Your scalp contains tens of thousands of hair follicles: small factories that produce hair. The average number of hair follicles or hair follicles on the scalp is around one hundred thousand and is genetically determined.People with blond hair typically have more hair follicles than dark-haired people. Hair follicles are coated with soft collagen, and develop in a cycle of three phases: growth, transition, and rest, when they lose their hair and go into stand-by mode. After two to twelve months the hairs become active again and the cycle starts from the beginning.
A normal hair growth cycle usually lasts two to five years and follows three phases: first the hair growth is active, then a resting period, after which the hair eventually falls out. Excessive natural hair loss occurs when the growth phase is too short. Although there are many causes and diseases that cause hair loss, androgenic alopecia is the most common cause for both men and women.