This shows stem cells

How stress causes gray hair

Study reveals a link between the nervous system and stem cells that regenerate pigment in hair follicles. When stressed, norepinephrine from the sympathetic nervous system causes melanocyte stem cells to activate excessively. The stem cells all convert into pigment-producing cells, prematurely depleting the reservoir. The findings explain the cellular and molecular links between stress and premature hair graying.... Read More...