• Question: Why do we get grey hair when were older?

    Asked by scotthoughton to Antonia, Douglas, Hugh, Matt, Tom on 15 Jun 2010 in Categories: . This question was also asked by madmaddz.
    • Photo: Matthew Hurley

      Matthew Hurley answered on 14 Jun 2010:

      The bit that puts colour in you hair is melanin (the as what gives our skin colour). As we age the cells that make this die – the hair then has no colour and it turns grey…. then white. Or the hair follicle itself dies and the hair falls out!

    • Photo: Douglas Blane

      Douglas Blane answered on 14 Jun 2010:

      When you say ‘we’ do you mean you’ve started already? Probably not, I’m guessing, but it can happen. My black hair started going grey when I was 20.

      It does that because the cell at the base of each hair that produces its colour stops. So grey/white hair doesn’t have any colour.

      But that’s not really an answer because the question then is, why does it stop? To answer that you’d need to know why it starts. What’s the point of hair colour and why don’t you need it as you get older?

      I don’t know, but my hypothesis – scientific guess that I’d need to go test with an experiment – is that it’s about attractiveness to the opposite sex.

      Far as nature is concerned once you’re past the age of having kids, there’s no point in being attractive. So there’s no pressure to get rid of genes that make the colour cells die. Or cause wrinkles. Or all the other things that happen as people age.

      So they do.

    • Photo: Tom Hardy

      Tom Hardy answered on 14 Jun 2010:

      Well luckily I’m too young to have any grey hairs, but I did study hair analysis as part of my first degree but from a forensic perspective. According to my lecture notes, grey hair is simply a loss of pigment. Our bodies have cells called melanocytes that produce a biological polymer called melanin. Melanin is the pigment responsible for hair colour as well as other bodily colouring like freckles.

      When we get older things stop working including our melanocyte cells. When these cells stop being produced by our bodies due to old age the cells stop producing the pigment melanin. This means when new hair grows there isn’t as much melanin around to colour it, so it turns grey.

    • Photo: Hugh Roderick

      Hugh Roderick answered on 15 Jun 2010:

      The pigment (what causes our hair to be coloured) cells at the base of the hairs die off but the follicle continues to produce hair. But this hair doesn’t have pigments so appears grey.

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