View Full Version : Questions regarding moisturizing vs sealant oils and hot oil treatments

February 24th, 2019, 04:22 PM
I have been experimenting recently and I had a questions regarding oils. I tried coconut oil on my hair a while back as a hot oil treatment and just for fun, added some to the ends of my hair and I noticed it was super shiny. I also really like grapeseed and almond oil but I have heard that these two oils are sealant oils and should only be used to seal moisture in hair rather than it penetrating the hair shaft. Does it matter what types of oils are used for what purpose? I don't want to buy both coconut oil and grapeseed/almond oil and would rather just use one single oil.

That brings me to my next question. Does adding heat make "sealant" oils to penetrate the hair shaft? Can I use any oil for a hot oil treatment?

I'm planning to purchase the Vatika coconut oil (the green bottle with the round green cap) and use that as a hot oil treatment because of the coconut oil (and its super cheap for the amount you get) and I'm thinking of using it as a leave-in also. Does anyone use coconut oil as a leave in? I've heard it should not be because it moisturizes but does not seal in moisture.

Sorry this was so long, just very confused and in need of hair help!

February 24th, 2019, 04:26 PM
Here's a link on penetrating vs. sealing oils: http://science-yhairblog.blogspot.com/2013/06/oils-which-ones-soak-in-vs-coat-hair.html

Coconut oil does both. I find that using it with heat is totally different than using it as a sealant - that being, it doesn't work well for my hair as a sealant unless my hair has been straightened with heat, but if I heat it up and use it my hair loves it. I don't think adding heat to a sealant oil would make it penetrate. Coconut oil both seals and penetrates, so it works in that case. For something like mineral oil, on the other hand, I don't think that would work.

I use that exact coconut oil as a hot oil treatment. I use an oil that contains coconut oil as a leave-in, but for some reason pure coconut oil doesn't work for me. Others have different experiences, so I think that depends on hair porosity. See what others says on the leave in part, but if you try and it like it, then you may as well use it. :)

February 24th, 2019, 04:29 PM
Water moisturizes. Oils can seal in moisture or can help hair feel softer, but oils don't moisturize. Usually with regards to hair we split oils into "penetrating" and "non-penetrating," referring to whether they can penetrate the hair shaft. There is some debate with various oils because research has produced some contradictory results, but generally coconut oil is considered penetrating.

As far as whether you should use it, the only hard and fast rule is, "Does your hair like it?" Everyone's hair seems partial to different things.

February 24th, 2019, 04:45 PM
Please look up the definition for moisturize. It says ANYTHING that relieves dryness. Oils certainly do that. As a matter of fact, hair has essential fatty acids as a part of healthy structure, and only oils replace that, not water.

February 24th, 2019, 04:49 PM
Please look up the definition for moisturize. It says ANYTHING that relieves dryness. Oils certainly do that. As a matter of fact, hair has essential fatty acids as a part of healthy structure, and only oils replace that, not water.

I tend to agree with this ^^ as otherwise it could not explain the rinse-out oil method, at all.

February 24th, 2019, 04:53 PM
I think I personally like to make a clear difference between moisturising and other stuff, with moisture meaning water only. Regarding oils and fatty acids, I would probably call that nourishment, which I suppose can include moisture as well. When figuring out what one's hair likes and needs, it's good to know what does what exactly, but in the end, I don't think it makes too much difference how one defines moisturising and the such. :)

February 24th, 2019, 05:32 PM
I think part of the lack of clarity on "moisturizing" as a term is that it's an umbrella term that covers (at least in dermatological context):
- humectant agents,
- emollient agents,
- occlusive agents.

Oils act as both emollient (softening) and occlusive (creating a protective film, preventing water/moisture loss) agents. So they do count as "moisturizers", together with silicones, for example, which are also both occlusive and emollient. If you want humectant action (bonding with water and attracting water to hair/skin), sugar, honey, glycerin, amino acids (proteins), etc can fit the bill. Many humectants are also emollients. Humectants on skin can draw water to the skin from two different places: drawing water from a humid environment, and they enhance water absorption from the outer layer of skin.

I'd just stick to how your hair feels after a specific oil (amount, method...) you use. Sometimes even the specific brand of oil or how and if the oil is refined will make a big difference. And of course, amounts and context (on wet, dry, which other products are used, humidity, etc...) matter a lot. So let your hair be the ultimate guide. ;)

You mentioned grapeseed oil, and that one is a drying oil (iodine value = 130-145, http://thesoapdish.com/oil-properties-chart.htm). It may become important if you use huge amounts without clarifying, because drying oils oxidize, polymerize fairly rapidly on contact with atmospheric oxygen and can leave resinous build-up if used very heavily. The things is... drying capacity of oils is studied mostly for oil-based painting purposes and not something hair related, so we just don't know how serious the issue is for hair specifically. Personally, I loved using grapeseed oil but after a while it did start building up on me, but that's just anecdotal evidence, at best.

(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.)

As for coconut oil's ability to penetrate, this interesting study showed that, after adjusting for the surface oil in the samples taken for the total oil measurement, 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)
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)
Yes, coconut oil both penetrates and seals (sits on top of hair, acting as an occlusive). The exact ratio of how much will get absorbed and how much will sit on top is hard to predict, because different hair has different porosity (even along the length of the same hair strand) and different application methods, different conditions, different amounts of oil and amounts of time will all be important factors...

February 24th, 2019, 06:04 PM
Thank you for the science, meteor. There are a lot of misleading websites regarding this issue.

February 24th, 2019, 06:55 PM
Thanks for your input, meteor! I always enjoy learning more about the science behind haircare. :)

February 24th, 2019, 08:45 PM
Wow. Thanks for the info, meteor. I learn something new every day!

February 26th, 2019, 07:07 AM
meteor, awesome info, thank you; glad to see you're back BTW! :D