A new study using rats has suggested the old wives’ tale that stress causes grey hair is scientifically true. 

Biochemist Professor Luke O’Neill explained we all know “anecdotally” stress can lead to greying – but there’s not a whole lot of scientific evidence. 

A study in Nature, however, found that there could be a real explanation for why our hair changes with our emotions. 

“The paper begins actually, with a discussion of a 1902 report in the British Medical Journal, a young woman witnessed a tragedy,” Prof O’Neill told Show Me the Science. 

“She saw someone being murdered horribly and she went grey.” 

The Nature study “subjected rats to a bit of stress”, Prof O’Neill explained, and monitored any physical changes. 

“There were three types of stress to make it scientifically robust,” he said. 

Grey hair and stress

The researchers measured for ‘restraint stress’ - when they’re made very uncomfortable - ‘unpredictable stress’ - when they get a fright – and ‘mild discomfort’. 

“Over the course of a few days, the rats began to display grey hair,” Prof O’Neill said. 

A capsaicin injection to cause stress worked the fasting, greying the rats within five days. 

To understand why their hair greyed, Prof O’Neill explained melanocytes affect the pigmentation of our skin and hair through melanin. 

Woman with grey hair at art gallery. Image: Nathaniel Noir / Alamy Stock Photo

“There are two types of melanocytes,” he said. “The one that makes the pigment and then the stem cells that come into the skin and turn into melanocytes. 

“[Researchers] noticed was the stress in the rats especially affected the stem cells. 

“The replenishment of the melanocytes was being compromised by the stress.” 

It appears that stress affects neurons in the skin, releasing a neurotransmitter that puts stem cells under pressure – eventually resulting in grey hair. 

Prof O’Neill discussed more on what can cause grey hair – such as genetics – and the scientific basis for balding: