Does stress cause grey hair?

There is a very common belief that grey hair is more than a mere matter of time and age, but an indicator of life experience. The saying "you’re making my hair gray" suggests that silver strands are a symptom of concern, while it is a widespread legend that Marie Antoinette’s hair turned white in one night after the news of her execution. But can someone's life experience actually change the color of their hair? 

Science suggests that it is possible that if the colour of the hair decreases naturally over time, certain factors can accelerate this change, including stress. Stress is a normal response to daily pressures, but it can get unhealthy when it disrupts a person's daily functioning, as the American Psychological Association explains. Stress is not the main cause of graying, as genes largely determine the phenomenon, but "stress can accelerate" the graying process, explained David Kingsley, researcher on hair loss and president of the World Trichology Society. Indirect stress, such as malnutrition, thyroid problems, hormonal imbalance and anemia, can also affect hair pigmentation, he explained. In mice, stress can deplete hair pigmentation cells known as melanocytes, according to a 2020 study in the journal Nature. Melanocytes are produced by stem cells that live in hair follicles. In the study, the researchers provoked a stress response in mice. In response, corticosterone (the rodent equivalent of the stress hormone cortisol) and norepinephrine (a neurotransmitter and hormone) poured into the follicle. Once in the follicle, norepinephrine caused the stem cell to turn into a normal melanocyte, which means it couldn’t divide indefinitely. With the stem cell permanently modified, the follicle no longer had a source of new pigment cells. That strand of hair, or in the case of the mouse, the hair, has lost its source of color. Although these results cannot necessarily be applied to humans, a 2021 study in the journal eLife found that stress can turn hair gray in humans, but not permanently. Participants with some gray hair or "two-tone hair" - gray and pigmented in the same strand - were asked to record their experiences and stress levels in recent months. They found that stressful experiences like losing a job were related to graying. However, removing the stress factor may reverse the graying. "There was one individual who went on vacation and five hairs on that person’s head turned dark during the vacation, synchronized over time," the lead author Martin Picard, said in a statement a neurologist from Columbia University.

Not only is there wide variation when people turn gray, from 30 to 80 years old, but "every hair has the same genome, is exposed to the same agents," Picard told WordsSideKick.com. "So, why a little bit of gray before and after?" Based on mathematical models, Picard and his colleagues suggested that hair must reach a certain threshold to become gray. In middle age, when a person is closer to that threshold, stress can cause a hair to turn white earlier than expected. Melanocyte stem cells become more vulnerable as they age, the expert added. So stress could "speed up" graying. Picard and his co-authors suggested that it might be possible to reverse hair color loss in someone who has recently noticed gray hair. For those with gray hair for years, however, it is unlikely that removing stress will return the locks to their original color, since the hair has exceeded the threshold. Basically, Kingsley said he doesn’t often see hair regaining pigment.