Hair cycle
Anagen phase, a period during which a hair is born and grows, lasts for two to five years. Anagen phase is further divided into two periods, namely, active period and transition period. Active period is the period in which cells of hair matrix around the hair papilla proliferate while in transition period the growth rate is getting slower.
Thereafter, the hair enters into two- to three-weeks catagen (involutional period) in which it stops growing because of inactive cell division of hair matrix. The hair then enter into telogen (dormant period) that lasts for three to four months. In telogen, the hair “prepares” to fall out. It does not fall out immediately after entering into telogen. While the hair remains on the head, the root of the hair is gradually pushed up toward the scalp. Finally the hair falls out three to four months after entering telogen.
Thereafter, the hair enters into two- to three-weeks catagen (involutional period) in which it stops growing because of inactive cell division of hair matrix. The hair then enter into telogen (dormant period) that lasts for three to four months. In telogen, the hair “prepares” to fall out. It does not fall out immediately after entering into telogen. While the hair remains on the head, the root of the hair is gradually pushed up toward the scalp. Finally the hair falls out three to four months after entering telogen.