The normal amount of hairs on the human scalp can range from 100,000 to 150,000. These hairs grow from chambers called follicles. On average hair grows at a rate of just under 2cm a month.
Losing hair is part of the hair’s normal growth cycle and is certainly nothing to be concered about. Normally about ninety per cent of hair will be in the growing phase while the remainder will be in the dormant phase. The dormant phase occurs immediately before the hair drops out and is replaced by a new hair which will grow for up to five year. This process of growth, dropping out and renewal is all part of a continuous process, which sees over 100 hairs a day being lost.
Most male baldness is the result of a condition known as androgenetic alopecia. Androgenetic alopecia is the result of genetic and hormonal factors. It is thought that about 25 percent of men will start to lose their hair by the age of 30.
Many types of hormone can affect the growth of human hair, but the two, which have the most significant affect, are the male hormone testosterones and dihydrotestosterone (DHT). Dihydrotestosterone causes the scalp follicles to shrink until they are no longer capable of supporting any hair growth. Conversely, DHT will cause hair follicles on other parts of the body to become more active. This bizarre mode of action is not fully understood.