Anagen Phase

Hair growth happens in stages, starting with the anagen phase. This is the longest phase, lasting anywhere from three to five years for the hair on the head. Different types of hair have different anagen phases. During the anagen phase, hair follicles produce hairs that grow until they're cut or naturally fall out when their lifespan ends. About 90% of the hair on our heads is in the anagen phase at any given time.