Towards a "free radical theory of graying": melanocyte apoptosis in the aging human hair follicle is an indicator of oxidative stress induced tissue damage.

Proposes a free radical theory of graying in analogy to the free radical theory of aging. Association of decreased numbers, morphology, and melanocyte apoptosis in hair follicles of aging individuals with oxidative stress in the pigmentary-unit; Oxidative stress induced permanent damage of graying hair follicles; Link of oxidative stress with apoptosis.