You’ve probably heard the old wives’ tales about how stress can lead to hair going grey prematurely. Well, it could be true after all, according to a study in mice.

Grey hair has been linked to stress for centuries, but no-one knows why. But now researchers may have discovered why stress makes hair turn grey.

Grey hair is hair without pigment, and it could be regarded as the hairs’ natural state. When we are younger, our hair is coloured by the pigments produced by cells in the hair follicle known as melanocytes. As we grow older, the melanocytes gradually become less active, so less pigment is produced, the colour fades, and grey hair grows instead.

Researchers from Harvard University in Cambridge, who published their findings in science journal Nature, found that stress causes the sympathetic nerve system to release the chemical norepinephrine (stress hormone), which in turn causes particular stem cells to multiply, but then those cells move away from the hair, removing a source of pigmentation — this in turn makes our hair turn silvery or grey. Once they blocked that response, however, the mice stopped going grey.

“Our study demonstrates that neuronal activity that is induced by acute stress can drive a rapid and permanent loss of somatic stem cells, and illustrates an example in which the maintenance of somatic stem cells is directly influenced by the overall physiological state of the organism,” the authors said.

This isn’t the first study to demonstrate the link between stress and hair turning prematurely grey. Another study, published in PLOS Biology, found that when the body is under attack our cells produce chemical signals called interferons. These interferons make our cells’ machinery undergo changes that ward-off viruses and generally boost defences. But the unexpected side effect of the defence system is that it turns off cells that produce hair colour.

As well as ‘turning off’ hair colour, it can also turn off colour in the skin, leading to the disease vitiligo, which occurs when pigment-producing cells die or stop functioning. Vitiligo, which causes discoloured skin patches, affects between 0.5 percent to 1 per cent of all humans.

IMPORTANT LEGAL INFO This article is of a general nature and FYI only, because it doesn’t take into account your personal health requirements or existing medical conditions. That means it’s not personalised health advice and shouldn’t be relied upon as if it is. Before making a health-related decision, you should work out if the info is appropriate for your situation and get professional medical advice.