August 4, 2022

Why Does Hair Turn Gray?

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Aging is an unavoidable part of life. It will slowly start to creep up on you, and bam! your first gray hair. The first instinct may be to pluck it, but as Samantha Jones from Sex in the City once said “I was going to tweeze but if you pluck it six more will come to its funeral.” Is this true though? What is the cause of gray hair? Is it genetic, is it a vitamin deficiency? According to Dr. Ya-Chieh Hsu of Harvard University in a study conducted on stress as the cause of gray hair, they found that high levels of stress did reduce melonocyte stem cells, causing the loss of pigmentation.

What determines gray hair?

A pigment in the hair called melanin determines hair color. Each hair carries a certain amount of melanin; large amounts of melanin in the hair create black-colored hair, while very little melanin causes blonde-colored hair (NIH, n.d.) Each hair also carries a certain amount of stem cells at the base of the hair. These stem cells produce the hair cells that create melanin and color in the hair. Stem cells gradually disappear with time, leading to a decreased amount of melanin present in the cell. Over time, the individual hair loses pigment and appears gray. (NIH, 2020)

Gray Hair Causes

Gray hair is a natural part of aging. Some people develop gray hair at much younger ages than others. Many different illnesses can cause hair graying or hair loss. According to Harvard, the following health problems may cause gray hair (Shmerling, 2022):

  • Vitamin B12 deficiency
  • Neurofibromatosis
  • Tuberous sclerosis
  • Thyroid disease
  • Vitiligo
  • Alopecia areata

Some researchers point to stress as a cause of gray hair. An NIH-funded study exposed mice to different types of stressors to determine the effect of stress on gray hair. In mice, exposure to each stressor led to the loss of stem cells and hair graying (NIH, 2020). Researchers cannot conclude if this same reaction plays a role in the graying of humans.

It’s Fetch is a community that provides a safe space for members to discuss health and wellness topics. We provide access to archived health related content, note the date of last review or update on all articles. No content shared, regardless of date should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician. 

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