Though advertisements for hair tonics may urge you to ‘Give New Life to your Hair’, all the hair you can see on your body is dead, and nothing will revive it. The only life is deep within the follicles that lie beneath the surface of your skin, where new hair cells are constantly formed.
Hair grows from almost all parts of your body. Some is so soft and fine that it is almost invisible. But fine or coarse, all hair grows in the same way and from the same kind of structure. Each strand emerges from a follicle nourished at its bulblike base, the papilla.
Growth takes three distinct phases. In the first, the anagen phase, new hair pushes out from the follicles at a rate, for scalp hair, of about 1 cm (nearly 1/2 in) a month.. After a period of between two and six years, growth stops. The machine takes a rest, but not for long. A few weeks later comes the third, telogen phase, in which the hair separates from the papilla. The next anagen phase begins, and new hair pushes out the old. At any time, some 15 percent of follicles on both the scalp and body are dormant.