Researchers may have discovered what makes, prompting hope that a treatment for preventing or reversing the process could be on the horizon.
Published Wednesday in the journal Nature, the study shows certain stem cells, which have the ability to move between growth compartments in hair follicles, get stuck as people age and lose their ability to mature and maintain hair color.
The research focused on cells in the skin of mice that are also found in humans called melanocyte stem cells. Over time, as hair ages, sheds and grows back, these cells may eventually cease to move as they used to, and thus fail to reach the part of the process where pigment is generated.
"Our study adds to our basic understanding of how melanocyte stem cells work to color hair," study lead investigator Qi Sun, a postdoctoral fellow at NYU Langone Health, said in a press release. "The newfound mechanisms raise the possibility that the same fixed-positioning of melanocyte stem cells may exist in humans. If so, it presents a potential pathway for reversing or preventing the graying of human hair by helping jammed cells to move again between developing hair follicle compartments."
Study senior investigator Mayumi Ito added, "it is the loss of chameleon-like function in melanocyte stem cells that may be responsible for graying and loss of hair color."
In a statement to CBS News, Ito, a professor in the Ronald O. Perelman Department of Dermatology and the Department of Cell Biology at NYU Langone Health, explained that the study suggests melanocyte stem cells are mobile but can only start regeneration of melanocytes — which produce hair pigmentation — when they are present in a specific area within the hair follicle called the hair germ compartment.
"Our study suggests that moving melanocytes to a proper location within the hair follicle may help prevent hair greying," Ito wrote, adding they "look forward to investigating to what extent our theory is applicable to humans."