Hair follicles lose pigmentation with age. Contrary to manufacturers' claims, no supplement exists that has been clinically proved to reverse gray. Premature gray occurs when your hair loses its pigment at an early age. This can even happen to children. The onset of gray hair earlier than usual remains somewhat of a mystery, but the condition is sometimes linked to an underlying condition. For now, hair colorants remain the primary way to get rid of gray hair.

While there is no supplement known to reverse gray hair, copper deficiency appears to contribute to premature graying. Copper plays a role in the formation of melanin, which is what gives your hair its color. Researchers found a link between low copper and premature gray, according to a study published in the April 2012 issue of the journal "Biological Trace Element Research." Copper is found in various foods, with meat, shellfish, nuts and seeds serving as particularly rich sources. So far, there is no evidence showing that improving copper levels reverses or prevents gray hair. More research is needed.