Hair Information
The Life Cycle of Hair
The Life Cycle of Hair Can Be Divided Into 3 Phases
Hairs spend a variable amount of time in each phase (listed below) determined by genetics, hormones, and area of the body. Laser energy has its greatest effect on the anagen phase (when hair grows). All of these factors must be considered when choosing a method of hair removal.
1) Anagen Phase:
The anagen phase is when a hair grows. The anagen phase lasts approximately 2 to 7 years but may vary from a few months to about 10 years. At any given time approximately 80 to 90 percent of our hair is in the anagen phase. During this phase the scalp hairs grow about 1 to 2 cm per month. The hair on the arms, legs, eyelashes, and eyebrows have a very short active growth phase of about 30 to 45 days explaining why they are so much shorter than scalp hair.
2) Catagen Phase:
The catagen phase is the transition period between the anagen and telogen phases, which is when hair growth begins to shut down and stop activity. Approximately 2 percent of our hair is in the catagen phase at any given time. The catagen phase lasts about 3 weeks while a club hair is formed. This process cuts the hair off from its blood supply and from the cells that produce new hair. A new hair is formed and pushes the club hair up the follicle and eventually out.
3) Telogen Phase:
The telogen phase is when a hair is resting. It is the resting phase for hairs on the scalp, usually lasting 3 weeks to 3 months, and the resting phase is much longer for hairs on the eyebrow, eyelash, arm and leg. Approximately 10 to 18 percent of our hair is in the telogen phase at any given time. About 25 to 150 telogen hairs are shed normally each day. After the telogen phase, the hair growth process starts over again to the anagen phase.
Recap
Each human hair grows in its own individual phase. Not all hairs are in the same phase at the same time.
- 1) Anagen Phase: (when a hair grows)
Approximately 80% to 90% of our hair is in this phase at any given time. - 2) Catagen Phase: (hair growth begins to shut down and stop activity)
Approximately 2% of our hair is in this phase at any given time. - 3) Telogen Phase: (a hair is resting)
Approximately 10% to 18% of our hair is in this phase at any given time.