Unpopular Opinion: I don't think hair porosity is what we have made it seem :bs:

[paulownia]

I recall I saw microscopical images from raw material supplier papers where some proteins are more penetrating on the cuticle level and some penetrate deeper into the cortex, but it all depends on the molecular structure and the size of a certain hydrolyzed protein molecule.

Well, size matters
Proteins are hydrolyzed to break the long molecule chains and make them small enough to penetrate hair. But those molecules also have different sizes. Milk protein is bigger, vegetable proteins like wheat, rice, oat, pea and so on are smaller. Keratin and silk are smallest.
There is also amino acids and those are even smaller than hydrolyzed proteins.
That's why I consider it inaccurate to call egg or yoghurt treatments "protein treatments," since those molecules are too big to enter the hair shafts. Well, yes, they are proteins but they will not repair as a hydrolyzed protein would. They will just have a conditioning effect.

[MusicalSpoons]

I agree. For some people, seemingly a small minority, porosity in the true sense does explain some things and helps them transform their hair care - like if they genuinely have low porosity (again in the true sense, not explained by any other factors you mention) or if their hair is high porosity and just keeps losing moisture really quickly.

But for the rest of us, it's just one aspect of our hair and may or may not need to be considered when evaluating or tweaking our routine. It's helpful to know roughly, I think, but it's absolutely not the key to hair health for most of us. I like Science-y Hair Blog's take on it, giving it the same kind of consideration as all other aspects of hair character and hair care, but not blowing it out of proportion - and the points you make especially about older ends and more textured hair agree with her, IIRC.

[Shorty89]

Well, size matters
Proteins are hydrolyzed to break the long molecule chains and make them small enough to penetrate hair. But those molecules also have different sizes. Milk protein is bigger, vegetable proteins like wheat, rice, oat, pea and so on are smaller. Keratin and silk are smallest.
There is also amino acids and those are even smaller than hydrolyzed proteins.
That's why I consider it inaccurate to call egg or yoghurt treatments "protein treatments," since those molecules are too big to enter the hair shafts. Well, yes, they are proteins but they will not repair as a hydrolyzed protein would. They will just have a conditioning effect.

I consider eggs a protein treatment because they act like protein to my hair. By that, I mean that they leave it "crispier" if they aren't followed by a moisture treatment. While it may not penetrate, it gives the same feeling to my hair as a penetrating protein treatment.


I have to agree with Autobot's post. I have been around since before porosity became a "thing" and I don't consider it a huge factor in my haircare. I think factors like hairtype and whether or not your hair likes cones is more important. That being said, if someone finds a good routine by determining or following low or high porosity haircare, then that's good.

[florenonite]

<snipped for length>
Now, I'm not saying porosity doesn't exist, but I'm definitely critiquing my own viewpoints i once held about it. I know there's ways to measure it, and I know our hair exhibits such characteristics. However I really think it's just not that big of a deal, like i once did, and like so many others seem to really hype up. I also think that one strand can have various porosity levels at various lengths/spots, and who knows where else on the same head. I rally think having low porosity seems to be some sort of desirable characteristic concerning one's own hair. I guess as a way to signify how healthy it is? To me at least, low porosity doesn't automatically mean hair health, and I think a lot of influencers seem to kind of piggy back off of one another just because others are doing so as well.

This is all just my two cents though. Sorry for the long post.

I think because damaged hair is more porous than non-damaged hair, people think that lower porosity is inherently better, so they all want to claim their hair is ~so healthy~ because it has low porosity. However, lower porosity hair can have its own problems, and it's a relative thing. My hair is, as far as I can tell, naturally very non-porous, but I have damaged ends that are more porous. Another person with more "normal" porosity might have a similar porosity at the roots as I do at the ends, and have less damage at the ends so the porosity is more consistent through the length - is my hair really healthier because it comes out of my head with a Teflon cuticle? Hardly.

I tend to think porosity is more useful for how it affects the way hair behaves than for how it might actually look under a microscope. I said that as far as I can tell my hair is very non-porous, and I think this because: it takes an eternity to dry, if I oil it wet it gets stringy, my 50/50ish henna/senna mix fades, water beads on it in the shower before soaking in, I never needed conditioner until I moved somewhere with hard water, and it never soaks up sebum at the roots. All of this means that advice for low porosity hair is *more likely* to work for me, but I still need to experiment with it, and it may not work. In other words, it's just one other characteristic that can help inform how I treat my hair, like how my hair is fine, very dense, and mostly straight, with a picky scalp.

When I joined LHC porosity wasn't really a thing. I remember when I first started noticing it was A Thing, and started researching it and kept on thinking HEY THAT'S ME the more I read about low porosity hair. So in that sense, it's helpful, because someone was describing characteristics of my hair and giving advice for how to handle it. But I don't think it's helpful to try and discern the porosity of your hair if the descriptions of high/low porosity don't resonate, and lower porosity doesn't inherently mean better, healthier hair (I wish I had hair that behaved like normal porosity hair).

[TatsuOni]

I've never really cared about porosity. My hair shows signs of both high and low porosity, according to the descriptions. Also, it's been many years since I realised that my ends, lengths and scalp hair need different things.

My hair needs a lot of moisture and oil, but a lot more during the winter (or a dry summer), than it does during the summer. I've gotten to know my hair by trial and error. So I know what it needs and when it needs it.

I know that this is about porosity, but my hair has never behaved "like straight hair should" either. Not even when it was fine. I've always needed more moisture and oil than is recommended for category 1 or fine hair (I'm now an M).

I think that porosity and hair type can be a good way to start, for someone who knows nothing about what their hair needs. But in the end, if one thing doesn't work, try something else until you've found the perfect routine for your hair and scalp.

[lapushka]

I want to add that even some people's unprocessed/virgin hair can become high porosity quickly if the cuticles are internally more prone to chipping and breaking due to higher sensitivity to environmental or mechanical damage. This is why my ends are prone to damage even being free of past heat damage.

But... how do you *know* that is due to high porosity and it is not just very dry hair that needs more moisture, or something like that.

[Entangled]

Yeah, high/low porosity has never factored much into my haircare routine. I think it's probably useful when describing how bleach, dyes, perms, and relaxers affect the structure of the hair and how you will might need to treat hair differently after using them, as well as explaining one of the reasons why curly hair needs a different routine than straighter hair, but beyond that haven't given it much thought.

[Ylva]

I don't think it hurts to be aware of porosity and understanding different types of hair damage that can occur, but one needs to keep the big picture in mind and understand that there is much more to hair than porosity.

I certainly notice three different porosity levels (on top of the other cumulative damage) throughout my hair as I grow out bleach damage. I've got very high porosity ends, a relatively nice medium porosity section, and then my virgin hair which very much seems like low porosity. But contrary to people saying that long drying times are a sign of low porosity, I think it can also go the other way. My roots dry the absolute fastest, and I think that could indeed be because of porosity: since the cuticles are so tightly shut together, the hair doesn't even get very soaked in water and therefore not much needs to get out either.

[MusicalSpoons]

But... how do you *know* that is due to high porosity and it is not just very dry hair that needs more moisture, or something like that.

It's a reasonable conclusion after months/years of a very moisturising routine if the hair still behaves like high porosity.

[Fimu]

But... how do you *know* that is due to high porosity and it is not just very dry hair that needs more moisture, or something like that.

If virgin hair has split ends or white dots (which is often inevitable with very long hair), then I think it means they have high porosity ends (damaged cuticles on that part of the hair shaft) from long-term daily wear and tear.

I hope I could clarify it a bit