Your hair turning grey could be down to your body's stem cells, according to scientists who say their discovery could lead to ways of preventing or even reversing the signs of ageing.
The study suggests stem cells may get "stuck" as hair grows older and therefore lose their ability to mature and maintain hair colour.
Led by researchers from NYU Grossman School of Medicine, in New York, USA, the study focused on cells in the skin of mice that are also found in humans called melanocyte stem cells, or McSCs.
