Detailed information about hair growth cycle

Hair Growth Cycle

Hair on the scalp grows about 0.3 to 0.4 mm a day. Our bodies contain all the hair follicles that will ever grow from the day we are born. Over time, some may change in size, but new hair follicles do not normally develop unless they are specifically induced to do so. Losing about 50-100 strands of hair every day is absolutely normal as it is a result of the natural hair growth cycle. This indicates that when an old hair dies, the growing phase starts again for a new hair to replace it.

At any given time, hairs are in various stages of growth. The hair growth cycle can be divided into 3 phases- catagen, telogen, and anagen.

Anagen

It is the phase of active growth. A new hair is formed which pushes the old club hair up the follicle and eventually out. During this phase the hair grows about 1 cm every 28 days. On the human scalp, the anagen phase of each hair follicle lasts for about 2 to 6 years.

The length of your anagen phase determines the length of your hair. Some people experience difficulty growing their hair long. This is particularly because they have a short active phase of growth. On the other hand, people with long hair have a long anagen phase. So, the longer is your anagen phase, the longer your hair will grow.

Catagen

This phase marks the follicular regression and at any given point 3% of hairs on the scalp are in this phase. This phase lasts approximately 2-3 weeks. During this time the hair stops growing and the hair follicle shrinks and part of it starts to die. This is the beginning of the formation of what is known as a “club” hair.

Telogen

Telogen is a resting phase and 10-15% of all scalp hairs are in the telogen phase. This phase normally lasts for about 3 months. During this phase the hair follicle is completely at rest and the club hair is completely formed. About 25 to 100 telogen hairs (club hairs) are shed normally each day.

Every single hair follicle goes through these three stages of hair growth. Noticeable hair thinning or baldness is partly a result of a short anagen phase and a particularly long telogen phase, which eventually leads to the shutting down of hair follicles completely which marks the end of their growth cycle.