Grey hair seems to remind most people of aging, but there is more to the process than just getting old. "Hair can go gray for several different reasons," explained Dr. Rajani Katta, a Clinical Assistant Professor of Medicine at Baylor College of Medicine. "The primary reason is genetics, and a lot of it depends on what age your parents went gray."
Environmental influences from physical and emotional stress also cause the hair to go grey. Smokers go grey earlier, and there is evidence that implicates emotional stress, ultraviolet light and pollution in the process. Some medical problems can also lead to grey hair; disrupted thyroid levels are another cause.
Katta also said there is no evidence that plucking the grey hairs will lead to additional growth of grey hairs, so pluck away. Reducing stress and limiting exposure to cigarette smoke may help prevent or might limit grey hairs. Ethnicity can also play an (unchangeable) role; Caucasians tend to go grey in their mid-thirties while it's the late-thirties as an average for Asians, and mid-forties in African-Americans.
