When does hair turn grey?

We all go "grey" in the course of our lives - some earlier and some later. Some people get their first grey hairs in their 20s, while others don't notice the effects until they are 50.

How early someone greys depends on genetic predisposition, among other things, but lifestyle can also have an influence. Statistically, there are ethnic/regional differences, e.g. Europeans show grey hair earlier than Asians. Men also go grey earlier than women.

Incidentally, hair does not actually turn grey, but rather white or transparent. This is because the so-called melanocytes (pigment-forming cells) at the roots of the hair produce less and less melanin over time. Over time, the melanocytes even die off completely. The colour pigment is then missing in the hair that grows back and is replaced by air bubbles. This makes the hair appear grey or white.