Why Does Our Hair Turn Gray As We Age And Can We Stop It?

Looking into the relationship between stress and gray hair, a new study tries to see if we can reverse this universal sign of aging.

By Donna Sarkar
Oct 12, 2022 4:00 PMOct 12, 2022 4:02 PM
Graying hair
(Credit: waewkid/Shutterstock)


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You may be combing through your hair when you first notice it: a small but present silver strand peeking through. Whether we like it or not, finding a gray hair is inevitable for all of us. Rather than asking ourselves if we’ll get it, the curiosity lies behind why we get it and what we can do to delay it.

While there is a biological reason to explain why this occurs, a question remains — is it possible to reverse graying?

Graying Gracefully

Whether your natural hair is blonde or jet black, melanin (yes, the same pigment that tints the skin) determines your hair’s hue. Melanin, or the pigment we have in our hair, produces melanocyte cells, located within each hair follicle. And these cells produce two different types of melanin, known as eumelanin and pheomelanin.

Eumelanin is a dark pigment, which means that the more present it is, the darker the hair is. Therefore, an abundance of eumelanin creates black or brown hair, while a lack of it, leads to blonde hair. A presence of pheomelanin combined with a lack of eumelanin leads to red hair.

But what about gray hair? The science behind a gray strand lies in the melanin, or in this case, a lack of it. Gray hair has minimal melanin, while white, or silver hair is colorless, meaning there is no melanin. And aging is the main cause. As we grow older, the melanocyte cells in our hair follicles start to die, causing a depletion in the melanin, or pigment. Over time, this leads to more colorless strands, which appear silver or gray.

While we understand why we go gray, experts still are trying to understand why our melanocyte cells die in the first place and there are a few theories for aging itself.

Essentially, there are two categories of aging: intrinsic and extrinsic aging. Intrinsic aging involves inner biological cells, which are programmed to divide to perform basic biological functions. Each time a cell divides, it loses DNA, which overtime causes the cells to age and therefore, decrease their ability to function properly. The depletion of melanocyte cells that causes gray hair is an example of this.

Extrinsic aging involves all the outside factors that can contribute to the aging process. For graying, this can include stress, diet and even certain illnesses like a vitamin B-12 deficiency or autoimmune diseases. And a recent study looks into the relationship between stress and those gray hairs.

Reversing the Clock

Graying can range from our mid-30s to mid-40s, based on race and ethnicity. Ultimately, it’s just a matter of time before all of us find our own gray hairs. However, a recent study published in eLife, discovered that graying could be reversible.

A group of researchers at Columbia University Vagelos College of Physicians and Surgeons found quantitative evidence to confirm the age-old suspicion that psychological stress and graying were related.

The researchers analyzed over 397 individual strands of hair from 14 healthy volunteers that ranged in age from 9 to 65. All individuals had not used any hair dye or chemical treatments to color their natural hair but had self-identified as having some gray or two-colored hair strands.

A high-resolution scanner captured images of their locks and it detected small, subtle variations in color that were otherwise invisible to the naked eye. The results were then compared to each volunteer’s stress diary, which included calendars, as well as their week’s level of stress.

Researchers were shocked to find that by eliminating stressors, the gray hairs reversed or returned to their original color. Of the participants, 10 saw this reversal and took active measures to reduce stress, like going on vacation or resolving a tense event. In all instances, the hairs had a white top segment near the root, but were darker, or regained color towards the bottom of the strand.

But if you're ready to trade in your hair dye for a long vacation to cure the grays, we have some bad news. While reducing stress is ideal for your hair and health, it won’t guarantee a reversal to your normal color.

Turns out, hair re-pigmentation is only possible for some because your hair needs to reach a certain threshold for reversal to be successful. This is largely because of biology. When we are in middle age, the hair is nearing its biological age to turn gray. According to the study’s findings, if stress is reduced at this time, the process is more likely to be reversed, or at least halted, rather than when you’ve had grays for years.

Regardless, for now, we can take comfort in the fact that we are not alone in finding that silver strand in our hair.

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