Hair Life Cycle:
Anagen, Catagen and Telogen

Our hair is constantly renewing itself: its life cycle is 3 years on average for men and from 4 to 7 years for women. Throughout that period, each hair grows without rest. When it dies, it is immediately replaced by another. The dead hair will only fall two to four months later, which is how long it takes for a new growth hair to definitely chase it away from its hair follicle.  

A FOUR-STEP SCENARIO

1) Growth phase: anagen. The hair is full of life, its growth is constant and regular, and its root fills the hair follicle all the way to the base. Length: from 2 to 7 years, depending on gender and personal characteristics.

2) Recession phase: catagen. The hair is between life and death. Its root climbs towards the epidermis, loses some volume and its activity suddenly stops. The hair therefore stops growing, but stays in place for another 2 to 4 months.

3) Expelling phase: telogen. The hair is dead but it stays on the head until the root of the hair replacing it is strong enough to remove it. Length: 2 to 4 months. 

4) Hair Loss: The freshly regrown hair makes it to the scalp’s surface and the old hair falls naturally. 

When the hair is healthy, 85 to 90% of it is in the anagen phase, and 15 to 10% in the telegen phase. During a period of intensive hair loss, such as season hair loss, the difference can decrease and 30% of the hair can be in the telegen phase. That condition is called "effluvium telogen".

FOR FURTHER INFORMATION

Daily Hair Loss: What is the Norm?  Men Women
Hair Properties(quiz)

Diagnosis In-depth Clauderer Diagnosis: Have a complete hair checkup