The life cycle of the hair
Each hair has a life cycle. The head of hair of adults consists, on the average, of 100 000 separate hairs, of which approximately:
• 80-90% are in a stage of active growth (anagenic phase), which continues from two to five years
• 1-3% are in a transition stage (catagenic phase)
• the remaining approximately 10-20% are in a quiescent state (telogenic phase)
Certain pathological changes in the life cycle of the hair follicles lead to impaired balance between hair growth and hair loss, which gradually causes baldness. The life cycle of follicles may be influenced by various states, which respectively characterize the different kinds of hair loss. .