The Cycles of Hair Growth
Every person's hair grows differently, depending on age, weight, metabolism, hormones, ethnicity, medications, and other factors. But all hair goes through three identifiable growth phases:

Active (anagen phase)
The active growth phase lasts up to several years. At any given time approximately 85% of body hair is in this phase. During anagen, the hair has an abundance of melanin.

Regressive (catagen phase)
The regressive phase lasts about two weeks, during which time the hair stops growing but is not yet shed. At any given time, approximately 3 – 4% of body hair is in this phase.

Resting (telogen phase)
The resting phase lasts five to six weeks, at the end of which hair falls out and new hair begins to form. At any given time, approximately 10-13% of body hair is in this phase.