Question: Why do some people get white hair earlier than others, and why (apparently) do some people's hair turn white overnight with fear?

Claire Lee answered on 25 Jun 2013:

I think genetics play a part here, as well as factors like hormones, climate, and chemicals in the body.

Your hair colour comes from pigment which is created as the hair grows. On it’s own hair is white, and depending on how much or how little pigment you have, you get a range of hair colours.

As you get older, the amount of pigment your scalp creates decreases, which is why your hair goes grey or white. As for fear, yes, stress and/or fear can affect how much pigment you produce, but this won’t change your hair white overnight.