Stress can turn hair grey - and it's reversible, researchers find

This discovery links stress and hair … and ageing too.

Key Points

  • Research links psychological stress to greying hair
  • Hair colour can be restored when stress is eliminated
  • Links between stress and human aging

Let’s not split hairs about this research. There is good news - grey hair can be restored to its previous colour and ageing may also be halted and even reversed.

Legend has it that Marie Antoinette's hair turned grey overnight just before her beheading in 1791.

Though the legend is inaccurate - hair that has already grown out of the follicle does not change colour - a new study from researchers at Columbia University Vagelos College of Physicians and Surgeons is the first to offer quantitative evidence linking psychological stress to greying hair in people.

And while it may seem intuitive that stress can accelerate greying, the researchers were surprised to discover that hair colour can be restored when stress is eliminated, a finding that contrasts with a recent study in mice that suggested that stressed-induced grey hairs are permanent.

The study has broader significance than confirming age-old speculation about the effects of stress on hair colour, says the study's senior author Dr Martin Picard from Columbia University Vagelos College of Physicians and Surgeons.

"Understanding the mechanisms that allow 'old' grey hairs to return to their 'young' pigmented states could yield new clues about the malleability of human aging in general and how it is influenced by stress," Picard says.

"Our data add to a growing body of evidence demonstrating that human aging is not a linear, fixed biological process but may, at least in part, be halted or even temporarily reversed."

Studying hair as an avenue to investigate aging

"Just as the rings in a tree trunk hold information about past decades in the life of a tree, our hair contains information about our biological history," Picard says.

"When hairs are still under the skin as follicles, they are subject to the influence of stress hormones and other things happening in our mind and body. Once hairs grow out of the scalp, they harden and permanently crystallize these exposures into a stable form."

Though people have long believed that psychological stress can accelerate grey hair, scientists have debated the connection due to the lack of sensitive methods that can precisely correlate times of stress with hair pigmentation at a single-follicle level.

The researchers analysed individual hairs from 14 volunteers. The results were compared with each volunteer's stress diary, in which individuals were asked to review their calendars and rate each week's level of stress.

The investigators immediately noticed that some grey hairs naturally regain their original colour, which had never been quantitatively documented, Picard says.

When hairs were aligned with stress diaries, striking associations between stress and hair greying were revealed and, in some cases, a reversal of greying with the lifting of stress.

"There was one individual who went on vacation, and five hairs on that person's head reverted back to dark during the vacation, synchronised in time," Picard says.

Re-pigmentation only possible for some

Reducing stress in your life is a good goal, but it won't necessarily turn your hair to a normal colour.

"Based on our mathematical modelling, we think hair needs to reach a threshold before it turns grey," Picard says. "In middle age, when the hair is near that threshold because of biological age and other factors, stress will push it over the threshold and it transitions to grey.

"But we don't think that reducing stress in a 70-year-old who's been grey for years will darken their hair or increasing stress in a 10-year-old will be enough to tip their hair over the grey threshold."

Source: Science Daily