Scientists have long believed that the appearance of white hair is an inevitable part of ageing, but research has revealed a hidden mechanism inside hair follicles that may be one of the main reasons hair loses its colour.
In a study published in the scientific journal Nature, a team of scientists from the NYU School of Medicine investigated the role of pigment stem cells known as Melanocyte Stem Cells (McSCs) — the cells responsible for producing the cells that give hair its natural colour.
The researchers found, through experiments conducted on mice, that these cells do not remain in one place inside the hair follicle. Instead, they move between different regions within the follicle, a process essential for them to mature and produce the pigment cells that maintain hair colour during growth.
However, with advancing age, a disruption may occur in this process: some melanocyte stem cells become trapped inside a region known as the Hair Follicle Bulge, losing their ability to return to another region within the follicle called the Germ Compartment, where they receive the signals needed to produce pigment.
When these cells lose their ability to move, they stop producing the cells responsible for hair colour — and the result is the appearance of white hair.
Mayumi Ito, the study's lead researcher and a professor in the Department of Dermatology and Cell Biology at NYU Langone Health, said that the loss of the melanocyte stem cells' ability to