Why hair turns gray: It's not just age and stress

The common perception that gray hair is solely a marker of aging and stress is being re-examined, with experts highlighting the significant role of genetics. While stress can contribute to the process, it is not the direct cause of hair turning gray, according to Robert H. Shmerling, a senior editor at Harvard Health Publishing.

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It seems that the stress of running a country would turn anyone's hair gray. But is stress really the culprit? And why does hair turn gray even for those of us who don't have a job as stressful as the President of the United States?

Shmerling uses the example of former U.S. President Barack Obama, whose hair visibly grayed during his term. While the immense stress of leading a nation might seem like an obvious culprit, the reality is more complex. Hair color is determined at the follicle level when a strand is produced. If a strand grows out brown, black, or blonde, it remains that color. Follicles produce less pigment as they age, meaning that as hair goes through its natural cycles of shedding and regrowth, new hairs are more likely to emerge gray.

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Hair aging depends on both genetic and environmental factors, and the key turning point occurs around the fifth or sixth decade of life, when hair becomes less quality and loses volume, becomes unruly, loses pigment, and gray hairs appear.

Genetics largely dictates when this process begins and to what extent hair will turn gray. "The time when hair starts to turn gray and the extent to which it will turn white largely depends on the genes we inherit from our parents," explains psychiatrist Judith Joseph. "While stress can play a role, it would be more beneficial to look at previous generations rather than our current stress levels to predict when or if we will go gray."

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The time when hair starts to turn gray and the extent to which it will turn white largely depends on the genes we inherit from our parents. While stress can play a role, it would be more beneficial to look at previous generations rather than our current stress levels to predict when or if we will go gray. This applies whether we are the President of the United States or have a less stressful job.

Stress does not alter the color of individual hair strands. However, it can trigger a condition called telogen effluvium, which causes hair to shed and regrow up to three times faster than normal. This condition does not lead to baldness, as the hair does regrow. But for individuals in middle age, this accelerated cycle means that the new hair emerging might be gray, indirectly contributing to the appearance of more gray hair. Nonetheless, the underlying predisposition to graying is primarily genetic.

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Most gray hairs in people are not related to stress. In fact, hair doesn't 'become' gray at all. When a hair follicle produces a strand, its color is determined. If a single strand grows out brown (or red, black, or blonde), it will never change color.