The normal hair cycle consists of three distinct phases: anagen (growth), catagen (transition), and telogen (resting). Each phase has a specific duration and role in hair growth.
- Anagen: This is the active growth phase where hair follicles produce new hair strands. It's the longest phase, lasting anywhere from two to seven years, depending on factors like genetics, health, and age. During anagen, hair shafts grow in length and thickness.
- Catagen: This is a short transitional phase that marks the end of the growth phase. It typically lasts for about two to three weeks, and during this time, the hair follicle shrinks and detaches from the hair shaft.
- Telogen: This is the resting phase where hair growth pauses. It typically lasts for about three months, during which the hair follicle remains inactive, and the hair shaft remains attached to the follicle. After telogen, the hair shaft sheds, and the cycle starts anew with anagen.
A healthy hair cycle involves a continuous turnover of hair, with some hairs constantly shedding and others growing simultaneously. While most individuals have about 100,000 scalp hairs at any time, normal shedding occurs at a rate of 100 to 150 telogen hairs per day.
Understanding the hair growth cycle is crucial for managing hair loss and promoting healthy hair growth. Factors like genetics, hormones, stress, nutrition, and lifestyle can affect the length of each phase and the overall health of the hair cycle.
