Final answer:
The anagen phase of hair growth typically lasts for 2 to 7 years. It is the period when the hair actively grows at approximately 0.3 mm per day before transitioning to the catagen and telogen phases.
Step-by-step explanation:
The anagen phase is the active growing stage of the hair cycle during which the hair fiber is produced. Typically, the anagen phase lasts between 2 to 7 years, which allows the hair to grow longer before entering the subsequent phases. After this phase, hair enters the catagen phase, a brief transitional period lasting 2 to 3 weeks, followed by the telogen phase, a resting stage that lasts for about 2 to 4 months before the cycle restarts.
Daily hair growth during the anagen phase is about 0.3 mm, and it's normal for a person to lose and replace about 50 hairs each day. Factors such as hormones and dietary changes can influence hair growth and hair loss, which may become more prominent with age.