• Question: Why does the sun make your skin dark but your hair light?

    Asked by sammieblues to David, Luna, Mark, Melanie, Probash on 22 Mar 2011 in Categories: .
    • Photo: David Pyle

      David Pyle answered on 21 Mar 2011:

      Good question – but one for one of the biologists, sorry!

    • Photo: Luna Munoz

      Luna Munoz answered on 21 Mar 2011:

      The melanin in the skin absorbs light and changes the colour. I don’t know about the hair.

    • Photo: Melanie Stefan

      Melanie Stefan answered on 22 Mar 2011:

      Solar radiation can cause DNA damage. To protect against this, the skin produces a dark pigment (called melanin) which will absorb most of the radiation and thereby protect the DNA. Tis is why the skin gets dark.

      Hair has no living cells (except at the root), so protection against DNA damage isn’t necessary. However, the sun causes damage to the proteins that hair is compose of (mostly keratin), which makes the hair appear lighter

    • Photo: Probash Chowdhury

      Probash Chowdhury answered on 22 Mar 2011:

      The skin contains living cells that produce melanin (which is a dark colour) as a protective mechanism in the presence of UV light (from the sun or sun beds). The more UV light, the more melanin is produced (until the cells are full).

      However, hair doesn’t contain any living cells, the colour was put there as the hair was growing from the base in the hair follicle (or by the hairdresser). This colouring gets bleached due to the UV light in sun light (and sunbeds) – kind of like some shop signs fade after a long time in sunlight.

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