Has the Mystery of Why Hair Turns Grey been Solved?

A new study might have solved the mystery of why hair turns grey. Credit: jennalex / Flickr / CC BY 2.0

A recent study published in the journal Nature suggests that scientists might have found the reason why hair turns gray. This discovery has raised hopes that there could be a way to prevent or reverse the graying process in the future.

The research focused on certain stem cells that can move between different parts of hair follicles, but as people age, these stem cells get stuck and lose their ability to mature and maintain hair color.

These stem cells, called melanocyte stem cells (McSCs), were studied in the skin of mice, but they are also found in humans.

As hair ages, it goes through a cycle of shedding and growing back. Over time, the melanocyte stem cells may stop moving as they used to, and this can cause them to fail to reach the part of the process where pigment is generated. This could lead to gray hair.

The lead investigator of the study, Qi Sun, who is a postdoctoral fellow at NYU Langone Health, explained that their research adds to our basic understanding of how melanocyte stem cells work to color hair. He further added that the newfound mechanisms raise the possibility that the same fixed-positioning of melanocyte stem cells may exist in humans.

If this is the case, it could present a potential pathway for reversing or preventing gray hair by helping the jammed cells move again between developing hair follicle compartments, explained Qi Sun.

Mayumi Ito, the senior investigator of the study, also stated that the reason for graying and loss of hair color could be the loss of the chameleon-like function in melanocyte stem cells.

Stress and grey hair

A study conducted in 2020 explained that stress could actually cause your hair to turn gray. The research team discovered that the body’s response to stressful situations, known as the fight-or-flight response, is a major contributor to graying hair.

Moreover, the color of your hair is determined by cells that produce pigments called melanocytes. These cells are derived from melanocyte stem cells, which reside in the hair follicle located at the base of each hair strand.

Additionally, as we age, these stem cells gradually decrease in number. The study revealed that stress could lead to the loss of these pigment-producing stem cells in mice.

The sympathetic nervous system, which is responsible for the fight-or-flight response, includes nerves that extend throughout the body, including into hair follicles. The study found that stress triggers the release of a chemical called norepinephrine into the hair follicle.

Norepinephrine impacts the melanocyte stem cells located in the hair follicle, causing them to quickly transform into pigment cells and migrate away from the follicle. When stem cells are depleted, new hair growth lacks pigmentation, resulting in gray or white hair.