Functions of the Kidneys
The Kidneys manifest on the hair.
Commentary: The Kidney Essence provides the nourishment for the hair to grow. The Chinese words for body hair (mao) and the hair on the head (tou fa) are different. The Kidneys influence the hair on the head. If the Kidney Essence is strong, the hair will be shiny and healthy. If the Kidney Essence is weak or declining, the hair will become thin or brittle, fall out, or gray prematurely.