Hair Science, Why Hair stops growing and we don't look like Chewbacca

[TheAbomb]

Source video for discussion

https://www.youtube.com/watch?v=Bby5-lYFyAs


Actually didn't think about Hair and how it's regulated. However it has a really unique system that determines when to stop growing. So we don't see wolves dragging their hair and our cats though sometimes extra fluffy can manage. Even Chewy doesn't need a hair cut as it is all determined by 3 stages the Anagen (growth phase) Catagen (Transition) and Telogen or ( Resting phase). While some people are exceptions to this rule in some area's with freaky long eyebrows or hair like rapunzel.

All hair does stop growing. Even the hair on your head. In some rare cases people with a short Anagen phase for Head hair growth don't ever need to get their hair cut as it naturally stops growing at that length. Must be nice. However typically it does last between 2-7 years for head hair so even those tails of Rapunzel are extremely rare for hair to keep growing.

[Vizardlorde]

I have 2 hairs on my right arm that dont stop growing like the the rest. One is thin and light like baby fuzz close to my wrist and the other is dark and thick almost like a pube near my shoulder and they grow to 1 1/2 inches to 2 inches every time i yank them out.

[Shadowferal]

pfft...as you grow older the hair atop your head may thin out/recede and fade, but it'll grow thicker everywhere else as if making up the difference.

As an old navy guy derisively chided me about growing a beard; "Why cultivate what you have growing on your face when it's growing wild up your ass?"

[Wyrt]

But do they know why hair grows in the buttcrack?

[Independent voter]

So a hair gets to the right length, say on your arm. It then gets plucked, how does it know to grow back?

[Ripster42]

I have 2 hairs on my right arm that dont stop growing like the the rest. One is thin and light like baby fuzz close to my wrist and the other is dark and thick almost like a pube near my shoulder and they grow to 1 1/2 inches to 2 inches every time i yank them out.

SO what you're saying is that you're going to have a sweater of back hair in 5 years?

[Khadgar]

there's some people irl that do look like chewy

[TheAbomb]

So a hair gets to the right length, say on your arm. It then gets plucked, how does it know to grow back?

Plucking that hair starts the Anagen phase again. It's a cycle. All hair in essence falls out just at different rates. Hair on your head is waiting to fall out so it can start growing again it's just it happens at all different times so we don't have a bald phase so it goes unoticed.

[Gheld]

Very interesting. Something I never bothered to look up on my own. Thank you for that.

[TheAbomb]

there's some people irl that do look like chewy

That is quite the picture and as mentioned. Genetics, hormones and well disorders will cause this.

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Very interesting. Something I never bothered to look up on my own. Thank you for that.

Yea just that random thought somehow hit me and I was like how does this work. So had to research it lol.

[Ripster42]

there's some people irl that do look like chewy

That's the hercules of beards.

[Powerogue]

That does explain why people that swear to never shave don't look like a bearded Rapunzel. I'll be honest I just never thought much about it.

[Deleted]

But do they know why hair grows in the buttcrack?

If it didnt you would have a really bad time with your cheeks sticking to eachother. Also men tend to sweat alot more around that general area so the smell get pretty rank. Hair keeps air being able to move through the area and makes it harder to form a sticky surface.

Less friction overall. Same reason you have it under your arms i recon.

[Vizardlorde]

SO what you're saying is that you're going to have a sweater of back hair in 5 years?

No im a hairless 23 year old with two freaky hairs on his right arm.
Well not harless but no chest hair and kiddy arm hair.

[Zepla]

I let my hair grow without cutting it for about 10 years. It's rather thin and never went too far past my shoulderblades. It just "knows" when to stop. Makes sense

[RenegadeXan]

Cause we have been inbreed with alien DNA obviously.

Dont you know that Darwin could not find the missing link in human evolution? That's the Alien DNA inbreed part.


We still require a constant tropical climate, thus why we have shelter and clothes, there is NO way we have adopted to a cold climate like we live in now.

[TheAbomb]

I let my hair grow without cutting it for about 10 years. It's rather thin and never went too far past my shoulderblades. It just "knows" when to stop. Makes sense

Yup bingo then depending on the person and how fast it grows in that growing phase will determine the length.