AccessMyLibrary provides FREE access to millions of articles from top publications available through your library.
Although it's a phenomenon deplored and often considered abnormal, hair loss is a genetically determined, irreversible, normal event in most men with advancing years. Some balding occurs in both men and women, but the pattern and type of hair loss varies in individuals and between the sexes. Humans are not the only primates to suffer baldness - orangutans and chimpanzees also start balding once they reach maturity. Despite popular folklore, there's no link between baldness and male potency.
The average human scalp contains 100,000 hair follicles. Blond-haired heads tend to average about 25 per cent more hairs and red-haired scalps about 25 per cent fewer hairs than brown-haired scalps. With the spurt in androgen secretion at puberty, the hairline moves back a bit in 96 per cent of boys by their late teens. Male balding or androgenic alopecia goes in waves. The loss may begin at age 20, then stop, only to start up again a few years later. By age 20-30, 30 per cent of men have bald spots; by age 35 to 40, two thirds of Caucasian men are noticeably balding; by age 40-50 it rises to 40 per cent, and by age 50-60, half the men are significantly bald.
The mechanism of balding
Male-pattern baldness usually starts with receding hair at the temples, often combined with a balding spot at the back of the head. It slowly spreads, ultimately leaving just a horse-shoe-shaped fringe. Any remaining hair in the balding areas usually manifests some miniaturization - it is thinner and grows at a below-normal rate, changing from long, thick, coarse, pigmented hair into fine, depigmented sprouts. In women, balding affects predominantly the top of the head, but sometimes spreads over the whole scalp.
The rate of hair shedding is speeded up by three forces: advancing age, an inherited tendency to bald early (genes) and an overabundance of the male hormone dihydrotestosterone within the hair follicle. The extent of hair loss in any man depends largely on the genes he inherits from mother, father or both. About 50 per cent of …