Hair: the life of hair

1) Growth phase.

2) Phase of stasis (1a: hair shaft) (1b: papilla).

3) Phase of rest (2a: hair bulb) (2b: cells of the papilla).

4) New growth phase (3a: new hair) (3b: old hair).

5) Growth phase: new hair.

The three phases in the life of a hair

During our lifetime, the hair follows a precise life cycle in an alternation of three different phases.

1) Anagen Phase

The bulb cells reproduce, enabling the growth of a new hair shaft. Duration:

3-5 years for man, 6-7 for woman.

2) Catagen Phase

The Anagen phase stops: the cells stop reproducing and, through a phase of stasis, the bulb rises to the surface and the shaft ceases growing. Duration: about 2 weeks.

3) Telogen Phase

All the activities of the hair cease and it prepares to fall out. Duration: about 3 months. At the end of the Telogen phase the three phases are repeated. 

After the age of 40, more and more hair becomes involved in the stasis phase and grows less frequently while falling out more easily, whereas the shafts become thinner and even the production of sebum decreases.