Why Is My Hair Turning Gray?

It was one wiry strand at your part, shining under the bathroom light like a fiber-optic cable. You pulled it. Two weeks later there were three more. Now you’re checking your hairline in every car window, counting.

What’s happening in the follicle

Hair doesn’t change color after it grows out. Harvard Health Publishing³ says follicles produce less color as you age, so when a hair goes through its natural cycle of dying and being replaced, the new one is more likely to come in gray, beginning after age 35.

The AAD¹ puts a number on it: after roughly 7 to 15 hair growth cycles, the melanin stops regrowing and the hair loses its color. On average, it says, graying starts in your 30s or 40s.

Why yours started when it did

Genes. Harvard Health says when and how thoroughly your hair grays is influenced mostly by the genes you inherit from your parents. The AAD¹ agrees that if your parents’ hair grayed early, yours may follow. Ask your mother when she noticed hers.

Age. Cleveland Clinic² says most people start seeing grays in their 30s or 40s, and calls graying premature before 20 with a light skin tone and before 30 with a dark skin tone.

Stress. The sources don’t fully agree. The AAD¹ says research shows stress speeds graying, because it prompts the body to release norepinephrine, which makes melanocytes move out of the follicles. Cleveland Clinic² says stress can trigger gray hair but not immediately, because hair gets its color before it grows out, and that when stress comes down, once-gray hairs can grow back in their original color. Harvard Health says stress doesn’t directly change hair color, but can trigger telogen effluvium, so you shed faster, and a middle-aged woman’s replacement hair can come in gray. For the shedding side, see thinning hair.

Other causes. Cleveland Clinic² lists vitamin deficiencies, smoking, certain medicines (it names cancer treatments, retinoids, antimalarial drugs and epilepsy medicines) and conditions including alopecia areata and vitiligo. The AAD¹ notes lifestyle and underlying health conditions as factors.

Our article on vitamins and biotin covers what supplements can and can’t do.

Can it be reversed?

Mostly, no. The AAD¹ says there are no medical treatments that add color back, though some research suggests it may be possible if an underlying condition is treated, and it says more research is needed. Cleveland Clinic² says that once gray hair is visible, it can’t be prevented or reversed, but treating an underlying condition may slow it.

Your options

Color. The AAD¹ says natural dyes like henna are gentler but fade quickly, and synthetic dyes last longer but may irritate a sensitive scalp. A board-certified dermatologist can help if your scalp reacts. See itchy, flaky scalp if it does.

Or skip it. There’s nothing about gray hair that needs fixing. Plenty of women keep it. If your strands feel dry or brittle, that’s a separate thing to look at. See dry, brittle hair.

Habits. The AAD¹ recommends balanced nutrition, enough sleep, not smoking, managing stress and UV protection, which can’t undo graying but fit any hair care routine.

The play

Try this: a family-and-habits check

Ask a parent or grandparent when their hair started graying. Write it down.

Then look at your own list: do you smoke, sleep badly or take any of the medicines Cleveland Clinic² names? Write what you find.

Bring both to your next appointment if you’re graying early.

When to get checked

The AAD¹ says to consult a board-certified dermatologist to diagnose underlying conditions that affect hair color. Cleveland Clinic’s² age cutoffs, before 20 with a light skin tone and before 30 with a dark one, are the definition of premature graying.

Book an appointment if any of these fit:

• Your hair is graying before the ages Cleveland Clinic² lists
• Graying came on fast, or with patches of lost color on your hair or skin
• You have fatigue, hair shedding or other new symptoms at the same time
• You take a medicine that’s on the list and your hair changed after you started
• Dye is irritating your scalp

A gray hair is a hair that’s finished a lot of growth cycles. Color it or keep it. That’s your call, and your health isn’t hanging on it.