Stress Will Give You Grey Hairs – But the Process is Naturally Reversible

Greying is generally considered to be progressive and irreversible. While some people acquire grey hairs more quickly than others, the importance of different environmental factors thought to be at play (such as stress and smoking) are not fully understood in humans. Here, a study presents the finding that white hairs can rapidly regain their pigmentation by themselves, and that hair greying and reversal corresponded to the occurrence of stressful life events.

Hairs are given their pigmentation by cells at the base of the hair follicle called melanocytes. As we age, melanocytes become depleted, probably primarily due to oxidative damage, leading to a loss of pigmentation. Evidence suggests that hair greying is associated with higher perceived life stress in humans, but in this study, researchers wanted to investigate the effects of stress on hair greying at the level of the individual hair shaft.

To do this, they examined the pigmentation patterns at high resolution on individual hair shafts. By knowing the rate of hair growth (around 1.0-1.3cm per month), researchers were able to link the onset of hair greying to specific moments in time. They also analysed and compared the proteins contained within pigmented and white hairs. Their main findings were as follows:

• White hairs showed an overall increase in protein production, mostly those involved in metabolic pathways such as the production of the cellular fuel ATP. As metabolic pathways tend to be rapidly affected by environmental factors and signalling molecules, this suggests that pathways involved in hair greying could potentially be targeted to reverse the process.
• White hairs could naturally return to their pigmented state over a period as short as 3 days, with some undergoing double transitions in which a hair turned white, then recovered a few months later.

• The occurrence of greying was significantly correlated with time periods that participants rated (retrospectively) as the most stressful, suggesting that the phenomenon of hair greying followed by reversal could be caused by stressful life events.

These findings provide the most convincing evidence to date that stress can affect hair greying, but importantly, suggests that this process is reversible. It may therefore be possible to target metabolic pathways pharmacologically in order to revert white hairs to a pigmented state.

This result provides a plausible biological basis for the reversibility of
greying and its association with psychological factors, and also supports the possibility that this process could be targeted pharmacologically. The upregulation of specific components of mitochondrial energy metabolism in white hairs suggests that metabolism regulates not only hair growth as previously demonstrated, but also HS pigmentation.