The Hair Growth Cycle
Hair follicles grow in repeated cycles. One hair growth cycle can be broken down into three phases.
- Anagen – Growth Phase
- Catagen – Transitional phase
- Telogen – Resting Phase
Each hair passes through the phases independent of the neighboring hairs. Hairs in different areas of the body will go through the hair growth cycles at different rates. Which is why effective hair removal treatments need to be timed according to the hair growth cycles for the specific area. And multiple sessions are always needed to catch new hairs “waking up” from the resting phase, in order to achieve optimum hair removal.
Anagen Phase – Growth Phase
Approximately 85% of all hairs are in the growing phase at any one time. The Anagen phase or growth phase can vary from two to six years. Hair grows approximately 10cm per year and any individual hair is unlikely to grow more than one meter long.
Catagen Phase – Transitional phase
At the end of the Anagen phase the hairs enters into a Catagen phase which lasts about one or two weeks, during the Catagen phase the hair follicle shrinks to about 1/6 of the normal length. The lower part is destroyed and the dermal papilla breaks away to rest below.
Telogen Phase – Resting phase
The resting phase follows the catagen phase and normally lasts about 5-6 weeks. During this time the hair does not grow but stays attached to the follicle while the dermal papilla stays in a resting phase below. Approximately 10-15 percent of all hairs are in this phase at an one time.
At the end of the Telogen phase the hair follicle re-enters the Anagen phase. The dermal papilla and the base of the follicle join together again and a new hair begins to form. If the old hair has not already been shed the new hair pushes the old one out and the growth cycle starts all over again.