And can you reverse this process?

Our bodies are constantly changing, and with time, our skin and hair change, too. Let's focus on the latter. As we age, hair often thins or falls out altogether, and virtually all women experience color fading. But why, exactly does hair turn gray? Here, our experts break down why this happens and what it means in the context of your health.

Mature woman with gray hair writing in diary while working at home
Credit: Cavan Images / Getty Images

Why does hair turn gray?

Graying is, ultimately, a natural process. "As we get older, the cells in our hair follicles that produce melanin (pigment) gradually reduce, causing our strands to grow in unpigmented or white," says Anabel Kingsley, a consulting trichologist and the brand president of Philip Kingsley. She notes that "gray" is not an actual hair pigment. In reality, it is a color that results from the normal pigment of your hair blending with white. "Your hair color turns from gray to white when all hair pigment cells stop being produced," she explains.

Dr. Tess Mauricio, a board-certified dermatologist, says that health factors are also part of this equation. "Some health issues, such as thyroid disease and vitamin deficiencies, can [impact] hair stem cells negatively and cause premature graying," she notes. Do you experience chronic stress? Data suggests emotional, environmental, or physical stress or a nutrient-deficient diet can cause premature graying, she adds. Otherwise, she continues, your hair is likely determined by your genetics—meaning, if your parents started graying at an early age, you probably will, too.

Is it possible to prevent hair from graying?

While the graying process can start at different points in people's lives, vitamin B—or a lack thereof—is known to play a role. "Various studies have shown that a lack of vitamin B can cause hair to turn white prematurely," Kingsley says. Supplementing this nutrient could, therefore, delay the process, if vitamin deficiencies are a root cause. Ultimately, though, multiple forms of stress and illness are to blame, which is why Dr. Mauricio recommends living a relaxed, balanced, and healthy lifestyle to ward off early onset.

Can you reverse graying hair?

"We technically cannot reverse graying hair, because once the hair is produced by the stem cells from the hair bulb, the amount of melanin pigment is already set (meaning the hair color is set, as well)," Dr. Mauricio says. The dermatologist notes that unless you color your hair, gray hair can't turn darker. There is, however, one exception: "If hair is graying from emotional, environmental, and physical stress from specialized diets or it is caused by a reversible disease—like vitamin deficiency or thyroid disease—then new hair can be produced with more pigment."

Comments (3)

Martha Stewart Member
March 5, 2021
I am proudly 66 years old, and still no gray hair except a little at the temples. Same with my sister who is now 79. Our father was the same, he died at 81 with no gray hair. Our Mom however, got gray in her early 40's; much of it is hereditary and genes I believe. Still the dishwater blonde I always was, amen!
Martha Stewart Member
January 31, 2021
Regarding the comment "or it is caused by a reversible disease---like a vitamin deficiency or thyroid disease—then new hair can be produced with more pigment." I have suffered from thyroid disease for decades and everyone in my immediate family suffers from the disease. We have been informed by multiple endocrinologists that thyroid disease is a permanent disease and cannot be reversed. have I been misled all along? I have researched the disease for decades and feel so hopeless saddled with hypothyroidism and stuck on Synthroid .175 for the rest of my life, always overweight, suffering from bouts of hair loss, and totally grey hair. HELP!
Martha Stewart Member
January 31, 2021
Oh, no!! Melatonin deficient. How dreary. If our hair has traces of the chemicals and other substances we consume, it seems color could be fed to the hair. Licensing tends to destroy thinking. I know a lot of brain-dead doctors and lawyers. Where is that stem cell research when you need it? ©2021