Also Known As: Grey hair, Greying hair, White hair
Gray or white hair — sometimes colloquially called "salt and pepper" when it is 'peppered' throughout dark hair — is not caused by a true gray or white pigment, but is due to a lack of pigmentation and melanin. The clear hairs appear as gray or white because of the way light reflects from the hairs. Gray hair color typically occurs naturally as people age (see "Effects of aging on hair color", below). For some people this can happen at a very young age (for example, at the age of 10). The same is true for white hair. In some cases, gray hair may be caused by thyroid deficiencies, Waardenburg syndrome or a deficiency of B12.
The Journal of Investigative Dermatology published a study in 2005 which found that Caucasian people will begin to gray in their mid thirties while Asian people begin graying in their late thirties, but most African-American people can retain their original hair color until their mid-forties. People with albinism may have white hair due to low amounts of melanin.