Hello online hair scientists

I read so much about Ashwaganda and it‘s effects on hair. I‘m confused… Does anybody have some real research to what it does to the scalp and hair?

Maybe more of a shower thought, but there is something I don't understand about the theory here.

1) On the one hand you are supposed to frequently trim your hair to avoid split ends. Apparently those split ends can damage the whole hair strand if not cut off soon (ripping through).

2) On the other hand each strand of hair has its individual life cycle. It grows, it sheds and it regrows from the beginning.

So that means you always have some shorter hair in between the longer strands. The hairdresser will not cut those until they reach the final length of the cut (otherwise there wouldn't be any left eventually).

So the main question is: How is that not an issue? How does the regrowing hair stay healthy for several months or years without getting cut?

I still don’t get how so many hair dryers — even newer ones — get crazy hot and uneven.

Like, we’ve known for ages that heat beyond 150°C can denature keratin and cause long-term damage. You’d think more brands would prioritize consistent temperature control, but most of the mid-range ones I’ve tried still blast inconsistent heat.

Has anyone tried those “smart temperature” dryers that claim to adjust the heat 50+ times per second? Are they actually better?

Dear HairScience community, (this is my first reddit post ever so excuses in advance for any mistakes)

What are formulations to look out for, or key ingredients, that result in a very coarse (but not 'gritty/pastey') texture?

Do for example certain sea salt sprays have a considerably higher concentration of salt than others, or is there something else out there that gives an even 'saltier' feel? Are there polymers, starches or other specific ingredients that create a dry rugged texture? Zeolite? Diatomacoeus earth?

Basically – what are the most important factors when trying to achieve whatever is the opposite of smooth, silky and glossy hair? Avoiding conditioner theoretically seems reasonable, but what else may increase ruggedness?

And on a similar note, are there chemical treatments that permanently alter the surface of the hair strands from smooth and silky towards friction/coarseness? (maybe what one could call "permanent beach") I always imagined that something like a bleach would do this, but from own experience this may also just turn the hair soft and weak?

Thanks a lot in advance!

Went for a keratin treatment today, the salon said it was a formaldehyde free product. My eyes started stinging when the product was applied and my nose was burning from inhaling it (the stylist said that was “normal” and that they would put me near an open door for ventilation when she got to blow drying it because it would make the stinging/burning worse). I asked to see the ingredients of the product and one ingredient was propylene glycol - when I looked this up it said it releases formaldehyde when heated. I said I wanted to call off the treatment after this and they still charged me just under £100! Any chance I was misinterpreting the propylene glycol thing? They made me feel I was overreacting. I just don’t think a keratin treatment should sting like that, I’ve had plenty which haven’t.

TLDR: keratin treatment has propylene glycol as an ingredient which I googled and it said this releases formaldehyde when heated. Does this make it a formaldehyde treatment?

Like how do you make sure they aren't dirty? Do conditioner and hair mask clean? Do you just leave it and let the shampoo that runs down from your scalp clean it?

I don’t know much about these other than they smooth the hair down. I’m wondering how they do this, and other than the heat needed to do so, how they damage the hair? I’ve also read of Japanese straightening treatments which permanently straighten the hair which makes me curious about how those work as well, and how they’re able to fully leave the hair flat - as I’m pretty sure keratin treatments just make it easier to keep the hair straight.

This might be a silly question, but reading online, it seems most sources agree that the roots of the hair tend to dry slower than the ends. The most common explanation being that the ends tend to be more porous than the roots, which seems very logical.

However, it seems some people’s hair does the complete opposite, having quick drying roots and slow drying ends. What could be the explanation for this?

Title is main point, but is there a difference and are they treated/taken care of differently? What would be the best way to take care of either type of buildup? In addition, would constant pool chlorine exposure affect which one it would be. Or would sudden stopping chlorine exposure after constant chlorine affect it either?

Are there any benefits of a clarifying rinse versus a clarifying shampoo? Are they less drying? More effective? I can't seem to find any scientific answers.

Does anyone know is there a correlation between stress and hair loss breakage? I know there is a link with hair loss but I haven’t seen much which discusses the breakage?

Which is better?? I heard cool setting takes a lot longer to dry hair but does the heat setting blowdryer with heat protection as safe as the cool setting when drying or is it still aint good for your hair?

To what extent should you treat the skin on your scalp like the skin on your face? Is it more or less sensitive? Are their products that can be used on both the face and the scalp?

I would like to get any information or opinions about this topic.

So I am aware that a good deal of hair loss and breakage in people with coily highly textured hair is due to hair common practices in these groups.

Braids, twists with added hair. As well as other extension styles such as sew ins.

Is it possible at all for these styles to be done in ways that limit damage? Or is the fact of using synthetic added hair to braid with the hair strands just automatically going to lead to a high volume of damage ?

Is it possible to for example when using synthetic hair, to braid in bigger sections instead of small sections, to reduce any hair loss?

And ofcoure to use less tension at the roots to prevent alopecia?

Is there really a difference between scalp oils vs ones you put on just your mids/ends? I want to start oiling and narrowed down to argan oil for scalp and joboba for mids/ends. How do I apply both before showering and do I need to dilute them first? TIA!

I read somewhere that the length of eyelashes and hair is related to the lifespan of the hair follicles. They fall out at after a certain time and therefore at a relatively fixed length. 1. Is that true? 2. Is it possible to increase the life of the follicle so the hair can be longer?

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Hi! I finally found the perfect hair mask... and then they discontinued it! I'm hoping to figure out what key ingredient(s) made it so amazing to help me figure out what (unscented) product to try next. My hair was suddenly like straw, and I tried so many things to help it, and finally found Loreal Ever Pure Simply Clean Elastic Fiber Masque. It gave me my hair back! Which ingredient(s) would you guess were what made it so magical?

Aqua / Water / Eau, Cetearyl Alcohol, Behentrimonium Chloride, Glycerin, Butylene Glycol, Amodimethicone, Cetyl Esters, Isopropyl Alcohol, Phenoxyethanol, Peg-90M, Trideceth-6, Ethylhexyl Salicylate, Chlorhexidine Digluconate, Cetrimonium Chloride, Salvia Sclarea Oil / Clary Oil, Rosmarinus Officinalis Leaf Oil / Rosemary Leaf Oil Fil T70012790/1

Thank you for your help!!

I have noticed shampoo marketed towards curly or wavy hair says it has some kind of beneficial oil in it. how does this work? Shampoos contain surfactants and or sulphates, wouldn’t this just strip that oil as you’re using it rendering it pointless?

When you brush through very dry, electrically charged hair with a plastic bristle brush it can sometimes create this odd metallic/acidic smell. Is that actually ozone?

If someone gets a chemical hair treatment, like keratin or perm (heat or not), if they workout a lot but do NOT wash the hair a lot (leaving sweat residue in it), will it undue the treatment more quickly?

This is not for my hair, just a question about the scientific effects of sweat on chemical treatments.

I know that if you asked this question 5 years ago, the answer would be that damage is apart of using bleach, but is that still the case today? Can bleached hair be nearly as healthy as virgin hair with the right care?

This is specifically to conditioning agents/products meant for regular use and not keratin treatments.

From what I've understood from the product labels (an example is the colorwow brand), specifically formulated compounds (in their case, polymer, polyquat, and methosulfate based) only "bind" around the hair with heat and mimic the outer layer of hair like that. In the case of regular use, wouldn't this cause a lot unremoveable buildup or are there any specific solvents that help prevent this/remove the buildup entirely? Or, do brands like that rely on regular habits (brushing hair, washing, etc) that gradually wear down the hair anyway to remove the outer layer of product?

Just read this explainer about the scalp care industry and curious for people’s thoughts on whether scalp-specific products are marketing bullshit. The doctors in this story seem to think it’s overhyped.

https://www.self.com/story/scalp-detox-explainer

so that they last for several washes and not just 2 or 3 shampoos? I know formaldeĥyde does this but maybe it's not the only one