Questions tagged [hair]

Hair is a biopolymer mostly made from keratin, which grows from the skin. Hair is exclusively found in mammals.

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1answer
132 views

Why is male balding so common in comparison to female balding?

I have heard that over 30% of men will be bald by 30, and that 60% will be bald by 50. However, I hardly ever see a bald woman unless it is a story about a cancer survivor or someone going through ...
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128 views

How long to regrow hair?

This is one of the questions I wasn't exactly sure where to post. Basically, I want to make an X-Men parody, and for the part of Professor X I need to shave off my hair. Now I have a simple french ...
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223 views

What function does a mane serve in animals that possess it?

Horses, Donkeys, Antilopes and Bovines grow masses of hair on top (and sometimes below) the neck. What function does it serve? Is that to hinder predators biting?
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Evolutionary selection pressure for human hair patterns?

Are there hypotheses or conjectures that postulate any selection pressures or benefits that account for the patterns of non-pubic human hair? Particularly: Humans do not grow notable (i.e., non-...
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646 views

What is the use of shampoo; is it for the hair or for the scalp?

Apologies for the confusing question; I did not know how to better ask it. I was doing a search on wikipedia when I found this statement. Wikipedia's entry on hair states; "The hair that is ...
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35 views

How many hairs per sq. cm. (or inch) do hamsters have on average?

How many hairs per square centimeter (or inch) do common pet hamsters (Mesocricetus auratus or Phodopus sungorus) have on average? I thought this would be easy to find by googling, but the best I've ...
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213 views

Do supplements that increase pheomelanin change hair color?

People take supplements and ivs with things like vitamin c, glutathione and msm that, over months, results in lighter skin color. This has been explained by the supplements increasing pheomelanin and ...
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224 views

Why is chemotherapy-related hair loss temporary?

Chemotherapy kills cancer cells by targeting rapidly growing cells. That is why patients lose hair as well. Why is chemotherapy-related hair loss temporary? The doctors say it is because healthy cells ...
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Do people with higher body hair growth (eg. Women with hirutism) need more protein? [closed]

Hair is protein. Does that mean that the body of a woman with hirutism is using more than usual protein to make hair and thus she needs more for building and repairing muscles?
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Is hair made of protein or dead cells or both?

Some sources say hair is made of dead cells: it's mentioned in many titles of Google searches, so I'm linking the Google search search Other sources say hair is a protein filament: Protein filament ...
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1answer
58 views

Aging: Only humans have grey hair?

I am not sure if I ever saw a monkey or a bird age and lose hair pigment as it grows. It maybe due to my lack of information. But it appears to be a general presumption that only humans age and lose ...
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Why do hair on head not get pilo-erected?

Whenever we have "goosebumps", there is a momentary piloerection, due to which hair on our elbows and legs get "erected" and "stand" almost perpendicular to the surface of our skin. But why do our "...
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Why does hair turn white but not skin?

From my understanding melanocyte stem cells (McSCs) stop being produced and we have a finite reserve that gets depleted with time. They're at the origin of melanocytes that create hair and skin ...
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Why are bald heads so “shiny”?

Why do males with baldness have shiny skin on their head, whereas we don't experience such "shiny skin" in other parts of body without hair.
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26k views

Why do Asian people have black hair and Northern people have golden hair? [closed]

I have got two questions. Why do majority of Asian people have black hair? Why do majority of people from the northern countries (Sweeden, Norway, Finland) have light (golden) hair? Thanks for an ...
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Is there a medical condition in which you can't cut your hair?

Just curious, does there exist a medical condition in which a patient is advised not to or simply cannot cut their (head) hair?
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178 views

Do bald people not grow hair, or does their hair simply fall out immediately? [closed]

This image is not directly related but it made me wonder if there was a relationship between the nature of the hair follicle and baldness, namely that the follicle cannot 'hold' the continuously ...
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Why can white hairs get dark again?

I have learned (probably in high school?) that hairs turning white is caused by the part of the folicle which produces the pigment dying and being replaced by an air bubble. This sounds very ...
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How can I extract DNA from horse hair?

For my project I have to find an inexpensive, quick and simple-to-use method to extract DNA from horse hair. The sample does not have to be purified because the sample will be used for LAMP and not ...
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Iron deficiency anemia symptoms explanation

In my classes and on the internet, brittle nails and dry hair (or hair loss) are described as symptoms of iron deficiency anemia, but none explains the cause of such symptoms. Does anyone have any ...
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Why are there sporadic lightly pigmented hairs in facial hair?

My body and scalp hair are entirely black. Until recently, I thought this was the case with my facial hair also, until I noticed a small handful of hairs that were anywhere from light brown to copper-...
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210 views

Were Neandertals as Hairy as We Are?

What I mean to say regards facial and androgenic hairs. There are many theories as to why some people have both kinds of hairs, while others have one or the same and others still have neither. The ...
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1answer
176 views

Identify the fluff that I have found in tea

I have just opened a new pack of a black Pu'er tea that I've bought at the local store selling it by weight, and found a piece of fluff in there. To me it looks much like some kind of a bird fluff. It ...
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Why did humans lose their fur?

The little amount of body hair humans have don't seem to be of much use for keeping warm. Our Simian cousins on the other hand sport thick furs. At which point during the species evolution and why ...
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111 views

Do individual mammal hairs absorb water?

In my look into the world of shaving I've seen claims that it is better to shave after a shower because the hairs will absorb water and soften, making the shave easier. Likewise, I've seen it claimed ...
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148 views

What is the biological/evolutionary advantage to baldness? [duplicate]

Male pattern baldness is a common genetic trait. With a distinctive pattern/ density gradent (as apposed to general old age thinning as the body ages) Hair has an advantage of protection from the sun/...
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The onset of hair loss in men

I've seen men starting to lose hair in almost all ages. Why is the onset of hair loss in men different? Is there a normal distribution?
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71 views

Why do men have a greater chance of suffering from hair loss?

If we look around we'll find that men are more likely to suffer from hair loss when compared to women. Is there is any specific reason for this?
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33k views

How do disulphide bonds in hair cause curling?

I understand that there are several characteristics of curly hair which differ from straight hair (such as an asymmetrical distribution of disulphide bonds in curly hair), but really am struggling to ...
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191 views

Why does the wavelength in curly hair differ?

Different people and animals have different wavelengths in the curls in their hair. I understand what purposes hair serves in protecting the skin from light and bugs. I am wondering about the eventual ...
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569 views

What is the structural/chemical difference leading to different shapes in facial/head/pubic hair?

Different hairs have different shapes, thicknesses, properties. What exactly is different between these types of hairs? a previous post implies that the root of the differing length (pun intended) ...
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Pigment returning to my grey [closed]

In the past I dyed my hair to cover the grey, but it became a more frequent event so I decided to just go grey. My hair has been almost entirely white for nearly 20 years. The pigment has been ...
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1answer
10k views

Do pulled hair from the root grow back?

There is not much to explain, I'm wondering if pulled hair, for example of the head, normally does grow back again or not. In reddit, It says this may depend on the follicle integrity, if the follicle ...
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1answer
2k views

Why does our hair turn white before we get old? [duplicate]

White hairs are considered a sign of old age, but they often occur in young boys. I want to ask why my hair is turning white? And why black hair turns white?
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Number of hair cycles in humans

I've seen several websites claim the amount of hair cycles a follicle will go through is predetermined at around 25-30 complete cycles. Is there any genetic evidence to validate this claim? How can ...
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88 views

How large are the inner ear hairs?

I was always under the impression that the auditory hairs located deep within the ear, past the ear drum, are microscopic. After taking a shower today, I was softly padding my outer ear with some ...
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5answers
27k views

Why does hair grow after trimming but remains at a constant length after a while?

Some hair especially body hair regrows after trimming but stops growing after a while. What is the mechanism behind control of hair growth and how is the length limit determined?
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1answer
111 views

Whitening of hair at old age [duplicate]

Human beings have evolved from their ancestors to their modern forms adapting many changes in structure and I would assume that every change has a significance. So, what is the cause of our hair ...
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Can hair follicle miniaturisation affect hair color?

We all know that follicle miniaturisation affects hair texture, making it look thinner(the hair shaft/root itself will be thinner), but does it affect hair color as well? So if an individual has thick ...
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2answers
785 views

Did baby bird hair and mammalian hair convergently evolve?

Chicks (baby of chickens) and ducklings seem to have fine hairs, at least something that look like hairs to me. Most mammals have hairs, but reptiles, fish, or other animal groups do not have hairs as ...
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Why does the scalp hair become grey first?

I understand that when the hair follicles produce less melanin or stop producing melanin altogether, hair becomes grey. But it seems like it is the scalp hair that becomes grey first. If follicles are ...
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6k views

What does static electricity generated by plastic combs do to our hair?

It is said that wooden combs should be preferred to comb hair as compared to plastic combs. Reason is that plastic combs generate static electricity. Question: What does static electricity do to our ...
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Did human hairs actually evolve from scales?

What is the evolution of hairs? Did they evolve from scales?
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1answer
6k views

Why can hair grow without limit while eyebrow cannot?

I cut my eyebrow and it grows until reach a certain length. Hair can grow without limit. Why can hair grow without limit while eyebrow cannot?
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2k views

Why do some moles grow longer and darker hair than the rest of the skin?

In different parts of the body I have skin moles or in medical terms, nevus. In some of them hair grow seemingly either darker/thicker (I'm not sure how much of the two) and notably longer. Here are ...
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1answer
223 views

Why does hair know when it needs to stop to grow [duplicate]

I'm still not quite sure if head hair grows endlessly, or if it stops at some point, but that's not the question. When the hair on my leg grows, it obviously doesn't grow endlessly, but it also stops ...
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222 views

Hair becoming white in one night after tremendous stress

You have surely heard about soldiers during the war whose hair became white in one night due to the tremendous stress. I was wondering how is this possible biologically ?
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642 views

Is Infra Red light safe to use on your scalp? [closed]

I own an Anodyne Infrared therapy device which I use to treat ligament/tendon/muscular pains and it works nicely. I see other infrared products used to combat hair loss (e.g. https://www.amazon.com/...
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What determines the length to which hair grows? [duplicate]

Correct me if i am wrong, if we cut 2mm from eyebrow hair, it will grow 2mm and then stop growing, or if we cut 5mm, then it will grow only 5mm. My question is, does hair know how long to grow ?
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Why human hair is losing its color over time? [duplicate]

Human hair is losing its color over time, that's a known fact. I would like to know why, meaning what biological processes are involved in this? Also, is it part of the DNA somehow, i.e. the exact ...