Is Your Stress Showing in Your Hair? What Experts Say About Going Gray

If you've ever spotted a silver strand after a rough few months, you might not be imagining the connection. Science has finally weighed in on one of the most common beauty worries out there.

Stress can show up in the body in many ways, from a clenched jaw to migraines to muscles we tense without even realizing it. What many people might not know, however, is that it can also show up in your hair in the form of premature graying.

So how exactly does that happen? In a Nature study published in 2020, a team of Harvard researchers became the first to dig into the phenomenon beyond personal stories and observation, exploring how stress affects the body.

Their findings showed that stress switches on the nerves behind the body's fight-or-flight response, and those nerves end up permanently damaging the stem cells in hair follicles that are responsible for restoring hair color.

"Everyone has an anecdote to share about how stress affects their body, particularly in their skin and hair — the only tissues we can see from the outside," said senior author Ya-Chieh Hsu, the Alvin and Esta Star Associate Professor of Stem Cell and Regenerative Biology at Harvard.

She continued, "We wanted to understand if this connection is true, and if so, how stress leads to changes in diverse tissues. Hair pigmentation is such an accessible and tractable system to start with — and besides, we were genuinely curious to see if stress indeed leads to hair graying."

To get to the bottom of it, Hsu and her team studied mice, ruling out different parts of the body's stress response one by one. Their first theory was that stress triggers the immune system to attack the cells that give hair its color.

But when mice without immune cells still went gray, the researchers shifted their attention to cortisol, the body's main stress hormone. Once again, the trail went cold. "Stress always elevates levels of the hormone cortisol in the body, so we thought that cortisol might play a role," Hsu said.

"But surprisingly, when we removed the adrenal gland from the mice so that they couldn't produce cortisol-like hormones, their hair still turned gray under stress," she continued.

Next, the team turned to the sympathetic nervous system, a network of nerves that reaches into every hair follicle on the skin. Under stress, these nerves release a chemical called norepinephrine, which is absorbed by the nearby stem cells that keep hair colored.

Think of these stem cells as a reserve supply of color. Each time hair grows back, some of them transform into pigment-producing cells that give the new strands their shade.

The researchers discovered that norepinephrine sends these stem cells into overdrive. They all transform at once, draining the reserve long before they normally would.

"When we started to study this, I expected that stress was bad for the body — but the detrimental impact of stress that we discovered was beyond what I imagined," Hsu said.

She added, "After just a few days, all of the pigment-regenerating stem cells were lost. Once they're gone, you can't regenerate pigments anymore. The damage is permanent."

The good news? In 2021, another study, published in eLife, found that while stress can cause premature graying, the change doesn't always have to be permanent.

According to the researchers, removing the source of stress seemed to reverse the process, letting some white strands regain their natural color from the root. There's a catch, though.

The effect is temporary, only works within a certain age window, and affects just a handful of hairs on a person's head.

Martin Picard, the study's co-author and an associate professor of behavioral medicine in psychiatry and neurology at Columbia University in New York, explained that hair has to reach a certain tipping point before it turns gray.

If strands are already close to going gray, perhaps around middle age, a stressful event could push them past that point sooner, the study noted. Once the stress eases and the hair is only just over the line, it may return to its darker shade.

Since some people spot their first gray hairs in their 20s while others don't see them until their 50s, that window looks different for everyone. "But the hairs that have been gray for 30 years are probably unlikely to be reversible," Picard noted.

Any reversal is also likely to be short-lived. Even then, the change probably won't last. Hair naturally crosses that threshold again with age, and when it does, the gray sticks around for good.

Until science catches up, the best options are to find healthy ways to manage stress and, for those already seeing silver, to reach for a box of hair dye. In the meantime, find out how to keep your hair full and protect it from thinning.