The hair growth cycle consists of four distinct stages: anagen, catagen, telogen and exogen.
- Anagen Phase: The period of hair growth. Hair grows around half an inch a month, and faster in the summer than in winter. The growth phase, lasts an average of 3-5 years. This phase is generally longer in Asian people and can last up to 7 years i.e. their hair can grow to 3 feet long!
- Catagen Phase: Begins at the end of the anagen phase. Hair stops growing as much and this transitional phase lasts up to 10 days.
- Telogen Phase: This is a resting period of around 3 months. Hair strands remain in their follicles but are not actively growing.
- Exogen Phase: the final stage where strands are released from their follicles and fall out. The growth cycle then begins again.
- Hair loss, hair thinning and problems with hair growth may occur when the growth cycle is disrupted. This is usually caused by genetics, metabolic imbalances, illness or improper nutrition.