Anagen is the active hair growth stage when the cells in the root undergo rapid division. In this stage, the formation of multiple new strands of hair takes place which gets pushed out of the hair follicle and eventually shows on the scalp. In a typical anagen period, the hair undergoes the growth of 1 cm in every 28 days. The scalp hair experience growth for at least a period of 2-6 years in this particular stage. The duration of this stage varies from one person to another. Few people experience a short Anagen phase because of which they experience the production of short length hair. On the other hand, people with long hair naturally experience a longer initial phase.  

The time frame of Anagen stage is different for every part of the body as well. The hair on the arms, eyelashes, legs and eyebrows have a very short period of active growth which lasts for around 3-45 days. This explains the reason these organs have much shorter hair than scalp. In most of the times, people face uninterrupted hair growth in this active stage. However, the growth of hair may sometimes face interruptions due to the intake of certain medications like anti-cancer drugs and more.