Hair Cycle

The hair growth cycle

The hair follicle produces a new hair every few years.

Growth (anagen) phase

This phase lasts for 3-5 years. The longer the phase the longer you will be able to grow your hair.
85-90% hairs

Involution (catagen) phase

The hair stops growing in this phase and the follicle involutes - gradually the hair root in the follicle becomes shrunken.
Lasts 1-2 weeks 1% of hairs

Resting (telogen) phase

This is the time between the involution of the follicle and the next growth phase.
Lasts 5 months 10-15% of hairs

In humans the hair follicles cycles start at different times so there is no specific period of growth or loss.