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Summer sun can lead to gray hair — here's how to prevent it

Research shows that sun damage to your hair can stop follicles from producing color, leading to gray hair.
/ Source: TODAY

Sunburn and heat exhaustion aren’t the only reasons to avoid too much sunshine this summer: Going gray is another consideration. 

Hair strands, which grow out of glands called follicles, can't change color once they start growing (unless you dye them). But certain circumstances, usually aging and genetics, can reduce the amount of color that a hair follicle can produce, leading to gray hair.

And research suggests stress can also play a role in hair color, as can sun damage. “While getting gray hairs is normal as we age, excessive sun exposure can accelerate this process and lead to premature graying of hairs,” Dr. Shilpi Khetarpal, dermatologist at the Cleveland Clinic, tells TODAY.com.

How sunlight causes gray hair

Sun damage contributes to the graying of hair at the molecular level, Dr. Michelle Henry, a board-certified dermatologist in New York City, tells TODAY.com. When hair is exposed to ultraviolet (UV) rays from the sun, it creates free radicals, a type of damaged molecule. These free radicals, in turn, harm the melanocytes, which are the cells that produce the melanin that gives hair its color, Henry says.

Free radicals also “induce DNA damage, promote inflammation in the scalp and gradually reduce melanin production,” Dr. Dustin Potela, a board-certified dermatologist and founder of Treasure Valley Dermatology in Boise, Idaho, tells TODAY.com.

Rays from the sun can also harm hair cuticles — the outside cover of each strand of hair. “All of these stresses affect the hair follicle by causing ... premature death of the melanocytes,” Khetarpal adds.

Another reason to protect your hair from the sun: Gray hairs are more fragile and lighter in color, making them more susceptible to sun damage than thick, dark hairs. So, sun damage can lead to premature graying and damage existing gray hairs.

Sunlight damages hair in other ways, too

Sun exposure can leave hair “feeling coarse and rough to the touch,” and may speed up hair’s aging process in other harmful ways, Henry says.

For example, UV rays damage a natural form of protein everyone has in their hair called keratin. Keratin strengthens and protects hair, making it look brighter and feel softer. When keratin becomes damaged, sun and heat can penetrate the strands more easily, leaving them less shiny and easier to break, says Dr F. Clarissa Yang, dermatology professor at Tufts University School of Medicine.

“People who color their hair should be especially careful with sun damage and exposure, as UV rays can affect the pigment of the strands,” adds Potela.

Sunlight can also cause hair to turn yellow, a phenomenon called "photo-yellowing," which is thought to happen more often to gray or white hair than other colors. Hairs that are affected by photo yellowing usually grow back in undamaged, says Yang.

How to protect hair from sun damage

The good news is that numerous things can be done to protect your hair from sun damage.

Spray your scalp with sunscreen. “Hair sunscreen works by forming a protective barrier on the surface of the hair to shield it from ultraviolet rays,” says Khetarpal. Lotions work similarly and “can be lightly distributed with fingers or a comb,” she adds. To be effective, the sunscreen should be completely dry before you go outside, and make sure the sunscreen is at least SPF 30.

Wear a hat when outdoors. “Shield your head with a wide-brimmed hat or cap when exposed to the sun for extended periods," Henry says. When a hat isn’t available, she suggests adopting a protective hairstyle, for example tying it up to reduce sun exposure.

Use of sulfate-free and color-safe shampoos. “These types of shampoos help maintain hair health, especially for colored hair, and reduce fading caused by sun exposure,” Henry explains.

Get plenty of antioxidants in your diet. Antioxidants have been shown to counteract free radicals, according to the National Cancer Institute. Antioxidant-rich foods include blueberries, black beans, squash, green tea, grapes, broccoli and dark leafy greens. “A healthy diet is important since hair quality is a reflection of your health,” says Yang. 

Don't spend too much time in the sun. “Avoid prolonged sun exposure, especially during peak hours when the sun is strongest,” recommends Henry.