Understanding why hair goes grey: the science and lifestyle factors behind it

Whether you’re embracing new silver growths or attacking them strand by strand with tweezers, grey hair is an inevitable part of getting older. “Just as the skin ages and the rest of the organs in your body age, the hair ages, too,” said Helen He, an assistant professor in the Kimberly and Eric J. Waldman Department of Dermatology at the Icahn School of Medicine at Mount Sinai.

The going-grey process happens at different speeds for different people, she said, but most of us start to notice increasing grey hair sometime in our 30s or 40s, according to the American Academy of Dermatology. Around this time, melanocyte stem cells, which are hair follicle cells responsible for depositing pigment into the hair shaft, can start to become depleted or dysfunctional.

“There’s not really a whole lot known about why the melanocyte stem cells die off,” said George Cotsarelis, chair of the dermatology department at the Perelman School of Medicine at the University of Pennsylvania and a hair-follicle stem-cell researcher. But there are a number of reasons, including stress or DNA damage, “that are thought to maybe prevent these stem cells from surviving,” he said.

The process, called cellular senescence, causes hair to “gradually lose its pigment over time,” He said. Strands that previously were black, brown, red or blond start to emerge from the follicle grey or silver-white. Some people also notice that their grey hair has a coarser texture.

Age remains a major predictor of when a person is likely to go grey. One 2012 study of more than 4,000 participants found that between ages 45 and 65, nearly three-quarters were at least partially grey. But experts increasingly think of this as “more of a dynamic process,” said Natasha Mesinkovska, a dermatologist at UCI Health who has studied hair greying.

Previously, experts viewed greying as something that inevitably happened to hair with age. Newer research suggests “the pattern of pigmentation is more of a live thing than something that’s set in stone,” Mesinkovska said. This means some factors may have more influence over the greying process than you think.

You’ll probably go grey similar to the way your parents did

Genes aren’t the only influence, but they do play a major role. “In the end, that’s what’s determining when you go grey,” Cotsarelis said.

Scientists have discovered genes that seem to have a hand in hair greying and may also affect characteristics such as balding, eyebrow shape and beard thickness. There can be ethnicity differences, too. People who are White tend to go grey earlier than people of African and Asian descent, research has found, and natural blonds may experience a higher percentage of greying sooner.

Premature hair greying - which has not been clearly defined, Cotsarelis said, but is sometimes considered greying before age 20 for Whites, before age 25 for Asians and before age 30 for Black people - also seems to be influenced by genes. One variant, called IRF4, is “strongly linked to earlier greying,” Mesinkovska said. And though rare, certain inherited disorders such as Griscelli syndrome, a condition that causes pigment issues, can result in grey hair from birth.

Men and women are equally likely to go grey, but biological sex might influence where those early grey hairs appear: Men tend to grey around the sideburns and temples, while women often notice greying around the front of the head first.

Lifestyle may influence greying, too

There’s a lot experts still don’t understand about how your lifestyle might affect greying. But some studies have found certain nutritional deficiencies, such as vitamin B12 and iron, are associated with early-onset grey hair. These nutritional deficiencies would probably be severe, though, Cotsarelis said.

Most people won’t need supplements, he said, but because certain mineral deficiencies have been linked to premature hair greying, it’s wise to make sure your diet checks all of your nutritional boxes.

Stress is also thought to play a role. “It’s always kind of noted that people who are under stress seem to go grey,” said Sarah Millar, a professor in the department of oncological sciences and the dermatology department at Mount Sinai.

A 2020 study in the journal Nature found that in mice, stress appeared to cause a loss of melanocyte stem cells. When the sympathetic nervous system, also known as the “fight or flight” response, was activated, those melanocyte stem cells seemed to “basically proliferate and differentiate and migrate away from their kind of niche home,” said Millar, who has researched melanocyte stem cells.

That study “was really the first time there’d been a mechanistic link between activation of neurons by stress and the result of hair greying,” she said. “That was very interesting.”

In another 2021 study, researchers from Columbia University Vagelos College of Physicians and Surgeons looked at individual hairs from 14 volunteers, and observed an association between greying and weeks where the participants reported higher levels of stress.

It’s not clear whether reducing stress will slow down the process, however; more research is needed. Still, “I do believe that chronic things exhaust you,” Mesinkovska said, “and that’s why mice studies show - if you bug them nonstop, it will make them go grey.”

Not smoking (a habit known to cause early greying), getting plenty of sleep, minimising stress, and eating a healthy diet will benefit your overall well-being and possibly support the health of your hair follicles, too. “These are, in general, great habits for antiaging, and part of that involves potentially delaying the hair-greying process,” He said.

That may also include exercise - one study has linked premature greying to a sedentary lifestyle - as well as limiting your alcohol consumption.

Can we slow grey hair progression - or even reverse it?

Other than making lifestyle changes, “there isn’t really a whole lot you can do” about grey strands, Cotsarelis said, other than dyeing your hair or loving your new shade.

At least, not yet: “In the past, the field was really focused on characterising the changes of melanocyte stem cells,” said Mayumi Ito Suzuki, a professor in the Ronald O. Perelman Department of Dermatology at NYU Grossman School of Medicine. “The next step is to understand how to reverse these changes to not have grey hair.”

Some experts have theorised that melanocyte stem cells might essentially become “stuck” in the wrong location during the process of regeneration. “In theory, if healthy stem cells are preserved, hair greying can be transient,” she said.

Her lab, which studies how melanocytes regenerate from stem cells, explored this idea in a 2023 Nature study. Ito’s team observed the localisation pattern of stem cells in young and older mice. “If they’re located in a different place somehow during aging, they remain dormant, and don’t produce mature melanocytes,” she said, and in turn don’t produce pigment. Her team is now looking at human samples to see if relocating melanocytes can help prevent the greying process.

There are some over-the-counter topical products that claim to reverse greying, but “none of them have proven efficacy,” He said. Topicals in general are challenging because pigment-producing melanocyte stem cells are in the deepest part of the hair follicle. This is why drugs which do successfully lengthen and darken eyelashes “just don’t work on the scalp,” Cotsarelis said. “The skin is too thick.”

Some research on potential new treatments “is getting a lot of attention,” Mesinkovska said. A 2023 study from the University of Miami Miller School of Medicine found topical rapamycin may help re-stimulate melanin. The drug, which is an immunosuppressant used to prevent organ rejection, is not approved by the Food and Drug Administration for this use and is “a fairly potent drug,” Millar cautioned.

If you think you’re experiencing early-onset grey, it’s worth consulting your doctor, Mesinkovska said. “If someone comes to me and says, ‘I have early greying,’ I look for the reason,” she said - while there isn’t always one specific cause that can be fixed, sometimes addressing nutritional deficiencies, a thyroid disorder or inflammation may help, she added.

Since every new hair cycle is an opportunity for a strand to regrow without pigment, “if you’re experiencing a lot of hair loss, you may accelerate the greying,” Cotsarelis said.

Hair loss can’t always be prevented - age, a hereditary disposition and chemotherapy are frequent culprits - but the American Academy of Dermatology recommends minimising breakage by avoiding treatments such as perms that may damage hair, as well as hairstyles that pull at the scalp.

Stay away from tweezers while you’re at it. “There is a myth that if you pluck out grey hair, you’re going to get more grey hairs - that’s not necessarily true, but it’s not an effective strategy,” He said. “More likely than not, the hair that grows out of the follicle next will be grey.”

The Washington Post