Besides natural pigment, stress and malnutrition can change your hair color. Grey hairs are the first sign of stress, while dull, lackluster hair can point to a vitamin deficiency.

In some cases, hair that has lost its color may darken again; however, if irreversible damage has occurred to the melanocytes, parts of the hair will remain permanently white.

But all this speculation is now a historical curiosity. The results are widely known from conference presentations that have been reported, but finally the paper is out in Science which solves the ...