The first onset of gray hair and the speed at which people go gray varies considerably from person to person. Most people actually start going gray in their late 20s but they don't notice it immediately. Premature graying is defined as gray hair onset before late teens for Caucasians and before age 30 in Africans and Asians, or alternatively 50% or more gray scalp hair before age 50.
The time and speed of gray hair onset is due in part to genetics, and early onset gray hair development can run in families.
Incidence; Causes and Development
Very occasionally, a few gray hairs can develop in children as young as 8 years and yet it indicates nothing other than an early onset of the gray hair that we all develop with increasing age. Typical gray hair first develops at age 34.2 +/- 9.6 years in Caucasians while for Black people the average age of onset is 43.9 +/-10.3 years [
Keogh 1965]. As a rough guide, 50% of the population in the US and Europe have 50% gray hair by age 50.
Gray hair is caused by the gradual reduction of
melanin production over time within the affected hair follicle. The melanocytes in the hair follicles produce less and less melanin, and the result is a loss of hair fiber color strength. What we call gray hair is not gray at all if you look at the individual hair fibers. Some hair fibers will contain some color while others are virtually white. What we describe as gray comes about from our perception of the overall scalp hair color. Blondes are most likely to develop a completely white head of hair in old age because their hair fiber has a very low density of pigment in it to start with.
Signs and Symptoms
The most common areas on the scalp in which to first see gray hair development are above the ears and/or at the temples. This first gray hair may spread around the sides and to the crown with time. Gray hair development in the beard and mustache may also start quite early, while gray hair on the chest and pubic region generally only occurs some years after onset of gray hair on the scalp.