In the United States, about 30 million men and 20 million women experience hair loss every year. Contrary to common belief, hereditary hair loss is not caused by a sudden stop in hair growth. Instead, it is the result of the gradual miniaturization of certain hair follicles: as this progress, hairs become shorter and thinner, eventually ceasing to grow. In most cases, hair loss is related to hereditary. Normal genes and androgens cause progressive shrinking of certain scalp follicles over time. In men, hereditary baldness is characterized by a receding hairline above the forehead and loss of hair at the crown.