The human body has millions of hair follicles or small sacs lining the skin. The follicles generate hair and color or pigment cells that contain melanin. Over time, hair follicles lose pigment cells, resulting in white hair color.
Premature graying of a person’s hair is
largely connected to genetics, according to a 2013 report in the
Indian Journal of Dermatology, Venereology and Leprology.
Race and ethnicity play roles, as well. Premature graying in white people can start as early as 20 years old, while a person can be as young as 25 years old among Asians, and 30 years in African-Americans populations, according to the
same 2013 study.
Chemical hair dyes and hair products, even shampoos, can contribute to premature hair graying. Many of these products contain harmful ingredients that decrease melanin.