If you're worried about going grey - try to relax. Scientists have found too much stress really does turn our hair white.
Researchers discovered the cells that give hair its colour disappear when the body is exposed to stress hormones.
And unfortunately for those affected, these "colourful" cells are unlikely to return, leaving the hair grey for good.
How do we know this? US scientists carried out experiments on mice which showed the startling effect that stress has on our hair.
They began with the premise that when the human body is injured, stem cells responsible for producing melanin - the dark pigment that protects us from sunlight - move from hair follicles to the skin, to help limit the damage.
In their tests on mice, the same permanent draining of colour occurred when the animals were exposed to stress hormones.
The researchers said this could explain why stress can also also cause pigmentation which makes the skin appear darker.
Most of us spot our first grey hairs around the age of 25, and everything from genes to alcohol and smoking and have been blamed for kicking off the process.
There are tales of people going grey overnight after bereavement or shock and previous research has also blamed adrenaline for turning hair prematurely grey.
Dr Mayumi Ito from New York University, who led the latest study, said there was evidence that stress could make melanin "migrate" away from the hair follicle to the skin.
"We thought it would be interesting to speculate that excessive stress might promote this migration too much," he said.
The study, published in the journal Nature Medicine, concludes: "Stress hormones are known to promote skin pigmentation, yet paradoxically and anecdotally, they are believed to promote hair greying.Our results may provide insight into the relationship between stress hormones and hair greying."
The New York University team hope to develop drugs to counter some of the effects of over-exposure to stress, suffered for example by those in a high-pressure job.
- DAILY MAIL