Naked Science Forum

General Science => Question of the Week => Topic started by: Nadeem Gabbani on 28/11/2019 09:41:26

Title: QotW - 28.11.19 - Do hairs grow out grey or turn grey?
Post by: Nadeem Gabbani on 28/11/2019 09:41:26
Elizabeth wants to know:

"Do hairs grow out grey or do hairs that had colour, eventually turn grey?”

Any ideas?
Title: Re: QotW - 28.11.19 - Do hairs grow out grey or turn grey?
Post by: evan_au on 28/11/2019 18:32:37
Hair colour is embedded in the hair by special cells in the hair follicle. The hair grows out of the follicle.

Genetic factors (eg age) and environmental factors (eg stress) affect the colour and darkness of the colour, and determine when the colour turns off, and how quickly the colour turns off in a given hair follicle. This happens at different times in different hair follicles.

See: https://en.wikipedia.org/wiki/Human_hair_color#Aging_or_achromotrichia
Title: Re: QotW - 28.11.19 - Do hairs grow out grey or turn grey?
Post by: Halc on 28/11/2019 18:46:10
Do hairs grow out grey or do hairs that had colour, eventually turn grey?
My grandmother's hair turned white in a week when her oldest son was killed (in WWII).
This suggests that dark hair can turn color in place, and not necessarily grow out that way.
I suspect it works both ways.  Evidence of hair growing out that way would be a long hair that changes color somewhere along its length (grey roots like a dye job growing out).
Title: Re: QotW - 28.11.19 - Do hairs grow out grey or turn grey?
Post by: evan_au on 29/11/2019 10:20:42
Quote from: Halc
This suggests that dark hair can turn color in place
The way to turn colored hair white after it has grown out is to treat it with hydrogen peroxide (or other bleaches).
Title: Re: QotW - 28.11.19 - Do hairs grow out grey or turn grey?
Post by: thompsonmax on 04/12/2019 13:00:55
Hello. I'm new here. An interesting question. I have gray hair on a beard despite the fact that I am щтдн 33 years old, and the color of the hair on my head is black :o
Title: Re: QotW - 28.11.19 - Do hairs grow out grey or turn grey?
Post by: katieHaylor on 16/12/2019 16:33:14
This question has now been answered, and you can access it here - https://www.thenakedscientists.com/articles/questions/qotw-do-hairs-grow-grey-or-turn-grey
Title: Re: QotW - 28.11.19 - Do hairs grow out grey or turn grey?
Post by: strongernow on 09/11/2020 12:22:06
Hair colour is embedded in the hair by special cells in the hair follicle. The hair grows out of the follicle.

Genetic factors (eg age) and environmental factors (eg stress) affect the colour and darkness of the colour, and determine when the colour turns off, and how quickly the colour turns off in a given hair follicle. This happens at different times in different hair follicles.

See: https://en.wikipedia.org/wiki/Human_hair_color#Aging_or_achromotrichia


Sounds logic because otherwise everybody must get grey hair just if they are exposed long enough to the sun but thats not happening. So it must start earlier.
Title: Re: QotW - 28.11.19 - Do hairs grow out grey or turn grey?
Post by: vhfpmr on 12/11/2020 15:36:46
My hair grows brown, then turns grey, if I pluck a hair it's easy to see that the root and tip are different colours. It's also conspicuous that I come out of the barbers less grey than I went in.
Title: Re: QotW - 28.11.19 - Do hairs grow out grey or turn grey?
Post by: Bored chemist on 12/11/2020 21:05:01
The most plausible explanation I have heard for the "her hair turned white overnight" story is that she had some white and some black hair- everybody was too polite to mention the white ones.
But the shock made the black hair fall out.
And the hair that was left was white.
Title: Re: QotW - 28.11.19 - Do hairs grow out grey or turn grey?
Post by: Zer0 on 24/03/2021 08:42:47
@thompsonmax

Hi there!
🙋

I found something online, relevant to your condition...

" As you age, the follicles produce less melanin, which causes either grey, silver, or white hair. Beard hair grows faster than hair on your head. This is why most people notice the depletion of melanin (or greying) in their beards first and then on their heads. "

Hence, it seems like a pretty natural occurrence.
👍

P.S. - From All of US...Welcome to TNS Forum!
😊
🍭
Title: Re: QotW - 28.11.19 - Do hairs grow out grey or turn grey?
Post by: podcastlover20 on 25/03/2021 08:32:30
Do hairs grow out grey or do hairs that had colour, eventually turn grey?
My grandmother's hair turned white in a week when her oldest son was killed (in WWII).
This suggests that dark hair can turn color in place, and not necessarily grow out that way.
I suspect it works both ways.  Evidence of hair growing out that way would be a long hair that changes color somewhere along its length (grey roots like a dye job growing out).

Same here! My Grandma turned grey from one day to another and she was 36! My mum (56) isn´t Grey yet. I think it also depends on the familiy and Generation.