Hair is made up of protein called keratin. The average adult head has about 100,000 to 150,000 hair. We lose 100 hair a day. As follicles produce new hair cells, old hair cells are being forced out through the skin. The hair we see is a form of dead keratin cells. At any one time, about 90% of the hair on a scalp is growing. Each follicle has its own life cycle. This can be influenced by age, disease and other factors.
There is three phases in this life cycle:
Anagen – or growth hair lasts approximately 2 to 6 years.
Catagen – or transient hair that last approximately 2 to 3 weeks
Telogen – or resting phase that lasts about 2 to 3 months. New protein cells are formed and a new hair replaces and the growth cycle starts again.
As people age, their rate of hair growth slows down.