The newest strand of hair on your head is already dead (since, like all its sisters, it is composed of inert keratin cells)—yet it will still manage to age, along with the rest of your body. As the years tick by, the cuticle, the hair’s outer protective layer, grows thinner and weaker. Meanwhile, oil production in your scalp slows down. In your thirties, dryness and breakage start to set in. “After age 40, more than half of all women experience some hair loss or thinning,” says Manhattan dermatologist David Orentreich. By 45, three fourths of us have begun to turn gray—and while that shade can be lovely, the strands themselves often have a texture that’s difficult to manage.
If you find any or all of these changes unwelcome, you should know that there’s a large arsenal of treatments—including topical products, oral medications and lasers—that can stop or even turn back the clock.
The cause: A key factor in color loss is a buildup of hydrogen peroxide in the hair follicles, the skin organs that produce hair strands. Hydrogen peroxide, which the body releases as a by-product of normal chemical reactions, interferes with an enzyme that is responsible for pigment production. When you’re young, your body is able to neutralize the hydrogen peroxide, but by your forties, that ability starts to decline. As a result, the chemical accumulates in the follicles and disrupts the synthesis of melanin, the natural pigment that gives hair its color. That’s when graying begins; at the far end of the spectrum, hair that’s completely devoid of melanin is white.
When and where you go gray is probably determined largely by your genes, but a recent study in Nature Medicine suggests that another factor may hasten the process: sun damage. Researchers at New York University School of Medicine and Baylor College of Medicine found that when UV rays harm skin, melanin--producing stem cells in nearby hair follicles abandon their posts, migrating upward to the skin and producing protective pigments (such as a tan) there. Occasionally, these melanin--producing cells are not replaced after they leave the follicles, which turns some hairs gray. So you mayslow down the graying of your hair by being religious about wearing sunscreen on your body and a hair product with UV protection (for the skin on the scalp) whenever you’re outside—something you should be doing anyway.
Another factor that appears to speed up graying is psychological stress. The same study in Nature Medicine showed that stress hormones contribute to the migration of melanin-producing cells out of hair follicles, providing a possible explanation for the rapid graying of many U.S. presidents while in office.
Ethnicity plays a role, too. Gray hair usually appears later in people of Asian and African descent than in their fair-skinned peers, presumably because darker hair starts out with more melanin.
The fix: It’s normal to sprout some gray hairs in your thirties, but if you’re going gray earlier or very rapidly, “see a doctor to rule out an underlying disease like hypothyroidism,” advises New York dermatologist Francesca Fusco. Hypothyroidism means you’re not producing enough of the thyroid hormones T3 (triiodothyronine) and T4 (thyroxine), which are essential for, among other things, pigment production in hair follicles. Reduced levels of these hormones can trigger graying, hair loss and changes in the texture of the hair shaft. Taking synthetic hormones typically remedies the health problems caused by hypothyroidism (fatigue is a big one) and may also slow down graying and hair loss.
If you’re dealing with the more typical pattern of gradually going gray in your thirties and later, there’s no known way to reverse the change. But a wide variety of products can help you cover or enhance your natural color.