Question: What causes grey hair?
Grey hair occurs when the cells responsible for hair color, also known as melanocytes, stop producing pigment or melanin. It is also believed that DNA damage or hydrogen peroxide build-up in the hair follicles may cause hair to grey. In addition, if your mother or father went grey early, your chances of the same thing happening increase. Smoking and Vitamin B12 deficiencies can also contribute to changes in hair color production.
Most people notice the appearance of grey hair in their 30s or 40s, although some people can turn grey as early as their 20s.