It’s often assumed that going gray is inevitable. But recently, researchers at the French Government Institute, Paris Hospital, and the Phytosolba Laboratory have been examining if it’s possible to rejuvenate our natural hair color as we age—and maybe even turn back the hands of time. In the process, they have discovered some interesting reasons why premature graying can occur. And, spoiler: coloring your hair could play a role.
It all comes down to melanin, the natural pigment in the body responsible for the color of a person’s hair, eyes, and skin. Melanin is present in everyone in various amounts and combinations, and aside from making us all look unique, it provides the extra bonus of protecting us from UV radiation and sun damage. It may even support the immune system and help reduce inflammation.
Melanin—or the lack thereof it—is also the culprit behind gray or white hair. While aging can naturally slow down or stop melanin production in the hair follicles, lifestyle factors like stress and diet can impact melanin production, too. But according to the research, that’s not all.
Melanin and hair follicles
Hair actually begins growing white inside the follicle. As it develops, pigment-producing cells called melanocytes release melanin, which gives the strand its color. When the follicle ages or becomes damaged—and melanin production slows, stops, or the pigment cells themselves deteriorate—the new hair emerging from that follicle grows in without pigment. The hair with no melanin appears white or gray.
How hair dye impacts hair follicles
Here’s where things get interesting: The research also suggests that one contributor to white hair is the buildup of hydrogen peroxide inside the hair follicle. When hydrogen peroxide accumulates, it oxidizes melanin, causing the strand to lose pigment and appear white.
What exactly is hydrogen peroxide? According to Dr. Priscilla Wu of the Department of Cosmetic Science at Ching-Yi University, hydrogen peroxide (H₂O₂) is a highly reactive oxidizing compound often stored as a 30%–60% aqueous solution. In hair coloring, stylists use products that contain hydrogen peroxide or related bleaching agents to lift or lighten pigment.
If hair is frequently bleached or dyed with peroxide-based formulas, excess hydrogen peroxide can build up in the follicle. Over time, that oxidative stress may make gray or white hairs more likely to appear. If you’re dyeing your hair to cover up your grays, you may actually be causing more gray hairs to appear.
Too much sun
Free radicals can also cause the hair follicles to oxidize early—and that means anything from sun exposure to pollution can cause premature aging. Ultraviolet (UV) rays from the sun generate free radicals that damage melanocytes, while airborne pollutants such as particulate matter, heavy metals, and ozone create oxidative reactions on the scalp and around the follicle. Both of these stresses can disrupt melanin production, inflame the follicle, and speed up the depletion of pigment-producing cells.
All the more reason to wear a hat when you’re outside—and maybe avoid peroxide-based hair dye, too.
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