h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

MEthink it unlikely.

Still what set me thinking about this was a guy I'm chatting to on a dating website and at 32 - he's totally grey!

Me and my brother, conincidentally were discussing this about a week ago, many of his friends (late 20 somethings) have mottled peppery colouration, me and brethren were gloating (just a little) that as he approaches 30 (26) and I zoom past it (31) so neither of us have any sign of greying (or hairloss come to it)

So I know genetics is a part of it, stress too probably - but this got me onto the question I asked about how rapidly can someone turn grey?

I was surprised to see this guy was totally grey-ified, so I wondered when did it start how long did it take - and that led me to this question: what is the quickest way to change someone's hair colour?

Bucket of paint?

I remember reading something about this in either Notes & Queries or the back page of New Scientist. The consensus was that it seemed unlikely but was feasible (not instantaneously, but certainly over the cause of a day), and there was documented evidence.

The mechanism is something to do with melanin. I can quite believe that an adrenalin shock would halt melanin production.

B

Even if your hair follicles stopped producing melanin, the hair itself wouldn't change colour. It would just start growing white from that point on. If you have short hair, it might be about three weeks before the effect would show through all your hair.

I can't think of anything which could cause the hairs themselves to turn white.

I've heard a first witness account of someone's hair turning prematurely white after a short period of time during the Iraq occupation of Kuwait.

I've had grey hair since I was 17. Well, one or two grey hairs, anyway. There are more of them now. But there's still plenty of hair, so that's alright.

TRiG.

A friend lost all her hair after her soldier son was killed in Ulster during the 70's.

When it grew back, it was pure white, and remained that way.

As lil's story demonstrates, horrible stress often causes hair to fall out. If a person had some white hair, not very noticeable because the rest was still pigmented, a bad shock could make a lot of the older (pigmented) hair fall out, and the remaining, younger, white hair would look much, much more noticeable. In these cases, hair can very much APPEAR to go grey overnight, or over a few days. And then, of course, any regrowth would also be unpigmented, as pigmentation was shutting down in that person's hair anyway. Individual hairs 'live' for up to six years, so the greying that would normally take six to ten years to become evident, as each pigmented hair reached the end of its lifespan, fell out, and was replaced by a white hair, would suddenly happen in the space of a few days or weeks. It'd look very dramatic.

There is also evidence that stress, illness and shock can shut down pigmentation temporarily (hair follicles are adrenaline-sensitive). I had a horrible time last year, and found, a few months later, several hairs that had a white section about an inch long half-way along the shaft.

mmm mmm mmm mmm

http://www.youtube.com/watch?v=vIbcqgXh5-4



Geggs

Ooh, Agapanthus, I've had that colour-white-colour thing occasionally on one or two of my hairs (I mean I've noticed it on one or two, for all I know I have hundreds of them, but distributed so that they don't particularly show). But my hair is so long that I have no way of working out when the 'white' period might have been.

Mol