A team in Europe has found that going grey is caused by a massive build up of hydrogen peroxide due to wear and tear of our hair follicles. The peroxide winds up blocking the normal synthesis of melanin, our hair's natural pigment.

According to Gerald Weissmann, the Editor-in-Chief of the 'FASEB Journal', which published the study, "All of our hair cells make a tiny bit of hydrogen peroxide, but as we get older, this little bit becomes a lot.

"We bleach our hair pigment from within, and our hair turns grey and then white. This research, however, is an important first step to get at the root of the problem, so to speak."

In fact, the scientists made this discovery by examining cell cultures of human hair follicles. They found the build up of hydrogen peroxide was caused by a reduction of an enzyme that breaks up hydrogen peroxide into water and oxygen (catalase).

They also discovered that hair follicles could not repair the damage caused by the hydrogen peroxide because of low levels of enzymes that normally serve this function (MSR A and B).

Further complicating matters, the high levels of hydrogen peroxide and low levels of MSR A and B, disrupt the formation of an enzyme (tyrosinase) that leads to production of melanin in hair follicles.

Melanin is the pigment responsible for hair colour, skin colour, and eye colour. The team speculates that a similar breakdown in the skin could be the root cause of vitiligo.