Chinese Association of Idaho State University (CAISU)
A hair growth cycle consists of three phases. During the anagen phase, hair grows actively. This phase may last for years. During the catagen phase, hair stops growing and separates from its follicle, which is the structure beneath the skin that holds the hair in place. The catagen phase lasts about 10 days. During the telogen phase, the follicle rests for two or three months, and then the hair falls out. The next anagen phase begins as a new hair grows in the same follicle. Most people lose 50 to 100 hairs per day as part of this natural cycle.