The Hair Growth Cycle

Normal hair growth happens in a cycle of three phases: Anagen, Catagen and Telogen. Every single hair goes through these phases, each relating to different states of activity. Read on to find out what on earth they mean.

Phase 1 ? the Anagen, or growing phase:

The Anagen phase is the growing phase, or the 'on' phase. It lasts for an average of approximately 1,000 days in the human scalp, but can last as long as six years! During the Anagen phase hair cells multiply rapidly. The hair shaft grows in diameter and the hair reaches maximum length.

Phase 2 ? the Catagen, or transitional phase:

The Catagen phase lasts only one to two weeks. It is the transitional or regressive phase, when the hair stops growing before the resting phase begins.

Phase 3 ? the Telogen, or resting phase:

The Telogen is the final resting stage, or 'off' phase which lasts for about five or six weeks. Towards the end of the Telogen phase, activity in the hair follicle starts again. A new hair in the Anagen phase develops and forces the old Telogen hair out.

At any one time, around 90 per cent of most people's hair follicles are in the Anagen, or growing, phase and approximately 10 per cent are in the Telogen, or resting, phase.

In the case of common baldness, male pattern baldness, or what is commonly called hereditary hair loss, genes and hormones cause the miniaturisation or 'shrinking' of the hair follicles. This results in a shorter Anagen phase and a particularly long Telogen phase so the hairs then become short and thin. They are soon barely visible to the naked eye and eventually the hair follicles shut down completely.