/r/HaircareScience
This subreddit aims to provide resources for achieving better hair quality through scientific research in trichology, physiology, chemistry, and biology
This subreddit is for discussion and dissemination of the science behind haircare products and processes. We aim to provide information and resources to achieve better hair quality through scientific research in trichology, physiology, chemistry, and biology.
see front page without Advice Request posts
Subreddit Rules
Source your facts - If you're making a statement of fact, you must provide a scientific source. If the information comes from somewhere non-scientific (your experience, a blog), you must make that clear and not frame the statement as fact. Do not tell others to look things up for themselves - the burden of proof is on the person who first posts something. Read more about what qualifies as a source here
We are not your doctor - Do not ask for a diagnosis or attempt to give one to anyone else. If you want to ask about a particular condition it must be in an impersonal way and it must not ask for how to diagnose.
Advice requests must be specific - Requests for personal haircare advice must have a specific question in the post title. Vague requests (“what’s wrong with my hair?" "Give me product recommendations”) will be removed. Please post general requests for help/recommendations in the stickied Haircare Advice megathread, or rewrite this post to have a more specific question. Read more about what makes a post specific vs. vague here
No repetitive posts - In order to keep the subreddit uncluttered, questions that are frequently posted will be removed. Before posting, use the search bar first to see if your question has already been discussed.
This is a science subreddit - This is not the place to ask for styling preferences - try other hairstyling subreddits for that. Pseudoscience, chemophobia, or other anti-science rhetoric will be removed and repeat offenders banned.
No advertising - Advertising a product without any scientific discussion is prohibited. If you are affiliated with any product you must disclose your relationship. You may discuss your products as long as you have disclosed your relationship and have been flaired as a product representative. Product recommendations are allowed as long as it is not repetitive and you do not ask to take the conversations to DM or post affiliate links. We have a zero tolerance policy for advertising or promoting MLMs.
Be respectful - Scientific arguments may sometimes occur, but always treat other users with respect. No harassment/racism/sexism/etc. will be tolerated. If you are combative or rude when others ask you to provide sources, you may be banned. This rule also applies to your communication with the mod team.
No asking for advice on balding or hair loss of any kind. - If you have any questions about hair loss, balding or thinning please consult a medical professional. Other subreddits you might be interested in include r/tressless and r/askdocs.
This is not a product review sub. - Product ingredient lists don't really tell us much about the product; formulation matters. If you're looking for product reviews, try another sub, or google it. Same applies to posts asking for dupes of a specific product. Posts asking for help checking a product ingredient list for "harsh" or "harmful" ingredients will be removed as it promotes chemophobia.
This is not a hair coloring or styling sub. - For hair color advice, try r/hairdye or r/fancyfollicles. For hair styling advice, start at r/hair.
This is not a DYI sub. - There is a perfectly good DIY subreddit, r/DIYbeauty. Post homegrown product questions and other DYI fair product questions to that sub.
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Resources
Alphabetical List of All HCS Guides
More Information
International Journal of Trichology Archive
North American Hair Research Society
Chemical and Physical Behavior of Human Hair by Clarence R. Robbins
Hair and Haircare, ed. Dale H. Johnson
Cosmetics & Toiletries Magazine
Journal of Cosmetic Science Archive
Brightest Bulb in the Box Blog
Related Subreddits
/r/HaircareScience
Sometimes this sub feels like the Andrew Huberman of haircare. That is, take one small study that is directly funded by a company trying to sell you their product and generalize to all of humanity. Then call it "scientific."
Multiple times I come here and see posts that go something like "I can't believe people do [x], it's so unscientific and RUINED my hair."
Usually by some European-descent person who tried an extremist version of something that was called "curly girl method" or "no poo" that they found on a random person's youtube channel in 2015 or something.
Then there will be a comment that basically implies all hair is actually the same (which is patently untrue under a microscope).
Then there will be as study linked that's funded by L'Oreal and shows that for 40 European-descent women living in the Los Angeles metropolitan area in 2012 a specific type of sulfate and amodimethicone worked great, so therefore every type of sulfate and silicone MUST work for everyone and anyone for whom it doesn't work for is lying/anti-science.
This is not science.
So many "studies" are one-off conference papers that have no peer review and no replicable results that will never be validated at a larger scale (see this post for an example, or this study done on a single bundle of Mongolian hair). Still more are funded by haircare or pharmaceutical companies with agendas reminiscent of how the sugar industry funded studies blaming heart disease on fat, not sugar, despite a clear correlation between the two harming millions and creating a discourse around diabetes that literally cost lives. Women, along with non-European-descent people, meanwhile spent years suffering because almost all medicinal and surgical studies were done on European-descent men. In the beauty industry, very few studies are done that have enough trials to be statistically significant to the general population.
I am not saying that all information is equally valid and true -- or that natural/clean/whatever bs buzzword is trending is inherently better and we should fearmonger the "evil chemicals," what I am saying is the SCIENTIFIC thing to do is critically examine sources and content. Don't fearmonger, but also don't ignore what is personally not working for you.
We are all unique. No dermatologist would ever dare to say one skin-routine fits all or one ingredient will be always be safe for everyone. People have allergies, genetic conditions, illnesses, environmental factors, etc. Similarly, there is no hair product that will work for everyone. If curly girl method doesn't work for you -- stop. If silicones and sulfates don't work for you -- also stop. If you can hygienically go 3 days without washing your hair, go for it. If you can't, it's no problem either! If your expensive products genuinely work better than drugstore for your hair type, I feel for your wallet but that's fine. If drugstore products work just fine for you, congrats and I am so envious. If you have bleach damage, your hair will respond differently to products than someone with virgin hair. Be a real scientist and experiment with what works best for you. Don't be fear-mongered into avoiding certain chemicals, but also don't be "science-mongered" into using those products if it makes your hair look like shit.
So I just had my balayage redone and when I applied shampoo after the salon, my scalp instantly felt dry and tangled and matted. I’ve never experienced this when I get my hair done and I’ve always been using the same shampoo which is the Moroccan oil moisturising one. I know I have high porosity hair but I’ve never had this experience before. I use moisturising masks and olaplex no 3 once a week.
Can anyone suggest why this is happening? Thank you all.
I’ve noticed a huge uptick in people parroting phrases like “determining your porosity will help you figure out what products to use” and I’m convinced they just like using the word “porosity” to sound smarter.
First of all, how is the average consumer supposed to accurately determine their porosity without a microscope? The cup test most of these folks recommend is wildly misleading, and spraying water on your hair to see how fast it absorbs and/or dries is dependant on a multitude of other factors (density, for instance) and doesn’t tell the whole story.
Second, the way people talk about porosity makes it seem as if it’s a relatively unchanging state like hair texture (eg: fine, coarse), and that it will be consistent across the entire length of the strand (which seems highly unlikely for anyone who doesn’t have very short hair).
Lastly, these people never use the 1-5 grading system, and they rarely mention that porosity is -from what I understand- basically a measure of cuticle damage. If we’re going to be reductive enough to declare our entire head of hair is either high or low porosity, why not just say “damaged” or “undamaged”? Most haircare products are not marketed towards specific porosity, but products for damaged hair are common.
To bring this rant full circle… There are now people all over hair subs asking for recommendations for (as an example) “low porosity 2a hair”. All that tells me is that you have wavy hair that probably floats in a cup of water because surface tension exists. — Texture (strand width) seems to be the most important factor, the easiest to determine, and -for some reason- the most overlooked.
Is anyone else annoyed by this? I think the importance of porosity is at best massively overstated, and at worst extremely confusing. Am I wrong?
Ok, I thoughț that this smoothing worked by stuffing the hair with keratiŋ that is fixed with formaļdehyde. Thanks to this sub, beauty brains and the comments, I understood that in reality, we put fragments of amino acids (hydrolyzed proteiŋ) in certain gaps in the keratiŋ, but we cannot target the areas of damage. With formaldehyde, it will be temporarily fixed and create temporary protein-protein bonds, we then obtain a temporary relaxation. (well we are really in biochemistry I have a little trouble understanding, correct me if I am wrong!)
Now, here is what I learned in training: virgin hair, having much fewer gaps, will fill much ļess (or almost none) with keratiŋ, so it will not work.
Given the real functioning, what really happens on virgin hair in good condition?
I must add that experience has indeed shown this: on virgin/good hair, these treatments do not hold. Many hairdressers or clients will be able to testify.
I am looking for the science behind this
I searched a bit and from what I saw, there is the hair strand test (which my hair floated) but I have read that it is not a good test. I also saw that if your hair takes hours to dry then it's low porosity too (which mine does). What are other ways yall found out your hairs porosity? (cause I'm still not sure about mine 😭)
Hello so basically I have used every top hair company and for every single one, the hair becomes super dry and frizzy after like 2-6 weeks once the silicone finish comes off of the hair. I was wondering if I could mimic the same process that companies use to restore the hair and a put a silicone finish onto it? I have previously used silicone mix but the results felt very superficial and underwhelming. I was wondering if using pure dimethicone would replicate the factory process? If not, does someone have incite into the recipe the companies use?
Hello! I lost about 50 pounds over the course of 6 ish months and the majority of my thick hair went with. I had it cut short in July to make it look fuller but that only lasted for a minute and now it’s grown back out (I love it long) and I just feel like it looks so thin again.
Any tips? What can I do to grow some of the thickness back? Products?
Thank you!
Is it really important to use UV lsun light protection in your hair?
If yes, what products do you use?
I use Pureology Leave In, but im not sure if it protect from UV sun light, as their description is a bit confusing: "This leave-in conditioner spray contains sunflower seed oil and vitamin E to help protect color-treated hair from the damaging effects of UV rays and the environment."
After a shower, my scalp gets dry as all heck. So I decided to add lotion/ oil to my scalp which in turn gets rid of dryness but immediately begins to become irritated like my pores are clogged. wtf am I supposed to? I truly feel like just throwing my scalp away.
Does bleach hair damage improve with time if you leave it alone for a while? Nothing near ramen noodle damage just some breakage and elasticity.
Hi, i have natural hair (no dye) and only use hair friendly products. No heat. I have had a healthy chop of 5 inchs from elbow length, i was expecting super healthy hair but realised one side at the front is not wavy. Its the side i sleep on. I use a satin pillow case and now i am using a satin bonet and trying my hardest to sleep on my back or at least even out which side.
I dont see split ends at all but the hair is fuzzy and the wave pattern is lost. Theres a drastic difference between both sides of my head and i know they would usually match in wave pattern and health
Can anything fix it?
Its only from me tossing and turning at night and only sleeping on one side, i am sure.
Thank you
I tried gelatin on my relaxed hair and it became curly its now curly when wet and kinky straight when i blow dry it. The hair is much thicker and healthier i dont lose hair in combs anymore howeverr it seems freezier than usual instead of smoother as i would expect can someone explain to me please why
My hair is constantly oily. I have used so many different clarifying shampoos and dry shampoo, but it is always oily. I have to wash my hair and blow dry every morning because it can't even last through the night.
There are even times it feels oily right after washing with a clarifying shampoo, its like its not oily but super soft and feels oily/sticky. I also have thinner hair, so it has almost no volume. Im wondering if there is like a barrier missing on my hair bc it always feels like it is soft and oily - it is quite literally impossible to make it feel dry at all.
Please, what can I do?? I have tried everything, oilying my hair, apple cider vinegar, blowdrying, dryshampoo, double shampooing, no conditioner, etc. But nothing helps it last more that 6 hours without getting greasy.
Hi, I got my 3b curls Japanese straightened about 7 months ago and now I have about 5 inches of regrowth that I usually flat iron. Is it safe to perm my hair to make it wavy or curly again?
Im a man, and now that my hair is not looking as good as it used to because of age, I started taking care of it, and ive been using a conditioner and hair masks. But I recently red that men should not use a conditioner, specially men with fine short hair!
My hair does look better, but it may not be the conditioner thats making it better because im also using alot of other stuff like Hair Oil, K18, Leave-In, Medication, and laser..
So should I continue conditioning my hair, or remove it from my hair routine?
Im a man, and now that my hair is not looking as good as it used to because of age, I started taking care of it, and ive been using a conditioner and hair masks. But I recently red that men should not use a conditioner, specially men with fine short hair!
My hair does look better, but it may not be the conditioner thats making it better because im also using alot of other stuff like Hair Oil, K18, Leave-In, Supplements, Medication, and laser treatment..
So should I continue conditioning my hair, or remove it from my hair routine?
i'm struggling with my frizzy, and less full hair. i have oily roots and dry ends most days and my hair looks dull. for reference, i'm 20F and half mexican, my family and i have always had beautiful thick hair due to good genes. unfortunately i have been under a lot of stress lately and due to mental health, my hair has been shedding significantly. i'm very insecure and can't seem to find a routine or product that works for me.
i'm looking for any tips on a routine for 2a waves. my goal is to grow fullness, lessen breakage, fix the dullness, and define my waves without the heavy product weigh down or greasiness :) if someone could leave some good suggestions/advice that would be lovely🙏
I used to have pin straight asian hair, although now I've bleached it alot. In both times, I've always used paraben kids shampoo and found my hair to be very thick, there were no problems with the change of my hair health. When I switched to a different shampoo, I was excessively shedding hair and finding my hairbrush containing ridiculous amounts of hair ripped off my head.
Just today, when I put up my hair it looked like I had a receeding hairline. I always thought it was stress, but at that point I had to stop using this popular asian hair shampoo and switch back to my kids fish shampoo😭.
Is there an explanation to this? Even adult shampoos without parabens are still stripping my hair.
Ok I have this great product from braziļian blowouț. When I asked the company what replaces formaldehyde and its releasers they told me "nothing. heat sets the kerațin without anything else." Yeah, liars! But this product works so well! What is the ingredient that does that?
Water Deionized, Glycerin, Cetyl Alcohol, Acorus Calamus Root Extract, Argania Spinosa Kernel Oil, Phytokeratin, Silk Protein, Butyrospermum Parkii (Shea) Butter, Camellia Sinensis Leaf Extract, Chamomilla Recutita Flower Extract, Cocos Nucifera Fruit Extract, Commiphora Myrrha Resin Extract, Glyceryl Stearate, Gossypium Herbaceum Seed Oil, Lecithin, Mauritia Flexuosa Fruit Oil, mentha piperita, Behentrimonium Chloride, Stearamidopropyl Dimethylamine, Parfum, Polyquatenuim-47, Citric Acid, Dissodium Edta, Cinnamomum Zeylanicum Bark Extract, Macadamia Ternifolia Seed Oil, Alpha-Isomethyl Ionone, Amyl Cinnamal, Benzyl Salicylate, Citronellol, D-Limonene, Hexyl Cinnamal, Linalool, Hydroxycitronellal, Citral, Polyglyceryl-3 Diisostearate, xylityl Sesquicaprylat
I know there are studies but I don't know how to interpret a study. Do treatments that release formaldehyde into the air and stay on the hair for a few days really harm people and what exactly do they do to a pregnant woman who is breastfeeding?
Theoretically it is feasible? How woulɗ a hand formulation be unsuitable for hair?
I washed mine with this one :
(Aqua, Sodium Laureth Sulfate, Cocamidopropyl Betaine, Sodium Chloride, Glycerin, Parfum, Styrene/Acrylates copolymer, polyquaternium-7, Tetrasodium EDTA, Methylisothiazolinone, Methylchloroisothiazolinone, Coco glucoside, Benzoic acid, Citric acid, Aloe barbadensis leaf extract, Mentha piperita leaf extract, Propylene glycol, Sodium benzoate, Linalool, Geraniol, Ci 42090, CI 19140.)
It left my hair clean and soft! Can I use it daily for my hair?
Does this mean that not washing your hair can damage it because of the build up of salt from sweat. Is there any measure of how much salt there even is on the hair/scalp?
I have curly hair, and the hair in the crown area seems extremely dry, and easily breaks off. It barely grows beyond 15 cm. If at all it grows beyond that, it eventually breaks off. The hair in the rest of my scalp grows pretty well. Again, the growth is a bit stunted - the most it has grown is about 10 cm down the shoulders, but it looks fairly moisturised and healthier. What is happening, and what care should I offer my hair?
There are three types of bond that link the protein chains together: disulphide bonds (which are strong); and hydrogen bonds and salt bonds (which are weaker).
in this article which explains how a treatment works keratin,
I quote:
They work by reforming a percentage of free bonds (and reducing a few bonds as well.).
and
Keratin smoothers don’t really work by adding keratin. Instead they work by either coating the hair, cross-linking some of the internal bonds, or breaking and reforming a bunch of bonds.
Can someone explain it to me in detail and tell me what type of connections are involved?
Can someone help me with hair care, I wash my hair usually every other day, I've tried several products the following products over time -
Olaplex shampoo and conditioner Quai clarifying shampoo Redken bonding shampoo and conditioner Several drug store brands
And my hair is usually fine on day one but then day 2 it is heavy and greasy. Can anymore let me know what I'm doing wrong?
I just got my hair rebonded yesterday. The girl in the salon told me to wash it after 3 days.
The thing is, my hair looks so flat. Too flat for my liking. It doesn't have volume. So I was thinking of washing it after 2 days.
Is it okay to that? This is my first time having my hair rebonded.
Will my hair revert back to original if I wash it too early?
Recently, posts from the NoPoo (no shampoo method) subreddit have been popping up on my feed.
It’ll be a photo of EXTREME buildup and the OP is like “ok I’ve been doing this NoPoo thing and I’m itchy and oily nonstop what now”. Everyone in the comments either says to persevere, use vinegar or aloe gel.
And I’m just here like… as an oily scalp person, I would be a MESS without my clarifying shampoo and Nizoral. I am getting secondhand itchy scalp from those posts and I feel so sorry for those people who are clearly suffering and getting terrible advice.
For the records, I’ve tried NoPoo before too and it WRECKED my scalp.
TLDR; NoPoo is crazy imho as an oily scalper, what do you think?
I have extremely oily skin and scalp, which is likely genetic. I use niacinamide on my face and it has worked wonders in keeping my sebaceous glands from overproducing oil.
I'm wondering if, in theory, I could also use my niacinamide serum as a leave-in treatment for my scalp to control oil? Oddly enough I haven't seen any niacinamide products for hair care and I'm wondering if anyone here has experimented with that particular ingredient.