female pattern hair loss: clinicopathological correlations: http://www.ncbi.nlm.nih.gov/pubmed/17034520

meteor, on post 36, the first link for the composition of sebum is broken. Also, did you mean to link post 45 (Alopecia) to the original post?
Thanks a lot! :D Fixed it! :thumbsup:

Concerning the physics article about curly hair and tangles, the theoretical math they were using was aligned with their experimental data. So the authors performed the experiment using hairdressers (I found it interesting that they relied on the hairdressers' definitions of "tangles" and "curly" - empowering, in a way), determining the amount of tangles in curly versus straight hair, and found that curly-haired people had significantly less tangles than straight haired people (straight-haired people most likely had 6 tangles; curly-haired, 3). Then they developed mathematical models using variables like the separation between hairs, their length, and the likelihood of the hairs crossing to explain why curly-haired people had less-tangly hair.

What is MOST interesting to me is that this is on the physics of hair! Not the biological or chemical behavior of hair, but the physical behavior. Fascinating :cool:

Yes, it's pretty awesome! They also hypothesized about clumping, that within curls the hairs aren't interacting at the kinds of angles that promote knot formation... which makes sense to me, if the curl clumps are left undisturbed. :)
The conclusion just sounds interesting and a bit counter-intuitive, since so many people say that their hair is so much easier to detangle when they flat-iron or chemically straighten it (relaxers, BKTs, etc...), and so many people say that their hair is much harder to detangle after all sorts of curling, perms, root boost-ups? :hmm:
That article also mentioned in passing that they think fine hair should be more tangle-prone, but I don't know if this subject was analyzed in the study or not? :hmm:

I have another question - what causes sebum to "smell"? I don't particularly smell mine, but I know other people can, because I've asked. Is it the composition of sebum, or the bacteria that live in it?

Awesome question! Added to the list of questions (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187907&viewfull=1#post3187907). (I would guess both fungi and bacteria can produce smelling compounds as part of their metabolism - different people have somewhat different "ecosystems" going on there, so a strong smell might indicate an imbalance? Just guessing! :) )

languagenut

March 14th, 2016, 01:38 PM

I didn't know about that Science-y Hair Blog; I'll have to check it out when I have time.

Oh, and happy Pi Day! :D
eta: Wonder if I could make a π-shaped hair fork?...

lapushka

March 14th, 2016, 01:49 PM

lapushka

March 14th, 2016, 01:51 PM

Awesome question! Added to the list of questions (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187907&viewfull=1#post3187907). (I would guess both fungi and bacteria can produce smelling compounds as part of their metabolism - different people have somewhat different "ecosystems" going on there, so a strong smell might indicate an imbalance? Just guessing! :) )

It's gotta be bacterial / fungal, because SD is explained that way too, and I always get that whenever my hair is at its oiliest.

Arctic

March 14th, 2016, 01:52 PM

Yet many people say their hair gets wiry and coarse when it grays. Must be YMMV things.

Arctic

March 14th, 2016, 02:04 PM

Darkhorse1

March 14th, 2016, 02:32 PM

rhosyn_du

March 14th, 2016, 02:37 PM

My mother and my sweetie both started out with super fine 1a hair before going gray. They now both have about the same amount of gray in their hair (my family goes gray really late), and my mom's is coarser and maybe 1b/1c these days, while my sweetie's is still 1a and super fine.

meteor

March 14th, 2016, 03:24 PM

Anti-bacterial and anti-fungal oils BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187906&viewfull=1#post3187906)

PART I

(Please note that many essential oils cannot be used during pregnancy and with some health conditions (consult your doctor). Essential oils can also be irritating, photo-sensitizing (for example, citrus oils). It's also important to note that quality of available research on EOs varies widely.)

Lots of other oils are not on the list yet. (To be updated.)

Essential oils:

- Antibacterial and antifungal activity of aromatic constituents of essential oils: http://www.ncbi.nlm.nih.gov/pubmed/9218354 "In terms of antibacterial activity linalool was the most effective and inhibited seventeen bacteria, followed by cineole, geraniol (each of which inhibited sixteen bacteria), menthol and citral aromatic compounds, which inhibited fifteen and fourteen bacteria, respectively. Against fungi the citral and geraniol oils were the most effective (inhibiting all twelve fungi), followed by linalool (inhibiting ten fungi), cineole and menthol (each of which inhibited seven fungi) compounds."

- Antibacterial and antifungal properties of essential oils: http://www.ncbi.nlm.nih.gov/pubmed/12678685

- Essential oils of aromatic plants with antibacterial, antifungal, antiviral, and cytotoxic properties--an overview: http://www.ncbi.nlm.nih.gov/pubmed/19420953

- Antibacterial and antifungal effects of essential oils from coniferous trees: http://www.ncbi.nlm.nih.gov/pubmed/15187434

- Comparison of chemical compositions and antimicrobial activities of essential oils from three conifer trees; Pinus densiflora, Cryptomeria japonica, and Chamaecyparis obtusa: http://www.ncbi.nlm.nih.gov/pubmed/19420996

- Antibacterial and antifungal properties of essential oils: http://www.ncbi.nlm.nih.gov/pubmed/12678685 "Essential oils of spices and herbs (thyme, origanum, mint, cinnamon, salvia and clove) were found to possess the strongest antimicrobial properties among many tested."

- Antibacterial and antifungal activity of ten essential oils in vitro: http://www.ncbi.nlm.nih.gov/pubmed/8893526
"Lemongrass, eucalyptus, peppermint and orange oils were effective against all the 22 bacterial strains. Aegle and palmarosa oils inhibited 21 bacteria; patchouli and ageratum oils inhibited 20 bacteria and citronella and geranium oils were inhibitory to 15 and 12 bacterial strains, respectively. All twelve fungi were inhibited by seven oils (aegle, citronella, geranium, lemongrass, orange, palmarosa and patchouli). Eucalyptus and peppermint oils were effective against eleven fungi."

- In vitro activity of essential oils extracted from plants used as spices against fluconazole-resistant and fluconazole-susceptible Candida spp: http://www.ncbi.nlm.nih.gov/pubmed/18997851 "The results showed that cinnamon, Mexican oregano, oregano, thyme, and ginger essential oils have different levels of antifungal activity. Oregano and ginger essential oils were found to be the most and the least efficient, respectively."

- A novel aromatic oil compound inhibits microbial overgrowth on feet: a case study: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1997117/

- Plants used to treat skin diseases: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3931201/

- Selected Antimicrobial Essential Oils Eradicate Pseudomonas spp. and Staphylococcus aureus Biofilms: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3346404/

Mint and peppermint oil:

- Chemical composition and antimicrobial and antioxidant activities of Mentha (longifolia L. and viridis) essential oils: http://www.ncbi.nlm.nih.gov/pubmed/19895481

- Antifungal activity of peppermint and sweet basil essential oils and their major aroma constituents on some plant pathogenic fungi from the vapor phase: http://www.ncbi.nlm.nih.gov/pubmed/12744290

- Antimicrobial efficacy of five essential oils against oral pathogens: An in vitro study: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4054083/ (tea tree oil, lavender oil, thyme oil, peppermint oil and eugenol oil)

Tea tree oil:

- Melaleuca alternifolia (Tea Tree) Oil: a Review of Antimicrobial and Other Medicinal Properties: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1360273/

- Antifungal activity of the components of Melaleuca alternifolia (tea tree) oil: http://www.ncbi.nlm.nih.gov/pubmed/12969301

- In-vitro activity of essential oils, in particular Melaleuca alternifolia (tea tree) oil and tea tree oil products, against Candida spp: http://www.ncbi.nlm.nih.gov/pubmed/9848442

- Antifungal effects of Melaleuca alternifolia (tea tree) oil and its components on Candida albicans, Candida glabrata and Saccharomyces cerevisiae: http://www.ncbi.nlm.nih.gov/pubmed/15140856

- Antifungal activity of the essential oil of Melaleuca alternifolia (tea tree oil) against pathogenic fungi in vitro: http://www.ncbi.nlm.nih.gov/pubmed/9055360

- Antifungal effect of Australian tea tree oil on Malassezia pachydermatis isolated from canines suffering from cutaneous skin disease: http://www.ncbi.nlm.nih.gov/pubmed/12070905

- The effect of tea tree oil and antifungal agents on a reporter for yeast cell integrity signalling: http://www.ncbi.nlm.nih.gov/pubmed/17397109

- Role of antifungal agents in the treatment of seborrheic dermatitis: http://www.ncbi.nlm.nih.gov/pubmed/15663338

Eucalyptus oil:

- Antibacterial, antifungal, and anticancer activities of volatile oils and extracts from stems, leaves, and flowers of Eucalyptus sideroxylon and Eucalyptus torquata: http://www.ncbi.nlm.nih.gov/pubmed/18075306

- Eucalyptus oleosa essential oils: chemical composition and antimicrobial and antioxidant activities of the oils from different plant parts (stems, leaves, flowers and fruits): http://www.ncbi.nlm.nih.gov/pubmed/21330958

- Chemical composition and in vitro evaluation of the antioxidant and antimicrobial activities of Eucalyptus gillii essential oil and extracts: http://www.ncbi.nlm.nih.gov/pubmed/22878228

- Antibacterial activity of essential oils from Eucalyptus and of selected components against multidrug-resistant bacterial pathogens: http://www.ncbi.nlm.nih.gov/pubmed/21591991

- Antimicrobial and antifungal properties of the essential oil and methanol extracts of Eucalyptus largiflorens and Eucalyptus intertexta: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2950377/

meteor

March 14th, 2016, 03:25 PM

Anti-bacterial and anti-fungal oils BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187906&viewfull=1#post3187906)

PART II

Basil oil:

- Essential oil from Ocimum basilicum (Omani Basil): a desert crop: http://www.ncbi.nlm.nih.gov/pubmed/22164790

- Antifungal activity of peppermint and sweet basil essential oils and their major aroma constituents on some plant pathogenic fungi from the vapor phase: http://www.ncbi.nlm.nih.gov/pubmed/12744290

- The main chemical composition and in vitro antifungal activity of the essential oils of Ocimum basilicum Linn. var. pilosum (Willd.) Benth: http://www.ncbi.nlm.nih.gov/pubmed/19136915

- Evaluation of bioactivity of linalool-rich essential oils from Ocimum basilucum and Coriandrum sativum varieties: http://www.ncbi.nlm.nih.gov/pubmed/20614837

- Tulsi - Ocimum sanctum: A herb for all reasons: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4296439/

- Evaluation of the antimicrobial activity of various concentrations of Tulsi (Ocimum sanctum) extract against Streptococcus mutans: an in vitro study: http://www.ncbi.nlm.nih.gov/pubmed/20930344

Myrtle oil:

- Essential oil of Myrtus communis L. as a potential antioxidant and antimutagenic agents: http://www.ncbi.nlm.nih.gov/pubmed/20428077

Clary sage oil:

- The effect of clary sage oil on staphylococci responsible for wound infections: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4360007/

Bergamot oil:

- In vitro activity of bergamot natural essence and furocoumarin-free and distilled extracts, and their associations with boric acid, against clinical yeast isolates: http://www.ncbi.nlm.nih.gov/pubmed/15574476

- Citrus bergamia essential oil: from basic research to clinical application: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4345801/

Grapefruit oil:

- The effectiveness of processed grapefruit-seed extract as an antibacterial agent: II. Mechanism of action and in vitro toxicity: http://www.ncbi.nlm.nih.gov/pubmed/12165191

Lemongrass oil:

- Antifungal activity of the lemongrass oil and citral against Candida spp: http://www.ncbi.nlm.nih.gov/pubmed/18553017

- Lemon grass (Cymbopogon citratus) essential oil as a potent anti-inflammatory and antifungal drug: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4170112/, http://www.ncbi.nlm.nih.gov/pubmed/25242268

Lavender oil:

- Antifungal activity of Lavandula angustifolia essential oil against Candida albicans yeast and mycelial form: http://www.ncbi.nlm.nih.gov/pubmed/16178366

Rosemary oil:

- Chemical composition and antifungal activity of rosemary (Rosmarinus officinalis L.) oil from Turkey: http://www.ncbi.nlm.nih.gov/pubmed/18654909

- Antimicrobial and antifungal activities of the extracts and essential oils of Bidens tripartita: http://www.ncbi.nlm.nih.gov/pubmed/19056546

- Antimicrobial screening of selected medicinal plants from India: http://www.ncbi.nlm.nih.gov/pubmed/9406894

- Antimicrobial activity of selected Peruvian medicinal plants: http://www.ncbi.nlm.nih.gov/pubmed/12963143

- Medicinal plants from Riau province, Sumatra, Indonesia. Part 2: Antibacterial and antifungal activity: http://www.ncbi.nlm.nih.gov/pubmed/7776665

Carrier Oils:

Lauric acid and Coconut oil:

- Antimicrobial property of lauric acid against Propionibacterium acnes: its therapeutic potential for inflammatory acne vulgaris: http://www.ncbi.nlm.nih.gov/pubmed/19387482, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2772209/

- Anti-bacterial and anti-inflammatory properties of capric acid against Propionibacterium acnes: a comparative study with lauric acid: http://www.ncbi.nlm.nih.gov/pubmed/24284257

- In vivo treatment of Propionibacterium acnes infection with liposomal lauric acids: http://www.ncbi.nlm.nih.gov/pubmed/23495239

- Antimicrobial effects of virgin coconut oil and its medium-chain fatty acids on Clostridium difficile: http://www.ncbi.nlm.nih.gov/pubmed/24328700

- Short- and medium-chain fatty acids exhibit antimicrobial activity for oral microorganisms: http://www.ncbi.nlm.nih.gov/pubmed/21333271

- Fatty Acids and Derivatives as Antimicrobial Agents: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC444260/

- Activity of virgin coconut oil, lauric acid or monolaurin in combination with lactic acid against Staphylococcus aureus: http://www.ncbi.nlm.nih.gov/pubmed/23077821

Neem oil:

- Antifungal activity of different neem leaf extracts and the nimonol against some important human pathogens: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768785/

- Effect of Neem oil and Haridra on non-healing wounds: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4492024/

- Effect of Neem Leaf Extract and Neem Oil on Penicillium Growth, Sporulation, Morphology and Ochratoxin. A Production: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3202777/

Black cumin seed oil (Nigella Sativa, blackseed):

- Black cumin (Nigella sativa) and its constituent (thymoquinone): a review on antimicrobial effects: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4387228/

- Anti-microbial effect of Nigella sativa seed extract against staphylococcal skin Infection: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4219874/

- A review on therapeutic potential of Nigella sativa: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3642442/
Detection of the Antibacterial Effect of Nigella Sativa Ground Seeds with Water: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3252685/

Castor oil:

- Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3621469/

- Essential oil of the leaves of Ricinus communis L.: In vitro cytotoxicity and antimicrobial properties: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3492038/

meteor

March 14th, 2016, 03:36 PM

Meteor thanks for all the work you've put into this already! Wow!

May I suggest that you'd add

bullet
points
to the lists of links, please? If possible, with empty line between? I have difficult time seeing a wall of text, and bullet points would help me a lot!

I'll definitely do it from now on. :) Sorry about that, Arctic! :flower:
In the old posts, I'll try to adjust this, too, but there was already a big problem with me exceeding limit of characters allowed in most posts - I'll try, though. :) You are right! I'll need to space it out much better, for sure! :agree:

Metor---I have found something online in regards to the molecular structure--will try to find it again---it was for both coconut oil and olive oil--was very fascinating. But, again, it's the internet :)

Oh, if you find something on it, it will be awesome! :D
You are right though, olive oil most likely does penetrate, since it has saturated and monounsaturated fats. It's just not 100% clear from the wording in the research that was available to me.
According to this study (Investigation of penetration abilities of various oils into human hair fibers: http://journal.scconline.org/pdf/cc2005/cc056n05/p00283-p00295.pdf), "In general, saturated and monounsaturated oils penetrate into the hair because of a compact molecular structure and the polar head group of the triglyceride molecules that constitute these oils. In a dynamic mode these molecules can reptate and squeeze through the CMCs. On the other hand, polyunsaturated oils do not penetrate into hair, most likely because of the more open and spread-out structures of their triglyceride molecules and because of the presence of multiple double bond."

And olive oil can penetrate (probably due to its saturated and monounsaturated fat content), according to studies reviewed by Science-y Hair Blog in this great post: http://science-yhairblog.blogspot.com/2013/06/oils-which-ones-soak-in-vs-coat-hair.html

Arctic

March 14th, 2016, 04:43 PM

Meteor you should have recerved the first 4 pages for links :D You are doing awesome, don't tired yourself! There is time to gather stuff slowly too, you know ;) Thank you for the improved links/lists! I don't know if I have a mild dyslexia or what, but if I see a long text without breaks, the letters and words just vanish.

meteor

March 14th, 2016, 06:23 PM

^ He-he! 4 pages! :lol:
Thanks a lot, Arctic! :flowers: I think I've fixed all the spacing. ;)
The whole indexing thing is work-in-progress though. ;) Guys, do let me know if you have ideas on how I can make indexing/linking more user-friendly for you! :D

mermaid lullaby

March 15th, 2016, 05:56 PM

I'm going to read through all this. This is amazing! Outstanding job!

pinutzz

March 15th, 2016, 07:18 PM

Arctic

March 15th, 2016, 07:23 PM

Oily skin and acne are different things. :flower:

I understand where you are coming from, of course.

***

Meteor index is looking mighty fine, and much more readable! Thank you!

mary*rose

March 15th, 2016, 07:35 PM

mary*rose

March 15th, 2016, 07:41 PM

Most of the articles I'm finding about washing and oil production (actually, I had to modify my search to sebum production, as I kept getting articles for bio-oil production, meaning fuel) were actually about reducing oil to decrease acne, which kind of relates to one of the articles about encouraging a microbiome, and that changing your bacterial microbiome might help more than eliminating the oil on one's face.

meteor

March 15th, 2016, 08:42 PM

This is a really great idea for a thread! I am a physicist - so no experience with the science of hair from my end, but I will definitely follow this thread! Sometimes I get a bit annoyed with things that are mentioned on this forum as if they are hard facts while in reality it is at best anectotal evidence.

Oh awesome! I actually hope that we'll do some myth-busting on this thread, too! :D I'm coming across so much contradictory data all over the Internet, even from trichologists' sites, lots of anecdotal evidence, of course, many assumptions that correlation must be pointing towards causation... and, of course, there are not many studies (I think it may be because the field is not necessarily one of the best funded ones out there, to be honest! ;) )

I actually do have a question for all of you:
Is there a scientific study out there that deals with the question if the frequency hair washes influence how quickly the scalp produces more sebum? It seems many people in this forum believe that if you wash your hair less often over time the scalp becomes used to that and produces less grease. However I never heard anyone tell a person with acne to wash their face less and that the acne would subsequently disappear. And I assume that the skin of my face and that of my scalp are not all that different. Is there any scientific consensus on this issue?

Great! I do know of a German study published in the Archives of Dermatological Research that supposedly shows that the presence of oil on the skin sends a signal to the sebaceous glands to turn off: the signal comes either from the pressure of the oil in the follicle or from creation of some chemical signal that travels back down through the skin - I think the mechanism was not exactly clear.

Unfortunately I can't access it - it's not in open access. :( If somebody has time and can access it, please let us know what you think! ;)

The regulation of sebum excretion in man: http://link.springer.com/article/10.1007%2FBF00560397
"The refatting curve of 21 test persons shows that the sebum excretion is highest during the first hour and decreases continously with every following refatting interval. Refatting after regular defatting every hour reveals a constant excretion rate over 7 hrs. Thus the conclusion can be drawn that sebum excretion is regulated by the excreted sebum itself."

However, that's all about sebum excretion...
Acne (though related to sebum) is a different phenomenon, with a strong hormonal component and other factors. I'm not sure that scalp and face are necessarily all that similar from this point of view - after all, acne can be quite limited to an area (say, just chin, or only T-zone, or chest, back...).

meteor

March 15th, 2016, 08:53 PM

Meteor index is looking mighty fine, and much more readable! Thank you!

Thanks a bunch! :D So happy to hear it works! :cheer:

I'll keep working on it, of course... And as I'm adding info on topics in the index, I have to move some information into separate threads... For example, just a heads-up: I've been working on a separate section for hair pictures under microscope. I'll be ready to post it in a few minutes. ;)

There is a place for you as a physicist! Just a little while back there was a physics article on the likelihood of hair to tangle, and the physicists developed models on their results :) You should check it out!

Oh yes! :agree:
Just in case, I'll mention it here, so you don't have to search ;)
http://scitation.aip.org/content/aapt/journal/ajp/75/8/10.1119/1.2733683 (quick article on the study: http://www.scientificamerican.com/article/straight-hair-is-knottier-than-curly-hair/)

meteor

March 15th, 2016, 09:01 PM

9. Pictures - Hair and Scalp under Microscope - PART I BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

Scalp Pictures:

Trichoscopy in alopecias: Diagnosis simplified: http://www.ijtrichology.com/article.asp?issn=0974-7753;year=2013;volume=5;issue=4;spage=170;epage=17 8;aulast=Jain

- Photos of hair and scalp (from doctor specialized in hair restoration and hair loss conditions): https://www.instagram.com/donovanmedical/ (from post # 177 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3200965&viewfull=1#post3200965))

- Normal scalp: Follicular units in normal scalp contain 2-4 terminal hairs and 1 or 2 vellus hairs inside. A homogenous pigment pattern is usually present: http://www.ijtrichology.com/viewimage.asp?img=IntJTrichol_2013_5_4_170_130385_ u2.jpg

- Healthy / Dry / Oily scalp / Dandruff: http://www.mediceuticals.eu/wp-content/uploads/scalp11-1024x240.jpg

- Dandruff, Infected scalp, Oily scalp, Hair density of normal scalp vs. thinning: http://farm8.staticflickr.com/7347/13189526613_186c161833_o.jpg

- Alopecia areata: characteristic yellow dots seen in alopecia areata and "exclamation hair" (tapered hair): http://www.ijtrichology.com/articles/2013/5/4/images/IntJTrichol_2013_5_4_170_130385_u3.jpg

- White dots characteristic of Cicatricial (scarring) Alopecia: http://www.ijtrichology.com/articles/2013/5/4/images/IntJTrichol_2013_5_4_170_130385_u4.jpg

- Androgenetic alopecia: early (perifollicular inflammation) and advanced (sparse follicles, single-hair follicles, significant hair shaft diameter variation, pearly white dots - hypertrophied sebaceous glands): http://www.ijtrichology.com/viewimage.asp?img=IntJTrichol_2013_5_4_170_130385_ u8.jpg

- Trichotillomania: (longitudinal splitting of hair shafts and coiling of hairs) http://www.ijtrichology.com/viewimage.asp?img=IntJTrichol_2013_5_4_170_130385_ u10.jpg

Roots and Ends Pictures: https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/jan2004/research/2004_01_research01b.htm and https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/july2000/deedric1.htm/

- Taper vs. Reverse Taper: http://i.imgur.com/laCSIXi.jpg (telogen phase?) and http://i.imgur.com/zpoBmqu.jpg, http://www.hairlosshelp.com/forums/messageview.cfm?catid=10&threadid=111676, discussion: http://forums.longhaircommunity.com/showthread.php?t=137267&p=3204634&viewfull=1#post3204634

- Fine / Medium / Coarse hair: http://www.philipkingsley.co.za/media//Picture12.jpg

- Naturally shed hair + bulb: https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/july2000/images/shedhair.jpg

- Pulled out hair + bulb: https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/july2000/images/pulled.jpg, https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/july2000/images/pulled2.jpg

- Comparison of different ends (cut with sharp vs. blunt scissors, snapped, split, weathered): http://www.blackhairinformation.com/wp-content/uploads/2013/08/types-of-hair-ends.png, http://3.bp.blogspot.com/-X-xkoh_glng/UvoddcRWktI/AAAAAAAABR8/Bwz5GGmoHe4/s1600/african_hair_microscope_cut_shears.jpg, http://forums.longhaircommunity.com/showthread.php?t=47891&p=1112056&viewfull=1#post1112056 (by Night Kitten)

- Glass-cut or broken hair tip: https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/jan2004/research/images/fig52.jpg

- Abraded hair tip: https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/jan2004/research/images/fig53.jpg

- Cut tip: https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/jan2004/research/images/fig54.jpg

- Razor-cut tip: https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/july2000/images/razorcut.jpg

- Worn razor-cut tip: https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/jan2004/research/images/fig55.jpg

- Burnt hair: https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/jan2004/research/images/fig74.jpg

- Very close shave: https://s-media-cache-ak0.pinimg.com/236x/2d/68/31/2d6831bb36189a355587cd1705aeaace.jpg

Texture Pictures:

- A hair showing buckling: https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/july2000/images/buckling.jpg

- Double kink in hair: http://1.bp.blogspot.com/-bDsYCAzlHg4/TqVuUQ5v_BI/AAAAAAAAA40/v6WYuaaD5yg/s200/kink_hair.jpg

- Single kink in hair: http://1.bp.blogspot.com/-3LoL5KLZ3Lc/TqVubQRhIrI/AAAAAAAAA48/mxXLS-tXKtc/s200/hair+kink.jpg, http://4.bp.blogspot.com/-yT17JJl6JJw/T-ITToqwlOI/AAAAAAAAAY0/Rtxlr_HjSSQ/s320/kink_white_hair+copy.jpg

- Corresponding hair shaft diameter with anagen hair follicle depth (the thinner/finer the strand, the shorter the follicle length): http://www.ijps.org/viewimage.asp?img=ijps_2008_41_3_101_43606_b1.jpg

meteor

March 15th, 2016, 10:02 PM

9. Pictures - Hair and Scalp under Microscope - PART II BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

Hair Damage and Treatments Pictures:

- Low vs. Normal vs. High Porosity: http://www.rejuvinicherbal.com.my/uploads/2/7/3/4/27345081/7607914_orig.jpg

- Porous hair in water: http://2.bp.blogspot.com/-n0bfI0WTNnM/UxjRUOGgnSI/AAAAAAAAAzg/lAhWOhb7uR8/s1600/porous_edge.jpg "The cuticles are pushed out from force beneath as the endocuticle swells with water. In this position, the cuticles are more vulnerable to chipping and breakage which causes loss of protein from the hair and further increases porosity"; http://science-yhairblog.blogspot.ca/2011/09/porosity-in-hair.html

- Oiled hair: the oil film obscures the cuticle and adds shine and lubrication: http://1.bp.blogspot.com/-DN7jKvm-q0A/VVrwc3WFt5I/AAAAAAAABEo/iWovKInflUU/s320/oily_roots.jpg

- Healthy cuticle layer vs. raised cuticle layer vs. damaged, missing scales: http://www.howtomakeyourhairgrowfastertips.com/wp-content/uploads/2014/06/hair-cuticle-layer.png

- UV damage (UVA 12 hr, 48 hr and UVB 12 hr, 48 hr) of Asian, Caucasian and African hair: http://synapse.koreamed.org/ArticleImage/0140AD/ad-25-54-g002-l.jpg

- Old (long) hair with lots of accumulated UV damage (cuticle worn off): http://1.bp.blogspot.com/-sEn5sJDr8uU/Tn4HkW5Yu9I/AAAAAAAAAMk/ffwimuosYEM/s320/Sun_damaged.jpg, http://science-yhairblog.blogspot.ca/2011/09/porosity-in-hair.html

- Bleached hair (6% vs. 9%) for 15 min vs. 30 min, single treatment vs. double-treatment: https://everydaybiochemistry.files.wordpress.com/2012/02/scanning-electron-microscope-hair.jpg

- Damaged hair by bleaching and color treatment (magnified 1,000 times under a microscope): http://www.mydome.jp/exhibition_ibo_image/open/cmp003592_3.jpg?1458072029

- Damage hair by normal shampoos while exposed to normal ultraviolet rays (magnified 500 times under a microscope): http://www.mydome.jp/exhibition_ibo_image/open/cmp003592_1.jpg?1458072029

- Henna, henndigo vs. natural hair: http://forums.longhaircommunity.com/showthread.php?t=126560&p=2834589&viewfull=1#post2834589 (by serin blackwood), http://www.southlandsoap.com/your-hairunder-the-microscope.html

- Relaxer: the shape of stress induced damage which has caused a change in the shape of the hair: http://www.angelfire.com/journal/nutrients/images/hair1.jpg, magnified: http://www.angelfire.com/journal/nutrients/images/hair2.jpg

- Porous hair swelling in Baking Soda solution: http://3.bp.blogspot.com/-FuuUngar4rY/UxjQoYbym-I/AAAAAAAAAzY/EQXP0YcKke8/s1600/baking_soda.jpg

- "Bubble hair" from heat used on wet hair: http://3.bp.blogspot.com/_GkQ08Dsvo30/TPOAWpOvOgI/AAAAAAAAAvE/ysWOYlUeqYA/s1600/bubble+hair.png, http://blackgirllonghair.com/wp-content/uploads/2015/04/bubble-hair.jpg, http://www.testmyhair.com/image/data/heat-damage-to-hair.jpg

- Hair surface / Cuticle damage from blow-drying at different temperatures and different distances: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3229938/figure/F2/

- Cell membrane complex (CMC) damage from air-drying: http://pmcc.web-t.cisti.nrc.ca/articlerender.cgi?accid=PMC3229938&rendertype=figure&id=F5

- Damage from Hair Spray "fusing" hairs: http://isaetno.free.fr/Fourches/fourche9.jpg

- Split ends: https://www.fbi.gov/about-us/lab/forensic-science-communications/fsc/july2000/images/split.jpg

- Mid-shaft split in hair: http://2.bp.blogspot.com/-Cvl0vTZCVqA/TqgbWqdcdDI/AAAAAAAAA5k/lT7VVCd7DkQ/s400/midshaft+split.jpg

- White dots: http://i1068.photobucket.com/albums/u452/raemarthe/IMG_2964_zps8a9a0ce3.jpg, http://www.naturalchica.com/wp-content/uploads/2012/01/pic1.jpg, http://pittsburghcurly.files.wordpress.com/2009/07/white-dot.jpg

- Trichorrhexis Nodosa: http://www.hairscientists.org/images/trichorrhexis%20nodosa.jpg, http://www.ijtrichology.com/viewimage.asp?img=IntJTrichol_2013_5_4_170_130385_ u14.jpg, http://www.dermnet.com/dn2/allJPG3/trichorrhexis-nodosa-1.jpg, http://longing4length.com/wp-content/uploads/2014/01/trichorrhexis-nodosa-longing-4-length.jpg

- Knots and breakage: http://urbanbushbabes.com/wp-content/uploads/2011/10/trichorrhexis-nosoda-resized-31.jpg

- Different knots and tangles: http://naturalnigerian.com/wp-content/uploads/2012/08/Corbis-42-29390673-1.jpg, http://www.blackhairinformation.com/wp-content/uploads/2012/07/Simple-knot-with-hair-fibre-damage.jpg, http://1.bp.blogspot.com/-GAFxn35cFCQ/TqgbqE4u7KI/AAAAAAAAA5s/6NwUL34ECdU/s1600/complex_hair_knot.jpg, http://www.blackhairinformation.com/wp-content/uploads/2012/07/complex-knot-graphic.png, http://www.fei.com/uploadedImages/FEISite/Content/Image_Gallery/Images/IM_20110506_Holthuysen_62_Knothumanhair_lg.jpg, http://3.bp.blogspot.com/-MKSnJjSW8bc/VfLqKRG3jDI/AAAAAAAA3kk/LkrcSlvXxCE/s1600/ssk-650x365.png

- Cuticle removed from sunlight, chlorine and friction damage: http://2.bp.blogspot.com/-fU1RZjM0C_A/T-ITLAOK0RI/AAAAAAAAAYs/0CmWI1B1bgs/s320/Sun_damaged+copy.jpg

Cleansing Methods Pictures:

- Conditioner (Co-Wash) vs. Shampoo vs. Water Only vs. Unwashed Hair : http://www.thenaturalhavenbloom.com/2014/02/does-co-washing-really-clean-your-hair.html

- Bentonite Clay vs. Rassoul Clay vs. Shampoo vs. Unwashed Hair: http://www.thenaturalhavenbloom.com/2014/02/can-you-really-wash-your-hair-with.html

- Baking Soda vs. ACV vs. Shampoo vs. Unwashed Hair: http://www.thenaturalhavenbloom.com/2014/07/can-you-wash-your-hair-with-baking-soda.html

- Shikakai vs. Bentonite Clay vs. Baking Soda vs. ACV vs. Shampoo vs. Conditioner (CO-Wash) vs. Water Only vs. Unwashed Hair: http://www.thenaturalhavenbloom.com/2014/11/caucasian-hair-cleansing-shikakai.html

- Compilation: Oat Water vs. Bentonite Clay vs. Rassoul Clay vs. Baking Soda vs. ACV vs. Shampoo Bar vs. Castile Soap vs. Shampoo vs. Conditioner (CO-Wash) vs. Unwashed Hair: http://www.thenaturalhavenbloom.com/2015/05/hair-science-how-well-do-mild-cleansers.html

meteor

March 15th, 2016, 10:36 PM

I actually do have a question for all of you:
Is there a scientific study out there that deals with the question if the frequency hair washes influence how quickly the scalp produces more sebum? It seems many people in this forum believe that if you wash your hair less often over time the scalp becomes used to that and produces less grease. However I never heard anyone tell a person with acne to wash their face less and that the acne would subsequently disappear. And I assume that the skin of my face and that of my scalp are not all that different. Is there any scientific consensus on this issue?
Great! I do know of a German study published in the Archives of Dermatological Research that supposedly shows that the presence of oil on the skin sends a signal to the sebaceous glands to turn off: the signal comes either from the pressure of the oil in the follicle or from creation of some chemical signal that travels back down through the skin - I think the mechanism was not exactly clear.

Unfortunately I can't access it - it's not in open access. :( If somebody has time and can access it, please let us know what you think! ;)

The regulation of sebum excretion in man: http://link.springer.com/article/10.1007%2FBF00560397
"The refatting curve of 21 test persons shows that the sebum excretion is highest during the first hour and decreases continously with every following refatting interval. Refatting after regular defatting every hour reveals a constant excretion rate over 7 hrs. Thus the conclusion can be drawn that sebum excretion is regulated by the excreted sebum itself."

So I looked at the sample pages (http://link.springer.com/article/10.1007/BF00560397#page-1) of this study that are in open access and they talk about "casual level" of oil on skin, that without external interference, sebum level on skin remains pretty constant. "The constancy of surface fat level suggests a decrease of the sebum excretion with increasing levels of excreted sebum. [...] The decrease means that the sebum excretion must be regulated." This "casual level" was different for different individuals and different parts of their bodies, but the re-fatting happened to the same level as before and leveled off at that prior level. :hmm:

This stuff is interesting, though it bothers me that they used only 21 subjects and didn't manage to control for rubbing off of oil, though they mentioned that it wasn't an important factor and didn't really put in question that "casual level" of sebum: https://static-content.springer.com/lookinside/art%3A10.1007%2FBF00560397/001.png

I'd love to read the whole article, of course, or anything else on this subject. :D
Though I think the fact that there seemingly aren't many studies following up on this at all, despite it being an ancient study, possibly means that the hypothesis was put on the back burner, possibly because other theories of sebum excretion explain the process much better? :hmm:

Arctic

March 16th, 2016, 03:48 AM

Meteor, as a thank you of the work you have put into this, I'd like to make a summary of one of your chosen research paper, that you can't access but I can. I could glance it through over the weekend. So, what have you? :D

meteor

March 16th, 2016, 09:37 AM

^ Oh, Thank you so very much, Arctic! :flowers: That's super kind! :D
I don't know which research paper to choose though! :hmm: Is there some study that was on your mind, maybe? ;) :eyebrows:
Or maybe others have a study in mind? :flower:

Arctic

March 16th, 2016, 10:00 AM

Well one thing I would be interested to read is about how dandruff shampoos can prevent and/or help with hairloss (and also to make hairs coarser). We had interesting and a bit heated discussions of that subject some time ago. It's called "Nudging hair shedding by antidandruff shampoos. A comparison of 1% ketoconazole, 1% piroctone olamine and 1% zinc pyrithione formulations."

Abstract here: http://www.ncbi.nlm.nih.gov/pubmed/18498517

The research itself is not openly accessible. It really interests me. But really, I can make summary of any article/paper you'd like, if I only have access to it.

mary*rose

March 16th, 2016, 10:54 AM

As a side note, I'm really interested in that sebum article you just shared, meteor. It's not available online (because it was published in 1974...), and it also might not be in English, since it looks like it was written in German. But I put in a library request for the article, and I plan on reading it and sharing what I find here. It'll also help narrow down some search terms for more recent research.

JSYK, don't pick that one :)

~~~

Arctic, the premise for that research seems really interesting. I'd love to hear more about that, too.

meteor

March 16th, 2016, 12:05 PM

^ Wow, thanks a bunch for that, mary*rose! :flowers: That's really awesome! I hope we'll find out more about this! :D
I have a theory: what if the reason the re-fatting happens so fast within the first hour (and then slows down when the sebum coat is sufficient) is because the stripped skin immediately needs to protect itself with that minimal "casual sebum level" from the environment (wind, sun, water, etc), dehydration which could lead to potential micro-cracks in skin, which could lead to bacterial or fungal invasion? Basically, it might be a protective mechanism? But why/how does it switch off? It's certainly helpful if it does (so we can skip washes or, vice versa, over-wash ourselves and still be fine! :eyebrows:)... but I wonder how? :hmm:

Well one thing I would be interested to read is about how dandruff shampoos can prevent and/or help with hairloss (and also to make hairs coarser). We had interesting and a bit heated discussions of that subject some time ago. It's called "Nudging hair shedding by antidandruff shampoos. A comparison of 1% ketoconazole, 1% piroctone olamine and 1% zinc pyrithione formulations."

Abstract here: http://www.ncbi.nlm.nih.gov/pubmed/18498517

The research itself is not openly accessible. It really interests me. But really, I can make summary of any article/paper you'd like, if I only have access to it.

Ha-ha, great minds think alike! :thumbsup: I was just going to bring up the whole issue of extremely popular off-label use of Nizoral (and ketoconazole, in general) for androgenetic alopecia and start adding links to the AGA studies post! :hifive:
I remember trying to access that study in the past for male pattern baldness DHT-controlling protocol, so I'm happy you can look at it! :joy:

By the way, members of the same team who worked on that study (Piérard-Franchimont C. and Piérard G.E.) came out with another study on this topic, and this study is in open access. So I'll link it here, just in case:
Ketoconazole Shampoo: Effect of Long-Term Use in Androgenic Alopecia: http://vipadenievolos.ru/files/research/ketokonazole/Ketoconazole_Shampoo_Study.pdf

It talks in part about the role of Malassezia spp. in inflammatory reaction and AGA. Hair density and hair shaft diameter and proportion of anagen follicles increased with both 2% ketoconazole and 2% minoxidil therapies. But with ketoconazole, the subjects' "casual sebum level" also went down. They've also noted a negative linear relationship between the hair shaft diameter and the area of the corresponding sebaceous gland. I don't think it means that having lots of oil can cause AGA directly, of course, but when patients already suffer from AGA, they often do observe increased scalp oiliness until they get on treatment, don't they? :hmm:
An excess of dihydrotestosterone (DHT), which is an androgen hormone and a metabolite of testosterone, can trigger sebaceous glands to produce sebum. Higher than normal levels of this hormone or an increased sensitivity of the glands to normal levels of DHT can lead to excessive sebum... And we all know how high levels of DHT are leading cause of androgenetic alopecia, so there's that connection...
(By the way, DHT first appears at puberty in both males and females - and that's when kids start producing massive amounts of sebum (compared to their earlier years). Oh, and that increase in oiliness and acne the week before period that many of us notice - well, that's linked to DHT levels, too, because DHT parallels the rise of progesterone (progesterone rises post ovulation and drops during the first part of the cycle).)
http://www.dermnetnz.org/acne/sebum.html (under Hormonal Control of Sebum), http://www.dermadoctor.com/blog/oily-skin/

There's another study on that ketoconazole and AGA connection that's extremely interesting, too: Comparative Efficacy of Various Treatment Regimens for Androgenetic Alopecia in Men: http://onlinelibrary.wiley.com/doi/10.1111/j.1346-8138.2002.tb00314.x/abstract;jsessionid=0A3A8B11744B50FE780EF853D328AD 0E.f04t01

- Group I (30 patients) was administered oral finasteride, -> (# 3)

- Group II (36 patients) was given a combination of finasteride and topical minoxidil, -> (# 1 best results)

- Group III (24 patients) applied minoxidil alone and -> (# 4)

- Group IV (10 patients) was administered finasteride with topical ketoconazole. -> (2nd best)

(Treatment efficacy was assessed during the study period of 1 year on the basis of patient and physician assessment scores and global photographic reviews. All groups showed hair regrowth.)
I wish they'd also compared all that to minoxidil + ketoconazole + finasteride combo, as well, since that's a very popular protocol for guys with MBP these days...

meteor

March 16th, 2016, 01:17 PM

Oh, and a few more links, somewhat related to pinutzz's question... there are quite a few studies on acne and sebum connection (thank goodness, acne is one of those well-researched topics - after all, who wouldn't want to find a silver bullet solution for acne? ;) )

- Acne and sebaceous gland function: http://www.ncbi.nlm.nih.gov/pubmed/15556719
"Current data indicate that acne vulgaris may be a primary inflammatory disease. Future drugs developed to treat acne not only should reduce sebum production and Propionibacterium acne populations, but also should be targeted to reduce pro-inflammatory lipids in sebum, down-regulate pro-inflammatory signals in the pilosebaceous unit, and inhibit leukotriene B(4)-induced accumulation of inflammatory cells. They should also influence peroxisome proliferator-activated receptor regulation. Isotretinoin is still the most active available drug for the treatment of severe acne."

- Can sebum reduction predict acne outcome? http://www.ncbi.nlm.nih.gov/pubmed/20518779 "The projected sebum reduction required to achieve 50% reduction in acne measures ranged from 30% to 50%."
Graph: difference in the casual sebum secretion levels between subjects with and without acne: https://www.researchgate.net/figure/51974631_fig3_Figure-6-Difference-in-the-casual-sebum-secretion-levels-between-subjects-with-and

- Facial sebum affects the development of acne, especially the distribution of inflammatory acne: http://www.ncbi.nlm.nih.gov/pubmed/22176122 reports "significant correlations between the casual sebum level and the number, proportion and location of acne lesions in a large acne patients group, using an objective, bioengineering method. Moreover, we also found that the influence of sebum was prominent on the inflammatory lesions. In addition, both age and gender influenced the correlation between the casual sebum level and the acne."

- Does facial sebum excretion really affect the development of acne? http://www.ncbi.nlm.nih.gov/pubmed/16225600 (46 female subjects) "Sebum secretions in the whole face and in the T- and U-zones (areas of high and low sebum secretion, respectively) were higher in patients with acne than in controls. There was no correlation between sebum quantity and acne lesion count in most facial regions."

- The role of facial sebum secretion in acne pathogenesis: facts and controversies: http://www.ncbi.nlm.nih.gov/pubmed/20082943
- etc...

mary*rose

March 16th, 2016, 04:33 PM

pinutzz

March 16th, 2016, 05:42 PM

Wow, meteor! You really put a lot of work into this! I will need days to read through all of the material you have linked here! I do have access to the sebum paper. It is online and not in german (just the abstract comes in both languages). It is a pity I can't share it publicly. I haven't had time yet to read it, but I am on it *puts her reading glasses on and brews herself a cup of tea*:eye:

mary*rose: I think "casual sebum level" is used whenever people mean the equilibrium amount of sebum that the skin has without influencing it through washing etc. This level is unique to every person and also every place on the body has a different level. The skin will re-fatten all the time to make sure this casual sebum level is reached.

The paper deals with sebum production of the forehead. I wonder if the same is true for the scalp - after all the goal is to make the oil travel along the hairs as much as possible. It might simply mean that the casual sebum level is higher on the scalp?
The paper attributes the slow down of sebum production to viscosity and surface tension effects. But it is not clear on how exactly that is supposed to work.

I am still trying to translate the results of this paper to the common practice on this forum of stretching washes. The paper says that the skin will reach its casual sebum level after just a few hours. If there is a person with a generally low casual level and the skin (and hence hair with a few hours delay) appears 'clean' enough, then a person can basically avoid washing indefinitely without raising the sebum level further. Which is why washing after 4,5,... days works so well for some people. For others with oily skin, this casual level is so high that they have to wash their hair much more often (=daily) for it to appear clean.

Many people on this forum believe if you wash your hair less often that after a month or two of doing this that your skin will get used to that. And that as a result the casual sebum level itself decreases. I am torn on this issue and wonder if this is actually true. And I would like to see some research about that. But since the paper we discussed only addresses a time-frame of hours and not weeks or months I guess this doesn't really answer my question. I don't know if I expressed clearly enough what I meant.

Anyway, I think it is stunning how simple the techniques are that are often used in hair science. You basically only need a somewhat decent microscope and you are ready to go. Especially for the pictures where you can see the hair cuticles open / closed and the surface roughness, I would like to know what microscope is necessary to make pictures like that. I might want to conduct some experiments myself and look at how my hair reacts to the actual products that I am using *totally hooked...*

ETA: I don't mean the images that look like they have been taken with an electron microscope of course...

Silverbleed

March 16th, 2016, 06:48 PM

meteor you're on a roll. You've done so much research already! And it's super helpful, your post about acne was the most perfect timing today when I was helping a friend who's trying to deal with her acne.

meteor

March 17th, 2016, 11:22 AM

Pinutzz, thank you so very much! :flowers: And perfect explanation of "re-fatting" and "casual sebum level"! I have the same feelings as you on this issue.
I also think that article was probably helpful for showing the phenomenon on the surface level, and the authors did mention that different people and different parts of their bodies have different "casual sebum levels". We know that sebum excretion is mostly hormonally-driven (http://www.dermnetnz.org/acne/sebum.html), so it feels a bit like: if you are oily (due to hormones, medical conditions, etc), you can wash/blot your face all the time, and you'll still have more oil excreted, and if you are dry, you can add moisturizers, oils all the time, but your own sebum will still be low... and we can only manage oiliness/dryness on the surface for comfort and aesthetics... until something changes internally.

I know hair photos can be taken by different types of microscopes (those electron microscopes can be ridiculously hard to access though!), but if you are interested in microscope types for some specific pictures, you can open the picture link, then right-click on the picture and select "Search Google For Image" - this will produce a page with links to all the sources that used that picture. Sometimes the source will list the exact microscope, the magnification... ;)

Silverbleed, thanks a lot! For help with acne, I'd recommend your friend research thoroughly things like Vitamin A and its compounds (tretinoin and all sorts of retinoids), benzoyl peroxide and salicylic acid (BHA) for cleansing and regular chemical exfoliation (though AHAs help a bit, too), niacinamide (a.k.a. Vitamin B3, nicotinic acid) & glucosamine combo for fading acne scars, Vitamin C and all sorts of other anti-oxidants, like green tea, also for fading scars - they all have some good research behind them (sorry, I'm not listing the links here, since there are so many). Also, avoid stuff that's too irritating (e.g. fragrances) and stripping, since the skin barrier function needs to be healed. Acne is very complicated though, and these ingredients work only on superficial level as part of a routine. :flower: I really hope your friend's skin will heal up soon! :pray:

lapushka

March 17th, 2016, 11:39 AM

Oily skin and acne are different things. :flower:

I understand where you are coming from, of course.

Yes they are two different things, because I had acne on extremely dry skin. ;)

pinutzz

March 17th, 2016, 11:39 AM

those electron microscopes can be ridiculously hard to access though!
I actually have access to one but I can't justify spending valuable time on the machine to look at my own hair and make my research group pay for it... :run:

if you are interested in microscope types for some specific pictures, you can open the picture link, then right-click on the picture and select "Search Google For Image" - this will produce a page with links to all the sources that used that picture. Sometimes the source will list the exact microscope, the magnification...
Thanks, I didn't know google has this feature. But then again: They can do just about everything... How cool! Will definitely try that!

mary*rose

March 17th, 2016, 11:40 AM

Gosh meteor you are such a font of knowledge.

meteor

March 17th, 2016, 03:08 PM

^ Oh, you are too kind! :o :flowers:

:?:Guys, what's your position on hair steamers? :) You know, those huge, pretty expensive contraptions (that look a bit like hooded hair dryers) that one is supposed to sit under for half an hour or so for "deep treatment"? They are super popular in Afro-textured hair communities for helping with moisture retention and elasticity, but I have no idea whether they are ultimately beneficial for hair or damaging or useless?

On the LHC we often talk about using humectants in steamy shower (to draw water and help hair hold onto it), e.g. SMT or glycerin, aloe, honey, etc... We know that steaming softens hair, and it's great for diffusing water quickly into dry hair, but doesn't the effect dissipate quickly (as water evaporates), unless it's sealed after steaming with occlusives (oils, cones, etc)?

We know that high heat is bad, but one can control the temperature in the steamer, of course. But if one uses low temperature setting... isn't it just like sitting next to a humidifier? And what's the benefit of steaming hair in a shower versus simply getting hair wet in the shower?

And is there any point to the so-called "greenhouse effect method" or the "baggy method" where one traps scalp heat under a plastic cap to help moisturize hair (some people even claim that it increases growth - I see no evidence for it, though)? Lots of people report moisturizing effect from this, which makes sense, but can this effect last on hair? :hmm: (By the way, I can see how it can be a big problem for SD (after all, Malassezia loves wet environments just like other fungi.)

JC from the Natural Haven Bloom (http://www.thenaturalhavenbloom.com/2014/01/are-steamers-really-worth-buying.html) mentions that steaming will allow hair to stretch more than dry or wet (cool or warm water) hair (http://3.bp.blogspot.com/-uS5Q1jQzc94/UtRwIcTNuoI/AAAAAAAABPQ/E7R9TqBh17g/s1600/effect_of_steam_on_hair.jpg). I had no idea that steamed hair could be more elastic than wet hair? :hmm: How does that work? And why is it good? After all, overstretching can damage hair...

By the way, this is the study the blog referred to (it's seriously ancient, but I haven't seen anything new published on this): X-Ray Studies of the Structure of Hair, Wool, and Related Fibres. II. The Molecular Structure and Elastic Properties of Hair Keratin: http://www.leeds.ac.uk/heritage/Astbury/bibliography/Astbury_and_Woods_1934.pdf

She also mentions that steaming for longer than 30 minutes can cause disulfide bonds to break (that's permanent hair damage). But, what about cumulative effect of steaming then? :hmm: If it's bad for longer than 30 minutes, why do it for 20 minutes? Isn't there hygral fatigue involved (from hair shaft swelling and then de-swelling from going wet and then dry)? And anyway, how is steaming and conditioning better than simple wetting and conditioning? I feel like I'm missing a part of the story, since hair steamers sell so well as a deep-conditioning tool, or maybe it's simply about marketing?

What are your thoughts? :flower:

pinutzz

March 17th, 2016, 04:09 PM

Hair swells when wet and can swell to the point where cuticles get damaged because they can't stretch - instead they pop off or rip. The buzzword in that context is "waterlogged". I read about this on the science-y blog on hair swelling (http://science-yhairblog.blogspot.ch/2013/07/hair-swelling-in-water.html). If you steam hair it will also swell, but the hair doesn't swell to the same diameter as a wet hair - unless you do it for too long and the hair swells too much. So there is a reason why 20 minutes might be ok, but 30 minutes causes problems. And of course: If there is nothing to seal in the humidity it is just going to evaporate again after the steaming stops. It is an equilibrium process after all.

meteor

March 17th, 2016, 04:39 PM

^ I couldn't agree more, pinutzz! :agree: Also, that's a really great article by Science-y Hair Blog! Thanks a lot for the link! :D

I also think her article on water & hair connection is very consistent with those interesting findings in the study Hair Shaft Damage from Heat and Drying Time of Hair Dryer: http://pmcc.web-t.cisti.nrc.ca/articlerender.cgi?accid=PMC3229938

Only the naturally dried group exhibited the bulging in the intercellular lipid layers of the cell-membrane-complex (that is the sign of damaged CMC, pictures: http://pmcc.web-t.cisti.nrc.ca/articlerender.cgi?accid=PMC3229938&rendertype=figure&id=F5), possibly due to being water-logged for a long time (2 hours in this study), while the blow-dried tresses didn't show any of this CMC damage, though they all exhibited cuticle damage instead.

"This result was quite unexpected, because increased temperatures generally led to more hair damage. It took over 2 h to dry the hair tress completely under ambient conditions. The hair shaft swells when in contact with water, as does the delta-layer of the CMC. The delta-layer is the sole route through which water diffuses into hair, and so we speculate that the CMC could be damaged when it is in contact with water for prolonged periods. Longer contact with water might be more harmful to the CMC compared to temperature of hair drying. Moisture content decreased in all treated groups (with and without the hair dryer) compared to the untreated control group. However, the differences between the groups were not statistically significant. The methods used to dry wet hair might not affect moisture content. With regard to color, the hair became lighter after repeated shampooing and drying. Drying under ambient temperatures and at 95℃ resulted in earlier changes in hair color (after just 10 treatments). The reason why the hair color is brighter after repeated shampooing and drying is unknown. On TEM examination, no decrease of melanin granules was found. However, after repeated shampooing and drying, definite damage to hair cuticle was evident on SEM examination. Therefore, we assume that the hair color change might be because of the damage to hair.
[...]
damage to the CMC was noted only in the naturally dried group and earlier changes in hair color were seen in this group and the 95℃ group. This effect of natural drying has not seen studied or described before. It is conceivable that a long lasting wet stage is as harmful as a high drying temperature (and may be even more dangerous to the CMC).
Further evaluation about contact time with water or wet environment and hair damage is needed.
Although using a hair dryer caused more surface damage than natural drying, the results of this study suggest that using a hair dryer at a distance of 15 cm with continuous motion causes less damage than drying hair naturally."

So wetting hair and shampooing it actually reduces water content (whether one air-dries or not!). I often read about recommendations to wash hair more often to "re-introduce moisture", but it looks like leaving it alone is more helpful for maintaining higher moisture content. Here's a graph on this from the study: http://pmcc.web-t.cisti.nrc.ca/articlerender.cgi?accid=PMC3229938&rendertype=figure&id=F6

rhosyn_du

March 17th, 2016, 04:48 PM

That's a really interesting study, meteor. I'd love to see it replicated with a third group that uses cool moving air to dry, such as a blow-dryer on "cold" setting or sitting under an air conditioning vent. I'd also be interested in seeing if there's any difference for hair that takes significantly longer than the cited 2 hours to air dry. I wish my hair dried that fast!

meteor

March 17th, 2016, 04:57 PM

^ Oh I agree wholeheartedly, rhosyn_du! :agree:
They did mention "further evaluation about contact time with water or wet environment and hair damage is needed", because damage from air-drying was clearly not what they expected to see, and the whole design of the study was geared simply towards differentiating between different kinds of damage from blow-drying at different temperatures and distances. So I really hope we'll see some more studies into the whole water & hair connection.
I bet keeping hair wet and exposed to some minerals in tap water for a long time is not great either - for example, there is some oxidative damage from copper and other metals in water: Preserving fibre health: reducing oxidative stress throughout the life of the hair fibre: http://onlinelibrary.wiley.com/doi/10.1111/ics.12285/full

(My hair takes ages to dry too, so I simply skip washes and do scalp-only washes instead of full washes whenever I can. ;) It saves on drying time massively.)

lapushka

March 17th, 2016, 05:11 PM

AJNinami

March 17th, 2016, 05:30 PM

I'm adding this to my summer reading list, I love science! (Especially things I can apply!)

Thank you meteor and Arctic

meteor

March 17th, 2016, 07:28 PM

1.4 Thermal / heat damage BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

Heat causes fast water evaporation (leading to dry hair) and protein denaturation (leading to damaged, porous hair).

Blow-drying:
- A hysteresis in heat dried hair: http://journal.scconline.org/pdf/cc1981/cc032n01/p00027-p00036.pdf
"Heat drying will increase the tendency of hair to acquire a static charge during combing and this charge buildup seems to be related to the heat drying hysteresis. Heat drying can also produce a short term decrease in fiber stiffness. This decrease in fiber stiffness is related to the action of heat on the fibers, but it is not related to the hysteresis. Heat drying at moderate temperature has no effect on the tensile properties, although small changes in the tensile properties were detected in hair dried at very high temperature."

- The cracking of human hair cuticles by cyclical thermal stresses: http://journal.scconline.org/pdf/cc1998/cc049n03/p00141-p00153.pdf
"In this figure it can be seen that temperatures lower than 50℃ do not increase the average number of cracks already present in unexposed hair, while temperatures higher than 95℃ lead rather to hair surface and bulk distortion. It is quite plausible, thus, that temperatures lower than 65℃ do not produce the critical rate of water evaporation needed for the top part of the cuticles to contract and become rigid, while temperatures higher than 85℃ might soften the cuticle proteins, releasing, thereby, the mechanical stresses by viscous flow." (from p. 148 )

- Hair shaft damage from heat and drying time of hair dryer: http://pmcc.web-t.cisti.nrc.ca/articlerender.cgi?accid=PMC3229938, http://www.ncbi.nlm.nih.gov/pubmed/22148012 Showed damage to cuticle with all blow-drying: the higher the heat and the shorter the distance, the more damage. Air-dried hair showed damage to the cell-membrane-complex (CMC bulging), consistent with hygral fatigue. More studies needed.
Some cuticle damage was observed even when drying with a hair dryer for 60 seconds at a distance of 15 cm, even at temperature of only 47℃. ("In the 47℃-treated group, multiple longitudinal cracks were observed in the cuticle".)
"Although using a hair dryer causes more surface damage than natural drying, using a hair dryer at a distance of 15 cm with continuous motion causes less damage than drying hair naturally."

- Bubble hair. Case caused by an overheating hair dryer and reproducibility in normal hair with heat: http://www.ncbi.nlm.nih.gov/pubmed/8277032
"RESULTS: No person's hair failed to develop bubbles when subjected to sufficient heat. The cause of bubble hair in the patient was an overheating hair dryer. The cavitations contained a gas.
CONCLUSION: Bubble hair is a reproducible hair shaft defect caused by heat. The use of overheating hair dryers, or any other hair care equipment that overheats, should be avoided."

- Bubble hair: a cosmetic abnormality caused by brief, focal heating of damp hair fibres: http://www.ncbi.nlm.nih.gov/pubmed/7857849

- Bubble hair: http://www.ncbi.nlm.nih.gov/pubmed/1474196

- Patterns of light interference produced by damaged cuticle cells in human hair: http://www.ncbi.nlm.nih.gov/pubmed/17728927
"The strong patterns of light interference appeared only in cuticle cells that had been damaged either mechanically or by thermal stresses."

- Wet degradation of keratin proteins: linking amino acid, elemental and isotopic composition: http://www.ncbi.nlm.nih.gov/pubmed/25156602

- Influence of internal structures of hair fiber on hair appearance. III. Generation of light-scattering factors in hair cuticles and the influence on hair shine: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.553.9320&rep=rep1&type=pdf, http://www.ncbi.nlm.nih.gov/pubmed/14528388
"The effects of thermal treatments on hair fiber induced by blow-drying have been investigated. It was found that the hair shows whitish and powdery appearance after heat drying, especially when dark hair is rapidly dried from a wet condition. For all kinds of hair, the appearance of numerous glittering speckles was confirmed on the cuticle surface by optical microscopic observations. SEM images of hair transverse and longitudinal sections with glittering speckles revealed that the splitting of cuticle layers generated by blow-drying occurred not only at the outermost parts of cuticle cells but also at the inner parts of the cellular interfaces. The release and uptake of moisture through fiber surfaces induces deformation of cuticle cells, probably because of anisotropic swelling or drying of the cells. The cuticles with glittering speckles are found to be fragile and are easily damaged in combination with other mechanical stresses such as combing force. Furthermore, the authors have found an efficient system for both improving hair shine and preventing cuticle damage caused by the blow-drying/combing process."

Direct heat (curling irons, flat irons):
- Effects of thermal treatments with a curling iron on hair fiber: http://journal.scconline.org/pdf/cc2004/cc055n01/p00013-p00027.pdf, http://www.ncbi.nlm.nih.gov/pubmed/15037918

- Thermal degradation of hair. I. Effect of curling irons:http://journal.scconline.org/pdf/cc1998/cc049n04/p00223-p00244.pdf

- Progressive hair straightening using an automated flat iron: function of silicones: http://www.ncbi.nlm.nih.gov/pubmed/23578835
"Irreversible straightening of curly hair was observed and depended on the temperature and the number of cycles. The birefringence data suggested that the straightening was related to a gradual decrease of the microfilament organization. Silicone treatment did not significantly affect the course of microfilament denaturation, but it improved the quality of straightening. It enhanced the fiber alignment under the gliding action of the iron. Progressive thermal straightening may be a promising method to achieve permanent smoothing of curly hair without chemical treatment. Ironing at the onset temperature (∼154°C), before substantial disulfide bond scission occurred, seemed to be a good compromise between process speed, straightening performance, and hair integrity (i.e., reduced loss of cross-linking)."

- The effect of various cosmetic pretreatments on protecting hair from thermal damage by hot flat ironing:
http://journal.scconline.org/pdf/cc2011/cc062n02/p00265-p00282.pdf, http://www.ncbi.nlm.nih.gov/pubmed/21635854

How Hot is Too Hot? Discussion: http://science-yhairblog.blogspot.ca/2012/02/how-hot-is-too-hot-for-healthy-hair.html
"It was notable that when hair was wetted in a solution containing 2% glycerin or propylene glycol instead of plain water, the cracks did not develop. But “conditioning agents” such as Polyquaternium-11, Cetrimonium chloride, and Stearylkonium chloride did not prevent cuticle cracking. Triglycerides, silicones, mineral oils and petrolatum also did not prevent cracking. The protein polymer, hydrolyzed wheat protein polysiloxane copolymer was found to prevent cuticle cracking. Other proteins and conditioners were not tested. Other testing has demonstrated that P/DMAPA Acrylates Copolymer and Polyquaternium-55 have good heat-protecting qualities."

dancingfrog

March 17th, 2016, 08:18 PM

I wish I had a firm enough grasp on chemistry to understand many of these. Attempts to explain in lay terms would be greatly appreciated!

dancingfrog

mary*rose

March 17th, 2016, 09:32 PM

I wish I had a firm enough grasp on chemistry to understand many of these. Attempts to explain in lay terms would be greatly appreciated!

dancingfrog

Haha there's a whole lot of articles on this thread :) Which specifically do you want help with first?

pinutzz

March 18th, 2016, 06:09 AM

Meteor, the hair drying study you cite is a little controversial. Here is a quote about it from the science-y hair blog (http://science-yhairblog.blogspot.ch/2014/10/huh-air-drying-is-bad-for-hair.html):

What would be a convincing result? I think a similar test would need to be done on hair from multiple donors, including a variety of hair widths (fine/medium, coarse, very coarse), including curly and kinking and coily (type 4) hair. A more convincing sample size (to me) would be about 3-5 of each of these. A result you can replicate in a variety of specimens is a result you can really get behind! If most hairs showed the same effect from air drying but not from blow-drying, then we can make some real conclusions. But we still wouldn't know the actual implications of the so-called damage. Maybe that's not structural damage at all. Maybe it's normal. It's not as though hair is meant to last forever.

pinutzz

March 18th, 2016, 06:16 AM

languagenut

March 18th, 2016, 10:01 AM

Does this imply that taking hour-long showers is bad for my hair? :bigeyes:

lapushka

March 18th, 2016, 11:50 AM

Does this imply that taking hour-long showers is bad for my hair? :bigeyes:

Hour-long showers?!

languagenut

March 18th, 2016, 12:26 PM

Hour-long showers?!

I know, I'm weird. But the warm water is so relaxing, I lose track of time, and mostly my hair just never feels clean enough for my satisfaction, so I keep trying to rinse it more, until I give up. Lately though I've been trying to keep it to half an hour regardless of how I feel about my hair. It always looks fine after it dries anyway.

lapushka

March 18th, 2016, 12:29 PM

I know, I'm weird. But the warm water is so relaxing, I lose track of time, and mostly my hair just never feels clean enough for my satisfaction, so I keep trying to rinse it more, until I give up. Lately though I've been trying to keep it to half an hour regardless of how I feel about my hair. It always looks fine after it dries anyway.

Good for you, for bringing it back to half an hour. What a waste of water, though!

meteor

March 18th, 2016, 03:00 PM

Lets say we draw the conclusion from the paper that using a combination of dryer on low heat and air drying is a good compromise between mechanical and heat damage from the dryer and CMC layer damage from air drying.
Is it better to use the dryer at the beginning of the process when the hair is really wet or at the end when the hair is damp - but for a much longer period of time? I think this paper definitely has potential for a follow up study.

^ Definitely! :agree: Drying should be both heat-free and fast.
Also, let's not forget the importance of movement (as long as it's not aggressive head-banging -> that might lead to mechanical damage) and aerating those strands, spreading them out, for speeding up the air-drying process:

A hysteresis in heat dried hair: http://journal.scconline.org/pdf/cc1981/cc032n01/p00027-p00036.pdf
"Work with tresses revealed slower and more variable rates [of drying time] compared with single fibers. This may arise from changes in heat transfer caused by neighboring fibers, and their different relative orientations in different tresses." (from p. 28 )

And also blotting hair with highly absorbent materials (micro-fiber, for example) helps, of course, and is probably non-damaging (as long as it's not rubbed/wrung out -> that could lead to mechanical damage).
Stuff like replacing T-shirts as they get soaked, drying hair in half-ups (and changing sections), fanning out sections (by lifting and dropping strands here and there), drying next to a heater and a fan... - all of this helps compared to damp-bunning which keeps hair wet for a long time.

I think that stuff like washing and drying being a little bit damaging to fiber is very normal - after all, fine silk is also preserved better if it's hidden in a drawer rather than washed and dried in a dryer every day. And no/low heat is obviously better for preserving silk and other fibers better, as well. Organic fiber like hair is very resilient but not indestructible. ;)

dancingfrog, please let us know which terms you'd like us to help you with! :thumbsup:

lunasea

March 18th, 2016, 09:39 PM

This is like- the most AWESOMEST thread ever!! Thank you meteor. I've only read two of the articles and have learned so much already it's not even funny. I just subscribed and I don't usually do that to threads but I know that I will be coming here again and again.

Arctic

March 19th, 2016, 07:08 AM

Ok I did a summary from the article, as I promised. It's quite precise, I hope not too much so, as this is not a Open Access article. I tried to write on a more general level, and I hope this is understandable text for everybody. Throw me a question if something isn't clear, and I'll try to answer (but cannot promise I'll be able to).

***

Nudging hair shedding by antidandruff shampoos. A comparison of 1% ketoconazole, 1% piroctone
olamine and 1% zinc pyrithione formulations

Researchers: C. Piérard-Franchimont, V. Goffin, F. Henry, I. Uhoda, C. Braham and G. E. Piérard, from Department of Dermatopathology, UniversityMedical Center Sart Tilman, B-4000 Lie'ge, Belgium.

International Journal of Cosmetic Science, 2002: Oct; 24(5): 249-56.
doi: 10.1046/j.1467-2494.2002.00145.x.

First of all this study took as given facts, based on previous studies, that there is a correlation between dandruff/seborrhoeic dermatitis and androgenic hair loss, and that dandruff (no inflammation) and seborrhoeic dermatitis (inflammation is present) are variations of the same cause, a yeast called Malassezia. Their starting assumption was, that dandruff can cause other issues than just flaking; it can cause, for example, skin becoming more oily, thinning hair (telogen effluvium), less hairs in a growth phase (anagen), and thinner individual hair shafts.

The starting arrangements for the study were the following. 150 males from 18 to 65 years old were chosen to the test group, all of them suffered from dandruff and/or seborrhoeic dermatitis, and also had male hormone related balding issues. The subjects were asked to commit to using a dandruff shampoo 2-3 times a week for the 6 months period.

Data was gathered right before the test period started, to be used as base line to which to compare the results. Later the exactly same tests were performed at 4 and 6 months mark.

The subjects were divided into 3 groups, 50 men in each, and each group were given one of the following anti-dandruff shampoos, all in 1% concentration of the active ingredient:

(1) Ketoconazole shampoo 1% (=KTZ)
(2) Piroctone Olamine shampoo 1% (=PTO)
(3) Zink pyrithione shampoo 1% (=ZPT)

No control group of bland shampoo was used. Each of these ingredients are well known to be able to help with dandruff/seborrhoeic dermatitis. The researchers broke down their study into different sub-questions, and wanted to see, how each ingredient would affect to the following issues:

(1) effects on dandruff/seborrhoeic dermatitis (wasn't a main interest).

(2) hair shedding quantity during shampooing.

(3) hair density on the top of the head (photographs always from same spot).

(4) the ratio of anagen hairs (hairs in growth phase of their cycle) compared to resting and shedding phase hairs.

(5) the average hair diameter, measured near roots (=newly grown hair), and lastly...

(6) the sebum excretion rate (= SER), which means the amount of sebum scalp has produced after one hour from through cleansing.

They noticed several interesting things:

(1) No side effects were found.

(2) Dandruff/seborrhoeic dermatitis was reported having been healed after 4-6 weeks on all participants, and on all shampoo groups.

(3) There was no significant effect on hair density on any shampoo groups.

(4) All shampoo groups saw significant increase of anagen hairs (from 30 to 40 % of the participants, PTO shampoo leading the way) and less shedding when washing hair.

(5) On KTZ and PTO groups, the hair shaft diameter of newly grown hair increased, ZPT did not give such effect. They did not measure from other spots of the hair shafts, than near the roots. PTO was again leading, and 34% of the PTO using participants had their hair shaft diameter increase 10% or more (28% in KTZ group). This is possibly caused by increased number of keratin producing cells inside the follicles.

In theory a 10% of increased shaft diameter translates into 20% of more volume.

(6) ZPT group saw significant (74% of participants) decrease of hair shaft diameter, while the other groups had noticeably smaller percentage of such cases.

(7) Sebum levels decreased in KTZ and PTO groups (i.e. scalp became less oily), where-as the ZPT group experienced more oily scalp than the base level had been.

When calculating all the data, the researchers found that increased oiliness (SER) seemed to correlate with thinner individual hairs, and on the flip side of coin, decreased oiliness seemed to correlate with thickening of individual hairs (new growth). SER did not seem to correlate with the proportion of anagen hairs. However, there seemed to be correlation between hair shaft diameter and anagen hair proportion, which makes sense when we think about the miniaturization of the hairs with male pattern baldness.

All of these shampoos were able to “improve the anagen to telogen ratio”, by increasing anagen hairs and reducing shedding during shampooing. The increased anagen phase hairs could also be expressed with a negation, by “increasing delayed teloptosis”, postponing the telogen (shedding) phase of large number of hairs. Any of the findings couldn't be explained with the anti-dandruff effects of the shampoos alone, so there are other factors in work too.

In the end they state that none of this should be taken as a universal fact, and that many new questions were risen and many aspects were left outside of this study (like possible seasonal shedding, hormonal changes including DHT levels). They highlight that the effects of the levels of sebum on hair shaft thickness will remain under debate.

***

I will also link to the discussion we had a while ago in another thread about this article/subject, without having seen other than the abstract at the time.

Previous discussion can be seen here: http://forums.longhaircommunity.com/showthread.php?t=136429
Abstract can be seen here: http://www.ncbi.nlm.nih.gov/pubmed/18498517

Now having read the whole article, when it comes to the hair shaft thickening effect, this research indeed implies that it is the new growth, that happens on the level of living cells inside hair follicles, that is affected by these shampoos, and not just "temporary beefing up the hair shafts" like I assumed before. It is also very clear why many people suffering from male hormone related hair loss have started to regularly use these shampoos. This study did mention in passing DHT and it's effects on male pattern baldness, but this study did not observe that aspect of hair loss.

Piroctone olamine shampoo out-performed the other two, ketoconazole being second, and zinc pyrithione being worse, when it comes to all these things this research was measuring.

One thing that is unclear to me: if shedding (during shampoo) decreased and the anagen hair ration increased, why didn't density increase? Shedding during other times than the 3 shampooings they tested in the 6 month period was not studied.

Very interesting all and all. If there is one thing to take home from this article, it's that if one has dandruff or seborrhoeic dermatitis, it's worth to take care of with medicated shampoo as soon as possibles, otherwise it might have wide range of negative effects on one's hair/scalp.

Arctic

March 19th, 2016, 08:31 AM

On personal level I have started to wonder even more, whether my hair type change to thicker strands has been, at least partially, an effect of piroctone olamine. I can't remember anymore if the time frames match exactly, but I do know that it was around the same-ish time (maybe few years before at most) that I started to use my trusty piroctone olamine shampoo regularly, and then noticed the hair type change. The hair type change, that I noticed about 8+ years ago, 8,5-ish years ago. I think I already used this shampoo then, I don't think I've used it more than a decade, though. So the two do slip into "eerily" same time frame.

Interesting. I have been having this idea in my mind a longer while now, but reading this article made it feel even more possible.

meteor

March 19th, 2016, 11:59 AM

^ Excellent summary! :applause Thank you so very much for sharing, Arctic! :flowers: (I've linked your summary to the index under "10. Hair Loss (Alopecia)".)
I knew a bit about the Ketoconazole and hair shedding connection (Ketoconazole Shampoo: Effect of Long-Term Use in Androgenic Alopecia: http://vipadenievolos.ru/files/research/ketokonazole/Ketoconazole_Shampoo_Study.pdf and Comparative Efficacy of Various Treatment Regimens for Androgenetic Alopecia in Men: http://onlinelibrary.wiley.com/doi/10.1111/j.1346-8138.2002.tb00314.x/abstract;jsessionid=0A3A8B11744B50FE780EF853D328AD 0E.f04t01), but Piroctone Olamine was new to me. Great stuff! :thumbsup:

I'm also surprised to see that zinc pyrithione shampoo increased oiliness, despite the fact that it does combat dandruff (The effects of a shampoo containing zinc pyrithione on the control of dandruff: http://www.ncbi.nlm.nih.gov/pubmed/3158327; Dandruff has an altered stratum corneum ultrastructure that is improved with zinc pyrithione shampoo: http://www.ncbi.nlm.nih.gov/pubmed/11712036; Dandruff/seborrhoeic dermatitis is characterized by an inflammatory genomic signature and possible immune dysfunction: transcriptional analysis of the condition and treatment effects of zinc pyrithione: http://www.ncbi.nlm.nih.gov/pubmed/22670617).
We can find zinc pyrithione in many anti-dandruff shampoos (Head & Shoulders, Clear Scalp Hair Therapy, etc...), though this ingredient (at 1%) was shown to be inferior to ketoconazole (at 2%) for fighting dandruff:
A multicenter randomized trial of ketoconazole 2% and zinc pyrithione 1% shampoos in severe dandruff and seborrheic dermatitis: http://www.ncbi.nlm.nih.gov/pubmed/12476017

Arctic

March 19th, 2016, 12:21 PM

Thank you meteor! I was especially interested in this article, as I am a long time user of piroctone olamine. I read somewhere that it's not very common ingredient in North America, but here in Finland it's pretty common.

I'll have to glance through the first article you linked to above, about long term ketoconazole use. I wonder if there is a study of long term piroctone olamine use?

I too was surprised by the zink pyrithione results.

What is also interesting, referring to the older thread I linked to where we had discussed about this study, to learn that piroctone olamine and ketoconazole are possibly able to create more keratin producing cells inside follicles. Are the effects lasting when these shampoos are stopped? Does the added keratin bulk go to the cortex or to the cuticles or everywhere? If these ingredients would help making cuticle layers stronger, then it might help grow long hair by making hairs more resilient, plus of course the lessened shedding and incresed growth phase hair ratio (versus resting and shedding phase hairs) wouldn't be half bad either.

meteor

March 19th, 2016, 01:05 PM

lunasea, I'm so happy you like it! And thank you so much! :flowers:

What is also interesting, referring to the older thread I linked to where we had discussed about this study, to learn that piroctone olamine and ketoconazole are possibly able to create more keratin producing cells inside follicles. Are the effects lasting when these shampoos are stopped? Does the added keratin bulk go to the cortex or to the cuticles or everywhere?

Yes, that would be great to know, Arctic! :agree: And that would be pretty easy to measure, if they did a study on it... :hmm:
I wonder, since you used piroctone olamine regularly and noticed clearly thickened strands, maybe it would be possible for you to check your shed strands (just by feel or with a magnifying glass might be enough) if there was visible thickening or vice versa thinning of strands (if you stopped using it), assuming hair grows about 1 cm a month? I definitely notice variation in thickness of strands (when I'm very healthy vs. had nutritional deficiencies, health issues) - the strands do not always have the same strand thickness as they grow (at least it's possible to notice it on my long strands). Does anybody else notice this?

Oh, and back to that study that we were discussing on previous page (Hair Shaft Damage from Heat and Drying Time of Hair Dryer: http://pmcc.web-t.cisti.nrc.ca/articlerender.cgi?accid=PMC3229938), I think a problem in the study design vs. the conclusions was that the hair that was washed ("using 1% (w/w) sodium dodecyl sulfate, and then thoroughly rinsed with tap water") and dried daily for 30 days was just separate untreated tresses, not hair on people. If the hair was still connected to scalp, it could still accumulate a bit of sebum to protect it from this daily washing and drying process. But, the way the study was set up, it shows you what happens to natural hair on extensions/wigs, if it's washed daily (it's not recommended to wash wigs/extensions often!), not hair still attached to scalp - which obviously gets a better chance to get oily.
Not to mention that in this study there were no pre-treatments, no oiling sessions, no conditioning at all, no styling products - so no product "barrier"... Not really what typically happens with daily washing... :hmm: Basically, the hair was washed when it wasn't dirty or oily and didn't need to be washed - and we already know not to over-wash hair.
So, the surfactants would affect already cleansed hair differently compared to how they would affect dirty, oily hair (i.e. probably stripping it in the former case and simply cleansing it in the latter case).

Guys, does anybody know if we might potentially have problems with quotations in the future, if this thread gets archived? :hmm: I know when I search old, archived threads, I sometimes can "revive" it by clicking on the name of the thread, but other times - it's impossible and one can't see any quotes in {QUOTE}{/QUOTE} type of format or any links that were layered under words (instead of simple URL text) or any "reply to" quotes. Does anybody know how to avoid this issue or, generally, how this stuff works, so we don't lose any info? Thank you! :flower:

Arctic

March 19th, 2016, 01:18 PM

I'm unlikely to stop piroctone olamine shampoo, as it changed my life literally. I have very sensitive scalp, and suffered from (TMI) bad, long term dandruff etc, until I found the piroctone olamine shampoo I have been religiously using since it was launched. It cured me from those very unpleasant problems, and apart some shorter phases where my scalp got irritated (like it has been on and off during the past year, and like it was as a new LHC member when I experimented a lot) to a point I needed medical strength (2%) ketoconazole shampoo (the piroctone olamine shampoo I use is just a market brand, not medical level), it has been working constantly, the effect has not diminished. I haven't really had any dandruff since I started using this (again apart from few washing method/hair product experiments, the latest was last autumn when I tried shampoo bars, which caused dandruff. But it cleared off after stopping shampoo bars and increasing PTO shampoo usage back to normal). I love that stuff! :inlove:

I can't see that kind of variation in hair thickness as you refer to, but I do have lot of wiry hairs which have uneven surface structure (also kinky hairs), but those are different thing. I was able to see my hairs under microscope several years ago (I was already LHC member then), and can't remember seeing that kind of diameter variation.

***

I have never seen that kind of issue with archived threads. And I don't think they'll archive active threads, do they? Probably better to ask mods, I don't have a clue. :(

meteor

March 19th, 2016, 01:56 PM

^ That's awesome! :D So you've been using it for many years regularly then, rather than as a temporary solution? :) That's so great to know that this stuff is safe to use without breaks! :thumbsup: Yes, I don't see this ingredient in grocery store products locally - but some (harder to find and more expensive) medicated shampoos do contain it. So happy to hear it's a different situation in Finland! :cheer:
Could you please share ingredients list or name of that product - it sounds like something I should search (at least something with similar INCI) when I get scalp flare-ups.

I think you are right: active threads shouldn't get archived, I was just thinking about this for future reference. Not sure how to contact a mod directly: is there a place to post and wait in line, since it's not something urgent, or does one need to PM somebody? :hmm:

Arctic

March 19th, 2016, 02:12 PM

For mod contacting, site support forum, this email address tlhcstaff@gmail.com, or PMing Gumball (http://forums.longhaircommunity.com/member.php?u=12653) or other mods (http://forums.longhaircommunity.com/showgroups.php) are probably the quickest ways.

Yes I've been using piroctone olamine containing shampoo almost non-stop for years and years, close to a decade. Looks weird to see it written like that!

The magical shampoo is Finnish XZ brand, their Suklaa Vanilja (chocolate vanilla) shampoo. It's a common market brand of relatively cheap products. I have seen piroctone olamine added in other market brands but also in brands only sold in pharmacies. My only complain with this shampoo is, that it contains proteins, which my hair isn't too fond of.

XZ Suklaa Vanilja shampoo's INCI:

Aqua
Sodium Laureth Sulfate
Lauryl Glucoside
Cocamidopropyl Betaine
Glycol Distearate
PEG-15 Cocopolyamine
Hydrolyzed Wheat Protein
Laurdimonium Hydroxypropyl Hydrolyzed Wheat Protein
Polyquaternium-10
Cocoa (Theobroma Cacao) extract
Propylene Glycol
Piroctone Olamine
Panthenol
Laureth-4
Wheat Amino Acids
Sodium Benzoate
Citric Acid
Parfum
Sodium Chloride
Hexyl Cinnamal

No percentage of piroctone olamine is given, and I'm sure it's relatively low concentration, this being a market brand, and it is not even marketed as dandruff shampoo but for irritated scalps, as a calming shampoo. This shampoo was literally the first one since my teen years that, with few washes, washed away the embarrassing problem I had had for so long. :inlove:

meteor

March 19th, 2016, 02:28 PM

mary*rose

March 19th, 2016, 02:38 PM

Wow Arctic that's awesome! I wish I had known about that in high school... I had such awful dandruff.

That article has made me wonder about a couple of things. I'm also surprised by the fact that zinc increases oiliness, and I wonder what the consequences of that are. What I'm concerned about is that increased oiliness is correlated with thinner hair. Is this oil production or oil presence? Because that might bode poorly for me, as I have quite a bit of sebum on my hair. It is natural oil that affects the thickness of hair? Or do other oils also affect it?

Also, an interesting (but not highly important) fact to note is that sodium dodecyl sulfate is the same exact thing as sodium laurel sulfate. Same chemical compound, same function/use, etc. I noticed you used "sodium dodecyl sulfate," meteor, and I wasn't sure if you knew! I just learned about the terms this semester in biochemistry.

I just got the old article about sebum production delivered to my library account, so I'll be back at some point with a summary of that!

Arctic

March 19th, 2016, 03:34 PM

^ Thanks a lot, Arctic! :flowers: That's great to know for future reference. Looks like a really nice product, indeed! :D
Oh, and I've asked a mod for help! Thank you so very much for explaining how to do it! :thumbsup:

Hope the mods will be able to help!

Yes this and many other XZ products are pretty nice, my go to brand for sure. Unfortunately to my knowledge not available outside Finland.

Wow Arctic that's awesome! I wish I had known about that in high school... I had such awful dandruff.

That article has made me wonder about a couple of things. I'm also surprised by the fact that zinc increases oiliness, and I wonder what the consequences of that are. What I'm concerned about is that increased oiliness is correlated with thinner hair. Is this oil production or oil presence? Because that might bode poorly for me, as I have quite a bit of sebum on my hair. It is natural oil that affects the thickness of hair? Or do other oils also affect it?

Also, an interesting (but not highly important) fact to note is that sodium dodecyl sulfate is the same exact thing as sodium laurel sulfate. Same chemical compound, same function/use, etc. I noticed you used "sodium dodecyl sulfate," meteor, and I wasn't sure if you knew! I just learned about the terms this semester in biochemistry.

I just got the old article about sebum production delivered to my library account, so I'll be back at some point with a summary of that!

I'm looking forward to your sebum article summary!

You know I've also seen it mentioned, that also Sodium Coco Sulfate is approximately same as Sodium Lauryl Sulfate, though some sources say it isn't. But I've started to think of it as a greenwashed Sodium Lauryl Sulfate. Interesting to hear about sodium dodecyl sulfate too.

I'm glad you liked the summary! I can warmly recommend piroctone olamine for dandruff issues, both based on my own experience, and the study I made the summary of, but also having read it being successful and well liked ingredient.

This study measured oiliness with a machine they called, IIRC, Sebumeter (LOL!!! :laugh:). They measured the sebum from front hairline area of the scalp, 1 hour after scalp/skin was cleaned with strong alcohol which removed all sebum. So they measured how much oil was produces during that time (how oily the skin became during that hour) - or how they put it, "the sebum excretion rate (SER)". So it was more about how much oil the follicles push out rather than about oil being present, what they concentrated on. How that translates into real life though, I don't know. In real life they go hand in hand: lot of oil secreted --> lot of oil present.

They also only measured the sebum (and all the other variables they measured) only 3 times total: one before, one after 4 months, and one after full 6 months. That's very few times only, and probably so many things could have effects on the sebum producing levels that 3 times measuring will not catch. They didn't research other oils than sebum.

They did "warn" in the end, that the oil producing rate and it's effect on hair shaft thickness remained under debate and would need more studying.

The zink pyrithione really was a surprise. It did well as an anti-dandruff medication, and it reduced shedding when shampooing (which again was only tested 3 times, so not very much) and increased the hairs that are in growth (anagen) phase in comparison to shedding and resting hairs. It was only the issue that sounded like a vicious cycle that seemed problematic: possibly causing more oil, possibly making strands thinner, which is possibly caused by increased oil. Of course there ARE people who would love to have thinner hair strands, so who knows, maybe this ingredient could help them?

The article used many diagrams to explain things and calculations and prevalences but I didn't really try to look into those much. I'm not educated in reading that kind of diagrams.

Hmm, anyone want to plan an LHC poll about scalp oiliness and hair strand thickness???

mary*rose

March 19th, 2016, 03:53 PM

"Sebumeter" HA. I love that. "Let me just get out my hand-dandy Sebumeter, patent pending..." :lol:

The limited number of tests might be limiting; you're right.

So it's more about sebum production, not presence. Then some process that produces sebum in our cells would have to be connected to the processes that contribute to the thickness of hair. Interesting! That sounds like it would be a complicated study. Haha how many pathways can you connect?

~~~

I like the poll idea! Perhaps people who kept track of the thickness of their hair through transition phases?

meteor

March 19th, 2016, 03:59 PM

Sounds great! I'm looking forward to hearing about that study, mary*rose! :cheer: Yes, Sodium Lauryl Sulfate (SLS) and Sodium Dodecyl Sulfate (SDS) are exactly the same, I was just quoting that study directly, using their own nomenclature for this surfactant. ;) If somebody is interested, here's more on this ingredient: https://pubchem.ncbi.nlm.nih.gov/compound/Sodium_dodecyl_sulfate#section=Top

As for Sodium Coco Sulfate, it is very similar to Sodium Lauryl Sulfate, except that, rather than isolate a single fatty acid from the coconut or other oil (lauric acid to ultimately create sodium lauryl sulfate with), they use more fatty acids from the original coconut oil and these are all turned into sulfates. So instead of using only lauric acid and reacting it with sulfuric acid, and then again with sodium carbonate to create sodium lauryl sulfate, they use a blend of fatty acids (lauric, PLUS caprilyc, capric, oleic, stearic, myristic, palmitic... - or at least some of them) from the coconut oil, react them all with sulfuric acid, then sodium carbonate, to create sodium coco sulfate. It's pretty much the same (or very similar) in its performance and irritation potential and all that.

I.e., to recap:
- Coconut oil (or other oils) -> isolate lauric acid -> .......... -> sodium lauryl sulfate
- Coconut oil -> isolate lauric acid, myristic acid, palmitic acid, etc -> ......... -> sodium coco sulfate (a bit like if it were a blend of sodium lauryl sulfate, sodium oleic sulfate, sodium stearyl sulfate etc)

Arctic

March 19th, 2016, 04:05 PM

meteor

March 19th, 2016, 07:20 PM

^ I really love the poll idea. :thumbsup: The only issue I foresee is how people can measure their strand thickness and degree of oiliness. It's all relative and a lot depends on the person's perceived norm unless a pretty specific measurement is given (and it should be an easy enough measurement)... :hmm: For example, a specific measurement could be something general like:

- Oily scalp - you need to wash daily,
- Dry scalp - you can wash less frequently than once a week,
- Normal scalp - something in between.

- Thick strands - comparable to toothbrush bristles,
- Thin strands - floaty, almost invisible and hard to feel between fingers,
- Normal strands - something in-between.

I suspect some people will say that their oiliness and degree of strand thickness changed at different times... not sure how to bring that dynamic element into the poll options...? Any ideas? :hmm:

By the way, while we are on the subject of polls: I remember I started a poll to test out that idea that curly hair tangles less than straight hair (according to that study by J.-B. Masson (http://scitation.aip.org/content/aapt/journal/ajp/75/8/10.1119/1.2733683)) and the results seem to contradict Masson's study, so far... But we most definitely need more people to answer the poll for it to start becoming a little bit representative (need more data):
Does your hair tangle more when it's straightened/curled?: http://forums.longhaircommunity.com/showthread.php?t=135584&highlight=curly+tangles

Oh, and, just a heads-up: I'll be splitting an old post with links on Alopecia-related studies (and posting links to studies on Androgenetic Alopecia here in just a couple minutes), because I've exceeded the limit of characters in the old post I've been updating, sorry about that!... :oops:

meteor

March 19th, 2016, 07:22 PM

10. Hair Loss (Alopecia) BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

10.1. Androgenetic Alopecia - PART I (Male or Female Pattern Baldness):

- Progression of hair loss in men with androgenetic alopecia (male pattern hair loss): long-term (5-year) controlled observational data in placebo-treated patients: http://www.ncbi.nlm.nih.gov/pubmed/18573713

- Photographic documentation of hair growth in androgenetic alopecia: http://www.ncbi.nlm.nih.gov/pubmed/9238329/

- Female patients complaining about hair loss: documentation of defective scalp hair dynamics with contrast-enhanced phototrichogram: http://www.ncbi.nlm.nih.gov/pubmed/16626380

- Thickness, medullation and growth rate of female scalp hair are subject to significant variation according to pigmentation and scalp location during ageing: http://www.ncbi.nlm.nih.gov/pubmed/14965792

- Contrast enhanced phototrichogram pinpoints scalp hair changes in androgen sensitive areas of male androgenetic alopecia: http://www.ncbi.nlm.nih.gov/pubmed/12060475

- Comparative Efficacy of Various Treatment Regimens for Androgenetic Alopecia in Men: http://onlinelibrary.wiley.com/doi/10.1111/j.1346-8138.2002.tb00314.x/abstract;jsessionid=0A3A8B11744B50FE780EF853D328AD 0E.f04t01

- Group I (30 patients) was administered oral finasteride, -> (# 3)

- Group II (36 patients) was given a combination of finasteride and topical minoxidil, -> (# 1 best results)

- Group III (24 patients) applied minoxidil alone and -> (# 4)

- Group IV (10 patients) was administered finasteride with topical ketoconazole. -> (2nd best)

- Male pattern baldness: http://www.ncbi.nlm.nih.gov/pubmed/10923949

- Androgenetic alopecia: an evidence-based treatment update: http://www.ncbi.nlm.nih.gov/pubmed/24848508

- Androgenetic alopecia and current methods of treatment: http://www.ncbi.nlm.nih.gov/pubmed/15818439

- Androgenetic alopecia: an update: http://www.ncbi.nlm.nih.gov/pubmed/23974579

- Management of androgenetic alopecia: http://www.ncbi.nlm.nih.gov/pubmed/10461639

- Androgenetic alopecia: combining medical and surgical treatments: http://www.ncbi.nlm.nih.gov/pubmed/14641340

- Hair restoration approaches for early onset male androgenetic alopecia: http://www.ncbi.nlm.nih.gov/pubmed/23992164

- Guidelines for the management of androgenetic alopecia (2010): http://www.ncbi.nlm.nih.gov/pubmed/22171995

- Treatments for androgenetic alopecia and alopecia areata: current options and future prospects: http://www.ncbi.nlm.nih.gov/pubmed/11217871

- Nonsurgical therapy for hair loss: http://www.ncbi.nlm.nih.gov/pubmed/24017975

- Pattern hair loss in men: diagnosis and medical treatment: http://www.ncbi.nlm.nih.gov/pubmed/23159182

- Novel agents for the treatment of alopecia: http://www.ncbi.nlm.nih.gov/pubmed/9859915/

Minoxidil:

- Minoxidil: mechanisms of action on hair growth: http://www.ncbi.nlm.nih.gov/pubmed/14996087

- Minoxidil use in dermatology, side effects and recent patents: http://www.ncbi.nlm.nih.gov/pubmed/22409453

- A randomized clinical trial of 5% topical minoxidil versus 2% topical minoxidil and placebo in the treatment of androgenetic alopecia in men: http://www.ncbi.nlm.nih.gov/pubmed/12196747

- A randomized, placebo-controlled trial of 5% and 2% topical minoxidil solutions in the treatment of female pattern hair loss: http://www.ncbi.nlm.nih.gov/pubmed/15034503

- Efficacy of 5% minoxidil versus combined 5% minoxidil and 0.01% tretinoin for male pattern hair loss: a randomized, double-blind, comparative clinical trial: http://www.ncbi.nlm.nih.gov/pubmed/17902730

- Use of topical minoxidil therapy for androgenetic alopecia in women: http://www.ncbi.nlm.nih.gov/pubmed/8225725

- Interventions for female pattern hair loss: http://www.ncbi.nlm.nih.gov/pubmed/22592723

- Effect of minoxidil on hair growth in androgenic alopecia in women: http://www.ncbi.nlm.nih.gov/pubmed/12474572

- Topical minoxidil therapy for hair regrowth: http://www.ncbi.nlm.nih.gov/pubmed/3311578

- Hair growth effect of minoxidil: http://www.ncbi.nlm.nih.gov/pubmed/11915519

- Minoxidil-induced hair growth is mediated by adenosine in cultured dermal papilla cells: possible involvement of sulfonylurea receptor 2B as a target of minoxidil: http://www.ncbi.nlm.nih.gov/pubmed/11886528

- Hair follicle biology and topical minoxidil: possible mechanisms of action: http://www.ncbi.nlm.nih.gov/pubmed/3319729

- Minoxidil upregulates the expression of vascular endothelial growth factor in human hair dermal papilla cells: http://www.ncbi.nlm.nih.gov/pubmed/9580790

- The potential role of minoxidil in the hair transplantation setting: http://www.ncbi.nlm.nih.gov/pubmed/12410672

- Hair regrowth. Therapeutic agents: http://www.ncbi.nlm.nih.gov/pubmed/9589208

meteor

March 19th, 2016, 07:52 PM

10. Hair Loss (Alopecia) BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

10.1. Androgenetic Alopecia - PART II (Male or Female Pattern Baldness):

Finasteride:

- Efficacy and safety of finasteride therapy for androgenetic alopecia: a systematic review: http://www.ncbi.nlm.nih.gov/pubmed/20956649

- Advances in the treatment of male androgenetic alopecia: a brief review of finasteride studies: http://www.ncbi.nlm.nih.gov/pubmed/11399540

- Use of finasteride in the treatment of men with androgenetic alopecia (male pattern hair loss): http://www.ncbi.nlm.nih.gov/pubmed/12894990

- The effects of finasteride on scalp skin and serum androgen levels in men with androgenetic alopecia: http://www.ncbi.nlm.nih.gov/pubmed/10495374 (doses of finasteride as low as 0.2 mg per day maximally decreased both scalp skin and serum DHT levels)

- Efficacy and tolerability of finasteride 1 mg in men aged 41 to 60 years with male pattern hair loss: http://www.ncbi.nlm.nih.gov/pubmed/12695131

- Finasteride in the treatment of men with androgenetic alopecia. Finasteride Male Pattern Hair Loss Study Group: http://www.ncbi.nlm.nih.gov/pubmed/9777765

- Evaluation of efficacy and safety of finasteride 1 mg in 3177 Japanese men with androgenetic alopecia: http://www.ncbi.nlm.nih.gov/pubmed/21980923

- Finasteride, 1 mg daily administration on male androgenetic alopecia in different age groups: 10-year follow-up: http://www.ncbi.nlm.nih.gov/pubmed/21910805

- A randomized, active- and placebo-controlled study of the efficacy and safety of different doses of dutasteride versus placebo and finasteride in the treatment of male subjects with androgenetic alopecia: http://www.ncbi.nlm.nih.gov/pubmed/24411083

- Finasteride treatment may not prevent telogen effluvium after minoxidil withdrawal: http://www.ncbi.nlm.nih.gov/pubmed/12975176

- Minoxidil vs finasteride in the treatment of men with androgenetic alopecia: http://www.ncbi.nlm.nih.gov/pubmed/12975174

- Improvement in androgenetic alopecia (stage V) using topical minoxidil in a retinoid vehicle and oral finasteride: http://www.ncbi.nlm.nih.gov/pubmed/7492124

- Effects of finasteride (1 mg) on hair transplant: http://www.ncbi.nlm.nih.gov/pubmed/16188178

- Finasteride in the treatment of men with frontal male pattern hair loss: http://www.ncbi.nlm.nih.gov/pubmed/10365924

- Changes in hair weight and hair count in men with androgenetic alopecia after treatment with finasteride, 1 mg, daily: http://www.ncbi.nlm.nih.gov/pubmed/11907500 "finasteride, 1 mg, increased hair weight in men with AGA. Hair weight increased to a larger extent than hair count, implying that factors other than the number of hairs, such as increased growth rate (length) and thickness of hairs, contribute to the beneficial effects of finasteride in treated men."

- Finasteride in the treatment of Japanese men with male pattern hair loss: http://www.ncbi.nlm.nih.gov/pubmed/15319158/

Ketoconazole:

- Ketoconazole Shampoo: Effect of Long-Term Use in Androgenic Alopecia: http://vipadenievolos.ru/files/research/ketokonazole/Ketoconazole_Shampoo_Study.pdf
Summary of the study: (post # 76 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3190148&viewfull=1#post3190148))

- Comparative Efficacy of Various Treatment Regimens for Androgenetic Alopecia in Men: http://onlinelibrary.wiley.com/doi/10.1111/j.1346-8138.2002.tb00314.x/abstract;jsessionid=0A3A8B11744B50FE780EF853D328AD 0E.f04t01

- Reversal of androgenetic alopecia by topical ketoconzole: relevance of anti-androgenic activity: http://www.ncbi.nlm.nih.gov/pubmed/16997533

Piroctone Olamine:

- Nudging hair shedding by antidandruff shampoos. A comparison of 1% ketoconazole, 1% piroctone olamine and 1% zinc pyrithione formulations: http://www.ncbi.nlm.nih.gov/pubmed/18498517
Summary of the study: (post # 103 (http://forums.longhaircommunity.com/showthread.php?t=136845&page=11&p=3192034&viewfull=1#post3192034))

- Efficacy of a piroctone olamine/climbazol shampoo in comparison with a zinc pyrithione shampoo in subjects with moderate to severe dandruff: http://www.ncbi.nlm.nih.gov/pubmed/21272039

Saw Palmetto (Serenoa repens):

- Treatment of male androgenetic alopecia with topical products containing Serenoa repens extract: http://www.ncbi.nlm.nih.gov/pubmed/26010505

- Sensitization to saw palmetto and minoxidil in separate topical extemporaneous treatments for androgenetic alopecia: http://www.ncbi.nlm.nih.gov/pubmed/12423443

- A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia: http://www.ncbi.nlm.nih.gov/pubmed/12006122 (botanically derived 5AR inhibitors, specifically the liposterolic extract of Serenoa repens (LSESr) and beta-sitosterol)

- Alternative formulation for patients with contact reactions to topical 2% and 5% minoxidil vehicle ingredients: http://www.ncbi.nlm.nih.gov/pubmed/10750861

- Comparitive effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year study: http://www.ncbi.nlm.nih.gov/pubmed/23298508

Pumpkin Seed Oil:

- Effect of Pumpkin Seed Oil on Hair Growth in Men with Androgenetic Alopecia: A Randomized, Double-Blind, Placebo-Controlled Trial: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4017725/; Comment: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4396906/

Green Tea:

- Human hair growth enhancement in vitro by green tea epigallocatechin-3-gallate (EGCG): http://www.ncbi.nlm.nih.gov/pubmed/17092697/

mary*rose

March 19th, 2016, 11:29 PM

Thanks Meteor, I've been wondering the coco sulfate a while now. It's on many "green" shampoos. Do you know if it is gentler than lauryl sulfate? More environmentally friendly? Some internet people claim it is, and some say it's as harsh as lauryl sulfate. I haven't been able to findtrustworthy information about it when I searched for it some years ago.

ETA: oops, wood eye! You already said it's as irritant :o

ETA2: mary*rose I also got some laughs of the name Sebumeter :face:

That's very interesting how you put it, the sebum's effect. We'll need to dig out this more!

If you have time, do create the poll. I was thinking something like

fine strands - not oily scalp
fine strands - oily scalp

fine/medium strands - not oily scalp
fine/medium strands - oily scalp

medium strands - not oily scalp
medium strands - oily scalp

medium/coarse - not oily scalp
medium/coarse - oily scalp

coarse strands - not oily scalp
coarse strands - oily scalp

I think 10 is max number of options. I would make it single option poll.

I didn't quite understand what you meant by transitioning? Transitioning phase between what?

^ I really love the poll idea. :thumbsup: The only issue I foresee is how people can measure their strand thickness and degree of oiliness. It's all relative and a lot depends on the person's perceived norm unless a pretty specific measurement is given (and it should be an easy enough measurement)... :hmm: For example, a specific measurement could be something general like:

- Oily scalp - you need to wash daily,
- Dry scalp - you can wash less frequently than once a week,
- Normal scalp - something in between.

- Thick strands - comparable to toothbrush bristles,
- Thin strands - floaty, almost invisible and hard to feel between fingers,
- Normal strands - something in-between.

I suspect some people will say that their oiliness and degree of strand thickness changed at different times... not sure how to bring that dynamic element into the poll options...? Any ideas? :hmm:

By the way, while we are on the subject of polls: I remember I started a poll to test out that idea that curly hair tangles less than straight hair (according to that study by J.-B. Masson (http://scitation.aip.org/content/aapt/journal/ajp/75/8/10.1119/1.2733683)) and the results seem to contradict Masson's study, so far... But we most definitely need more people to answer the poll for it to start becoming a little bit representative (need more data):
Does your hair tangle more when it's straightened/curled?: http://forums.longhaircommunity.com/showthread.php?t=135584&highlight=curly+tangles

Oh, and, just a heads-up: I'll be splitting an old post with links on Alopecia-related studies (and posting links to studies on Androgenetic Alopecia here in just a couple minutes), because I've exceeded the limit of characters in the old post I've been updating, sorry about that!... :oops:

I'm on it! Before I start it, does anyone else have any suggestions for the polls, to get as much input as possible?

meteor there's no need to apologize for providing too much information! :):flower:

pinutzz

March 20th, 2016, 06:44 AM

I like the idea of a poll. I think though that the same amount of sebum will be much more visible in fine straight hair than in curly coarse hair. I am pretty sure you are going to see that people with fine straight hair wash theirs more often - because of the way it looks and not the actual amount of grease. But I guess there is only one way to find out: create the poll!

Arctic

March 20th, 2016, 09:09 AM

These are all good points about the poll.

But first thing I think we need to toss perfectionism. This is a simple LHC poll and not gathering data for a scientific research. It can only have max 10 options and it doesn't allow complex structures. And no matter how detailed the instructions are, people might not follow them, OR are put off by them and won't vote at all, if it's too complex/time consuming.

It needs to be simple for people to actually vote, and there could be very short and sweet instructions, and it might be good to encourage people to write their additional thoughts in the comments too.

The problem that we can't know for sure, if people have typed them selves properly - I don't think there is much to do about that. Other than maybe only asking for those, who feel they are relatively sure about their hair fineness-coarseness level.

Maybe it could be multi-choice after all, since there might be many who, like me, have gone through a hair type change.

The washing frequency and perceived oiliness like was brought up, is also a problem. I have seen people say they have oily hair, yet they wash once a week, which to me sounds contradictory. Some kind of limits about needed washing frequency would then be good. Maybe

oily: washing 7-5 days a week,
normal: washing 4-2 times a week
dry: washing once a week or less

I'm not that great at creating polls though, so I will give you guys free hands on it. My "advice" if someone want's that could be crystallize with 3 points:

- toss perfectionism, polls are supposed to be fun and this is not a scientific research
- avoid too much limits and restrictions and conditions (too complex)
- some guidelines could be useful about how to define these terms

ETA: About the hair typing again, I forgot to write this. I think many people here at LHC who have medium strands, have actually categorized themselves as F strands. I have came to this conclusion because basically all the polls I have seen where fineness-corseness is one variable, there is ALWAYS most votes on F options and often only few C option votes (this being said, I haven't of course seen ALL the polls). Also, while assessing fineness isn't foolproof from photos, I often see photos of hair which to me clearly is not F, yet the person has categorized it as F. I have sometimes even asked them, are they sure they are F and not M.

So either it so happens that most people who grow long hair and join LHC are, in fact, fineys, or fineys like polls more than Ms and Cs, OR there is an err on the F-side of things in the LHC membership base. I think there should be M-voters the most, it being the most common hair type.

ETA2: I did a membership search, and looked how many F, M and C members we have. I didn't include the inbetween types, and of course not everyone has their type visible/chosen.

We have 111 pages of Fs, 128 pages of Ms and measly 18 pages of Cs. Interesting!

meteor

March 20th, 2016, 01:16 PM

Hey guys: I got an update from a mod about quotes. We should be fine! :joy: Phew! That was only the really ancient posts (pre-2008 server crash) that had those problems with URL of quotes and that data would be irretrievable, but we are good to go for future archiving! :cheer:

ETA: About the hair typing again, I forgot to write this. I think many people here at LHC who have medium strands, have actually categorized themselves as F strands. I have came to this conclusion because basically all the polls I have seen where fineness-corseness is one variable, there is ALWAYS most votes on F options and often only few C option votes (this being said, I haven't of course seen ALL the polls). Also, while assessing fineness isn't foolproof from photos, I often see photos of hair which to me clearly is not F, yet the person has categorized it as F. I have sometimes even asked them, are they sure they are F and not M.

So either it so happens that most people who grow long hair and join LHC are, in fact, fineys, or fineys like polls more than Ms and Cs, OR there is an err on the F-side of things in the LHC membership base. I think there should be M-voters the most, it being the most common hair type.

ETA2: I did a membership search, and looked how many F, M and C members we have. I didn't include the inbetween types, and of course not everyone has their type visible/chosen.

We have 111 pages of Fs, 128 pages of Ms and measly 18 pages of Cs. Interesting!

Oh my :bigeyes:, I noticed the exact same thing on the LHC, too! :hifive: - and I remember often thinking to myself: "Hmm, that doesn't look like fine hair to me, maybe the person thinks "coarse" hair is about texture rather than diameter of hair strands? Because those strands are visibly thick and glassy." Anyway, I agree, if people actually saw thickness of 40 microns (fine) vs. 80 microns (coarse), it would be easier to figure that out! ;) Which is why I posted that method with comparing hair strands with book pages and calculating micron ranges from there (http://forums.longhaircommunity.com/showthread.php?t=136858). To me, fine hair is really baby-fine hair, and most adults seem to have significantly thicker strands than that (though they may have had super-fine hair as children).

meteor

March 20th, 2016, 01:31 PM

Oh, and while we are on the subject of fine vs. coarse hair, Chemical and Physical Behavior of Human Hair (awesome book on hair, btw!) has a great table on it:

Human scalp hair and age:

Hair type
Approximate age (years)
Approximate maximum length (cm)
Approximate maximum diameter (microns)

Infant hair (lanugo)
< 1
15
20

Children's hair (primary terminal)
1 to 12
60
60

Adult hair (secondary terminal)
> 13
100
100

Vellus hair
> 30
0.1
4

Source: https://books.google.com/books?id=Xq7hBwAAQBAJ&pg=PA10&lpg=PA10&dq=microns+robbins+cr+chemical+and+physical+behavi or+of+human+hair&source=bl&ots=XNYYhIJ7OX&sig=kHwj0E7rY9dUewvy9OkIn_k7xjc&hl=en&sa=X&ved=0ahUKEwiLreiO_M_LAhVJdz4KHQxLAdQQ6AEIQTAG#v=on epage&q&f=false

There is also a great compilation of 3 separate studies on hair fiber diameter and age in that book.
Summarizing it (these are approximations, because precise numbers weren't clear from the graph), the hair shaft diameters would be around:
Age 2 = ~ 55 - 63 microns
Age 7 = ~ 63 - 73 microns
Age 12 = ~ 68 - 78 microns
Age 17.5 = ~ 73 - 83 microns
Age 25 = ~ 68 - 80 microns
Age 40 = ~ 67 - 81 microns
Age 70 = ~ 77 microns

Link to pages (https://books.google.ca/books?id=Xq7hBwAAQBAJ&pg=PA10&lpg=PA10&dq=microns+robbins+cr+chemical+and+physical+behavi or+of+human+hair&source=bl&ots=XNYYhIJ7OX&sig=kHwj0E7rY9dUewvy9OkIn_k7xjc&hl=en&sa=X&ved=0ahUKEwiLreiO_M_LAhVJdz4KHQxLAdQQ6AEIQTAG#v=on epage&q&f=false) in Chemical and Physical Behavior of Human Hair by Clarence R. Robbins

Arctic

March 20th, 2016, 01:36 PM

It might also be about semantics. Fine sounds valuable, beautiful and lovely, coarse sounds rough, inferior and unpleasant. The terms are taken as value judgements and not signifiers of strand diameter.

Glad to hear I'm not the onlyone who has paid attention to the seeming domination of Fineys over LHC :)

rhosyn_du

March 20th, 2016, 03:08 PM

The washing frequency and perceived oiliness like was brought up, is also a problem. I have seen people say they have oily hair, yet they wash once a week, which to me sounds contradictory. Some kind of limits about needed washing frequency would then be good. Maybe

oily: washing 7-5 days a week,
normal: washing 4-2 times a week
dry: washing once a week or less

I'm not sure basing it on how often people wash will give us a more accurate picture of oily vs. dry than just asking people to self-identify. There are a lot more factors that go into how often people wash than just sebum production (workouts, dirty jobs, how much of a hassle it is to wash/dry their particular head of hair, what level of sebum-y they personally consider "dirty," etc.).

meteor

March 20th, 2016, 03:15 PM

1.2 Chemical Damage: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904):

PART I

- Cuticle damage and the tensile properties of human hair: http://journal.scconline.org/pdf/cc1991/cc042n01/p00059-p00067.pdf
"Oxidation of hair fibers with diperisophthalic acid can produce extensive damage to the cuticle that can be readily observed microscopically. At the same time, no detectable changes in the tensile properties (wet or dry) are detectable. These results are consistent with the hypothesis that the tensile properties of human hair are due primarily to the cortex, with essentially no cuticle involvement, and support the two-phase model of Feughelman that explains the mechanical properties of human hair in terms of its cortical components. Furthermore, these results show clearly that one cannot rely on the tensile properties alone to assess damage to human hair. This study shows that it is possible to produce extensive damage to the cuticle with no detectable changes in the tensile properties of human hair."

- Analysis of structural change in keratin fibers resulting from chemical treatments using Raman spectroscopy: http://www.ncbi.nlm.nih.gov/pubmed/15739182 (reduction, heating and oxidation)

- Failure of intercellular adhesion in hair fibers with regard to hair condition and strain conditions: http://www.ncbi.nlm.nih.gov/pubmed/15386026
"Although adhesion failure in hair fibers can occur inside cells, it occurs more frequently in the cell membrane complex (CMC), often involving the rupture of interlayer bonds. Therefore, a model of the CMC is presented, based on prior research in which we propose interconnecting bonds between the layers to assist in our interpretation of hair-fracturing mechanisms for cuticle chipping, deep transverse cuticle cracks, cracks during heat drying, scale lifting by surfactants, and catastrophic failure. Failure in the wet state generally involves hydrophilic layers, e.g., the contact zone of the CMC or the endocuticle or bonding to these hydrophilic layers, whereas failure in the dry state generally involves bonding between hydrophobic layers, e.g., beta-delta failure. Chemical damage by perms, bleaches, and sunlight, by breaking specific chemical bonds, influences the sites of initial failure and increases the number of routes for crack propagation, leading to more complex fracture patterns."

Bleaching:

- Significant damage of the skin and hair following hair bleaching: http://www.ncbi.nlm.nih.gov/pubmed/20860738
"After bleaching, scanning electron microscopy (SEM) was used to observe that the cuticle scales of the hairs were irregular and lifted. The mechanical properties of the bleached hairs, such as tensile strength and elongation, were slightly different than the untreated hairs."

- Impairment of hair mechanical properties by sun exposure and bleaching treatments: http://www.ncbi.nlm.nih.gov/pubmed/15645109
"Breaking elongation and breaking strength were the main parameters affected by both treatments. Reduction in the breaking strength was observed for the photo-oxidized and bleached hair (compared to untreated samples). A reduction in the breaking elongation was also observed for the photo-oxidized samples."

- True porosity measurement of hair: a new way to study hair damage mechanisms: http://www.ncbi.nlm.nih.gov/pubmed/18818850
"The results suggest that hair damage caused by oxidative bleach and UV oxidation follows different pathways. Chemical damage (oxidative bleach) nearly triples the hair surface area in the first minute of bleaching due to the increase in the number of pores, followed by a sudden drop after 10 min of bleaching from smaller pores breaking down into larger ones. In contrast, UV damage shows an immediate loss in surface area in the first 200 hr of exposure and a gradual increase as exposure time continues."

- The influence of hair bleach on the ultrastructure of human hair with special reference to hair damage: http://www.ncbi.nlm.nih.gov/pubmed/21882590
"The bleaching action provoked the decomposition of melanin granules and the flow out of granular contents into the intermacrofibrillar matrix. Some metal elements were detected in the melanin granular matrix by EDS-TEM. As a result, the diffusion of metal elements into the intermacrofibrillar matrix promoted further damage to the hair by catalytic action with the hydrogen peroxide in the bleaching agents outside the melanin granules." -> points to the importance of chelating hair with oxidative damage (e.g. bleach)

- Compositional changes of human hair melanin resulting from bleach treatment investigated by nanoscale secondary ion mass spectrometry: http://www.ncbi.nlm.nih.gov/pubmed/24506326
"Nanoscale secondary ion mass spectrometry analysis of the cross-sections of virgin black hair and bleached hair indicated that the oxygen content in melanin granules was increased by bleach treatment."

- Hair breakage during combing. III. The effects of bleaching and conditioning on short and long segment breakage by wet and dry combing of tresses: http://www.ncbi.nlm.nih.gov/pubmed/17728947

- Analysis of structural changes in bleached keratin fibers (black and white human hair) using Raman spectroscopy: http://www.ncbi.nlm.nih.gov/pubmed/16425172
"From these experiments, we concluded that the melanin granules including metal ions act as a decomposition accelerator for the oxidizing agent, thereby leading to a higher level of disulfide (-SS-) group cleavage in the black human hair compared with that of the white human hair."

- The effect of treatments on the shear modulus of human hair measured by the single fiber torsion pendulum: http://journal.scconline.org/pdf/cc2007/cc058n04/p00329-p00337.pdf
"Bleaching also lowers the shear modulus of hair by approximately 40% indicating softening of the cuticle layer."

- Evaluation of hair humidity resistance/moisturization from hair elasticity: http://www.ncbi.nlm.nih.gov/pubmed/17728940

Oxidative Dyes:

- Dyeing regions of oxidative hair dyes in human hair investigated by nanoscale secondary ion mass spectrometry: http://www.ncbi.nlm.nih.gov/pubmed/23434703

- Investigation of dyeing behavior of oxidative dye in fine structures of the human hair cuticle by nanoscale secondary ion mass spectrometry: http://www.ncbi.nlm.nih.gov/pubmed/25323334
"The cuticle layer thickness of the hair cross-section could be widened. It was confirmed that (12) C(-) ions were more strongly detected from endocuticle than from other fine structures of cuticle. The NanoSIMS (12) C(-) image and hue saturation intensity (HSI) D(-) /(1) H(-) ratio image of the hair, dyed with deuterium-labeled oxidative dye, indicated that the endocuticle had a higher D(-) /(1) H(-) ratio than the other fine structures of the cuticle. It was substantiated that more colored chromophores were fixated in the endocuticle than in other fine structures of the cuticle."

- Effects of arginine on hair damage via oxidative coloring process: http://www.ncbi.nlm.nih.gov/pubmed/15645092
"As the first step, it was shown that oxidative coloring or bleaching process decreases hair surface hydrophobicity and tensile strength in wet condition. Next the study has been conducted with coloring agents in which part of the ammonia was replaced with arginine, to find that arginine reduced the oxidative change in contact angle and tensile strength. These results suggest that arginine prevents the undesirable attack by hydrogen peroxide on hair proteins and hair surface lipids."

- Protection of oxidative hair color fading from shampoo washing by hydrophobically modified cationic polymers: http://www.ncbi.nlm.nih.gov/pubmed/19450422
"Polyquaternium-55 provides a high level of color protection when formulated in a hair color protection regimen with up to 50% color protection. This regimen significantly outperforms commercial products that were tested containing a color protection claim. The proposed mechanism for the anti-fading action of hydrophobically modified polymers includes a cationic charge-reinforced hydrophobic barrier. This model is supported by evaluating the color fastness effect of several different polymer chemistries and by measuring hair surface hydrophobicity changes."

- Contact allergy to hair colouring products. The cosmetovigilance experience of 4 companies (2003-2006): http://www.ncbi.nlm.nih.gov/pubmed/19797040

- Hair dye contact allergy: quantitative exposure assessment of selected products and clinical cases: http://www.ncbi.nlm.nih.gov/pubmed/15274724

- p-Phenylenediamine and other allergens in hair dye products in the United States: a consumer exposure study: http://www.ncbi.nlm.nih.gov/pubmed/24628345

- Side-effects of henna and semi-permanent 'black henna' tattoos: a full review: http://www.ncbi.nlm.nih.gov/pubmed/23782354

- A review of allergens found in current hair-care products: http://www.ncbi.nlm.nih.gov/pubmed/16191022

meteor

March 20th, 2016, 03:16 PM

1.2 Chemical Damage: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904):

PART II

- Dyeing regions of oxidative hair dyes in human hair investigated by nanoscale secondary ion mass spectrometry: http://www.ncbi.nlm.nih.gov/pubmed/23434703

- The effects of chelating agents on radical generation in alkaline peroxide systems, and the relevance to substrate damage: http://www.ncbi.nlm.nih.gov/pubmed/17454134

- Hair coloring systems delivering color with reduced fiber damage: http://www.ncbi.nlm.nih.gov/pubmed/17938825

Perming and Relaxing:

- Dissimilar effect of perming and bleaching treatments on cuticles: advanced hair damage model based on elution and oxidation of S100A3 protein: http://www.ncbi.nlm.nih.gov/pubmed/16130044

- Labile proteins accumulated in damaged hair upon permanent waving and bleaching treatments: http://www.ncbi.nlm.nih.gov/pubmed/12512011

- Effects of permanent waving on changes of protein and physicomorphological properties in human head hair: http://www.ncbi.nlm.nih.gov/pubmed/18528588

- Analysis of structural changes in permanent waved human hair using Raman spectroscopy: http://www.ncbi.nlm.nih.gov/pubmed/17143860

- Permanent waving and hair straightening: http://www.ncbi.nlm.nih.gov/pubmed/2467731

- Permanent waving and straightening of hair: http://www.ncbi.nlm.nih.gov/pubmed/3608576
"The most popular waving products contain salts of thioglycolic acid to break the bonds and hydrogen peroxide to reform them. Straighteners generally rely on high alkalinity to break the bonds and reform them with acid."

- Hair care products: waving, straightening, conditioning, and coloring: http://www.ncbi.nlm.nih.gov/pubmed/11535384

- Protein structural changes in keratin fibers induced by chemical modification using 2-iminothiolane hydrochloride: a Raman spectroscopic investigation: http://www.ncbi.nlm.nih.gov/pubmed/16145652

- Heading off hair-care disasters. Use caution with relaxers and dyes: http://www.ncbi.nlm.nih.gov/pubmed/11930919

- Permanent waving does not change mercury concentration in the proximal segment of hair close to scalp: http://www.ncbi.nlm.nih.gov/pubmed/18212489

- Effects of permanent waving on changes of protein and physicomorphological properties in human head hair: http://www.ncbi.nlm.nih.gov/pubmed/18528588
"The protein content was decreased by permanent waving treatments on the whole, and the degree of reduction was dependent on the hair styling and waving lotion used."

- Relaxers damage hair and increase fragility: http://www.ncbi.nlm.nih.gov/pubmed/24571594

- Chemical Hair Relaxers Have Adverse Effects a Myth or Reality: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3746223/

- 'Relaxers' damage hair: evidence from amino acid analysis: http://www.ncbi.nlm.nih.gov/pubmed/20159306
"Relaxers' are associated with reduced cystine consistent with fragile damaged hair. A decrease in citrulline and glutamine has been associated with inflammation; prospective studies are needed to investigate whether or how 'relaxers' induce inflammation."

- Cosmetic and amino acid analysis of the effects of lye and no-lye relaxer treatment on adult black female South African hair: http://www.ncbi.nlm.nih.gov/pubmed/23931091

- No-lye not better than lye relaxers: http://www.ncbi.nlm.nih.gov/pubmed/25898766

- The application of polymethylene waxes as conditioning agent in hair relaxers: http://www.ncbi.nlm.nih.gov/pubmed/15645095
"The polymethylene wax, used in combination with the mineral oil gel and phosphate salt, coats the hair during the relaxing process, leaving it shiny, soft and conditioned as opposed to the poor condition of the hair relaxed by traditional, commercially available NaOH and LiOH relaxers. An additional benefit of using polymethylene wax in relaxer systems is that the conditioning agents that are normally added to the neutralizing shampoo to repair or mask the damage as a result of the relaxing process can be omitted."

- Impact of hair relaxers in women in Nakuru, Kenya: http://www.ncbi.nlm.nih.gov/pubmed/17919201
"The problems encountered included hair loss, burns to the scalp, and color change."

- A nationwide outbreak of alopecia associated with the use of a hair-relaxing formulation: http://www.ncbi.nlm.nih.gov/pubmed/10987865

- Fundamental properties of Afro-American hair as related to their straightening/relaxing behaviour: http://sylvester.bth.rwth-aachen.de/dissertationen/2004/094/04_094.pdf

Keratin Straightening (Brazilian, Japanese straightening):

- Brazilian keratin hair treatment: a review: http://www.ncbi.nlm.nih.gov/pubmed/23725308

- Formaldehyde replacement with glyoxylic acid in semipermanent hair straightening: a new and multidisciplinary investigation: http://www.pubfacts.com/detail/24962464/Formaldehyde-replacement-with-glyoxylic-acid-in-semipermanent-hair-straightening:-a-new-and-multidis

- Analysis of structural change in keratin fibers resulting from chemical treatments using Raman spectroscopy: http://www.pubfacts.com/detail/15739182/Analysis-of-structural-change-in-keratin-fibers-resulting-from-chemical-treatments-using-Raman-spect

- An overview of chemical straightening of human hair: technical aspects, potential risks to hair fibre and health and legal issues: http://www.ncbi.nlm.nih.gov/pubmed/24102549

- Elevated formaldehyde concentration in "Brazilian keratin type" hair-straightening products: a cross-sectional study: http://www.ncbi.nlm.nih.gov/pubmed/24332313
"Formaldehyde concentrations in BKT (Brazilian Keratin Treatments) products may exceed recommended levels and serve as a health hazard. Industry monitoring is needed to improve compliance and protection of hairdressers and consumers."

- Quantification and Prevention of Hair Damage: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.471.2274&rep=rep1&type=pdf
"We found that combing produced secondary damage and that conditioner use reduced or prevented the damaging effects of combing. Damage from combing was more severe in bleached than in unbleached hair. The application of conditioner after shampooing resulted in less damage in both bleached and unbleached hair."
"Wettability. The surface of intact untreated hair is dominated by the hydrophobic epicuticle, while bleaching produces a hydrophilic hair fiber surface."
"As shown above, bleaching destroys the hydrophobicity of the untreated fiber surface, rendering it quite hydrophilic."

lapushka

March 20th, 2016, 04:00 PM

meteor

March 20th, 2016, 04:50 PM

2. Hair Structure: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

PART I

- Hair fiber characteristics and methods to evaluate hair physical and mechanical properties (http://www.scielo.br/pdf/bjps/v45n1/19.pdf)

- Hair follicle differentiation and regulation: http://www.ncbi.nlm.nih.gov/pubmed/15272381

- Healthy hair: what is it? http://www.ncbi.nlm.nih.gov/pubmed/18004288

- A practical, algorithmic approach to diagnosing hair shaft disorders: http://www.ncbi.nlm.nih.gov/pubmed/21182495

- Structural abnormalities of the hair shaft: http://www.ncbi.nlm.nih.gov/pubmed/3805378

- A critical review of the structural mechanics of wool and hair fibres: http://www.ncbi.nlm.nih.gov/pubmed/10771062

- Diffraction of light by the cuticle structure of hair: http://www.ncbi.nlm.nih.gov/pubmed/17728929

- Structural analysis of human hair single fibres by scanning microbeam SAXS: http://www.ncbi.nlm.nih.gov/pubmed/16774836

- Comparative aspects of the inner root sheath in adult and developing hairs of mammals in relation to the evolution of hairs: http://www.ncbi.nlm.nih.gov/pubmed/15379924

- Human hair form. Morphology revealed by light and scanning electron microscopy and computer aided three-dimensional reconstruction: http://www.ncbi.nlm.nih.gov/pubmed/3415278

- Cortical cell types and intermediate filament arrangements correlate with fiber curvature in Japanese human hair: http://www.ncbi.nlm.nih.gov/pubmed/19159689

- Studies of human hair by friction force microscopy with the hair-model-probe: http://www.ncbi.nlm.nih.gov/pubmed/16872812
"We have concluded that loss of the F-layer is a dominant cause of strong friction detected at the hair tip, and at the striations of the hair root."

- Atomic force microscopy of human hair: http://www.ncbi.nlm.nih.gov/pubmed/11023235
"AFM studies have revealed that the surface of the freshly emergent hair gradually changes over a distance of about 20 mm and that the surface of the hair for most of its length is quite different from that near the root. This is likely to be of import to those engaged in the hair toiletries industry."

- Hair sulfur amino acid analysis: http://www.ncbi.nlm.nih.gov/pubmed/8962496

- Investigation of human hair fibers using lateral force microscopy: http://www.ncbi.nlm.nih.gov/pubmed/11587327
"Ambient AFM and LFM studies of surface modified and native fibers clearly indicate that when investigated as a function of tip loading force, the different modifications result in changes of the friction coefficient, which increase in this order: native, bleached, solvent extracted, and polymer-treated hair. Friction images show surface variations that are interpreted as areas of varying lipid film coverage. In addition, topographic images of the fibers show the presence of small pores, which become increasingly prevalent upon solvent extraction."

- Charge density alterations in human hair fibers: an investigation using electrostatic force microscopy: http://www.ncbi.nlm.nih.gov/pubmed/18492143

Keratin:

- Keratins of the human hair follicle: http://www.ncbi.nlm.nih.gov/pubmed/15797458

- Human hair keratin network and curvature: http://www.ncbi.nlm.nih.gov/pubmed/17919197

- Study of the keratinization process in human hair follicle by X-ray microdiffraction: http://www.ncbi.nlm.nih.gov/pubmed/10976881

- Hair follicle differentiation and regulation: http://www.ncbi.nlm.nih.gov/pubmed/15272381

- The role of keratin proteins and their genes in the growth, structure and properties of hair: http://www.ncbi.nlm.nih.gov/pubmed/8962491

- Human hair keratin-associated proteins (KAPs): http://www.ncbi.nlm.nih.gov/pubmed/16939781

- Hair follicle-specific keratins and their diseases: http://www.ncbi.nlm.nih.gov/pubmed/17428470

- Keratin disorders: from gene to therapy: http://www.ncbi.nlm.nih.gov/pubmed/21890491

- Hair keratin pattern in human hair follicles grown in vitro: http://www.ncbi.nlm.nih.gov/pubmed/12702144

- The catalog of human hair keratins. I. Expression of the nine type I members in the hair follicle: http://www.ncbi.nlm.nih.gov/pubmed/10391933

- The catalog of human hair keratins. II. Expression of the six type II members in the hair follicle and the combined catalog of human type I and II keratins: http://www.ncbi.nlm.nih.gov/pubmed/11445569

18-MEA:

The outer lipid layer of epicuticle is predominately 18-methyleicosanoic acid, a branched fatty acid consisting of 21 carbon atoms, and this fatty acid represents about 25% of the epicuticle. The is a model that fatty-acid layer is connected to the underlying fibrous protein layer through thioester linkages involving the cysteine residues of the protein. (Chemical and Physical Behavior of Human Hair by C. Robbins (p. 81))

- The role of 18-methyleicosanoic acid in the structure and formation of mammalian hair fibres: http://www.ncbi.nlm.nih.gov/pubmed/9519472

- Effect of the covalently linked fatty acid 18-MEA on the nanotribology of hair's outermost surface: http://www.ncbi.nlm.nih.gov/pubmed/15721577

- Integral lipids of hair and stratum corneum: http://www.ncbi.nlm.nih.gov/pubmed/8962495

- Insights into the structure of covalently bound fatty acid monolayers on a simplified model of the hair epicuticle from molecular dynamics simulations: http://www.ncbi.nlm.nih.gov/pubmed/22891705

- Molecular dynamic simulations of eicosanoic acid and 18-methyleicosanoic acid langmuir monolayers: http://www.ncbi.nlm.nih.gov/pubmed/17718471

- Deposition of 18-MEA onto alkaline-color-treated weathered hair to form a persistent hydrophobicity: http://www.ncbi.nlm.nih.gov/pubmed/19296894

- The thickness of 18-MEA on an ultra-high-sulfur protein surface by molecular modeling: http://www.ncbi.nlm.nih.gov/pubmed/21241636

- A role of the anteiso branch of 18-MEA in 18-MEA/SPDA to form a persistent hydrophobicity to alkaline-color-treated weathered hair: http://www.ncbi.nlm.nih.gov/pubmed/19822108

- Effect of the covalently linked fatty acid 18-MEA on the nanotribology of hair's outermost surface: http://www.ncbi.nlm.nih.gov/pubmed/15721577

Other Intercellular Lipids:

- Integral lipids of hair and stratum corneum: http://www.ncbi.nlm.nih.gov/pubmed/8962495

- Lipids and barrier function of the skin: http://www.ncbi.nlm.nih.gov/pubmed/10884933

- Epidermal lipids: http://www.ncbi.nlm.nih.gov/pubmed/1498013

- Molecular models of the intercellular lipid lamellae from epidermal stratum corneum: http://www.ncbi.nlm.nih.gov/pubmed/14561469

- Stratum corneum lipids: the effect of ageing and the seasons: http://www.ncbi.nlm.nih.gov/pubmed/8950457

- Studies of epidermal lipids using electron microscopy: http://www.ncbi.nlm.nih.gov/pubmed/1498019

- Ceramides and skin function: http://www.ncbi.nlm.nih.gov/pubmed/12553851

- Role of ceramides in barrier function of healthy and diseased skin: http://www.ncbi.nlm.nih.gov/pubmed/16060709

- Characterization of the lipid composition at the proximal root regions of human hair: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.544.8322&rep=rep1&type=pdf, http://www.ncbi.nlm.nih.gov/pubmed/15744437
Hair lipid composition was examined for eight lipids including hydrocarbons (HCs), squalene (SQ), wax esters (WEs), triglycerides (TGs), fatty acids (FAs), cholesterol (CH), ceramides (CERs), and 18-methyl eicosanoic acid (MEA).
"Since endogenous lipids in group B are the main components of cell membrane lipids that form CMC, they can lead to the formation of stable and strong CMC.
Therefore, stable and strong CMC may result in enhancing the barrier function, which is attributable to preventing external materials from entering into hair fibers as is the case in skin. Consequently, higher levels of endogenous lipids in group B may result in diminished levels of exogenous ones due to their difficulty in penetration, while lower levels of endogenous lipids in group B may result in increased exogenous ones in hair fibers."

meteor

March 20th, 2016, 04:58 PM

meteor

March 20th, 2016, 06:26 PM

8. Hair Texture: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

- Human hair shape is programmed from the bulb: http://www.ncbi.nlm.nih.gov/pubmed/15840091

- Human hair keratin network and curvature: http://www.ncbi.nlm.nih.gov/pubmed/17919197

- Human hair form. Morphology revealed by light and scanning electron microscopy and computer aided three-dimensional reconstruction: http://www.ncbi.nlm.nih.gov/pubmed/3415278

- Hair shape of curly hair: http://www.ncbi.nlm.nih.gov/pubmed/12789164

- Human hair shape is programmed from the bulb: http://www.ncbi.nlm.nih.gov/pubmed/15840091

- Shape variability and classification of human hair: a worldwide approach: http://www.ncbi.nlm.nih.gov/pubmed/18078200

- Morphology and properties of Asian and Caucasian hair: http://journal.scconline.org/pdf/cc2006/cc057n04/p00327-p00338.pdf, http://www.ncbi.nlm.nih.gov/pubmed/16957811

- Mechanobiology and cell tensegrity: the root of ethnic hair curling? http://www.ncbi.nlm.nih.gov/pubmed/21649823

- Curly hair: measured differences and contributions to breakage: http://www.ncbi.nlm.nih.gov/pubmed/23210940

- Worldwide diversity of hair curliness: a new method of assessment: http://www.ncbi.nlm.nih.gov/pubmed/17919196

- Fundamental properties of Afro-American hair as related to their straightening/relaxing behaviour: http://sylvester.bth.rwth-aachen.de/dissertationen/2004/094/04_094.pdf (post # 163 (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3195390&viewfull=1#post3195390))

meteor

March 20th, 2016, 06:54 PM

Hair Shine: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187906&viewfull=1#post3187906)

- Hair fiber characteristics and methods to evaluate physical and mechanical properties of hair:
http://www.scielo.br/pdf/bjps/v45n1/19.pdf
"Since this is a surface propriety, cuticle is the main responsible by it. Damages on cuticle (opening and breakage of scales), as well as dust particles and scalp secretions built up over threads reduce the shine. The increase of curls bending reduces its visualization and darker hair seems to be more brilliant than the light ones.
When a light beam reaches the hair surface, a part of it is reflected, another part is absorbed, and a third part is dispersed. The amount of light corresponding to each of these phenomena depends on the surface geometry, on the refraction index of the thread, and on the light incidence angle.
Factors influencing the shine perception, by order of importance are: reflection, light dispersion, alignment, and color.
These present favorable effect of hair shine:
• continuous and thin film over the scales;
• film with high refraction index;
• reflection being higher than diffuse dispersion.

These present unfavorable effects:
• higher light dispersion;
• film coating – irregular or discontinuous – over threads;
• chemical treatments as permanent waving and discoloration, which cause changes on the flat positioning of the cuticle due to the scales lifting (Reimer et al., 1995; Ishii, 1997; Starch, 1999; Schueller, Romanowski, 2001)."

- Diffraction of light by the cuticle structure of hair: http://www.ncbi.nlm.nih.gov/pubmed/17728929

- Study of hair shine and hair surface smoothness: http://www.ncbi.nlm.nih.gov/pubmed/19450419

- Influence of internal structures of hair fiber on hair appearance. I. Light scattering from the porous structure of the medulla of human hair: http://www.ncbi.nlm.nih.gov/pubmed/11919644
"Hair with a porous medulla gave a whitish and lusterless appearance because of light scattering from the fiber center, whereas in the cases without pores, a clear and brilliant appearance was observed. [...] Both contrasts in lightness and apparent color (chroma and hue) decreased in the hair with medulla pores, and the decreases in contrast caused a whitish and lusterless appearance. [...] The histogram was further analyzed by hair care behavior of individual panelists, and it was found that the pores in the medulla can be generated in a heat-drying process."

- Influence of internal structure of hair fiber on hair appearance. II. Consideration of the visual perception mechanism of hair appearance: http://journal.scconline.org/pdf/cc2002/cc053n06/p00387-p00402.pdf

- Influence of internal structures of hair fiber on hair appearance. III. Generation of light-scattering factors in hair cuticles and the influence on hair shine: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.553.9320&rep=rep1&type=pdf, http://www.ncbi.nlm.nih.gov/pubmed/14528388
"The effects of thermal treatments on hair fiber induced by blow-drying have been investigated. It was found that the hair shows whitish and powdery appearance after heat drying, especially when dark hair is rapidly dried from a wet condition. For all kinds of hair, the appearance of numerous glittering speckles was confirmed on the cuticle surface by optical microscopic observations. SEM images of hair transverse and longitudinal sections with glittering speckles revealed that the splitting of cuticle layers generated by blow-drying occurred not only at the outermost parts of cuticle cells but also at the inner parts of the cellular interfaces. The release and uptake of moisture through fiber surfaces induces deformation of cuticle cells, probably because of anisotropic swelling or drying of the cells. The cuticles with glittering speckles are found to be fragile and are easily damaged in combination with other mechanical stresses such as combing force."
"Both procedures only result from rapid shrinkage or swelling of the cuticle cell, and therefore a gradual change in moisture does not cause these phenomena. The glittering speckles are observed to a high degree just after an abrupt change in moisture occurs. The moisture content will soon be in equilibrium, and thus these speckles almost disappear within ten minutes. These structural changes in hair cuticles are believed to occur in a daily hair care routine, but they have been unnoticed thus far because deformation of cuticle layers will disappear upon relaxing at high humidity conditions or wetting with water."

- Patterns of light interference produced by damaged cuticle cells in human hair: http://www.ncbi.nlm.nih.gov/pubmed/17728927
"The strong patterns of light interference appeared only in cuticle cells that had been damaged either mechanically or by thermal stresses. Cuticle cells that were not damaged did not produce this phenomenon. The zones of light interference on the hair surface were seen to extend to cuticle sheath areas whose damage was not apparent when analyzed under the Scanning Electron Microscope. The presence of oils and other hydrophobic materials in the hair had a strong effect in the appearance or disappearance of the interference patterns."

- Analyzing the laser-light reflection from human hair fibers. I. Light components underlying the goniophotometric curves and fiber cuticle angles: http://www.ncbi.nlm.nih.gov/pubmed/12858229

- Analyzing the laser-light reflection from human hair fibers. II. Deriving a measure of hair luster: http://www.ncbi.nlm.nih.gov/pubmed/15037922

- A study correlating between instrumental and consumers' subjective luster values in oriental hair tresses: http://www.ncbi.nlm.nih.gov/pubmed/17256077

- Studies of light scattering from ethnic hair fibers: http://www.ncbi.nlm.nih.gov/pubmed/15037920

- A new multifunctional, shine-enhancing emollient: PPG-3 benzyl ether myristate: http://www.ncbi.nlm.nih.gov/pubmed/15645090

- Optical properties of hair: effect of treatments on luster as quantified by image analysis: http://www.ncbi.nlm.nih.gov/pubmed/14528387
"The procedure was employed to assess the luster of natural white, light blonde, light brown, medium brown, and dark brown hair, and revealed an increase in luster indices in proportion to an increase in fiber pigmentation. Cosmetic oils such as phenyl trimethicone, amodimethicone, and castor oil were also found to increase the luster of hair as a result of the change in contrast between specular and diffuse reflection. Styling resins such as butyl ester of PVM/MA copolymer, vinyl caprolactam/PVP/dimethylaminoethyl methacrylate copolymer, and isobutylene/ethylmaleimide/hydroxyethylmaleimide copolymer were shown to increase hair gloss by a similar mechanism, as evidenced by calculated higher values of the Stamm and Reich-Robbins luster parameters. An effect of hair dulling by deposition of micronized ZnO at various concentrations, as well as by synthetic sebum, is also discussed."

- Formation of nanostructure on hair surface: its characteristic optical properties and application to hair care products: http://www.ncbi.nlm.nih.gov/pubmed/17728928
"Uneven structures on hair fiber surface, such as lift up of cuticle or build up of hair spray ingredients, generally cause a diffuse reflection which results in a dull and unhealthy appearance. However, in the case of finer structure than wavelength of visible light, the optical properties change significantly. An application of the phenomenon to hair care products is reported in this paper. Formation of the fine structure on hair surface was achieved by only a shampoo and rinse-off conditioner system including amino-silicone."

- New luster formula for the characterization of hair tresses using polarization imaging: http://www.ncbi.nlm.nih.gov/pubmed/19450417

- A reciprocal lattice approach to assessing the luster of hair fibers, based on scattering by periodically deformed cylinders: http://www.ncbi.nlm.nih.gov/pubmed/15645101

- Understanding colors in nature: http://www.ncbi.nlm.nih.gov/pubmed/3070522

- Structural colors in nature: the role of regularity and irregularity in the structure: http://www.ncbi.nlm.nih.gov/pubmed/16015669

meteor

March 20th, 2016, 07:54 PM

Conventional Products: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187906&viewfull=1#post3187906)
Shampoos:
Anti-dandruff Shampoos: - Studies:

General studies on dandruff and SD:

- Malassezia Fungi Are Specialized to Live on Skin and Associated with Dandruff, Eczema, and Other Skin Diseases: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3380954/

- The Malassezia Genus in Skin and Systemic Diseases: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3255962/

- Malassezia Yeasts: How Many Species Infect Humans and Animals? http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3937305/

- Stratum corneum dysfunction in dandruff: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3494381/

- Three etiologic facets of dandruff and seborrheic dermatitis: Malassezia fungi, sebaceous lipids, and individual sensitivity: http://www.ncbi.nlm.nih.gov/pubmed/16382685

- Seborrheic dermatitis due to Malassezia species in Ahvaz, Iran: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3895566/

- Malassezia globosa and restricta: breakthrough understanding of the etiology and treatment of dandruff and seborrheic dermatitis through whole-genome analysis: http://www.ncbi.nlm.nih.gov/pubmed/18004291

- The role of sebaceous gland activity and scalp microfloral metabolism in the etiology of seborrheic dermatitis and dandruff: http://www.ncbi.nlm.nih.gov/pubmed/16382662

- Metabolic analysis of the cutaneous fungi Malassezia globosa and M. restricta for insights on scalp condition and dandruff: http://www.ncbi.nlm.nih.gov/pubmed/23106637

- Dandruff: a condition characterized by decreased levels of intercellular lipids in scalp stratum corneum and impaired barrier function: http://www.ncbi.nlm.nih.gov/pubmed/12115025

- Dandruff and seborrhoeic dermatitis: causes and management: http://www.ncbi.nlm.nih.gov/pubmed/9330043

- The aetiology of dandruff and the mode of action of therapeutic agents: http://www.ncbi.nlm.nih.gov/pubmed/6235835

- Role of microorganisms in dandruff: http://www.ncbi.nlm.nih.gov/pubmed/130835

- Dandruff-associated Malassezia genomes reveal convergent and divergent virulence traits shared with plant and human fungal pathogens: http://www.ncbi.nlm.nih.gov/pubmed/18000048

- Malassezia, dandruff and seborrhoeic dermatitis: an overview: http://www.ncbi.nlm.nih.gov/pubmed/21919896

- Quantitative microbiology of the scalp in non-dandruff, dandruff, and seborrheic dermatitis: http://www.ncbi.nlm.nih.gov/pubmed/237965

Shampoos / Treatments:

- Medicated shampoos for the treatment of seborrheic dermatitis: http://www.ncbi.nlm.nih.gov/pubmed/18664167

- A comparison of hair quality and cosmetic acceptance following the use of two anti-dandruff shampoos: http://www.ncbi.nlm.nih.gov/pubmed/16382664

- Evaluation of safety and efficacy of ketoconazole 2% and zinc pyrithione 1% shampoo in patients with moderate to severe dandruff--a postmarketing study: http://www.ncbi.nlm.nih.gov/pubmed/11394481

- A multicenter randomized trial of ketoconazole 2% and zinc pyrithione 1% shampoos in severe dandruff and seborrheic dermatitis: http://www.ncbi.nlm.nih.gov/pubmed/12476017

- A randomized, double-blind, placebo-controlled trial of ketoconazole 2% shampoo versus selenium sulfide 2.5% shampoo in the treatment of moderate to severe dandruff: http://www.ncbi.nlm.nih.gov/pubmed/8245236

- Successful treatment and prophylaxis of scalp seborrhoeic dermatitis and dandruff with 2% ketoconazole shampoo: results of a multicentre, double-blind, placebo-controlled trial: http://www.ncbi.nlm.nih.gov/pubmed/7718463

- Treatment of seborrhoeic dermatitis of the scalp with ketoconazole shampoo. A double-blind study: http://www.ncbi.nlm.nih.gov/pubmed/1969208

- Effect of ketoconazole 1% and 2% shampoos on severe dandruff and seborrhoeic dermatitis: clinical, squamometric and mycological assessments: http://www.ncbi.nlm.nih.gov/pubmed/11306850

- An overview of experience with ketoconazole shampoo: http://www.ncbi.nlm.nih.gov/pubmed/1839767

- The antifungal activity of a coal tar gel on Malassezia furfur in vitro: http://www.ncbi.nlm.nih.gov/pubmed/8573928

- In vitro comparison of antifungal effects of a coal tar gel and a ketoconazole gel on Malassezia furfur: http://www.ncbi.nlm.nih.gov/pubmed/8264719

- Clinical efficacies of shampoos containing ciclopirox olamine (1.5%) and ketoconazole (2.0%) in the treatment of seborrhoeic dermatitis: http://www.ncbi.nlm.nih.gov/pubmed/17520465

- Topical antifungals for seborrhoeic dermatitis: http://www.ncbi.nlm.nih.gov/pubmed/25933684

- Treatment of dandruff with 5% tea tree oil shampoo: http://www.ncbi.nlm.nih.gov/pubmed/12451368

- Successful treatment of dandruff with 1.5% ciclopirox olamine shampoo in Korea: http://www.ncbi.nlm.nih.gov/pubmed/14660265

- Ciclopirox shampoo for treating seborrheic dermatitis: http://www.ncbi.nlm.nih.gov/pubmed/15334279

- Ciclopirox 1% shampoo for the treatment of seborrheic dermatitis: http://www.ncbi.nlm.nih.gov/pubmed/16426382

- Efficacy of different concentrations of ciclopirox shampoo for the treatment of seborrheic dermatitis of the scalp: results of a randomized, double-blind, vehicle-controlled trial: http://www.ncbi.nlm.nih.gov/pubmed/15271194

- Rationale of frequency of use of ciclopirox 1% shampoo in the treatment of seborrheic dermatitis: results of a double-blind, placebo-controlled study comparing the efficacy of once, twice, and three times weekly usage: http://www.ncbi.nlm.nih.gov/pubmed/15271195

- Safety and efficacy of ciclopirox 1% shampoo for the treatment of seborrheic dermatitis of the scalp in the US population: results of a double-blind, vehicle-controlled trial: http://www.ncbi.nlm.nih.gov/pubmed/15271196

- The control of seborrhoeic dermatitis and dandruff by antipityrosporal drugs: http://www.ncbi.nlm.nih.gov/pubmed/1709848

- Efficacy of a piroctone olamine/climbazol shampoo in comparison with a zinc pyrithione shampoo in subjects with moderate to severe dandruff: http://www.ncbi.nlm.nih.gov/pubmed/21272039

LongCurlyTress

March 20th, 2016, 09:42 PM

This is absolutely fascinating, meteor!! As always, thank you so much for sharing your information about hair! It's interesting that on these LHC threads, we each offer our own opinions based on our own experience mostly but learning the facts from microscopic photos really tells the truth!! Wow!! shudder: Thank you!!

Arctic

March 21st, 2016, 02:13 AM

That is probably why the Urtekram shampoo has worked for me in the past, even though it is without "SLS/SLES". I found it to be equally as cleansing as my regular shampoo. I never knew why, because normally with milder shampoos I can get bouts of SD. That didn't happen with this one.

I have often pointed out that I don't think Urtekram shampoos are particularly mild nor are they sulphate-free, like sometimes is being claimed. I love them to bits, but at the same time I have to say they do quite a bit of greenwashing.

They work very well for me too. They also lack the kind of coating ingredients many contemporary shampoos have, which also adds to the clean feel they leave behind.

I don't find they drying, either, nor harsh - but also not particularly gentle either. They do what they are supposed to - clean - very effectively. They seem to have perfect balance for me to clean my hair and scalp.

One other thing Urtekram shampoos do (not going into the double ingredient lists - one for fool consumers, one law-forced one to show the truth), is they make it appear that they are low-sulphate, by listing coco-sulphate as 3rd ingredient, where as in "normal" shampoos it's usually a 2nd. They can do this trick because instead of purely water as first ingredient, they have water-aloe vera juice mixture. I am quite positive the sulphate concentration is similar as in most shampoos, though.

Arctic

March 21st, 2016, 02:25 AM

I'm not sure basing it on how often people wash will give us a more accurate picture of oily vs. dry than just asking people to self-identify. There are a lot more factors that go into how often people wash than just sebum production (workouts, dirty jobs, how much of a hassle it is to wash/dry their particular head of hair, what level of sebum-y they personally consider "dirty," etc.).

You do have good point, but note that this is LHC, and we have probably more people here who sretch washes than there are in RL, and people tend to define the "acceptable cleanliness" differently too (not trying to be provocative, but this is probably how Jane Doe would feel about hair washing habits of many LHCers). Or at least in my cutural surroundings, where most people have fine, thin straight-ish hair types, it's not common to go days without washing (I know it can be very different with people who have very curly, thick hair types as the most common type).

The suggestion I gave was more on the "real world" standards of oily, not LHC standards.

We have many members who won't wash untill X days have passed even if they drip oil.

We have members who never wash.

We have members who say they have oily hair, but wash once a week. That is just not comparable to someone whose hair is oily after 12 hours has passed, IMHO.

I think because this is LHC there needs to be some kind of definition of what is meant with oily scalp. We are not ordinary bunch here when it comes to hair washing. It may be defined with different mechanism that washing frequency which I suggested, but it needs to be defined.

The oil producing rate was integral to the study, on which the whole poll idea was based, and I think it is very important to define what is oily and what is not (since we don't have that handy dandy Sebumeter! :laugh:).

ETA: Going off tangent... "we have more people who stretch washes" and "we have unnaturally large percentage of F-type members and even more unnaturally small percentage of C-type members"... Hmmm :D (just kidding!)

Zesty

March 21st, 2016, 07:47 AM

Do we have any scientific basis for preferring wet/damp or dry hair while trimming? :hmm: I know there's some debate about which (if either) is more damaging. I would almost think that dry would be better because hair isn't compromised as it is when wet?

lapushka

March 21st, 2016, 11:11 AM

meteor

March 21st, 2016, 12:01 PM

One other thing Urtekram shampoos do (not going into the double ingredient lists - one for fool consumers, one law-forced one to show the truth), is they make it appear that they are low-sulphate, by listing coco-sulphate as 3rd ingredient, where as in "normal" shampoos it's usually a 2nd. They can do this trick because instead of purely water as first ingredient, they have water-aloe vera juice mixture. I am quite positive the sulphate concentration is similar as in most shampoos, though.

He-he, that Desert Essence I mentioned does the exact same thing, too (and I know lots of other "natural" brands around the world do, too) - they list all the stuff infused into water, rather than just say "water", e.g. :

Water (Aqua), Rosmarinus Officinalis (Rosemary) Leaf Extract *, Arctium Lappa (Burdock) Root Extract*, Achillea Millefolium (Yarrow) Extract*, Hamamelis Virginiana (Witch Hazel) Leaf Extract *, Foeniculum Vulgare (Fennel) Seed Extract*, Sambucus Nigra (Black Elderberry) Flower Extract*, Aloe Barbadensis Leaf Extract *, Sodium Coco-Sulfate (Coconut Derived), Decyl Glucoside (Coconut and Corn Derived), Propanediol (Corn Derived), Coco-Glucoside (Coconut Derived), etc [...](https://www.desertessence.com/store/coconut-shampoo#ingredients)
So it's not that obvious that the sulfate is the second ingredient. ;)

Other things they often do these days are:

- emphasize if a sulfate (or another surfactant) is coconut-derived (most sulfates usually are anyway, or derived from other natural oils, but the end result chemically has very little to do with the original oil(s)) - this prevalence of coconut-derived ingredients makes coconut allergies particularly tricky to accommodate when shopping for S&C, by the way;

- emphasize if something is made of natural products (again, it's obvious that most ingredients are derived from natural products, but their chemistry changes so much through processing, that it becomes almost irrelevant to anyone other than somebody with allergies to said natural products).

Do we have any scientific basis for preferring wet/damp or dry hair while trimming? :hmm: I know there's some debate about which (if either) is more damaging. I would almost think that dry would be better because hair isn't compromised as it is when wet?

Excellent question! (I've linked it to the Index with questions.)

I don't know the answer to this, unfortunately.

I want to say you are probably right, since hair swells a lot when wet and keratin kind of changes its form temporarily when it's wet:
Regulation of hard α-keratin mechanics via control of intermediate filament hydration: matrix squeeze revisited: http://www.ncbi.nlm.nih.gov/pubmed/23135675
Hair's plasticity increases and its length can supposedly increase by 2% and its diameter by 15% to 20% (http://www.hair-science.com/_int/_en/topic/topic_sousrub.aspx?tc=ROOT-HAIR-SCIENCE^SO-STURDY-SO-FRAGILE^PROPERTIES-OF-HAIR&cur=PROPERTIES-OF-HAIR) when wet.
You don't want to mess with wet hair much due to its fragility at that moment, but at the same time I'm not too sure about specifically cutting... For example, isn't cutting fingernails and toenails better when wet :hmm: - doesn't that help produce smoother surface than if it was done dry? Does the thickness of the nail plate or hair strand matter for this? I'm not sure if comparison with nail keratin can work here though... :hmm:

And let's not forget that it's best to cut hair dry if it's textured (wavy or curly), because getting hair wet breaks its hydrogen bonds (and this helps temporarily obscure its natural texture).
Cutting dry length helps see and respect the curl pattern better for maximum aesthetic effect of the cut.

Zesty

March 21st, 2016, 01:03 PM

meteor

March 21st, 2016, 01:10 PM

LongCurlyTress, I'm so happy you like the studies and the pictures! :thumbsup:

Guys, I just found a study that explains in part that phenomenon of high shine from blow-drying and heat-styling hair vs. air-dried hair! :D

It's been bothering me for a while, and I often read reports of people saying that they like to heat-style because their hair is much shinier as a result and "isn't that a sign that it's good for hair on some level?" and all that... And beyond heat straightening hair surface, thus making it more reflective, I didn't know any other reasons behind it. Well, there's a study on that, and it shows that it's actually the damage to the cuticles and the abrupt change in moisture levels that are responsible for the glittering! :bigeyes: A bit counter-intuitive, but here's the study (bonus: there are some *excellent* pictures in it!):

Enjoy! :)

Influence of internal structures of hair fiber on hair appearance. III. Generation of light-scattering factors in hair cuticles and the influence on hair shine: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.553.9320&rep=rep1&type=pdf, Summary: http://www.ncbi.nlm.nih.gov/pubmed/14528388

"Many consumers perceive some changes in their hair such as disentangling, feel, bounce, shine, etc., after using a hair dryer. The half-head test was carried out in order to elucidate the effect of blow-drying applied to hair in a wet condition (Figure 1). The left half-head was dried by applied hot air drying, and the right half-head was air-dried. It was confirmed that the left half-head showed a whitish and powdery appearance, and consequently hair gloss was suppressed. Optical microscope observations of the hair fiber revealed that several glittering speckles appeared after heat drying (Figure 2). Several colored glittering speckles, sometimes red, blue, green, etc., were shown in the high magnification optical microscopic image (Figure 3), suggesting light reflection due to interference of light at the cuticle layer. SEM analysis results of fiber surfaces before and after blow-drying are shown in Figure 4. The existence of concave-shaped scale edges owing to cuticle layer splitting are shown (circled in Figure 4) in blow-dried fibers. Through SEM observations of transverse and longitudinal sections, it was confirmed that structural changes caused by blow-drying also occurred between inner cuticle layers (Figure 5)."

"The effects of thermal treatments on hair fiber induced by blow-drying have been investigated. It was found that the hair shows whitish and powdery appearance after heat drying, especially when dark hair is rapidly dried from a wet condition. For all kinds of hair, the appearance of numerous glittering speckles was confirmed on the cuticle surface by optical microscopic observations. SEM images of hair transverse and longitudinal sections with glittering speckles revealed that the splitting of cuticle layers generated by blow-drying occurred not only at the outermost parts of cuticle cells but also at the inner parts of the cellular interfaces. The release and uptake of moisture through fiber surfaces induces deformation of cuticle cells, probably because of anisotropic swelling or drying of the cells. The cuticles with glittering speckles are found to be fragile and are easily damaged in combination with other mechanical stresses such as combing force."

"Both procedures only result from rapid shrinkage or swelling of the cuticle cell, and therefore a gradual change in moisture does not cause these phenomena. The glittering speckles are observed to a high degree just after an abrupt change in moisture occurs. The moisture content will soon be in equilibrium, and thus these speckles almost disappear within ten minutes. These structural changes in hair cuticles are believed to occur in a daily hair care routine, but they have been unnoticed thus far because deformation of cuticle layers will disappear upon relaxing at high humidity conditions or wetting with water."

meteor

March 21st, 2016, 01:18 PM

Is it supposed to be better to cut nails when wet? I've not heard that. Maybe the increased plasticity keeps it from splintering/forming cracks radiating out from the original cut (if that makes sense) as it might when dry? If that's the case then it could make sense for wet cutting to be less damaging. Though I'm sure cutting wet is more a matter of increased control when we're talking about salon haircuts, which seem to almost invariably be done wet/damp.

Unless there's a definite conclusion though I'll probably continue trimming dry, because I hate manipulating my hair when it's wet for various reasons, some less scientific than others. :silly:

I don't know about nails either, I just notice that I get more split, rough edges and more resistance when I cut nails dry... Wet works better for me in that respect, but wet nails can split further if I mess with them, rather than just cut in a straight line (all the little cracks kind of expand as the nail absorbs water), so I don't know, I really wish I knew though. :)

What are your thoughts on wet vs. dry cutting in terms of damage on the edge, guys? :)

pinutzz

March 21st, 2016, 05:52 PM

I did a membership search, and looked how many F, M and C members we have. I didn't include the inbetween types, and of course not everyone has their type visible/chosen.

We have 111 pages of Fs, 128 pages of Ms and measly 18 pages of Cs. Interesting!

How do you do this member search? Is it not allowed for people with less than x posts? Because I can't find this option anywhere?

As many here on this forum I am obsessed with growing my hair super long, but it is very fine and my pony circumference is small so I am not sure if I can ever achieve the hair growth goals of my dreams. In an ideal world this should only depend on for how many years a hair grows before it falls out and this has nothing to do with hair thickness or number of hairs. But since hairs also get damaged and strong taper combined with few hairs doesn't look very appealing: I wanted to figure out just how disadvantaged that makes me in comparison to others. So I used the data from the quote above, together with a poll about ponytail circumference (http://forums.longhaircommunity.com/showthread.php?t=40892http://).

Then I read through the ENTIRE thread on people who have grown their hair to knee length and beyond (http://forums.longhaircommunity.com/showthread.php?t=54031) (don't ask, long but boring day at work) and catalogued all people that reached knee at some point (or more than 59" if only a number was given) and the hair categories they had filled in their profile (i-iii, F-C). I found 81 members total. If I could use the member search function I would probably find even more.

Because people like to chose combinations like i/ii instead of either i or ii I decided to put half of those in the "i" bin and the other half in the "ii" bin for easier comparison. Same for hair thickness.

What I found is this:
http://i.imgur.com/quy6yeN.png

While the thickness of individual hairs doesn't seem to have a big influence on successfull growth to knee length, we can see big differences in the chart with the ponytail circumference. There was actually only 1 member with i-circumference on the knee-length thread and from her profile picture one could clearly see that she had miscategorized herself (Indian lady with lots of wavy thick black hair that had categorized herself as 1a/F/i). But it wasn't objective to exclude her from the data set.

While people with thick ponytails are clearly overrepresented among extreme long-hairs, this can be attributed just as much to aesthetics as genetics. If one has a look at this poll about hair length (http://forums.longhaircommunity.com/showthread.php?t=135920), there is a sharp drop at classic length. Ideally we would expect a more or less gaussian distribution though.

I would love to repeat this with better data from the member search function! :eye:

Zesty

March 21st, 2016, 06:39 PM

pinutzz, that's great! I've been wondering about that, and judging from past thread topics I'm sure others would like to see this breakdown as well. And it would indeed be cool if we got more precise data along these lines. Thanks for sharing!

Arctic

March 22nd, 2016, 01:21 AM

How do you do this member search? Is it not allowed for people with less than x posts? Because I can't find this option anywhere?

As many here on this forum I am obsessed with growing my hair super long, but it is very fine and my pony circumference is small so I am not sure if I can ever achieve the hair growth goals of my dreams. In an ideal world this should only depend on for how many years a hair grows before it falls out and this has nothing to do with hair thickness or number of hairs. But since hairs also get damaged and strong taper combined with few hairs doesn't look very appealing: I wanted to figure out just how disadvantaged that makes me in comparison to others. So I used the data from the quote above, together with a poll about ponytail circumference (http://forums.longhaircommunity.com/showthread.php?t=40892http://).

Then I read through the ENTIRE thread on people who have grown their hair to knee length and beyond (http://forums.longhaircommunity.com/showthread.php?t=54031) (don't ask, long but boring day at work) and catalogued all people that reached knee at some point (or more than 59" if only a number was given) and the hair categories they had filled in their profile (i-iii, F-C). I found 81 members total. If I could use the member search function I would probably find even more.

Because people like to chose combinations like i/ii instead of either i or ii I decided to put half of those in the "i" bin and the other half in the "ii" bin for easier comparison. Same for hair thickness.

What I found is this:
http://i.imgur.com/quy6yeN.png

While the thickness of individual hairs doesn't seem to have a big influence on successfull growth to knee length, we can see big differences in the chart with the ponytail circumference. There was actually only 1 member with i-circumference on the knee-length thread and from her profile picture one could clearly see that she had miscategorized herself (Indian lady with lots of wavy thick black hair that had categorized herself as 1a/F/i). But it wasn't objective to exclude her from the data set.

While people with thick ponytails are clearly overrepresented among extreme long-hairs, this can be attributed just as much to aesthetics as genetics. If one has a look at this poll about hair length (http://forums.longhaircommunity.com/showthread.php?t=135920), there is a sharp drop at classic length. Ideally we would expect a more or less gaussian distribution though.

I would love to repeat this with better data from the member search function! :eye:

Cool! I'm happy to help provide more data, this is interesting!

I don't think membership search is restricted by postnumber.

Click:

Community
--> Member list
--> Search members
--> Advanced search
--> then choose what ever option you want it to search for you, I chose from the dropdown menu "Hair Type - Second Classifier" the F, M and C options and left all the other fields empty
--> Click Search Now, when it should give you a list of members who have those/that variable(s) you wanted to search.

Totty

March 22nd, 2016, 02:57 AM

I was wondering, are there less coarse haired knee haired folks due to the weight?

pinutzz

March 22nd, 2016, 04:33 AM

Click:

Community
--> Member list
--> Search members
--> Advanced search
--> then choose what ever option you want it to search for you, I chose from the dropdown menu "Hair Type - Second Classifier" the F, M and C optiona and left all the other field empty
--> Click Search Now, when it should give you a list of members who has those/that variable(s) you wanted to search.

Ah perfect! Yes, works for me! I hope I'll get around to doing something with this data soon!

I was wondering, are there less coarse haired knee haired folks due to the weight?

There are more coarse haired knee-length folk (11.7%) compared to forum members overall (7%). Or do you mean there is less of a difference between the two than you expected?

Totty

March 22nd, 2016, 11:33 AM

There are more coarse haired knee-length folk (11.7%) compared to forum members overall (7%). Or do you mean there is less of a difference between the two than you expected?

Ok, I get it. I've read it wrong. Thank you for your reply

meteor

March 22nd, 2016, 01:01 PM

Great stuff, pinutzz!! Thanks so much for sharing! :thumbsup:

Arctic, thanks so much for that - it's great to know! :applause
And I think there are some ways of pulling data from multiple threads, but it requires some coding.

Arctic

March 22nd, 2016, 02:02 PM

Arctic, thanks so much for that - it's great to know! :applause
And I think there are some ways of pulling data from multiple threads, but it requires some coding.

Your welcome, it's a handy feature!

Maybe goneJackal could help, he seems to be skilled with coding that kind thing. In fact, I think he has already made such code for hair video thread.

pinutzz

March 23rd, 2016, 01:59 AM

I don't think coding would work for pulling data from threads about who made it to what length if you want to find all matches. Often people just post a picture without words of their achievement. Many people post in these threads to congratulate others who themselves haven't reached that length yet and you don't want them in your dataset. Or people post that they achieved a certain length, then somebody else tells them that they are not there yet after looking at their pictures. It would take longer to write code that can process this automatically than to just do it by hand. Which is why I wouldn't want to do it for a BSL to Waist thread for example - because there are way more members in that length rage.

meteor

March 23rd, 2016, 08:46 AM

2. Hair Structure: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

PART II

CMC:

CMC (epicuticle or portion of epicuticle) consists of 20-30% fatty acid and 60-70% protein, rich in amino acid lysine (Chemical and Physical Behavior of Human Hair by C. Robbins (p. 81))

"The inert beta layers of the cell membrane complex are lipid-proteintype structures. [...] Fatty acids and wax esters are the main components of the internal lipids of human hair. [...] Hilterhaus-Bong and Zahn also find fatty acids, cholesteryl esters, and wax esters as main components; however, they find polar lipids as major components. The fatty acids of this important component of human hair are predominately palmitic, stearic, and oleic acids." (Chemical and Physical Behavior of Human Hair by C. Robbins (p. 82))

"[It was] shown that the cell membrane complex lipids of hair fibers are degraded more by visible light, although these are also degraded by UV-A and by UV-B light helping to explain the weakened cell membrane complex and the multiple step fractures observed in sunlight oxidized hair [... It was also] demonstrated that the cell membrane complex lipids of chemically bleached hair are more readily degraded than the lipids of chemically unaltered hair. Longer-term irradiation does not provide for clean breakage between structural components of hair as was observed for peroxide oxidized hair." (Chemical and Physical Behavior of Human Hair by C. Robbins (p. 82))

- The cell membrane complex: three related but different cellular cohesion components of mammalian hair fibers: http://www.ncbi.nlm.nih.gov/pubmed/19691940

- Failure of intercellular adhesion in hair fibers with regard to hair condition and strain conditions: http://www.ncbi.nlm.nih.gov/pubmed/15386026

- Structural analysis of the cell membrane complex in the human hair cuticle using microbeam X-ray diffraction: relationship with the effects of hair dyeing: http://www.ncbi.nlm.nih.gov/pubmed/17342264

- Investigation of human hair cuticle structure by microdiffraction: direct observation of cell membrane complex swelling: http://www.ncbi.nlm.nih.gov/pubmed/11410283

- Lamellar subcomponents of the cuticular cell membrane complex of mammalian keratin fibres show friction and hardness contrast by AFM: http://www.ncbi.nlm.nih.gov/pubmed/12067362

Cuticle:

The two main fractions of the hair cuticle are the exocuticle and the endocuticle.
"Their chemical compositions are quite different. The proteins of the exocuticle and its A-layer are highly cross-linked by cystine (more than 30%)
and, therefore, are extremely tough and resilient. In contrast, the proteins of the endocuticle contain very little cystine (3 to 6%) and relatively large amounts of the dibasic and diacidic amino acids.
As a result of these large compositional differences, these two layers of the cuticle can be expected to react differently to permanent waves, bleaches, and even water and surfactants." (Chemical and Physical Behavior of Human Hair by C. Robbins (p. 80))

It was suggested that the cuticle of human hair contains more cystine, cysteic acid, proline, serine, threonine, isoleucine, methionine, leucine, tyrosine, phenylalanine, and arginine than does whole fiber. ((Chemical and Physical Behavior of Human Hair by C. Robbins (p. 80))

- Microscopical investigations on the epicuticle of mammalian keratin fibres: http://www.ncbi.nlm.nih.gov/pubmed/11903797

- Returning to the same area of hair surfaces before and after treatment: a longitudinal AFM technique: http://www.ncbi.nlm.nih.gov/pubmed/15230873
"LFM traces, however, showed regions between the ghost edge, marking the original position of the scale edge before cuticular erosion, and the existing scale edge, to have higher frictional properties than distal regions of the cuticle. A thin film of the leave-on product thus seems to form in this region and extends from the foot of the scale edge."

- Calculation of cuticle step heights from AFM images of outer surfaces of human hair: http://www.ncbi.nlm.nih.gov/pubmed/14578516

- Morphology and properties of Asian and Caucasian hair: http://journal.scconline.org/pdf/cc2006/cc057n04/p00327-p00338.pdf, http://www.ncbi.nlm.nih.gov/pubmed/16957811
Study of cuticle structures - the number of cuticle layers, width of the cuticle cells, degree of their inclination, and the interval between surface cuticle edges, etc.

- A quantitative method for analysing AFM images of the outer surfaces of human hair: http://www.ncbi.nlm.nih.gov/pubmed/9755495

meteor

March 23rd, 2016, 09:35 AM

So I found an interesting study that relates to the LHC stats pulled up on the previous page on hair thickness vs. length:

Relationships between hair growth rate and morphological parameters of human straight hair: a same law above ethnical origins? http://www.ncbi.nlm.nih.gov/pubmed/21951315
From Summary: "A thicker hair fibre corresponds to a faster growth rate, a shorter interscale distance (ISD) and greater probability to have a medulla, and vice versa, a thin hair fibre shows slower growth rate, a larger interscale distance and a lower probability to have a medulla."

They analyzed over 1,000 hair strands in total (from 6 Caucasian, 13 Japanese and 13 Chinese volunteers), focusing only on straight or semi-straight hair and excluding other variations in natural shape.

"Figure 3 shows direct relationship between interscale distance and growth rate, for each diameter cluster. There are direct relationships between diameter, growth rate and interscale distance, regardless of ethnic origin, with a statistical analysis of P < 0.0001."

"The fibre by fibre measurements of the growth rate, diameter and ISD seems to open new insight into human hair. Despite a great diversity of sizes within the same head of hair, all hair fibres seem to obey to the same law: the thicker the hair, the faster it grows and the shorter the ISD. These observations are consistent regardless of the hair origin. Our results showed on average that an 80-micron fibre would statistically show a growth rate of 0.38 mm per day with an ISD of 7.8 micron, irrespective of the ethnic origin of its ‘owner’.
Moreover, an increased hair growth rate does not only correspond to an increased hair length per time. Let us assume, in a given elementary hair volume, a constant ratio between cuticle cells (seen through ISD) and cortical cells (mostly seen through diameter as cortical cells are about 90%). Therefore, an increase in hair growth should correspond to a few additional cells produced by the hair follicle. These additional cells would presumably produce an additional volume, i.e. an additional diameter accounting at its square (D^2). Lastly, it can be inferred that a faster growth rate results in a faster supply of the cells from the follicle and thus closer cuticle cells, that is, a smaller ISD."

"With ageing, it is widely accepted that hair becomes sparse and thinner. For example, it was showed that, in female alopecia, total hair density (number of fibres per cm^2) declined with age, together with a clear decrease in the density of thicker hair. Our results fully support a link between hair diameter and growth rate, indicating a reduction in follicle cell renewal, the hallmark of biological ageing."

The study supports the link between having a medulla and increased diameter of the fiber. "Assuming again a correlation between diameter and follicle cell renewal, the decrease in the underlying biological activity of thin hairs does not seem to ‘program’ the formation of medulla".

Silverbleed

March 23rd, 2016, 04:22 PM

Ugh I want to read all of it! But I haven't had the time so far. I'm so curious about all the information you've found @_@

pinutzz

March 23rd, 2016, 05:04 PM

So I found an interesting study that relates to the LHC stats pulled up on the previous page on hair thickness vs. length
That article really explains a lot! Thanks for digging it up. I am amazed by how strong the correlation between thickness and growth rate is!

Sarahm

March 24th, 2016, 10:54 AM

Arctic

March 24th, 2016, 11:10 AM

Dear Hair Scientists,

Today, I bought a tube of aloe vera gel for my skin. Now off course I immediately thought I might use it in an SMT (Snowymoon's Moisture Treatment). But I have a question: it isn't 100% pure aloe vera gel. The ingredient list is:

Aloe barbadensis leaf juice, Acrylates/C10-30 alkyl acrylate crosspolymer, Glyceryl caprylate, Sodium benzoate, Potassium sorbate, Aqua, Sodium phytate, Sodium hydroxide.

Now my question is if these other ingredients would be harmful for my hair or not?
Thank you so much in advance.

I'm not a hair scientist, but here's my view anyway.

While I didn't google each ingredients (feel free to do so yourself, though), it looks fine. It will possible leave some residue (buildup) on your hair over time, but what wouldn't.

All comercial aloe gels are a mixture of ingredients: to keep it gel like, to preserve, to improve look and feel, and so on. Things to watch out for are, or at least what I pay attention to, the aloe juice's position on the inci list, how much the product says it has aloe juice (note this is different than saying 100% pure aloe vera), does it have drying alcohols or other ingredients I'd like to avoid, is the ingredient list relatively short and simple, and so on.

Your's looks pretty typical for a nice aloe gel INCI, from what I have seen them (again without googling each ingredient). Enjoy your SMTs!

Alex Lou

March 24th, 2016, 12:37 PM

Whoa, so much interesting information, meteor. I don't know how you found all this.

I found this site super interesting when it comes to genetics of hair color:
http://genetics.thetech.org/genetic-categories/hair-color

Arctic

March 24th, 2016, 01:53 PM

Meteor the front page index is looking really good! I feels it's a good idea, even if there wouldn't be a limited characters, to post locigally related subjects to individual posts, and leave the index more clear and clutterfree, with hyperlinks to the posts. The simpler the index, the easier it is to find stuff.

You have done amazing job thus far, I am still picking the crumbles of my broken jaw bone from the floor - I hit it so powerfully when I saw the whirlwind of hair related research material coming this way :D

***

I saw an interesting article. I didn't read it very throughly, only glanced, but based on what I did read, I dare to ask:

Are cowlicks worth celebrating after all??? Do cowlicks protect us from cancer??? What do Brad Pitt and fruit flies have in common??? *cue dramatic music*
https://www.sciencedaily.com/releases/2016/03/160323115502.htm

lapushka

March 24th, 2016, 02:17 PM

meteor

March 24th, 2016, 02:29 PM

Pinutzz, I was amazed by that high correlation, too. :agree:

Arctic, Alex Lou, those are fascinating articles. :thumbsup:

Sarahm, I agree completely with Arctic. :agree: All packaged aloe vera gels need stabilizers and preservatives like that. Sure, things like those salts and can be problematic at high concentrations, but they are probably included in that gel product at very low concentrations indeed, so nothing to worry about. :D
However, if you'd still like to avoid them, you could go for aloe vera juice (you still need to check the ingredients) or aloe vera gel straight from the plant (in this case, I'd recommend blending and straining it (though a cheesecloth or something) to remove fibers).

Arctic

March 24th, 2016, 02:55 PM

Sarahm

March 24th, 2016, 02:57 PM

Arctic, lapushka and meteor. Thank you for your quick replies. I tried researching a few ingredients on Google myself and I didn't find anything alarming but when it comes to hair, I tend to be careful.

So yay, I'll finally be able to experience the SMT magic myself.

There's a nice organic supermarket in Antwerp that sells aloe leaves. I considered buying them but I'm kind of intimidated by the size of them. I might have to look into the storage options, then.

meteor

March 25th, 2016, 07:33 PM

PhD thesis of Jutta Maria Quadflieg, if I understood correctly, the author behind the popular blog "The Natural Haven (http://www.thenaturalhavenbloom.com/)":

"Fundamental properties of Afro-American hair as related to their straightening/relaxing behaviour"
(http://sylvester.bth.rwth-aachen.de/dissertationen/2004/094/04_094.pdf)

Looks very interesting, too bad I don't have time to read!

That's an awesome thesis, Arctic! It gives a great overview of hair structure and effect of hair straightening and relaxing. And I've linked your post and the study to the list of studies on Hair Texture (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3193068&viewfull=1#post3193068).
(I know this work was referenced on JC's Natural Haven Bloom (e.g. here (http://www.thenaturalhavenbloom.com/2011/05/curly-vs-kinky-what-is-difference.html)), but I didn't know the author was the same? :hmm:)

Pinutzz, I came across another interesting study done by L'Oréal (Changes in Chinese hair growth along a full year:
https://www.researchgate.net/publication/264243256_Monthly_changes_in_hair_growth_parameter s_of_Chinese_subjects_observed_along_a_full_year) that shows (among other things) a strong positive relationship between strand diameter and growth rate: "Fig.9 illustrates, both genders included, a linear and highly significant correlation between both parameters, i.e the thicker the hair, the faster growing." (p. 13)

It's a pretty interesting study, because it focuses on that old question of possible seasonality of hair growth: (Note: in the study, "T" stands for Telogen, and "A" stands for Anagen)

"With regard to T%, Fig. 1a below illustrates the average changes in T% along a full year for Chinese subjects, for both genders, indicating a higher value in September, as compared to other months. Whereas Fig. 1b illustrates the average changes in A% along a full year, indicating a lower value in September. Separating genders indicate that such changes appear not only more pronounced in men but show an earlier onset (July) than women as shown by Fig. 2 However, all T% values remain in the range of a normal healthy head of hair (i.e. below 15%)."

From Summary (http://www.ncbi.nlm.nih.gov/pubmed/25065943): "Results show an increased rate of telogen hairs (growing arrest) around August-September in the study group, as previously reported in European subjects albeit of a lower extent and remaining within the normal range of healthy head hair parameters."

The study also notes some minor fluctuations month-to-month in strand diameter (not more than 5 microns, judging by the graphs). I'm glad to see this, as I've often sensed that the diameter isn't 100% uniform along the hair shaft (just by running fingers down a thick strand, for example).

As for hair density, it stays pretty stable (with very minor fluctuations):
"With regard to hair density, Chinese women present slightly higher values than men by about 10 hairs/cm2 (approx. 225 vs 215, respectively). However, hair density of both genders do not show significant changes along the year, the average monthly values oscillating around 220/cm^2." (p. 10)

Climatic influences discussion:
"Analyzing all parameters in connection with changes in climatic factors in Shanghai (T° and daylight duration) only indicates a non-significant trend (Fig. 10 below) towards increased T% average values (from about 9% to 12%) with increased daylight periods (ranging 10-14 hours). Variations in T° along the year do not seem to influence any of the recorded hair parameters. "

From discussion: "The data collected monthly over a full year globally confirms the existence of a seasonal hair growth cycle (increased T% at late summer) among Chinese subjects. As compared to other ethnics, Chinese hairs appear thicker and of a faster growth, in agreement with previous findings. In addition, this data confirms the strong link between hair growth and hair thickness (and inter-scale distance, not studied here) that was illustrated in a previous paper, by analyzing about 1600 individualized straight hairs from Asian subjects. " (p. 14)
"Similar to Caucasian subjects, Chinese subjects show a comparable timing in an increased T%, i.e around August/September, the extent of which being slightly lower (2 to 3% in absolute values) than that of the previously observed Caucasian subjects. However, the latter comprised a significant proportion of alopecia prone subjects (or entering in such process), unlike in Chinese volunteers studied here. It cannot be excluded that changes in T%, along the year, are much amplified in alopecia pre-disposed men. Such a possibility clearly calls for a similar protocol adapted to alopecia prone subjects, i.e. of a higher T% range (above 20%)." (p. 15)

meteor

March 25th, 2016, 09:01 PM

1.3 Mechanical damage: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

PART I

- The effect of brushing on hair loss in women: http://www.ncbi.nlm.nih.gov/pubmed/19016066

- Hair breakage during combing. I. Pathways of breakage: http://www.ncbi.nlm.nih.gov/pubmed/16832574

- Hair breakage during combing. II. Impact loading and hair breakage: http://www.ncbi.nlm.nih.gov/pubmed/16832575

- Hair breakage during combing. III. The effects of bleaching and conditioning on short and long segment breakage by wet and dry combing of tresses: http://www.ncbi.nlm.nih.gov/pubmed/17728947

- Hair breakage during combing. IV. Brushing and combing hair: http://www.ncbi.nlm.nih.gov/pubmed/18305876
"During combing of hair, longer fiber breaks (>2.5 cm) occur principally by impact loading of looped crossover hairs, while short segment breaks (<2.5 cm) occur primarily by end wrapping. Brushing provides breakage similarly but with a higher ratio of long-to-short segment breaks [...] bleaching hair, a longer comb stroke, increasing fiber curvature, wet combing versus dry combing, and brushing versus combing all provide for an increase in long segment breaks and this ratio, with the largest effect produced by brushing"

- Cuticle decementation and cuticle buckling produced by Poisson contraction on the cuticular envelope of human hair: http://journal.scconline.org/pdf/cc1998/cc049n04/p00213-p00222.pdf
"The experiments show that strain cycles at low extensions in dry hair fibers produce lifting and buckling at the cuticle edges. Strain-cycling experiments with swollen fibers indicate that decementation and buckling of the cuticles is caused by circular compression stresses on the cuticular envelope. It is also shown that this type of damage can be prevented and repaired by using appropriate hair swelling actives or by pretreating the fibers with appropriate polymeric substances capable of recementing the cuticles." (p. 221)

"Hair fibers that were pretreated with 3% aqueous solutions of glycerin or propylene glycol without rinsing, followed by a drying period of six hours, did not present severe patterns of cuticle lifting and buckling when strain-cycled. However, if the hair fibers were rinsed before cycling, cuticle decementation took place. These experiments indicate that the presence of small amounts of low-vapor-pressure swelling solvents in the hair fibers helps to swell and plasticize the cuticle, preventing lifting and buckling. Treatment of hair fibers with a 3% w/w aqueous solution of a cationically modified gluconamide compound was also effective in preventing cuticle lifting and buckling, even when the fiber was rinsed after treatment. The preventive effect of some cosmetic actives like these probably arises as a consequence of the presence of moisture or swelling solvents in the hair, which were already seen to inhibit cuticle lifting and buckling.
It was also observed that lifted and buckled cuticles returned to their normal appearance after immersion in water; a similar observation was also made by Reutsch et al. Decementation of the cuticles could, however, be easily brought back with a lower number of strain cycles at very low strain levels. This was not the case when the lifted cuticle cells were treated with a hydrolyzed wheat protein polysiloxane copolymer. This cosmetic active, which crosslinks upon drying, was seen to form a flexible thin film capable of recementing the lifted cuticles, increasing the decementing strain threshold. The thin film was also seen to be very smooth, i.e., in Figure 6 it is shown that the half portion of a hair fiber treated with this protein/copolymer is smoother than the other half, which was untreated. It is interesting to note that polymeric materials have been used in the past to stabilize the intercellular cement of wool.
An even stronger cuticle-cementing polymer was cystine polysiloxane; this proteinsilicone copolymer when used at 2% or 3% w/w levels was capable of rendering lifted cuticles very resistant to redecementation. For instance, it was observed that lifted and buckled cuticles returned to their natural position upon water immersion; however, when the hair fibers were tightly knotted, the cuticles lifted again. This was not the case when the cuticles were treated with a 3% aqueous solution of cystine polysiloxane prior to knotting." (p. 219 - 220)

- Hair Damage and Attempts to its Repair: http://journal.scconline.org/pdf/cc1987/cc038n04/p00263-p00286.pdf
"Owing to its unique composition and structure, human hair displays greater resistance to mechanical damage while dry than in the wet state. Structural integrity is derived mainly from the high density of disulfide bridges between cystine components of the protein. [...]
Surface despoliation, by mechanical abrasion in the wet state or by the chemical action of chlorine, bleaching, or dyeing compositions, is an important aspect of hair destruction, resulting in an increase in frictional coefficients and, consequently, combing forces."

- Fatigue testing of hair-a statistical approach to hair breakage: http://www.ncbi.nlm.nih.gov/pubmed/20038349

- A statistical analysis of hair breakage. II. Repeated grooming experiments: http://www.ncbi.nlm.nih.gov/pubmed/21241634
"In mechanical testing terms, the brushing and combing of hair represents a fatiguing process wherein individual strands experience repeated exposure to an external stimulus."

- Hair breakage by combing and brushing--a comment on: T. A. Evans and K. Park, A statistical analysis of hair breakage. II. Repeated grooming experiments: http://www.ncbi.nlm.nih.gov/pubmed/22682401
"Accumulated knowledge about hair breakage in these grooming processes indicates that hair breakage in combing and brushing results from tangling, looping, knotting, and impact loading. Fatiguing, though responsible for some weakening of the fiber in the grooming process, it is unlikely to be a significant factor in hair breakage in combing and brushing."

meteor

March 25th, 2016, 09:02 PM

1.3 Mechanical damage: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)

PART II

- Tensile properties of twisted hair fibers: http://www.ncbi.nlm.nih.gov/pubmed/15645104
"The major conclusion from this study was that at low and moderate twist levels, the tensile mechanical properties of human hair are recoverable."

- Torsional method for evaluating hair damage and performance of hair care ingredients: http://www.ncbi.nlm.nih.gov/pubmed/15645103
"Our results demonstrate that in fine diameter fibers with a high cuticle-to-cortex ratio, the cuticula exert a significant effect on the torsional deformation behavior of hair fibers at both normal humidities and in the wet condition. In addition, our data indicate that energy dissipation is confined to fibers with a high cuticle-to-cortex ratio, and the amount of energy dissipated becomes more pronounced with increasing water content. The torsional properties of hair spray-treated fibers suggest that the deposited hair spray film masks the properties of the base fiber and imparts its own dissipative character to the measurement. Since tensile mechanical properties are often used to make claims about the performance of hair care products, we have compared the results obtained from torsional and tensile measurements on over-processed bleached hair fibers conditioned with Polyquaternium-10 and cetyl trimethylammonium bromide (CETAB) to evaluate which method is more advantageous. Our data demonstrate that torsional measurements can distinguish hair care products which reinforce the cuticle from those which affect the cortex, while tensile measurements showed no significant differences."

- A critical review of the structural mechanics of wool and hair fibres: http://www.ncbi.nlm.nih.gov/pubmed/10771062

- A new deformation model of hard alpha-keratin fibers at the nanometer scale: implications for hard alpha-keratin intermediate filament mechanical properties: http://www.ncbi.nlm.nih.gov/pubmed/11916881

- Hair breakage index: an alternative tool for damage assessment of human hair: http://www.ncbi.nlm.nih.gov/pubmed/21635848
"Higher HBI value is an indicator of hair damage.A study was conducted for duration of 16 weeks to assess the effect of weathering due to grooming practices on HBI values. The HBI and break stress for a group of 30 subjects were measured at baseline and at the end of 16 weeks (NU). Since Coconut oil (CNO) is known to have a positive benefit on tensile properties of hair, another matched group of 30 subjects who oiled their hair daily with CNO was used as a positive control (CNO). The HBI and break stress for this group were also measured at the baseline and after 16 weeks. It was observed that the HBI significantly increased in the NU group versus the CNO user group. The break stress also significantly decreased in the NU group suggesting its correlation with the HBI data."

- The effect of treatments on the shear modulus of human hair measured by the single fiber torsion pendulum: http://journal.scconline.org/pdf/cc2007/cc058n04/p00329-p00337.pdf

- Evaluation of hair humidity resistance/moisturization from hair elasticity: http://www.ncbi.nlm.nih.gov/pubmed/17728940

- Effects of low-level hydrophobic substitution on conditioning properties of cationic cellulosic polymers in shampoo systems: http://www.ncbi.nlm.nih.gov/pubmed/15645097

- Hair breakage--how to measure and counteract: http://www.ncbi.nlm.nih.gov/pubmed/19450416

- Effects of conditioners on surface hardness of hair fibers: an investigation using atomic force microscopy: http://www.ncbi.nlm.nih.gov/pubmed/14730374

- Nanotribological effects of silicone type, silicone deposition level, and surfactant type on human hair using atomic force microscopy: http://www.ncbi.nlm.nih.gov/pubmed/16676122

- Semipermanent split end mending with a polyelectrolyte complex: http://journal.scconline.org/pdf/cc2007/cc058n04/p00451-p00476.pdf, http://www.ncbi.nlm.nih.gov/pubmed/17728946

- Morphological, nanomechanical and cellular structural characterization of human hair and conditioner distribution using torsional resonance mode with an atomic force microscope: http://www.ncbi.nlm.nih.gov/pubmed/16313489

- Investigation of scale effects and directionality dependence on friction and adhesion of human hair using AFM and macroscale friction test apparatus: http://www.ncbi.nlm.nih.gov/pubmed/16675116
"Since the coefficient of friction changes drastically (on any scale) depending on whether the direction of motion is along or against the cuticle scales, the directionality dependence and responsible mechanisms are discussed."

- Fractography of Human Hair: http://journal.scconline.org/pdf/cc1978/cc029n08/p00449-p00467.pdf
"The fracture pattern of fibres can be classified into three principal patterns depending on the nature of the resulting fractured fibre ends. These fracture patterns are: (i) Fracture occurring in a single plane perpendicular to the fibre axis, known as "smooth" fracture; (ii) fracture initiated in a plane perpendicular to the fibre axis and resulting in the splitting of the fibre along the axis known as "step" fracture; (ii) fracture with the fracture end split open giving the appearance of the bristles of a brush, known as "fibrillation"."

- Some simple theoretical considerations on the bending stiffness of human hair: http://www.ncbi.nlm.nih.gov/pubmed/19245472

- The mechanics of fracture of human hair: http://www.ncbi.nlm.nih.gov/pubmed/18503441
"A significant conclusion is that hair 'strength', as might be assessed by the consumer, has little to do with the tensile mechanical properties of the fibres but that bending and associated longitudinal shear processes are of much greater relevance."

meteor

March 25th, 2016, 10:05 PM

Conditioners: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187906&viewfull=1#post3187906)

- Hair cosmetics: http://www.ncbi.nlm.nih.gov/pubmed/2022094

- Hair shaft effects from cosmetics and styling: http://www.ncbi.nlm.nih.gov/pubmed/10439246

- Atomic force microscopy studies of conditioner thickness distribution and binding interactions on the hair surface: http://www.ncbi.nlm.nih.gov/pubmed/16551281

- Penetration of cationic conditioning compounds into hair fibers: a TOF-SIMS approach: http://www.ncbi.nlm.nih.gov/pubmed/16258698

- Time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of the application of a cationic conditioner to "clean" hair: http://www.ncbi.nlm.nih.gov/pubmed/15264054

- Protection of oxidative hair color fading from shampoo washing by hydrophobically modified cationic polymers: http://www.ncbi.nlm.nih.gov/pubmed/19450422

- Semi-permanent split end mending with a polyelectrolyte complex: http://journal.scconline.org/pdf/cc2007/cc058n04/p00451-p00476.pdf, http://www.ncbi.nlm.nih.gov/pubmed/17728946

- Morphological, nanomechanical and cellular structural characterization of human hair and conditioner distribution using torsional resonance mode with an atomic force microscope: http://www.ncbi.nlm.nih.gov/pubmed/16313489

- Investigation of scale effects and directionality dependence on friction and adhesion of human hair using AFM and macroscale friction test apparatus: http://www.ncbi.nlm.nih.gov/pubmed/16675116

- Effects of conditioners on surface hardness of hair fibers: an investigation using atomic force microscopy: http://www.ncbi.nlm.nih.gov/pubmed/14730374
"This latter study has led to a rather definite conclusion that the scale face is indeed softened by polymeric conditioners such as Polyquaternium-10 (PQ-10)."

- Evaluation of hair humidity resistance/moisturization from hair elasticity: http://www.ncbi.nlm.nih.gov/pubmed/17728940

- The effect of treatments on the shear modulus of human hair measured by the single fiber torsion pendulum: http://www.ncbi.nlm.nih.gov/pubmed/17728933

- Hair breakage - how to measure and counteract: http://www.ncbi.nlm.nih.gov/pubmed/19450416

- A statistical analysis of hair breakage. II. Repeated grooming experiments: http://www.ncbi.nlm.nih.gov/pubmed/21241634

INGREDIENTS:

Silicones:

- Nanotribological effects of silicone type, silicone deposition level, and surfactant type on human hair using atomic force microscopy: http://www.ncbi.nlm.nih.gov/pubmed/16676122

Silicone Solubility List: http://science-yhairblog.blogspot.com/2014/04/silicone-ingredient-solubility-list.html

Hydrolyzed Proteins:

- http://science-yhairblog.blogspot.ca/2012/02/how-hot-is-too-hot-for-healthy-hair.html "It was notable that when hair was wetted in a solution containing 2% glycerin or propylene glycol instead of plain water, the cracks did not develop. But “conditioning agents” such as Polyquaternium-11, Cetrimonium chloride, and Stearylkonium chloride did not prevent cuticle cracking. Triglycerides, silicones, mineral oils and petrolatum also did not prevent cracking. The protein polymer, hydrolyzed wheat protein polysiloxane copolymer was found to prevent cuticle cracking. Other proteins and conditioners were not tested. Other testing has demonstrated that P/DMAPA Acrylates Copolymer and Polyquaternium-55 have good heat-protecting qualities."

- Cuticle decementation and cuticle buckling produced by Poisson contraction on the cuticular envelope of human hair: http://journal.scconline.org/pdf/cc1998/cc049n04/p00213-p00222.pdf
"Decementation of the cuticles could, however, be easily brought back with a lower number of strain cycles at very low strain levels. This was not the case when the lifted
cuticle cells were treated with a hydrolyzed wheat protein polysiloxane copolymer. This cosmetic active, which crosslinks upon drying, was seen to form a flexible thin film capable of recementing the lifted cuticles, increasing the decementing strain threshold. The thin film was also seen to be very smooth, i.e., in Figure 6 it is shown that the half portion of a hair fiber treated with this protein/copolymer is smoother than the other half, which was untreated. It is interesting to note that polymeric materials have been used in the past to stabilize the intercellular cement of wool. An even stronger cuticle-cementing polymer was cystine polysiloxane; this proteinsilicone copolymer when used at 2% or 3% w/w levels was capable of rendering lifted cuticles very resistant to redecementation. For instance, it was observed that lifted and buckled cuticles returned to their natural position upon water immersion; however, when the hair fibers were tightly knotted, the cuticles lifted again. This was not the case when the cuticles were treated with a 3% aqueous solution of cystine polysiloxane prior to knotting." (p. 219 - 220)

Amino Acids:
- Hair and amino acids: the interactions and the effects: http://www.ncbi.nlm.nih.gov/pubmed/17728935

Basics on hydrolyzed proteins: http://science-yhairblog.blogspot.com/2015/10/protein-101-lots-of-basic-information.html and http://science-yhairblog.blogspot.com/2013/09/more-about-protein.html

Protein size - http://www.thenaturalhavenbloom.com/2009/06/size-matters-protein-conditioning-part.html)

Humectants:

Film-forming humectants: (blog) http://science-yhairblog.blogspot.com/2014/07/film-forming-humectants-what-they-are.html

Glycerin:

- Cuticle decementation and cuticle buckling produced by Poisson contraction on the cuticular envelope of human hair: http://journal.scconline.org/pdf/cc1998/cc049n04/p00213-p00222.pdf
"Hair fibers that were pretreated with 3% aqueous solutions of glycerin or propylene glycol without rinsing, followed by a drying period of six hours, did not present severe
patterns of cuticle lifting and buckling when strain-cycled. However, if the hair fibers were rinsed before cycling, cuticle decementation took place."

Polymers:

- Conditioning polymers in today's shampoo formulations - efficacy, mechanism and test methods: http://www.ncbi.nlm.nih.gov/pubmed/18503458

- Quantitative methods for evaluating optical and frictional properties of cationic polymers: http://www.ncbi.nlm.nih.gov/pubmed/11382843

- Surfactants, polymers and their nanoparticles for personal care applications: http://www.ncbi.nlm.nih.gov/pubmed/15645085

- Polymer/surfactant interactions and nanostructures: current development for cleansing, release, and deposition of actives: http://www.ncbi.nlm.nih.gov/pubmed/21635852

- Effects of low-level hydrophobic substitution on conditioning properties of cationic cellulosic polymers in shampoo systems: http://www.ncbi.nlm.nih.gov/pubmed/15645097

- Evaluation of novel synthetic conditioning polymers for shampoos: http://www.ncbi.nlm.nih.gov/pubmed/19450423

- New high-charge density hydrophobically modified cationic HEC polymers for improved co-deposition of benefit agents and serious conditioning for problem hair: http://www.ncbi.nlm.nih.gov/pubmed/17728943

- Determination of physicochemical properties of delipidized hair: http://www.ncbi.nlm.nih.gov/pubmed/24139434
"[...]differences were found in the chemical composition and physical behavior of virgin and delipidized hair. To better understand the influence of hair lipid composition on hair styling treatments, we conducted mechanical analyses of hair shaped into omega loops to determine the stiffness, elasticity, and flexibility of hair-polymer assemblies. Although there were no discernible differences between untreated virgin and delipidized hair, in terms of stiffness and elasticity, we found that treatment with hair styling agents produced different effects depending on the hair type used. Likewise, streaming potential measurements were carried out to monitor the binding capacity of rinse-off treatments on virgin and delipidized hair. Using this technique, we monitored the surface potential of hair and found significant differences in the binding behavior of cationic polymers and surfactants (polyquaternium-55 and quaternium-26) on both hair types."

- Mechanical analysis of elasticity and flexibility of virgin and polymer-treated hair fiber assemblies: http://www.ncbi.nlm.nih.gov/pubmed/12512012

- Use of quaternized cassia galactomannan for hair conditioning: http://www.ncbi.nlm.nih.gov/pubmed/18305877

- Use of statistical modeling to predict the effect of formulation composition on coacervation, silicone deposition, and conditioning sensory performance of cationic cassia polymers: http://www.ncbi.nlm.nih.gov/pubmed/21635845

Arctic

March 26th, 2016, 02:29 AM

That's an awesome thesis, Arctic! It gives a great overview of hair structure and effect of hair straightening and relaxing. And I've linked your post and the study to the list of studies on Hair Texture (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3193068&viewfull=1#post3193068).
(I know this work was referenced on JC's Natural Haven Bloom (e.g. here (http://www.thenaturalhavenbloom.com/2011/05/curly-vs-kinky-what-is-difference.html)), but I didn't know the author was the same? :hmm:)

It might be that they are different persons, the source is marked in a unclear way, and since her husband draw the models I thought that maybe they are the same. I might be totally wrong, because the blog author hasn't been telling her name anywhere, that I could found (I tried to check if it's really her).

But I agree, awesome thesis from the little glance I had time to go through it, and nice photos!

meteor

March 26th, 2016, 06:51 PM

I found a couple more interesting studies on oils:

1) Quantitative measurement of the penetration of coconut oil into human hair using radio-labeled coconut oil: http://journal.scconline.org/pdf/cc2012/cc063n01/p00027-p00032.pdf
This new method used a scintillation fluid to radioactively tag the coconut oil. The researchers were then able to track how much of the oil actually penetrated into the hair versus how much stayed on the surface.
After adjusting for the surface oil in the samples taken for the total oil measurement, the study showed that hair absorbed:
- around 14.5% - 21.5% of its weight in coconut oil in 1 hour;
- around 20.4% - 26.3% of its weight in coconut oil in 6 hours. (Table 1, p. 4)

2) Brazilian oils and butters: the effect of different fatty acid chain composition on human hair physiochemical properties: http://journal.scconline.org/pdf/cc2009/cc060n02/p00273-p00280.pdf, http://www.ncbi.nlm.nih.gov/pubmed/19450426

SUMMARY:

The five oils used in this work were:
- passion fruit seeds extract (Passifl ora edulis),
- Brazilian nuts extract (Bertholletia excelsa),
- palm olein (a low-melting fraction of palm oil (Elaeis Guineensis)),
- buriti extract (Mauritia flexuosa) and
- palm stearin (the most solid fraction of palm oil (Elaeis Guineensis)).

The three butters used in this work were:
- tucumã (Astrocarium tucuma),
- ucuúba (Virola surinamensis) and
- sapucainha (Carpotroche brasiliensis).

Mineral oil was used as the control.

The composition of the fatty acids is described as follows:
- passion fruit seed (77% linoleic acid),
- Brazilian nut (38% oleic acid and 35% linoleic acid),
- palm olein (47% oleic acid),
- buriti (79% oleic acid),
- palm stearin (42% palmitic acid and 41% oleic acid),
- tucumã (48% lauric acid and 27% myristic acid),
- ucuúba (75% myristic acid),
- sapucainha (47% chaulmoogric acid, 27% hidnocarpic and 19% gorlic acid).

"This study evaluated the performance of five oils and three butters extracted from Brazilian plants with different fatty chain composition on hair mechanical properties, split end formation, combing analysis and gloss measurements. Oil treatment reduced the combing force percentage for wet conditions. However, the hair treated with butters showed poor combing. Except for ucuúba butter, oils and butters used in this work had generally no influence on hair tensile properties. In general, hair treated with oils showed a significant gloss increase and a decrease for split end formation. The fatty acid composition of the oils and butters tested showed an effect on the physicochemical properties of hair."

RESULTS:

1. GLOSS:
"All treatments provide an increase in the gloss difference of the hair tress compared to reference (tresses before treatment). [...] Treatments were statistically different among themselves and between the hair tresses treated and the reference. The buriti and mineral oils render the highest significant values of gloss difference. As expected, oils promote higher gloss difference than butter. These effects are closely related to the lubricating and the easy spreading characteristics of oils on the hair."

2. SPLITS:
"Treatments using oils reduced the formation of split ends in the hair compared to reference. Tresses treated with Brazilian nut and mineral oils gave the lowest formation of split ends which was around 4 split ends per gram of hair."

3. COMBING:
"Oil treatments rendered about a 60% reduction of combing force at wet conditions. The reduction of combing forces is a combination of water wetting and the lubricant effects of the oil on the fibers. Butters, however, increased the combing force giving negative values for the reduction of combing force percentage. As expected, butters in raw state are not as fluid as oils and do not spread easily along hair tresses. The Brazilian nut, passion fruit seed, palm olein, buriti and mineral oils (control) produced a combing force reduction statistically different from the reference (hair tress before treatment)."

"In dry condition combing analysis, the reduction of combing force percentage is around 19% and statistically different after treatments with Brazilian nut, passion fruit seed and mineral oil. Once again, butters rendered negative values of reduction of combing force percentage. This results point that the lubricating effect of oils is less pronounced to dry tresses."

4. TENSILE STRENGTH:
"A slight but statistically significant increase in the stress at break was observed for the hair treated using ucuúba butter. The other treatments showed no difference compared to the reference."

Discussion:
"The combing facility is the result of the decrease in friction on the hair surfaces. The degree of the triglycerides attachment to the hair surface is influenced by its molecular chain conformation and is responsible for the increase or decrease of frictional forces. The oils composed of triglycerides with linear chain, lower ramification and higher number of carbons may increase the film formation, which results in the best spreading. The triglycerides chains with more ramifications and high melting point may decrease the spreading by increasing frictional force, which explains the behavior of butters on the hair observed in this study."

- Buriti oil is very homogeneous in its fatty acid distribution (79% of oleic acid) -> smoother surface, high specular light reflection from surface (i.e. gloss).

- Ucuúba butter showed a slight increase in the stress to break (i.e. increase in tensile strength). "This butter has a high amount of low molar mass triglycerides composed of short and straight linear fatty acid chains (75% miristic acid). This may point to the conclusion that low molecules from vegetal origin are able to diffuse into hair fiber. It is observed with coconut oil, which has lauric acid in its major composition."

- Mineral oil has no affinity to hair’s proteins, not able to diffuse in the fiber. "Mineral oil main effects are its higher spreading capability on the hair surface which improves gloss, combing facility and reduces split end formation."

LongCurlyTress

March 26th, 2016, 07:24 PM

Absolutely fascinating scientific test results meteor!! Thank you so much for sharing! :cool:

meteor

March 27th, 2016, 04:24 PM

^ I'm so happy you like it, LongCurlyTress! :flowers:

I found it interesting how they broke down performance of oils by gloss, combing (wet & dry), tensile strength and prevention of split end formation.

It was great to see confirmation that:
- oils reduce split end formation,
- spreadability & lubrication are responsible for gloss (so runnier oils give more gloss),
- short and straight linear fatty acid chains responsible for added strength (so I'd go for coconut oil with its lauric acid, ucuúba butter with its miristic acid and other oils in this category for pre-poo treatments, for example),
- butters actually increase combing force, both wet and dry (I've often noticed that cocoa or shea butter make hair stickier and much harder to detangle),
- oils reduce combing force (especially when wet - by 60%, only by 19% when dry -> so for curlies/wavies who love detangling soaking wet hair in the shower with conditioner, I'd recommend doing it with an added oil rinse to reduce combing force ;) )

It also shows some of the reasons why mineral oil is so well loved: it was consistently among top performers for added gloss, easier combing (both wet and dry) and reduction in split end formation. :thumbsup:

And while I'm on an oil kick, I wanted to share another study, this one on much-loved argan oil and cupuassu butter:
- Hair Protective Effect of Argan Oil (Argania spinosa Kernel Oil) and Cupuassu Butter (Theobroma grandiflorum Seed Butter) Post Treatment with Hair Dye: http://dx.doi.org/10.4236/jcdsa.2013.33A1006

They've measured damage by protein loss albumin equivalent of hair samples for:
- untreated hair (I);
- treated with a commercial oxidative ultra-blond hair dye (II);
- post treatment II (i.e. after oxidative ultra-blond hair dye) and F1: base hair care formulation/conditioner (III),
- post treatment II and F2: Base hair care formulation containing 1.0% (w/w) Argania spinosa kernel oil (IV);
- post treatment II and F3: Base hair care formulation containing 1.0% (w/w) Theobroma grandiflorum seed butter (V); and
- post treatment II and F4: Base hair care formulation containing 0.5% (w/w) Argania spinosa kernel oil and 0.5% (w/w) Theobroma grandiflorum seed butter (VI).

"Using conditioners on hair (III, IV, V and VI treatments) has a positive effect on reducing of protein loss in hair post treated with a commercial oxidative ultra-blond hair dye. The effectiveness of (III treatment) are expected, since the base hair care formulation contains a cationic compounds (cetrimonium chloride and behentrimonium methosulfate), which is substantive to hair and adsorbs on hair surface following a charge-driven mechanism and silicone (PEG-12 dimethicone) that involved their adsorption to the hair fiber, because of its hydrophobic characteristics that reduce the intermolecular forces and surface tension leading to the formation of a hydrophobic film other the cuticle.
The addition of Argania spinosa kernel oil and/or Theobroma grandiflorum seed butter in the base hair care formulation (IV, V and VI treatments) statistically reduced the protein loss when compared to just base formulation (III treatment). This difference in results could arise from the composition of each of these oils."

Interestingly, judging by the graph (p. 4) protein loss was at its lowest when the tresses were treated with formulation with 1% argan oil. So there's some support for the widespread love of argan oil in hair care products.

:!:Now, of course, I wish they'd done a test like that by PRE-treating hair with oils of different kinds before bleach/dye (and maybe other chemical treatments), rather than AFTER the fact.
That would help us figure out if coconut oil and argan oil actually do prevent some peroxide damage (as many of us believe: http://forums.longhaircommunity.com/showthread.php?t=10495), and, if so, to what extent exactly. :hmm:

meteor

March 27th, 2016, 04:30 PM

Drying capacity of oils: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187906&viewfull=1#post3187906)

How drying capacity of oils can relate to hair: (blog) http://ktanihairsense.blogspot.com/2011/12/understanding-drying-capacity-of-oils.html

Organic Analysis: A Manual of the Descriptive and Analytical Chemistry of Certain Carbon Compounds in Common Use (pp. 282 - 284)

List of common hair/skin oils and their iodine values: http://thesoapdish.com/oil-properties-chart.htm
Alternatively: http://soapcalc.net/calc/OilList.asp (Click on "Iodine Value" and "download" if you want to get it in Excel file.)

Iodine value < 100 : Non-drying oil (Contact with oxygen does not cause any appreciable drying.)
Iodine value 100 - 130 : Semi-drying oil
Iodine value 130 - 190+ : Drying oil (They dry, oxidize, polymerize fairly rapidly on contact with atmospheric oxygen and can leave resinous build-up if used very heavily.)

The iodine value is a measure of the amount of unsaturated fatty acids in the oil. A fatty acid that is missing any hydrogen atoms is classified as unsaturated. The higher the iodine value, the greater the amount of "unsaturation" and the less stable the oil is and the more vulnerable it is to oxidation and free radical production with time and heat. Oils rich in polyunsaturated fats tend to have higher iodine value.

MsPharaohMoan

March 29th, 2016, 07:20 PM

pinutzz

March 30th, 2016, 07:06 AM

Pinutzz, I came across another interesting study done by L'Oréal (Changes in Chinese hair growth along a full year:
https://www.researchgate.net/publication/264243256_Monthly_changes_in_hair_growth_parameter s_of_Chinese_subjects_observed_along_a_full_year) that shows (among other things) a strong positive relationship between strand diameter and growth rate: "Fig.9 illustrates, both genders included, a linear and highly significant correlation between both parameters, i.e the thicker the hair, the faster growing." (p. 13)

Thanks, meteor! It is always good to know that several groups report the same thing.

After looking at the statistics of the self reported hair thickness of users on this forum recently it has become somewhat obvious that most people report their thickness (ie fine / medium / coarse) wrong. Maybe for those that dye their hair it would be better to measure how fast their hair grows from the color change at the roots and find out their hair thickness that way.

meteor

March 30th, 2016, 03:28 PM

Here's my question: what's the science behind hot spots? Another thread popped up discussing it http://forums.longhaircommunity.com/showthread.php?t=88063&page=3 I wish there was a way to look super close at the scalp when it's clean and when it's feeling inflamed!

I'm not too sure about the definition of a "hot spot"? :hmm: The only definition I found was for "acute moist dermatitis"... but I don't really think that's necessarily what that thread was talking about... more likely accumulation of oils that needed to be cleansed? :hmm:

If you mean by a "hot spot" the situation when the skin gets wet and doesn't try fast enough, yes, it can lead to problems, especially of the fungal kind (fungi love dark, wet environments, especially where they are sheltered by clothing or hair).

Also, oils sitting on scalp - either sebum or plant oils rich in oleic acid - can feed Malassezia fungus directly linked to seborrheic dermatitis:

- Three etiologic facets of dandruff and seborrheic dermatitis: Malassezia fungi, sebaceous lipids, and individual sensitivity: http://www.ncbi.nlm.nih.gov/pubmed/16382685

- Malassezia Fungi Are Specialized to Live on Skin and Associated with Dandruff, Eczema, and Other Skin Diseases: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3380954/

- Malassezia globosa and restricta: breakthrough understanding of the etiology and treatment of dandruff and seborrheic dermatitis through whole-genome analysis: http://www.ncbi.nlm.nih.gov/pubmed/18004291

- Seborrheic dermatitis: etiology, risk factors, and treatments: facts and controversies: http://www.ncbi.nlm.nih.gov/pubmed/23806151

One can also have atopic dermatitis and other forms of dermatitis... it's just hard to pinpoint because one can have similar symptoms and those uncomfortable, itchy "hot spots" from a bunch of different conditions... :hmm:

This general study might be of interest, I think:

- Sensitive Scalp: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3500070/

"Scalp sensitivity may be varied according to scalp characteristics and was clearly more frequent and intense in patients with greasy or dry scalps. Scalp sensitivity, probably, belongs to sensitive skin syndrome and most patients declared sensitive skin in another area.[6–8]

In our experience, sensitive scalp is often seen in the individuals with atopic background.[5,6] Psychogenic factors[6,7] or sudden alteration in weather, especially during winter, may precipitate the symptoms in Indian patients. Erythema may be sometimes observed[5] but we believe, pustule formation is rare in untreated sensitive scalp. Local scalp diseases of scalp may occasionally play a role in exacerbation. Practice of head massage with herbal oils is common in India. This involves vigorous rubbing of hair oil in the scalp, which might result into pustule formation due to mechanical and microbial factors (secondary bacterial invasion), as it happened in our patient.

The pathogenesis of sensitive scalp is poorly understood. Frequent shampooing is an important predisposing factor for scalp sensitivity, which could be due to disturbance of barrier function resulting from excessive transepidermal water loss, thus permitting increased exposure to detergents."

Arctic

April 3rd, 2016, 01:11 AM

Lot of cool photos of hair and scalp (from doctor specialized in hair restoration and hair loss conditions): https://www.instagram.com/donovanmedical/ (https://www.instagram.com/donovanmedical/)

meteor

April 3rd, 2016, 11:18 AM

^ That's so great! :D Thank you so much, Arctic! :flowers: I've added your post to the first list with links on Hair/Scalp Photos (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3189819&viewfull=1#post3189819). ;)

meteor

April 3rd, 2016, 03:47 PM

So I often hear stories about how chemical treatments can be tolerable for some hair but breaking off other hair. So it's hard to tell in advance if hair can take it or not. I think it's clear that individual hair structure (e. strand thickness, porosity...), conditioning and the technical variations in specific chemical treatments account for a big part of the differences. But I also wonder if split ends that often happen on bleached (or otherwise chemically treated) hair are more about a combination of bleach + mechanical damage of wear & tear post-chemical treatment, rather than simply bleach (or other chemical treatment) alone. Basically, bleach breaks disulfide bonds and weakens the hair's structure, making it more fragile, but if you bleach some tresses and then hide them in a drawer, they won't automatically develop split ends, IMHO. I think hair needs to go through some mechanical stress to develop splits, breakage... but that result will be easier to achieve on chemically treated (impaired) hair. I think that's what we mean when we say that chemically treated hair needs extra protection and reduction in manipulation. What do you guys think? :)

I think this interesting study does cover this topic a bit (though indirectly):

Tensile Strength of Bleached and Sun-Bleached Hair

Study:
- True porosity measurement of hair: a new way to study hair damage mechanisms: http://journal.scconline.org/pdf/cc2008/cc059n04/p00303-p00315.pdf, summary: http://www.ncbi.nlm.nih.gov/pubmed/18818850

Results:

BLEACH DAMAGE:

The oxidation of cystine due to bleach causes the disruption of crosslinks, which results in the reduced wet tensile strength.

The wet hair tensile strength analysis showed a significant decrease in breaking force (about 20%) after the 1st minute of bleaching, then stabilization and then another decrease in breaking force after 10 min. (pp. 305 - 306)

Tensile strength of bleached hair

Bleaching Time (min)
0
1
5
10
15
20

Total Work Force for Breaking Hair (mJ)
1.718
1.306
1.442
1.118
1.188
1.054

(based on p. 306, see statistical analysis on p. 306 for details)

"The oxidative attack on hair not only causes the breakage of disulfide bonds in hair protein, but it also breaks down the melanins. Wolfram and co-workers (16,17) have investigated the oxidation of human hair with and without pigment. Their research concluded that hair with pigment consumes hydrogen peroxide at a measurably faster rate than hair without pigment, suggesting a faster reaction of peroxide with hair pigment than with hair protein. Based on that conclusion, the initial response of oxidative damage to hair fiber should be color change." (p. 306)
^I wonder, maybe that's why coconut oil is a good oil pre-bleach (due to its affinity to hair's protein, it can protect the hair's protein a bit, while still allowing color to lighten? :hmm:

"The virgin hair has a set of pores that essentially triple (2.83 times) after 1 min of bleaching. The number of pores increases lightly after 5 min of bleaching. The next significant change happens after 10 min, in which the surface area decreases to almost that of the virgin hair. This might be due to the smaller pores breaking down into larger pores. The 15 min of bleaching time is just more of the smaller pores breaking down to form larger pores, while the 20 rain of bleaching time gives a slightly higher surface area, possibly indicating penetration of the walls between the newly created larger pores." (p. 309)

UV DAMAGE:

"UV light degrades the amino acids of the hair fiber at the outer layer (cuticle) to a greater extent than the inter layer (cortex). The work of Ruetsch et al. from
the Textile Research Institute (20) has shown microscopically that fusion reactions of UV irradiation happen more in the periphery of hair, where it receives higher intensities of radiation than at the core, providing the smooth break at the periphery and fractures toward the interior of hair following a multiple-step process." (p. 309)

Tensile Strength:
Several other studies have proven that UV light decreases the wet tensile properties of hair (22). [...] [This study] indicates that the tensile strength already shows a noticeable decrease after 200hr of UV exposure, and it remains unchanged after 400 hours. Finally, there is another significant decrease after 1200 hr of exposure. The results illustrate that UV irradiation already attacks the hair cortex in a relatively short period of time, resulting in decreased tensile strength. However, much longer UV exposure times are needed to further damage the cortex after the initial damage occurs." (p. 310)

Tensile strength of UV-damaged hair

Exposure Time (Hr)
0
200
400
1200

Total Work Force for Breaking Hair (mJ)
1.718
1.143
1.049
0.681

(based on p. 310)

The study shows an immediate loss in surface area in the first 200 hr of exposure to UV rays and a gradual increase as exposure time continues, which is most likely due to the fusion of cuticle cells followed by an increase in pores or cracks.

"We have also found that the different parts of hair show different porosity: hair toward the root has much less porosity than the tip ends, which indicates that hair is more damaged in the tips due to abrasive combing." (p. 314)

meteor

April 5th, 2016, 01:05 PM

Water Hardness, Mineral Build-Up, Chelating: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187906&viewfull=1#post3187906)

PART I

Hard water build-up can make hair feel more dry than normal or more rigid/coarse to touch. It may cause hair to look more dull and frizzy.
Chlorine can feel drying, and its concentrations in some water areas are higher. The highest concentrations tend to be in chlorinated pools, which is why chelating/swimmers' shampoos/packs, rinsing and conditioning after-pool, and oiling/conditioning pre-pool are good practice for swimmers.
Copper can leave more greyish-greenish tones, iron can leave more brassy tones - this is an issue for light-colored hair, especially after long-term exposure without chelating.

Hair tends to have negative charge along cuticle edges and in damaged areas (the more damaged, the more pronounced this effect is). Because positive and negative charges attract - both cationic conditioners and mineral cations from hard water can bind to hair. So damaged hair (e.g. bleached, relaxed, etc) not only absorbs more conditioners, it also absorbs more metals from water.

- Copper and calcium uptake in colored hair: http://www.ncbi.nlm.nih.gov/pubmed/19586601
"During hair coloring a number of disulfide bonds in cystine are oxidized (1) to create cysteic acid, forming binding sites for metal ions such as Ca(2+ ) and Cu(2+ ) from tap water. The increased uptake of these metals can have a detrimental impact on fiber properties-for example, reducing shine and causing a poor wet and dry feel. In addition, the increased uptake of copper can also contribute to further fiber damage during subsequent coloring due to its ability to take part in metal-induced radical chemistry."

- Preserving fibre health: reducing oxidative stress throughout the life of the hair fibre: (P&G study) http://onlinelibrary.wiley.com/doi/10.1111/ics.12285/full
Investigates two mechanisms of damage - hair colouring and UV exposure - where oxidative processes are involved. The role of copper in these oxidative processes was then investigated: its presence in hair and its consequent impact on hair damage via free radical formation. Finally, the role of chelants N,N'-ethylene diamine disuccinic acid (EDDS) and histidine was discussed.
Focus on copper, calcium, magnesium, iron.
"Exogenous copper is both present inside hair coming from tap water and causes oxidative degradation to proteins."
"It is well known that even very low levels of metals such as copper can accelerate free radical generation due to their catalytic nature. This is supported by the fact that we do see a correlation between self-perception of hair damage and level of copper in hair."

- The role of chelants in controlling Cu(II)-induced radical chemistry in oxidative hair colouring products: http://www.ncbi.nlm.nih.gov/pubmed/22950483
"The ability of chelants ethylenediamine tetraacetic acid (EDTA) and N,N'-ethylenediamine disuccinic acid (EDDS) to moderate the flux of hydroxyl radicals formed in solution systems was demonstrated in the presence of copper ions alone. However, only EDDS was successful in the presence of both calcium and copper ions. This was confirmed in the hair experiments where again only EDDS was successful at preventing hydroxyl radical formation where hair is added as the source of copper and calcium ions. These results are explained using metal speciation modelling and demonstrate the importance of the chelant to be able to specifically bind and prevent the one-electron redox chemistry of copper in the presence of high levels of calcium ions as found in hair. The formation of hydroxyl radicals during the colouring process was shown to lead to hair structure damage as measured by protein loss. EDDS was demonstrated to significantly reduce cuticle damage by suppressing the formation of the hydroxyl radicals in systems with realistic concentrations of calcium and copper."

- Advanced hair damage model from ultra-violet radiation in the presence of copper: http://www.ncbi.nlm.nih.gov/pubmed/25923177
"The role of copper in accelerating UV damage to hair has been demonstrated as well as the ability of chelants such as EDDS and histidine in shampoo and conditioner products to reduce this damage."

- Hair coloring systems delivering color with reduced fiber damage: http://www.ncbi.nlm.nih.gov/pubmed/17938825
"The possible metal-induced formation of free radical species such as the hydroxyl radical (HO*) during the use of permanent hair coloring products has been demonstrated. These highly reactive species are formed from the reaction of hydrogen peroxide with redox metals such as copper, which are thought to be absorbed by the hair from the from-the-tap wash water. Formation of such radical species has been shown to lead to measurable keratin fiber damage. The incorporation of chelants such as N,N'-ethylenediamine disuccinic acid (EDDS) has been demonstrated to prevent this metal-induced radical formation and thus significantly reduce the fiber damage. This chelant is highly effective due to its ability to specifically bind low levels of copper in the presence of relatively high levels of calcium, as is found in hair."

- Role of copper in photochemical damage to hair: http://www.ncbi.nlm.nih.gov/pubmed/23962007
"We have also identified for the first time in hair the role of exogenous copper in increasing UV damage both in terms of total protein degradation and also increased formation of the marker fragment and proposed a mechanism of action. It has been demonstrated that shampoo treatment containing a chelant such as N,N'-ethylenediamine disuccinic acid (EDDS) reduced copper accumulation in hair."

- The uptake of water hardness metals by human hair: http://journal.scconline.org/pdf/cc2011/cc062n04/p00383-p00392.pdf
Summary: http://www.ncbi.nlm.nih.gov/pubmed/21982353

The most-damaged hair showed the highest mineral uptake, because of reduction in fatty-acid 18-MEA layer (which repels water and cations). But lightly damaged and virgin hair also took up mineral cations.

"Upon treatment with alkaline hydrogen peroxide products, peptide and disulfide bonds inside the hair and 18-methyleicosanoic acid (18-MEA) on the hair’s surface are cleaved. This exposes anionic carboxylate and sulfonate (of cysteic acid) groups, which render the hair an ideal cation exchange resin. It should be noted that the calcium and magnesium levels of the highly damaged hair are comparable to the levels found in the hair of consumers who regularly use oxidative colorant products." (p. 386)

The harder the water, the more minerals bonded with all hair - but in the same pattern - more damaged hair takes up more mineral cations.
The higher the pH of your water, the more minerals will bind to your hair from hard water. In pH 7 ("neutral") water, both bleached and unbleached hair took up lesser amounts of mineral cations than in pH 8 and pH 9 water (see Figure 3 on p. 389 of the study for details). As the pH of water goes up, the amount of minerals that will bind to hair (or penetrate hair) goes up too, but more significantly for already damaged hair.

"A positive relationship between water pH and metal uptake was observed. This can be related to the binding capacity of the hair because as pH increases, more groups become available for metal interaction due to the progressive ionization of carboxyl groups and amino groups participating in electrostatic interactions with carboxyl groups. Similar pH-dependent increases in the uptake of cationic moieties by keratin and other charged macromolecules have been reported. "

From Conclusion:
"Hair that contains more anionic moieties, the result of chemical treatments such as bleaching and chemical relaxing, has a higher cationic binding capacity and is thus more susceptible to water hardness metal uptake than virgin hair. At a certain level, this binding capacity dominates the effect of water hardness levels, such that the hair will attract significant levels of metal from water that has even a low degree of hardness. This suggests that the effects of water hardness are not just confined to consumers that reside in areas of very hard water, but to a much wider population that encompasses residents of lower water hardness areas. Additionally, the pH of the rinse water can also influence uptake." (p. 390)

meteor

April 5th, 2016, 01:06 PM

Water Hardness, Mineral Build-Up, Chelating: BACK TO INDEX
(http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187906&viewfull=1#post3187906)
PART II

- The structural implications of water hardness metal uptake by human hair: http://www.ncbi.nlm.nih.gov/pubmed/21923661

TENSILE PROPERTIES:
"The wet tensile properties of virgin hair were affected by calcium and magnesium, but those of bleached hair were unaffected. [...] Calcium and magnesium made the hair more resistant to extension and breakage by contributing to the existing coulombic interactions (salt links) that would be disrupted by water otherwise."
"Bleached hair was affected by calcium and magnesium in the dry state. Hard water-treated bleached hair fibres were 4% stiffer than soft water-treated bleached hair fibres, but there was not a significant difference between the break stress of the two samples."

TORSIONAL PROPERTIES:
"Contrary to the cortex-dominated tensile properties of hair, torsional properties are driven by the cuticle because the most strain is induced at the outer regions of the hair fibre in twisting deformation. As such, torsional properties are affected by the presence of materials such as cationic conditioning agents and polymers in the cuticle layers."
"Hard water-treated virgin hair was 4% more rigid than soft water-treated virgin hair at 50% RH. Under conditions of high humidity (80% RH), hard water-treated bleached hair was 15% more rigid than soft water-treated bleached hair. This difference was observed at 80% RH vs. 50% RH because the hair was in a more plasticized state in the higher humidity environment. The observed stiffening effect was likely due to calcium and magnesium ions serving as bridging agents between anionic groups within the cuticle."
"Our evaluations of single-fibre mechanical properties indicated that calcium and magnesium could induce the stiffening of hair, depending on the hydration state of the fibre."

COMBABILITY:
"Wet and dry combability are influenced by fibre curvature, diameter, stiffness and the frictional forces arising from fibre–fibre and comb–fibre interactions. It can be reasonably assumed that fibre stiffening and/or interfibre friction reduction was the key mechanism for the combing force reductions because curvature and diameter were likely unaltered. Calcium and magnesium ions stabilized the fibres, which in turn decreased interaction between them. The difficulty in drawing accurate conclusions from instrumental measurements of the dry combability of hair, even when evaluating the effects of product formulations, should be noted. This is attributed to the high variance associated with the hair substrates and the sensitivity of the instrument."

WET SET HOLD:
"The wet set hold of virgin hair was improved by calcium and magnesium. Hard water-treated virgin hair swatches experienced a 39% increase in style retention over their soft water-treated counterparts at 2 h of exposure (P =0.001). On the one hand, this finding was unexpected because virgin hair consistently showed hair property effects that suggested or were attributed to hard water-induced fibre stiffening. An inverse relationship between fibre stiffness and style retention exists, but it is possible that the observed increases in stiffness were not appreciable enough to affect style retention. On the other hand, it is possible that calcium and magnesium prevented the disruption of binding sites that are susceptible to water vapour. Contrary to virgin hair, the wet set hold of soft and hard water-treated bleached hair was not statistically different."

CONCLUSION:
"[...]our findings suggest that calcium and magnesium impart a slight stiffening of hair fibres, an effect that is contingent on the hair type and environmental conditions. This stiffening effect may partially explain water hardness metal-induced reductions in wet and dry combing forces and changes in the wet set style retention of hair."
"Our work has indicated that water hardness can affect hair properties. Fibre stiffening was induced by the presence of water hardness metals inside the fibres of both virgin and bleached hair. A reduction in combing forces was also observed, and this effect is believed to be a result of the stiffening. The style retention of virgin hair was improved by water hardness metals, whereas that of bleached hair was slightly reduced."

meteor

April 5th, 2016, 01:11 PM

^ I have to say, I find it really surprising that hard water actually reduced combing force (made combing easier) as compared to soft water. :hmm: And in some situations increased tensile & torsional strength (though this one is easier to understand, since added ions increase the # of bonds, thus stiffening the fiber).

By the way, if anybody finds something about chelating properties of oils, please do share! :flower: It's just that it's often claimed as the reason for why coconut oil and argan oil are protective pre-bleach (http://forums.longhaircommunity.com/showthread.php?t=10495), but I haven't yet seen any reliable sources for that information. It would be really interesting to read... and maybe some other oils have those properties as well? :)

Mavi

April 7th, 2016, 10:38 AM

I was given the go-ahead by Arctic to post this here. I made a blog post about trying to calculate the number of hairs on my head. Hopefully this might interest some of you? It's not the most precise method because it is very difficult to squeeze all air spaces out of your ponytail for circumference measuring, and a microscope would be best for measuring hair strand diameter, but all of the math is sound.
Enjoy! :)

I should be studying, so naturally I instead chose to engage in some hair-related mathematics, and try and calculate the number of hairs on my head.

I was unsatisfied with the commonly accepted notion of blondes having ~120 000, brunettes having ~100 000, and red-heads having ~90 000. This just didn't make sense to me! Someone with coarse, (i) thickness hair is going to have fewer hairs than someone with fine hair and a 10cm pony circumference, regardless of hair colour.

I therefore took matters into my own hands.

First, what is the area of the cross section of my individual hairs?
We need to start with a diameter measurement.
I used the science-y hair blog method of determining strand thickness and was able to pack 12 hairs into a mm, making each hair roughly 83um in diameter.
The area of a cross section of an average hair would therefore be:
A=Pi(41.5um)2
A=5411um2

Second, what is the area of the cross section of my ponytail?
My circumference is 9.525cm (squeezed as tightly as humanly possible).
Radius=9.525cm/2Pi
Radius=1.516cm or 15160um (converted by multiplying by 10 000)

Ponytail XS Area=Pi(15160um)2
=722 018 417um2

Next, divide the two.
722 018 417um2/5411um2=133 435 hairs (there will be error for air spaces in the ponytail, that's why you really have to squeeze)

15 minutes well spent

How many hairs do you have?

meteor

April 7th, 2016, 02:30 PM

^ That's pure awesomeness, Mavi! :applause Thank you so very much for sharing it here! :flowers:

(I know I personally can't search blogs (I find it pretty hard even to search the boards sometimes :oops: ), so thank you very much for sharing this very useful info here! :D)

If it's OK, I've linked your post to the Index (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187904&viewfull=1#post3187904)(under "5. Hair Thickness/Density"), so it's easier to find for new members. :)

I will try to calculate my own numbers, too... but I think I'll have massive variations, because I have this problem: I always get different measurements on my ponytail depending on the products I use (probably cuticles lying flat vs. raised make a huge difference), no matter how hard I squeeze out the air... And the strand thickness differences are very significant on my multi-textured F/M/C hair... but it's a really awesome approach regardless! :thumbsup:

By the way, for those who don't want to do the calculation by hand, just a heads-up that there is a spreadsheet that was linked in the Index - called downloadable Excel table for Managing Your Hair Growth Data (for growth and thickness estimates). And if you go to the 3rd (last) point (from Row 72 down) in "Terminal Length Calculations" Tab on the spreadsheet here: http://forums.longhaircommunity.com/showthread.php?t=36275 - you can have it calculated automatically for you. ;) It also adds laser thickness for helping measure the micron thickness of strands.

Mavi

April 7th, 2016, 02:51 PM

Cool, thanks for linking me, I'm totally okay with it :)

pinutzz

April 9th, 2016, 05:34 AM

In order to approximate how much space in a ponytail is taken up by hair and how big the air gaps between the hairs are we can simplify slightly and assume all hairs have a round profile, all have the same diameter and that we are dealing with an "optimally packed" ponytail (https://en.wikipedia.org/wiki/Circle_packing). Then about 90% is hair and the rest is air. So the number that Mavi calculated has be corrected by ay least this factor.

SparrowWings

April 21st, 2016, 11:27 AM

Hey meteor, here's another one for you to work on with your scientific article-finding superpower! I'm not sure which category it goes under, since it's more of a multi-part, boundary-crossing question.

I guess the base question is "What specifically causes the color changes?"

Let's see if I can clarify that a bit. When someone is trying to naturally lighten their hair, it seems like common suggestions are honey or lemon juice in the sun (among others, but we'll start there). Honey works because it creates hydrogen peroxide. What is it about the lemon juice that works, though? What I've found so far is that it's not the lemon directly, but rather the lemon acts as an aid to speed the process of the sun lightening the hair. But even so, is it helpful because of the citric acid in the lemon? The vitamin C? Some other compound? Strictly the fact of it being acidic? I've found conflicting anecdotal reports on that part, which leads me to believe it might be the simple fact of being acidic. Yet I've seen no reports of citric acid rinses, or "miracle water" rinses with both citric acid and vitamin C, or white vinegar, or any number of other acidic rinses leading to lighter hair (short of possibly chelation-related changes), even with pretty high concentrations, so that suggests acidity alone doesn't trigger increased lightening. But at the same time, there are reports of acidic ACV, even highly diluted, causing lightening, without sunlight. So what actually triggers the changes (or lack thereof) for all of these products?

meteor

April 21st, 2016, 03:18 PM

^ SparrowWings, I haven't looked into this enough (and I hope others will jump in on this, too ;) ), but my understanding is that, unlike hydrogen peroxide which is an oxidizing bleach, lemon juice lightening is a reduction–oxidation reaction ("redox" reaction, for short - https://en.wikipedia.org/wiki/Redox). It's not just lemon juice... but quite a few acids (most notably, for hair - ascorbic acid).

"Reducing bleaches such as lemon juice (in combination with sunlight) or sulfur dioxide, convert the double bonds in the chromophore into single bonds, eliminating its ability to absorb visible light. Sometimes the reaction is reversible, where oxygen in the air reacts with the molecule to repair the chromophore, and the stain returns." (http://sci-toys.com/ingredients/bleach.html)

To read more about redox reaction and how it's relevant to hair and things like lye, baking soda, acids, etc, etc that are sometimes used on hair... here is a great article: http://science-yhairblog.blogspot.ca/2013/07/ph-and-your-hair-little-redox-to-make.html

Some other substances that can lighten hair:
"The calcium hypochlorite or sodium dichloroisocyanurate used to disinfect swimming pools also bleaches hair, although (contrary to popular belief) it does not turn the hair green. It bleaches the hair, allowing the green copper sulfate in the water to show in the hair. The copper sulfate comes from the reaction of the copper pipes in the plumbing to the sulfuric acid used to neutralize the alkalies in the chlorination chemicals." (http://sci-toys.com/ingredients/bleach.html)

Sun (photo damage): see post # 5 on this thread for details and studies - http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187913&viewfull=1#post3187913

Honey: bleaching action from low hydrogen peroxide content (http://www.ncbi.nlm.nih.gov/pubmed/12804080). Additionally, honey contains gluconic acid, which can chelate minerals, esp. in alkaline solutions - esp. calcium and iron (http://pubs.acs.org/doi/abs/10.1021/jf970012c, https://en.wikipedia.org/wiki/Gluconic_acid), and removing mineral deposits can make hair appear lighter, less stained.

SparrowWings

May 11th, 2016, 01:30 PM

I see there are a ton of links relating to dandruff, anti-dandruff shampoos, and anti-fungal oils (posts 57, 58, and 134). What information has already circulated around here about how well the oils work as compared to the shampoos? Or even more, about non-oil, non-shampoo anti-fungals, especially in regards to how people may already be (probably unknowingly!) treating their (presumably mild) dandruff issues with their current routines?

For a bit of background, and to clarify the question, this current thread (http://forums.longhaircommunity.com/showthread.php?t=137788) (among others, I suspect) is showing that even mild dandruff could become a huge problem, and this article I found (https://www.researchgate.net/publication/261071142_Analysis_on_the_Natural_Remedies_to_Cure _DandruffSkin_Disease-causing_Fungus_-_Malassezia_furfur) shows things as mundane as lemon juice or rice water act as fungus-fighters. The article says it's the citric acid that actually does the work in the lemon juice, but given that they used the juice, rather than just a citric acid solution, I have to wonder how much the other components might have had an effect. It also sounds like it was used full strength, which is not recommended for hair/scalp, but it's still an interesting reference point. The part that makes me even more curious, though, is this line in the article: "... the citric acid content has been proven to be a causative of hair graying." I have never heard or seen that mentioned as a result of any acids (lightening, yes, but not greying), so it definitely makes me wonder. Any insights?

I also saw a passing mention somewhere to witch hazel being a dandruff reducer. I don't know if that's something that anyone uses regularly, but I know various acid rinses and food-water (rice, oat, etc.) washes are reasonably popular.

What other common methods double as anti-fungal? What sort of strength, frequency, duration, or techniques (don't rinse after, wait x time before rinsing, use a strong sulfate shampoo first, scritch first, apply wet or dry, etc.) are needed for any of these methods to be effective? To what degree are they effective? What other effects do they have, good or bad?

meteor

May 12th, 2016, 09:20 AM

^ Those are some great questions, SparrowWings! :D

I don't think I can answer them, personally. :flower: There is just a whole world of medical mycology and studies I haven't looked at.

From what I understand so far, I think there are many actives that have anti-fungal properties to some extent, but their efficacy may vary a lot (by species of fungi, by time frames of activity, etc...). We all have fungi on our skin, of course, but it's about healthy balance. The idea is that, even if you create an environment that's somewhat unfriendly to fungal overgrowth, you can already use that for anti-fungal properties. But it won't necessarily be effective on a serious overgrowth problem. So a situation where just a weak dilution of tea tree oil works is possible, but a situation where prescription-strength ketoconazole or stronger prescription anti-fungals are needed is possible, too.

Many studies do compare effectiveness of different anti-fungals in vitro (like the one you linked or this one is good, too: In Vitro Activities of Ketoconazole, Econazole, Miconazole, and Melaleuca alternifolia (Tea Tree) Oil against Malassezia Species - http://www.ncbi.nlm.nih.gov/pmc/articles/PMC89709/), but one still needs to get a diagnosis of their specific situation. Ideally, doctors should do tests for fungal culture (https://labtestsonline.org/understanding/analytes/fungal/tab/test/), but depending on medical practices where you live, for scalp, that's usually done only in more severe cases, after trying anti-fungal shampoos/creams/etc first)
With fungal issues, not only the right prescription is important, but also time (frequency and persistence of application) is critical, and one needs to keep at it for the full duration of prescribed therapy (it can be different in different cases), even when the symptoms are long gone, to get the fungal culture under control.

(Also, I should clarify, just in case, since dandruff was mentioned... Dandruff is only a symptom. It could be a symptom of many different skin conditions, SD, psoriasis, eczema, just to name a few... and it can have different appearances. It's the diagnosis (not the symptom, which can happen with various conditions) that should drive the treatment. The stuff we've been discussing is relevant to SD (which we still don't understand everything about, but so far, it's linked to fungal overgrowth of Malassezia species). It's very important to diagnose the condition, the cause of dandruff correctly, in order not to do more harm than good while trying to treat this problem.)

Entangled

September 26th, 2016, 09:32 AM

I'm bumping this thread, as a similar one has been made.:)

animetor7

September 26th, 2016, 09:42 AM

I'm bumping this thread, as a similar one has been made.:)

Thanks for bumping it! I didn't know this existed, I edited the one I started to include a link to this thread rather than having a duplicate thread topic. :)

Entangled

September 26th, 2016, 10:14 AM

Thanks for bumping it! I didn't know this existed, I edited the one I started to include a link to this thread rather than having a duplicate thread topic. :)

No problem! I just remembered this thread and its great info, so I thought I'd bump it because it already had so much stuff.

Arctic

September 26th, 2016, 10:19 AM

Yes, this thread is chock full of greatness (thanks to Meteor!), I'm glad it was bumped!

meteor

September 26th, 2016, 11:19 AM

Thank you so very much for the bump, Entangled! :thumbsup:

Arctic, thank you for your kind words :heartbeat, but it's actually *you* and all the other awesome members on this thread that make it a great place! :love:

Animetor7, so happy to see you join! :joy:
I'll do my best to keep the first pages (index) continuously updated with all the links, and if you want, you can also create your additional index within the thread, for example, with information and links related directly to chemical composition of specific products or ingredients, etc, if you'd prefer that...
And of course, if folks find it easier to create their own indices to different studies or topics inside their posts (to make it easier for them to read), please do! :D I think this thread can be arranged in so many ways in terms of making it user-friendly and easy to read for everyone! :D

Kat-Rinnè Naido

September 26th, 2016, 12:09 PM

I'm subscribed. I have a lot of reading to catch up on. Thank you Arctic & Meteor

Kajzh

September 26th, 2016, 03:35 PM

I love all the resources in this thread! I've been referring to lots of them for years now, and now that I've found this thread, I even have more! :D

Lize

October 2nd, 2016, 11:44 AM

Lovely to find this thread! I have often thought about searching for hair studies, but it's so time consuming. Great job creating this!

Interesting stuff about strand thickness/coarseness and how it's related to growth rate. I have a couple of random coarse hair strands on my head and I have noticed that they grow much faster than the rest of my hair which is fine. So it seems to work like that even on the same head. :) My few coarse strands are also much darker than the rest of my hair. They are so different that it's like having a couple of strands of someone else's hair on my head. :lol:

meteor

October 2nd, 2016, 02:01 PM

^ My hair has the same thing going on, Lize. :agree:
My finer hair doesn't seem grow as fast, and it's been like that my whole life, however, those strands could also simply have a shorter anagen (growth) phase and shorter terminal length compared to my coarser hair in the back? :hmm:

Of course, that study (https://www.ncbi.nlm.nih.gov/pubmed/21951315) only noted a correlation, and it could potentially be spurious and maybe, for example, there is a hidden third variable that affects both causes of the correlation, plus the size of the study was small ("1,000 hair strands in total (from 6 Caucasian, 13 Japanese and 13 Chinese volunteers)"), but it's pretty interesting anyway. :)

I also suspect, just like some parts of our body (apart from hairless palms, soles, lips, of course) are covered with hairs of different terminal lengths and different diameters, so are different parts of the scalp also covered with hairs of different terminal lengths and different diameters of strands (genetically driven) - hence perpetually shorter and finer "baby hair" around the hairline/nape that many people experience, for example. Some of that hair likely simply has a shorter cycle genetically: thus has shorter terminal and is shed more frequently. The same thing could also explain why some people always have natural taper, no matter how much they baby hair and for how many years they've been microtrimming to achieve a thicker hemline (in this case, some hairs will never reach others because they simply have a shorter terminal genetically compared to other strands on that scalp). I haven't seen specific studies on this though... If anybody has, please share. :flower:

Lize

October 3rd, 2016, 09:45 AM

For me it's just a few thicker strands (I noticed maybe two or three of them on my whole head). I notice their faster growth what I haven't trimmed for a while and they start to come out of my hemline getting longer than the bulk of fine hair. It's quite funny. :)

October 4th, 2016, 08:58 AM

Seems to me that genetics is a factor. I always had very fine but thick hair that grew rapidly during most of my life. My cousin also with fine but sparse hair experienced very slow growth. As always, general findings may or may not apply to individuals.

OhSuzi

October 23rd, 2016, 04:51 AM

So I've had a very brief slightly lazy skim through these pages, and couldn't see anything similar to my question. So apologies if you've already addressed this.

From the point of view of both actual science and peoples experiences / opinions do multivitamins/ pre natal vitamins / biotin/ supplements in general work?

Generally I'm a skeptic and don't believe in quick fixes e.g. Forever Living and similar products promise they are all natural allo Vera, and will magically restore all ailments diabetes, obesity, immune system and there's toothpaste and moisturiser and gels you eat etc. But they are very wish washy with the details, the product contains 100 different man made chemicals it costs a rediculous amount and is basically the same as every other vitamin / bathroom spa set pyramid schemes that have been going on since about the 1920s. If allo is that effective, just buy yourself an allo plant.
I personally believe healthy diet and exercise is going to cure / help a lot more ailments and cost you less.

The point is my skepticism for supplements is based on
1. The fact a supplement company just wants to make money out of you.
2. Articles that state supplements have never been proven to work.
3. Articles that state myths like pre natal vits make your hair grow is because actual pregnant ladies can experience extreme hair growth. This due to the boost of crazy growing hormones and things in their body that they need to make a baby grow, you can't recreate the conditions of pregnancy with just a multivitamin. In fact you don't need half the stuff in there, you're more likely to do your body harm than good. ( It was more scientific than that I'm obviously paraphrasing from memory.)
4. My pal who has various degrees in sport science and nutrition. They've looked after olympians and are currently studying to be a doctor, so for me their opinion carries weight: Unlike food that gets digested and slowly broken down, supplements are pretty much killed instantly by stomach acids, very little gets absorbed and most of it is just peed out. It's always better to get nutrition from actual food. ( Again their words were more sciency, I'm just a simpleton paraphrasing).

My hope that supplements could work is based on:
1. People on lhc / various you tube videos who state they do work for them / recommend them as an aid to hair growth. They generally seem to have no agenda other than achieving long hair / supporting others who are trying to grow their hair - so why would they lie?
2. The fact that it has not been proved. Just because it's not officially been proven does not mean it doesn't work Technically you can't prove a negative, but has any one officially proven the reverse? That supplements have no effect on hair?

Is it because an experiment would involve to many factors. E.g. 50 people take supplements, 50 take placebos, 50 do nothing. How long does their hair grow in a year. But each individual has different growth rates, perhaps some of the placebos have freakishly fast growth rate any way. Perhaps you did speed up the growth rate on a supplement taker, but they had such a slow growth rate you wouldn't know.

That would suggest you'd have to do the experiment on individuals and onlly compare them to them selves. E.g. Each person does 1 year supplements, 1 year nothing what's the growth rates in those two years - but again other factors come into play, were they really ill for a long time during the non supplement year, did they have a really long hot summer, did they do a lot more swimming in the sea and buy a different shampoo etc.

Perhaps supplements do work but can't be accurately proven.

Please share sciency articles / your own experiences that show whether supplements do / dont work.

Entangled

October 23rd, 2016, 08:29 AM

I don't have an article, but it's commonly said around here that vitamins only help if you have a deficiency. Igor's biotin rant (http://igorsbelltower.blogspot.com/p/infamous-biotin-rant.html?m=1) addresses that. She also has a good article on supplements (http://igorsbelltower.blogspot.com/p/supplements-and-hair-growth.html?m=1). Neither article is a study, but they both have good information.

OhSuzi

October 23rd, 2016, 01:50 PM

Interesting stuff!

gypsycolleen

October 23rd, 2016, 02:22 PM

Great thread and info! Thank you!

meteor

October 23rd, 2016, 02:22 PM

^ OhSuzi, your questions are pretty broad, so I'm not sure how to address them in full... :flower:

If you are looking for specific studies on specific supplementation, I'd search NCBI database (https://www.ncbi.nlm.nih.gov/) or other databases and input specific stuff like, for example, "iron supplementation", "B12 supplementation", etc... to search for relevant studies. There are *lots* of them out there.

I'm not a doctor and I highly recommend discussing all this with your family doctor or at least a registered dietician.

My general understanding is that we may or may not necessarily absorb enough vitamins or minerals from food, partly it depends on what you eat, but it also really depends on your health status, on your medications (drug interactions), etc... That's why some of us can be deficient even on the most optimal of diets. It just depends... you'll need to work very closely with your doctor. First and foremost, make sure you get bloodwork done to check for common deficiencies, but there could also be things like certain medications causing body to use up more of certain vitamin or mineral (so one may suddenly need a heavier load of certain vitamin or mineral when sick or on some medication)...

Also, what's viewed as healthy ranges of vitamins or minerals can actually change over the years as we find out more and can be viewed differently by health professionals in different countries, and those ranges can be pretty broad anyway. Sometimes you may be marginally fitting within the norm based on blood tests, but may still experience symptoms... and the acceptable ranges change with age and depending on whether one is pregnant or not...

And yes, bioavailability of supplements is often significantly lower than in naturally occurring sources, but, like I mentioned before, some of us have trouble getting enough from diets alone, especially if the diets are restrictive. Of course, I wouldn't supplement without getting bloodwork done and without discussing it with a doctor, because certain supplements can be overdone, causing side effects (think iron and some fat-soluble vitamins, for example), not to mention the extra work for kidneys and liver, etc...

Sorry, I realize I've talked a lot and didn't actually *say* anything of substance, but it kind of all goes back to discussing specific supplementation with your doctor. :flower:

Annalouise

October 23rd, 2016, 03:53 PM

I have thinning hair and an auto-immune disease that effects my absorption of vitamins. So YES, for me vitamins do help. My hair has gotten a tiny bit thicker after taking a hair vitamin. I also was able to stop my insomnia with a good quality vitamin/mineral supplement. If I don't take them every night before bed I won't sleep. So they do work for me there is no doubt about it.:toast:

Silverbleed

November 17th, 2016, 03:25 PM

Does anyone know if salicylic acid is bad for the hair?

I use BHA with salicylic acid almost daily and I've been wondering about this because I have acne very often right on the hair line. I've also been wondering this because of my eyebrows.

I'd love to know if it's okay to use on my hair line once in a while. I'm well aware that acne on the hairline isn't good for the hair follicles either, but I don't want to damage my hair as well.

Thank you in advance :flower:

Entangled

November 17th, 2016, 03:35 PM

meteor

November 17th, 2016, 03:41 PM

^ Great question, Silverbleed!

Salicylic acid is an exfoliant, peeling agent (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4554394/), and depending on the concentration, it could be drying to hair maybe? We do know that salicylic acid can be drying and irritating to skin (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4025519/). But it's pretty useful for some skin conditions, such as seborrheic dermatitis, for example (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3579488/). It's often found in anti-dandruff shampoos and shampoos for oily scalps. Personally, when I use such products, I concentrate them on scalp only to avoid drying out the length (or I cover length with oil and/or conditioner and/or condition more thoroughly after).

I wish I knew at which concentration or in what formulation it becomes drying to hair, but I haven't seen relevant studies yet.

I hope somebody can help us with more information. :)

Silverbleed

November 17th, 2016, 04:05 PM

Thank you very much for your replies!! :flower:

I read the articles you've linked, but I admit I had a lot of trouble with it, hahahaah.

I do not experience irritation on the skin, which is good. It's been the only thing that really helps me with my acne, and also prevents it. If it isn't as bad, I try to skip as many days as I can.

Since I it on the scalp, it really only touches the very beginning of the hair, so it won't touch my lengths at all. Also since I do use a moisturizer and sunscreen like recommended in the second article, I wonder if it would help if I applied aloe vera as a moisturizer for my hair? My face loves it, and I know my scalp and hair does too.

meteor

November 17th, 2016, 04:20 PM

^ Sounds great! If your skin doesn't experience any dryness at all from it, it should work fine, even without spacing it out. :) If your skin is oily, the "drying" effect of SA could be quite useful anyway. Again, depends on the concentration and your "baseline", so you can judge by how your scalp responds.

As for aloe vera, it is a nice moisturizer (https://www.ncbi.nlm.nih.gov/pubmed/17026654) thanks to its humectant nature, so it helps attract and hold onto moisture, but in very dry environment, it could attract moisture to itself even from hair, so I'd be aware of relative humidity/dew points if I were to use it at high concentrations in leave-ins. If it works well, great! If not, you may want to look for other combinations, e.g. maybe more occlusive ingredients, etc...

Silverbleed

November 18th, 2016, 03:53 AM

That's very helpful. Thank you for your help, meteor! c: I feel much more comfortable applying it at my hair line now. I'll try this for a while and if I see any positive (or negative) results, I'll report back in the future.

maxa

November 18th, 2016, 04:52 AM

LadyCelestina

November 18th, 2016, 05:31 AM

this isn't a study, but I'v noticed that the skin on my face has become somewhat resistant to Apple cider vinegar. The first time I used it with a 4 to 1 - water to vinegar solution, and that alone made my skin go red. Now I just used a 4 to 1 - Vinegar to water solution, and my skin didn't even go red. This is very anecdotal, I just wanted to share it for I find it bizarre.

Be careful. By getting the ph of your skin out of whack, you are destroying your skin barrier. A damaged skin barrier leads to all kind of problems like oil overproduction, acne, dehydrated skin...
Anectodal evidence: ever since my barrier is somewhat in check, I don't really get so much acne, my pores/SF's are smaller and best of all, a fine line on one side of my mouth and was very self conscious about literally *dissappeared*. Now, I can still see it if I do a lot of grimaces on purpose, but it's not visible most of the time.

Arctic

January 20th, 2017, 09:16 AM

Bumping this thread for new members!

And at the same breath I'll ask, if anyone know if "18 MEA Amidoamide" has same effect on hair as 18-MEA? And if it (the first mentioned 18 MEA Amidoamide) is a last ingredient on a list (of a leave in conditioner cream) is the level helpful at all (of course no percentage is being known).

Serimel

January 20th, 2017, 10:16 AM

Thanks for bumping, I subscribed! :) Going through some articles now and adding to my newbie confusion. :D

hanne jensen

January 25th, 2017, 12:53 PM

Aunty Miki

January 25th, 2017, 01:20 PM

Truth or myth: hair opens in warm water, closes in cold?

Ophidian

January 25th, 2017, 02:06 PM

Truth or myth: hair opens in warm water, closes in cold?

According to my favorite science-y hair blogger, not exactly

http://science-yhairblog.blogspot.com/2014/01/do-cold-water-rinses-make-hair-shine.html?m=1

meteor

January 25th, 2017, 02:37 PM

Thanks for all the sciency information. My hair takes forever to air dry so I'm probably damaging it. Would it be better to blow dry on a cool setting to speed up the process? My hair takes about 4 hours to air dry.

Yes, I think it may possibly be better to blow-dry on cool setting or use a floor fan and agitate the hair to aerate it more, for example. The safest drying methods so far seem to be both fast and heat-free.

Here are a couple relevant studies:

Repeated cycles of wetting and blow-drying can cause multiple cracks on hair cuticles. (Gamez-Garcia M. The Cracking of Human Hair Cuticles by Cyclical Thermal Stresses. J Cosmet Sci. 1998; 49:141 - http://journal.scconline.org/pdf/cc1998/cc049n03/p00141-p00153.pdf)

From Hair Shaft Damage From Heat and Drying Time of Hair Dryer study, where hair was dried with a hair dryer at a range of temperatures (natural ambient temperature, 47℃, 61℃, and 95℃), drying distances, and drying times:

Hair drying without a hair dryer produced a relatively well protected hair surface, while hair that was dried using a hair dryer showed more damage of hair surfaces. In addition, the hair surfaces showed an overall tendency to become more damaged as the temperature increased, with the most severe surface damage produced after drying with the highest temperature (95℃). No cortex damage was noted in any group, suggesting that the surface of the hair might play a role as a barrier to prevent cortex damage. The cortex might be more damaged with increased repetition of the process, when the barrier of hair surface is broken. The CMC was damaged only in the naturally dried group. This result was quite unexpected, because increased temperatures generally led to more hair damage. It took over 2 h to dry the hair tress completely under ambient conditions. The hair shaft swells when in contact with water, as does the delta-layer of the CMC. The delta-layer is the sole route through which water diffuses into hair, and so we speculate that the CMC could be damaged when it is in contact with water for prolonged periods. Longer contact with water might be more harmful to the CMC compared to temperature of hair drying.
[...]
Drying under ambient temperatures and at 95℃ resulted in earlier changes in hair color (after just 10 treatments). The reason why the hair color is brighter after repeated shampooing and drying is unknown. On TEM examination, no decrease of melanin granules was found. However, after repeated shampooing and drying, definite damage to hair cuticle was evident on SEM examination. Therefore, we assume that the hair color change might be because of the damage to hair. Further study is needed to explain the reasons for hair color changes.
(Lee Y., Kim YD, Hyun HJ, Pi LQ, Jin X, Lee WS. Hair Shaft Damage From Heat and Drying Time of Hair Dryer. Ann Dermatol. 2011 Nov; 23(4): 455–462. - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3229938/)

But it looks like more studies are needed to understand why exactly the CMC bulging occurs in the naturally dried hair tresses group.

mizukitty

January 25th, 2017, 02:47 PM

Truth or myth: hair opens in warm water, closes in cold?

Myth. Hair can *swell* which causes the cuticles to raise up to accommodate that water.

The reason heat is used in hot oil treatments, deep conditioning treatments, etc, is because it helps the products/oils adhere TO the hair better. It doesn't "open" anything up, and nothing aBsorbs (except for obvious knowns - coconut oil, partial olive, avocado, sunflower, etc. and hydrolyzed stuff), but rather, adsorbs . Also, many people think that silicone free conditioners don't "coat" the hair. This is exactly what *all* conditioners do, regardless of silicone presence. They bond to your hair via cationic charge - one tail end sticks to your hair, one sticks out and creates that smoothness.

Cold water also has been debunked as "sealing" your cuticle, by the blogger above, in a microscopic photo.

You can help seal that cuticle with acidic solutions (conditioner, ACV, citric acid), but if your hair is taking up a ton of water, the cuticles won't "seal" until most of that water evaporates.

Hay_jules

January 27th, 2017, 12:24 PM

Wow! Great thread Meteor and Arctic. I've spent the last week reading through it and the various links as of it was a good book I couldn't put down. I just wish I had found this sooner, I could have saved myself some money (products bought unnecessarily). Subscribing.

Meteor, in post 69, (I believe it's hair and scalp images) every single link that is from the FBI Web page doesn't work for me...it either takes me to a "page not found" page or the FBI home page, not sure of that's just cuz I'm canadian and the FBI doesn't want me seeing their pics or if it's the links themselves.

In post 143 Meteor pondered if it was vest to cut nails wet or dry. Before I got into hair I was into nails, every blogger and nail enthusiast I followed seem to say it's best to file nails (they'll also tell you to file not clip) only dry nails as nails are their weakest when they're wet and are more likely to split, peel and other nefarious things. A no longer active blogger that I learned a lot from touches on it in this post. (http://loodieloodieloodie.blogspot.ca/2010/11/ready-set-file-taking-down-length.html?m=1)

Meteor also posited in post 179 that perhaps bleaching alone doesn't cause split ends but the mechanical damage after bleaching causing it. I'd like to offer my anecdotal story to support this theory. I bleached my APL hair in 2 full bleach sessions plus a couple bleach baths to get it from about level 2 dark brown to about level 7-8 blonde, and then I dyed it purple. I was very pleased that my hair still *seemed* healthy and I continued to straighten it daily. After a couple weeks my ends were like velcro. I cut it back to shoulder and put away the straightener and joined LHC. I examine my ends regularly to s&d any splits. Usually I can't find any. One day I used my straightener, a few days later there were quite a few new split ends that I had to cut out. Again more than a month with no splits and I tried to force fade my hair by soaking it in clarifying shampoo 3x and a few days later a had several splits again. The purple shade of my hair makes the splits very easy to see and I use a magnifying mirror and reading magnifiers to make sure I catch them all. There is no question that any time I discover new splits it's as a direct result of some mechanical damage I've done. If I don't do bad things to my hair, it doesn't split on its own, even though it is severely damaged. It does reassure me though that I can still get some length before I have to worry about chopping off all the bleach, as long I take extra care.

meteor

January 27th, 2017, 01:00 PM

^ Hay_jules, the URL links to those FBI pictures keep getting changed, unfortunately, but you can find those photos on these webpages currently:
https://archives.fbi.gov/archives/about-us/lab/forensic-science-communications/fsc/july2000/deedric1.htm
https://archives.fbi.gov/archives/about-us/lab/forensic-science-communications/fsc/july2004/research/2004_03_research02.htm
https://archives.fbi.gov/archives/about-us/lab/forensic-science-communications/fsc/jan2004/research/2004_01_research01b.htm

As for bleaching, studies showed immediate increase in porosity (e.g. https://www.ncbi.nlm.nih.gov/pubmed/18818850), changes in chemical and structural composition of the hair (e.g. https://www.ncbi.nlm.nih.gov/pubmed/16425172, https://www.ncbi.nlm.nih.gov/pubmed/24506326, https://www.ncbi.nlm.nih.gov/pubmed/21882590, https://www.ncbi.nlm.nih.gov/pubmed/25323334), but I think specifically for splits to occur you normally need to start manipulating that hair, for example, washing, detangling, styling, etc... At least, all the studies on splits I've seen so far involved repeated brushing or other forms of manipulation (sometimes on virgin hair, sometimes on bleached or otherwise damaged hair, and the damaged hair showed more splits from the same amount of manipulation). I think, after bleaching, detangling gets harder and one needs to be gentler (e.g. using WT seamless combs, keeping hair in buns, braids, sections or otherwise contained to reduce the frequency of detangling, etc). To be honest, I'd try to drastically reduce or eliminate heat styling (some studies on thermal damage here (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3191167&viewfull=1#post3191167)), if I were you. It's just that if you want to grow bleached hair long, you may need to be a bit more careful, especially with naturally fine or fragile hair, and one can straighten hair or style it in curls or waves with heat-free methods anyway. ;)

Swan Maiden

January 27th, 2017, 09:11 PM

This is Seborrhea Dermatitis related. I wonder how long it takes the scales/flakes to grow back after they are removed with anti-flake shampoo (Nizoral, etc) I wonder which shampoo will keep them away longer. I know I washed my hair last night and the scales were gone but when I looked in the mirror this morning there was a nice big gross patch back.

Siv

July 17th, 2017, 05:57 AM

Just wanted to stop by and say thanks for all your hard work! I'm going to slowly plough through the articles through the index over the next few weeks. I really appreciate you lot taking the time to put this all together! :flowers:

parkmikii

July 17th, 2017, 09:09 AM

Siv

July 17th, 2017, 11:31 AM

Can clotrimazole damage scalp in any way? I've found that clotrimazole solution 1% helps a lot with my SD (way more that nizoral and such which only helped for 2-3 days at max) and I don't know if it's damaging to the follicles in any way.

I've no good answer, and hoping someone more knowledgable will add, but in the meantime - I think clotrimazole is related to miconazole, which was used as some sort of hair growth hack on tumblr awhile ago :rolleyes: I've seen it around LHC as well. I've never heard of it being harmful for hair - just increasing hair growth. Check out this (http://forums.longhaircommunity.com/showthread.php?t=61228) thread, it's about miconazole - Monistat brand name in the US - and it mentions clotrimazole as well! It doesn't seem people think it's damaging, but that doesn't mean it isn't damaging either I suppose! Though, how it can increase growth and be damaging at the same time I dunno...

meteor

July 18th, 2017, 10:00 AM

^ Thank you very much, Siv. :D And thank you for your kind words, as well. :heartbeat

parkmikii, I haven't seen any studies specifically into clotrimazole and hair growth either, however, we know that anti-fungals can help with increased growth: case in point - ketoconazole. The problem is researchers are kind of speculating on what exactly makes ketoconazole work so well for growth rate (and even diameter) and we need further studies to understand the mechanism behind it. One of the theories is its interaction with androgen receptors. And in this study in particular (Ketoconazole binds to the human androgen receptor - https://www.ncbi.nlm.nih.gov/pubmed/1526623) researchers found that "androgen binding studies performed with other imidazoles, such as clotrimazole, miconazole, and fluconozole, revealed that in this class of compounds only ketoconazole appears to interact with the androgen receptor". What I'm saying is it may work, but I haven't seen studies into it, so personally I'd focus on the anti-fungals which *do* have a lot of studies to support their action, including specific % and frequency of application. I think it would be just a safer approach.

On the question of damage, I don't know, I've never seen studies that would show that. I think things that can be good for growth could under some conditions be a problem in other ways - e.g. excessively drying or irritating to scalp (which could cause excessive shedding), things like that. I haven't seen anything to show that anti-fungals are damaging, but at the same time, products available to us through pharmacies have specific (and normally pretty low) concentrations... To make a product available, certain safety regulations must be followed.
I'd be much more worried about at-home hair growth preparations, which could be highly irritating, like things with capsicum, garlic and onion, coffee, essential oils, etc... at high concentrations.

But back to your situation, parkmikii, if that prescription is working for your SD, that in itself is already reason enough to continue using it IMO. :flower: SD-free scalp will support hair growth a lot better anyway. If it happens to be drying, there are ways of counteracting it - Scalp-Only washes, double-conditioning or using an anti-fungal oil on hair pre-wash. But honestly, once SD is under control, you'll get back to your original products and hair should get back to normal, if the issue is just excessive dryness.

parkmikii

July 18th, 2017, 01:47 PM

I've no good answer, and hoping someone more knowledgable will add, but in the meantime - I think clotrimazole is related to miconazole, which was used as some sort of hair growth hack on tumblr awhile ago :rolleyes: I've seen it around LHC as well. I've never heard of it being harmful for hair - just increasing hair growth. Check out this (http://forums.longhaircommunity.com/showthread.php?t=61228) thread, it's about miconazole - Monistat brand name in the US - and it mentions clotrimazole as well! It doesn't seem people think it's damaging, but that doesn't mean it isn't damaging either I suppose! Though, how it can increase growth and be damaging at the same time I dunno...

^ Thank you very much, Siv. :D And thank you for your kind words, as well. :heartbeat

parkmikii, I haven't seen any studies specifically into clotrimazole and hair growth either, however, we know that anti-fungals can help with increased growth: case in point - ketoconazole. The problem is researchers are kind of speculating on what exactly makes ketoconazole work so well for growth rate (and even diameter) and we need further studies to understand the mechanism behind it. One of the theories is its interaction with androgen receptors. And in this study in particular (Ketoconazole binds to the human androgen receptor - https://www.ncbi.nlm.nih.gov/pubmed/1526623) researchers found that "androgen binding studies performed with other imidazoles, such as clotrimazole, miconazole, and fluconozole, revealed that in this class of compounds only ketoconazole appears to interact with the androgen receptor". What I'm saying is it may work, but I haven't seen studies into it, so personally I'd focus on the anti-fungals which *do* have a lot of studies to support their action, including specific % and frequency of application. I think it would be just a safer approach.

On the question of damage, I don't know, I've never seen studies that would show that. I think things that can be good for growth could under some conditions be a problem in other ways - e.g. excessively drying or irritating to scalp (which could cause excessive shedding), things like that. I haven't seen anything to show that anti-fungals are damaging, but at the same time, products available to us through pharmacies have specific (and normally pretty low) concentrations... To make a product available, certain safety regulations must be followed.
I'd be much more worried about at-home hair growth preparations, which could be highly irritating, like things with capsicum, garlic and onion, coffee, essential oils, etc... at high concentrations.

But back to your situation, parkmikii, if that prescription is working for your SD, that in itself is already reason enough to continue using it IMO. :flower: SD-free scalp will support hair growth a lot better anyway. If it happens to be drying, there are ways of counteracting it - Scalp-Only washes, double-conditioning or using an anti-fungal oil on hair pre-wash. But honestly, once SD is under control, you'll get back to your original products and hair should get back to normal, if the issue is just excessive dryness.

Thank you! Yes, I'm not actually trying to get extra growth, just to get rid of the SD flakes and I was questioning if it can be damaging in any way since I've seen that the cream version (clotrimazole ATB (?)) states on the leaflet that it shouldn't be used on the scalp or nails. The lotion version that I'm using doesn't mention anything like that so it just seemed a bit weird that the cream one had this warning and I thought to be better safe than sorry. I did use different things for my SD, but all of them made my scalp really dry and hair very tangly and the SD came back right after stopping to use them. For example, I was using a shampoo with piroctone olamine and it worked for the 4 weeks that I used it (twice a week) but then within a week of returning to my normal sulfate shampoo the flakes were back. It would just get too costly to keep using a medicated shampoo until forever.
I've used miconazole cream diluted in water as well a while ago but it didn't do much either, I suppose this was because I was diluting the 2% concentration even further, so it probably wasn't as strong as it was required, but I needed to thin it somehow since the cream was really thick and if I wanted to apply it it would have went mostly on the hairs rather than on the scalp.

Thank you a lot for the replies!

akurah

July 18th, 2017, 06:02 PM

parkmikii, have you had opportunity to possibly ask a doctor or pharmacist? They might know if no one else here does. Clotrimazole was prescribed by my doctor to clear up a fungal infection on my toenails alongside a second anti fungal whose name escapes me. I'm wondering if the disclaimer on your tube leaflet to not use on "hair and nails" is from a "cover our hinies" perspective or if it's a legitimate warning?

If we had the other ingredients we might could potentially identify what ingredient is problematic. Maybe.

*Wednesday*

July 18th, 2017, 06:36 PM

What a great thread. Joined.😀

peachyleshy

July 18th, 2017, 08:23 PM

This is great! Peppermint oil is on my to do list now! :disco:

Siv

July 22nd, 2017, 05:19 AM

I've been reading some of the articles here, blogs, and whatnot and have a few questions about fatty acids and affinity for hair protein :) Four questions all in all, they're bolded and italicised for clarity.

Mostly inspired by this much quoted article: Effect of mineral oil, sunflower oil, and coconut oil on prevention of hair damage. (https://www.ncbi.nlm.nih.gov/pubmed/12715094)

So if I understand correctly, coconut oil has a low molecular size, so it penetrates the hair shaft, and a high content of lauric fatty acid, which has a high affinity for hair protein. So the lauric acid forms some sort of compound with the hair protein, and when you wash, style, bleach, whatever, you lose a lot less hair proteins if you pre-treated with coconut oil. This should in theory go for other oils with high lauric acid content, such as palm kernel oil. I don't know about the molecular sizes (and thus penetrative ability) of palm oil and other lauric acid rich oils, but they are generally difficult to get a hold of around here, plus a lot more expensive than coconut oil, so I haven't looked into that.

Olive oil, on the other hand, doesn't contain lauric acid. It's highest content of fatty acid is oleic acid. Olive oil does penetrate the hair shaft as well, perhaps not as well as coconut oil, but decently enough. So does anyone know if oleic acid has any affinity for hair protein at all? Or rather, would olive oil prevent protein loss in any way?

This article, Hair Cosmetics: An Overview - Section "Diffusion Into Keratin Fibres" (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4387693/#sec1-9title), makes me think I've missed something about hair shaft penetration.

There are two main ways for a substance to penetrate the hair fiber: Transcellular and intercellular diffusion, transcellular diffusion envolves epicuticle, A-layer, exocuticle, endocuticle and is much harder path way because of the high cross-linked regions. Intercellular diffusion envolves the intercellular cement, and it is the preferred route for large molecules because the low-sulfur and nonkeratin proteins are more easily swollen. Both routes can occur depending on the size of the molecule, hair damage and cosmetic system of the applied product.[5]

Diffusion rate into keratin fibers depends on the cross-link density of hair. Reactions like bleaching, that decreases the cross-link density increases the rate of transcellular diffusion, meaning that bleached hair is more rapid penetrated by conditioners, dyes, hair straightening substances or any product applied to the hair fiber. However, penetration into the intercellular regions can lead to scale lifting and cause hair damage. Scale lifting is induced by the deposit of insoluble cationic-anionic complex, meaning which can occur because of the interaction and bonding of the anionic surfactants of the shampoo with the cationic conditioning ingredients.[5,35]

The first underlined section: nonkertain proteins - are these proteins in hair or in products/oils etc.? And what does it mean for hair that they are more easily swollen?

The second underlined section: again, products penetrate into the hair protein fiber, but does it prevent protein loss at all if done before shampooing or dyeing since they say nothing about chemical affinity with keratin?

Third underlined section: is this referring to first shampooing, then conditioning, or only products that contain both anionic and cationic surfactants?

meteor

July 22nd, 2017, 08:06 AM

^ Siv, those are some great questions.

First about the oils that should be able to penetrate hair...
It's true that the ones that have high lauric acid content should penetrate, so that's:
- Coconut (both unrefined and refined, as long as it's not fractionated; ~ 49% lauric acid): "coconut oil, being a triglyceride of lauric acid (principal fatty acid), has a high affinity for hair proteins and, because of its low molecular weight and straight linear chain, is able to penetrate inside the hair shaft."(Effect of mineral oil, sunflower oil, and coconut oil on prevention of hair damage. - http://journal.scconline.org/pdf/cc2003/cc054n02/p00175-p00192.pdf)
Maybe also:
- Babassu oil (~ 50% lauric acid)
- Palm kernel oil (~ 48% lauric acid)
- etc...

Oils without lauric acid may still penetrate, though the instances are less documented (see below).
Olive oil can penetrate (probably due to its saturated and monounsaturated fat content), according to studies reviewed by Science-y Hair Blog: http://science-yhairblog.blogspot.com/2013/06/oils-which-ones-soak-in-vs-coat-hair.html (please scroll down to the table with oils).
According to this study (Investigation of penetration abilities of various oils into human hair fibers: http://journal.scconline.org/pdf/cc2005/cc056n05/p00283-p00295.pdf), "In general, saturated and monounsaturated oils penetrate into the hair because of a compact molecular structure and the polar head group of the triglyceride molecules that constitute these oils. In a dynamic mode these molecules can reptate and squeeze through the CMCs. On the other hand, polyunsaturated oils do not penetrate into hair, most likely because of the more open and spread-out structures of their triglyceride molecules and because of the presence of multiple double bond."

See fatty acid composition of oils: https://docs.google.com/spreadsheets/d/1-lDtdpjbJopUEvpk0vjNbDt_mE_prCCCZtOqfRnzIaw/edit?pref=2&pli=1#gid=3

Now onto the other questions - I'm just answering in terms of what I understood from the study you referenced, but I could be completely wrong in my understanding. :flower:

The first underlined section: nonkertain proteins - are these proteins in hair or in products/oils etc.? And what does it mean for hair that they are more easily swollen?
In this instance, it looks like the authors are talking about nonkeratin proteins specifically in products (depositing proteins on hair) and the ways those proteins can be diffused.

The second underlined section: again, products penetrate into the hair protein fiber, but does it prevent protein loss at all if done before shampooing or dyeing since they say nothing about chemical affinity with keratin?
They don't answer that question specifically in this overview, but it's a good theory and it's possible, and maybe we simply don't have support for that idea yet. But there is some support for the idea of at least substantivity, adsorption on cuticle level, which would be particularly useful for damaged, porous hair to temporarily fill in gaps, cracks in the cuticle and there is more substantivity, more adsorption of proteins specifically to more damaged (sections of) hair - https://www.researchgate.net/publication/23160190_Role_of_protein_in_cosmetics (Protein-hair interactions - pp. 50 - 63, pp. 71 - 72)
Whether or not they reduce effect of other agents, I don't know, and it probably depends on a lot of factors. But, theoretically, if that space (gaps) is taken up by these ingredients, there is less space for others to go to. I think it's kind of the idea behind so-called "protein fillers" (if you want to avoid hair absorbing too many dye molecules too fast, going too dark, when you dye it after many chemical processes, esp. involving overly lightened hair) as well as clarifying washes to remove silicones and other occlusive agents, etc prior to some chemical processes, if you want to ensure your predicted outcome for your chemical process.

Third underlined section: is this referring to first shampooing, then conditioning, or only products that contain both anionic and cationic surfactants?
I can't tell. think it might be the latter in this overview, because they are talking about specifically insoluble cationic-anionic complex probably in one product (possibly conditioning shampoos or 2-in-1 products, depending on specific formulation). However, I read the Beauty Brains take on those "Reverse Wash" hair systems (conditioning first and shampooing later) (http://thebeautybrains.com/2016/09/how-does-tresemme-beauty-full-volume-reverse-wash-haircare-system-work-episode-151/) and they hypothesize that you could get similar effect (less soluble, conditioning "cat-an wax") there. It depends on the formulations.

mermaid_pranu

July 23rd, 2017, 10:24 AM

Siv

July 25th, 2017, 10:37 AM

Thank you so much meteor!! That did explain a lot :flowers: I feel more confident trying to pre-poo with olive oil now, since it's cheaper and could possibly be somewhat beneficial as well :)

I have a question- if after putting an XYZ oil, if the hair shaft feels crispy, then does that mean your hair isn't liking the oil? this happens to my hair when I put pure coconut oil. is it an indication that my hair isn't protein loving?

Crispiness could be an indication of protein overload. Perhaps your hair doesn't like protein at all, or maybe it's just "sensitive" and you used too much oil for your hairtype. So far I've only figured out how to use coconut oil right before washing, otherwise my hair is left a crispy mess. But if I oil and then wash, my hair is soft, wavy and moisturised. I think you have to experiment at bit :)

meteor

July 25th, 2017, 10:52 AM

Thanks a lot, Siv! :D Sorry for replying so late. For some reason I didn't see the thread's latest posts...

I have a question- if after putting an XYZ oil, if the hair shaft feels crispy, then does that mean your hair isn't liking the oil? this happens to my hair when I put pure coconut oil. is it an indication that my hair isn't protein loving?

I think it's likely just build-up - I know that word doesn't mean anything very specific, but it could be simply too much stuff or the molecules are too large and sit on top of hair shaft, so yes the hair doesn't "like" the oil, so to speak.

Another possibility is that it's a "drying" or "semi-drying" oil (just a few examples: grapeseed, rosehip, safflower, sea buckthorn, walnut oil, etc...), which, when used in large enough quantities on surface, tend to start polymerizing with oxygen exposure, forming a film that can feel crunchy. Not sure about how exactly it works specifically on hair strands, but this film-forming effect was certainly tried and tested on many surfaces, like canvases, all sorts of furniture, metal work finishing, etc... (for more on drying capacity of oils see the post linked below).

Oils are 100% fat and don't have proteins, so it can't be specifically protein build-up. It's build-up from oil, which can in some circumstances still feel quite similar.

Drying capacity of oils: BACK TO INDEX (http://forums.longhaircommunity.com/showthread.php?t=136845&p=3187906&viewfull=1#post3187906)

How drying capacity of oils can relate to hair: (blog) http://ktanihairsense.blogspot.com/2011/12/understanding-drying-capacity-of-oils.html

Organic Analysis: A Manual of the Descriptive and Analytical Chemistry of Certain Carbon Compounds in Common Use (pp. 282 - 284)

List of common hair/skin oils and their iodine values: http://thesoapdish.com/oil-properties-chart.htm
Alternatively: http://soapcalc.net/calc/OilList.asp (Click on "Iodine Value" and "download" if you want to get it in Excel file.)

Iodine value < 100 : Non-drying oil (Contact with oxygen does not cause any appreciable drying.)
Iodine value 100 - 130 : Semi-drying oil
Iodine value 130 - 190+ : Drying oil (They dry, oxidize, polymerize fairly rapidly on contact with atmospheric oxygen and can leave resinous build-up if used very heavily.)

The iodine value is a measure of the amount of unsaturated fatty acids in the oil. A fatty acid that is missing any hydrogen atoms is classified as unsaturated. The higher the iodine value, the greater the amount of "unsaturation" and the less stable the oil is and the more vulnerable it is to oxidation and free radical production with time and heat. Oils rich in polyunsaturated fats tend to have higher iodine value.

animetor7

July 25th, 2017, 11:10 PM

I have a question- if after putting an XYZ oil, if the hair shaft feels crispy, then does that mean your hair isn't liking the oil? this happens to my hair when I put pure coconut oil. is it an indication that my hair isn't protein loving?

I agree with the others about it most likely just being build-up and probably doesn't indicate any sort of protein sensitivity. How much oil do you use when you've been oiling your hair? Besides using less to avoid buildup, another solution might be oiling when wet or damp. I find my hair absorbs oil more readily when I put it on while my hair is damp and I never get that crispy feeling. I believe hair expands some when wet, and I'm not sure if this or something else is the scientific reason for this result, but it's something to try at least if you still want to oil your hair but want to avoid the crispies. Also here is a useful chart about the absorption properties of different types of oil: http://science-yhairblog.blogspot.com/2013/06/oils-which-ones-soak-in-vs-coat-hair.html Good luck!!

gthlvrmx

July 30th, 2017, 01:45 PM

My best friend was the one who informed me that she found out about the scienctific evidence backing up peppermint oil hair growth and I mentioned it to my mom and now we are also trying it out. Thanks guys! You can really see the fullness of hair on the mice by week 4 on peppermint.

*Wednesday*

August 27th, 2017, 02:46 PM

Meteor...A conversation was going on about the Rapunzel Family.
http://forums.longhaircommunity.com/showthread.php?t=143950

What do you think about the LHX2 gene they believe they have? Do you think it is that rare? I linked the article below.

"Activation of the gene Lhx2 leads to increased hair growth. This is shown by Leif Carlsson's research team at Umeå University in Sweden in an article in the latest Web edition of the respected scientific journal PLoS Genetics. The findings partly refute earlier research results in the field"
https://www.news-medical.net/news/20100415/Study-Activation-of-Lhx2-gene-promotes-hair-growth.aspx

meteor

August 27th, 2017, 03:54 PM

^ I quickly looked at the study that article is referring to (Cyclic Expression of Lhx2 Regulates Hair Formation - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851574/) and it seems that Lhx2 is "required for postnatal hair formation" anyway, but we already know that hair growth is genetically regulated.

I can see the need to study this further, at least due to potential for using some form of activating the gene to, let's say, promote hair growth for hair loss patients maybe with gene therapy in the future. It does look like it could be pretty promising in the future, even though this was only tested on mice. Lots of research would need to be done on this though.

As for terminal length, I don't know if actual terminal length has been well researched at all. I've never seen an actual scientific study into what average terminal lengths might be and I can see why it would be difficult to do in practice (think of how many years would be needed and conditions required for the subjects to follow, etc).

divinedobbie

August 27th, 2017, 06:46 PM

< I have nothing to contribute at this time and I'm just on my phone at work so I'm not able to get into this thread too much but I just wanted to say this is the most amazing thread ever and I cant believe I haven't seen it until now!! >

*Wednesday*

August 27th, 2017, 07:57 PM

meteor

August 27th, 2017, 08:24 PM

^ Thank you kindly. And I'm very sorry I don't know more about this. :flower: Honestly, I wish I could be of more help, but I'm not a geneticist and this research into genes that drive hair growth is new-ish and will probably get a lot more impressive in the future... Hopefully, it will at some point result in some practical help for hair loss patients, etc... (For now, we don't even have a complete and thorough understanding of such simple things like graying or curling, though we've recently discovered that IRF4 gene influences for the former and PRSS53 the latter; and some genes related to eyebrows and beard growth have been identified, as well...)

For now, if you want to get an idea of average terminal lengths empirically, I'd simply look into populations that have a tradition of never cutting hair (e.g. Sikhs) to get a big enough sample so one could get a bit of an idea of how long hair can grow without interference, but even then, it's probably not a good predictor: possibly the no-trim group(s) may have a narrow gene pool (so their hair growth may be more representative of that gene pool rather than overall population) or maybe their hair care is something that limits their length compared to potential maximum length that the same people could get under perfect conditions? It's just hard to tell...

Zesty

August 29th, 2017, 04:29 PM

I'm just stopping by here to share what I thought was an interesting bit of information about an ingredient. I was waiting for my conditioner to marinate in my shower cap and started reading the ingredients list on my products. I noticed that my second conditioner and my leave in have an ingredient I had never noticed before: Behentrimonium Methosulfate. I thought it was weird that a sulfate was in two products designed for moisture and slip. I was going to ask meteor here on this thread, but then I realized that I could just look it up. :p According to what I found in my (admittedly brief) search, it's not a sulfate but rather a thickener and detangler. There were a couple of search results where curly girls were talking about specifically seeking out products with this ingredient. I might do that too, since the two products I mentioned have become favorites.

Has anyone heard of this before? Or is it old need to everyone but me? :p I'd be interested to learn more about it.

meteor

August 29th, 2017, 05:27 PM

^ Oh, I like that ingredient in conditioners, too. :agree: It helps with slip. It's typically paired with fatty alcohols to boost its substantivity. You can also look for "BTMS" on the ingredients lists if you are searching for it, and it's really common. One can think of it as a quat and as a conditioning emulsifier...

divinedobbie

August 30th, 2017, 10:15 PM

my2cats1

September 5th, 2017, 05:02 PM

meteor

September 5th, 2017, 05:40 PM

have any of you seen this study that says blow drying (under certain conditions) is less damaging than air drying? what do you think of it?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3229938/

I originally read about it here http://www.reallyree.com/air-drying-hair-is-more-damaging-than-blow-drying-say-what/

Yes, it's a very interesting study. :) We discussed it a little bit around pages 9 - 11:
http://forums.longhaircommunity.com/showthread.php?t=136845&p=3191068&viewfull=1#post3191068
http://forums.longhaircommunity.com/showthread.php?t=136845&p=3191687&viewfull=1#post3191687
http://forums.longhaircommunity.com/showthread.php?t=136845&p=3192273&viewfull=1#post3192273

And there have also been quite a few big threads on that study on the LHC.

It suggested that air-drying could be more damaging to internal level (CMC bulging) but less damaging to the cuticle. The cuticle was damaged with heat (the higher the heat, the longer the exposure to the heat and the shorter the distance, the higher the damage to the cuticle).
The study seems to suggest that best drying is fast, but also heat-free and at a good distance. Also, all strands showed reduction in moisture levels and even color changes (slightly lighter over time) after all the wash cycles, except control (hair that wasn't washed/dried at all in the experiment).

The researchers themselves admitted that "further evaluation about contact time with water or wet environment and hair damage is needed".
I have some reservations about the study, in particular, since the sample was small, they used separate tresses (not attached to scalp, so no natural "re-fatting" was possible) and washed hair every day for 30 days straight without conditioner or oil or anything like that. These conditions might not represent standard washing and drying practices very well. I'd love to see more studies on this, and I found the study and its findings extremely interesting.