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By pointing to pigment-producing cells that lose the capacity to mature, US researchers think they may have discovered why hair becomes grey with age.

The arrested development affects immature cells which would otherwise have evolved into melanocytes which provide hair with its natural color.

The mechanism was investigated by the New York University (NYU) team using mice, whose fur color is determined by the same cells.

They suggest that the research could serve as a foundation for reversing the greying process.

The study of melanocytes may also aid in the understanding and treatment of some malignancies and other diseases, as per the British Association of Dermatologists (BAD).

Here's what you should know

Hair follicles, which are located in the skin and are home to melanocytes, the cells that produce pigment, are where new hair grows.

Melanocytes also continually die and regenerate. Stem cells are used to create new ones, and it's thought that in persons with grey hair, these stem cells get "stuck" in limbo.

The cell aging process was investigated by the NYU Langone Health team using specialized scanning and lab methods.

A growing percentage of the melanocyte stem cells become ineffective at their work as hair ages, sheds, and then grows back continuously.

The stem cells become stuck and cease moving throughout the follicle, failing to develop into fully developed melanocytes. The absence of pigment causes the hair to become silver, white, or grey.

The possibility that greying hair might be a partially reversible process has been raised by scientists before.

Premature greying may have several causes, some of which are curable.

According to some researchers, stress may be a factor in the whitening of human hair, and it has been hypothesized that reducing anxiety may temporarily restore color.

Other studies argue that heredity, or our DNA, may have a role in when we start to get older.

"The recent study in mice adds to our understanding of the hair follicle and how the pigment-producing cells function. We are already discovering more about the potential of stem cell therapies for conditions including hair loss and studies such as this one, with new findings about the color-producing cells, may lead to an array of future treatment options for our patients," said Yusur Al-Nuaimi from the British Hair and Nail Society.

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