Scientists believe they have discovered the reason why stress can make hair turn white. They’ve also found a potential way of preventing it from happening which doesn’t involve hair dye. In a chance finding while studying mice, the scientists noticed that dark-furred mice turned completely white within weeks after experiencing stress. The reason for this, the scientists say, is because the stress damaged stem cells that control hair and skin colour. The US and Brazilian researchers say their discovery is significant as it could lead to new treatments being developed that can protect hair colour from the effects of stress and ageing. Publishing their findings in the journal Nature, the researchers Universities of Sao Paulo and Harvard say the effects are linked to melanocyte stem cells, which produce melanin and are responsible for hair and skin colour. In a separate experiment, the researchers found they could prevent stress from affecting hair colour by giving the mice an anti-hypertensive, which treats high blood pressure. They were also able to identify the specific protein that causes damage to the stem cells. When this protein, cyclin-dependent kinase (CDK), was suppressed, mice that were subjected to stress did not experience the same fur colour change. It’s a breakthrough that could lead to drugs being developed which suppress CDK and delay the onset of grey/white hair.