Most don't work. Two products help a few people re-grow hair. Baldness isn't the only hair characteristic that's inherited. So are hair color and texture. As with skin, a pigment called melanin gives the hair its color.
Pure melanin makes hair brown or black.
About 80 percent of people in the United States have black or brown hair. If the melanin contains iron or sulfur, the hair is blonde or red. Hair turns gray when the body stops producing the pigment. Hair texture and color vary by ethnic background. The hair of natives of Africa, Papua and Melanesia is nearly black.