Researchers say they now think they know how stress causes gray hair.
The hair color change may be linked to nerves in the “fight or flight” response system.
Experts say stress is only one factor that can cause gray hair. Genetics also plays a major role.
Sorry Mom and Dad: It turns out you might not have been exaggerating when you told us your children made your hair turn gray.
Stress may play a key role in just how quickly hair goes from colored to ashen, a studyTrusted Source published this past week in the journal Nature suggests.
Scientists have long understood some link is possible between stress and gray hair, but this new research from Harvard University in Massachusetts more deeply probes the exact mechanisms at play.
The researchers’ initial tests looked closely at cortisol, the “stress hormone” that surges in the body when a person experiences a “fight or flight” response.
It’s an important bodily function, but the long-term presence of heightened cortisol is linked to a host of negative health outcomes.
But the culprit ended up being a different part of the body’s fight or flight response — the sympathetic nervous system.
These nerves are all over the body, including making inroads to each hair follicle, the researchers reported.
Chemicals released during the stress response — specifically norepinephrine — causes pigment-producing stem cells to activate prematurely, depleting the hair’s “reserves” of color.
“The detrimental impact of stress that we discovered was beyond what I imagined,” Ya-Chieh Hsu, PhD, a lead study author and an associate professor of stem cell and regenerative biology at Harvard, said in a press release. “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.”
Why we go gray
But stress isn’t the only — or even the primary — reason that most people get gray hair.
In most cases, it’s simple genetics.
“Gray hair is caused by loss of melanocytes (pigment cells) in the hair follicle. This happens as we age and, unfortunately, there is no treatment that can restore these cells and the pigment they produce, melanin,” Dr. Lindsey A. Bordone, a dermatologist at ColumbiaDoctors and an assistant professor of dermatology at Columbia University Medical Center in New York, told Healthline. “Genetic factors determine when you go gray. There is nothing that can be done medically to prevent this from happening when it is genetically predetermined to happen.”
That doesn’t mean environmental factors — such as stress — don’t play a role.
Smoking, for instance, is a known risk factor for premature graying, according to a 2013 studyTrusted Source. So kick the habit if you want to keep that color a little longer.
Other contributing factors to premature graying include deficiencies in protein, vitamin B-12, copper, and iron as well as aging due in part to an accumulation of oxidative stress.
That stress is prompted by an imbalance between free radicals and antioxidants in your body that can damage tissue, proteins, and DNA, Kasey Nichols, NMD, an Arizona physician and a health expert at Rave Reviews, told Healthline.
And some degree of oxidative stress is a natural part of life.
“We would expect increasing gray hair as we advance in age, and we see about a 10 percent increase in the chance of developing gray hair for every decade after age 30,” Nichols said.
Changes you can pursue to delay premature grays include eating a diet high in omega-3 fatty acids such as walnuts and fatty fish, not spending too much time in the skin-damaging and hair-damaging ultraviolet light of the sun, and taking vitamin B-12 and vitamin B-6 supplements.
That said, if you are going gray prematurely, it wouldn’t hurt to go have a checkup just in case natural genetic factors aren’t the sole culprit.
The new Harvard research is only a mouse study, so replicating the same results in a human study would be necessary to strengthen the findings.
But the Harvard research has implications far beyond graying hair, with the hair color change merely one obvious sign of other internal changes as a result of prolonged stress.
“By understanding precisely how stress affects stem cells that regenerate pigment, we’ve laid the groundwork for understanding how stress affects other tissues and organs in the body,” said Hsu. “Understanding how our tissues change under stress is the first critical step towards eventual treatment that can halt or revert the detrimental impact of stress.”
Might that also mean someday halting and reverting the march of premature gray hair? It’s too soon to tell.
“We still have a lot to learn in this area,” Hsu said.