All hairs are not visible on the surface of the skin at the same time, due to varying stages in the hair growth cycle.
Following the first three stages of the hair growth cycle, the hair is shed, and the follicle moves into a dormant period.
Following this dormant period, the hair producing cells are once again stimulated to produce a new hair and repeat the cycle.
The dormant period varies between 3 to 12 months.
Note: The surfacing of coarse replacement hairs from an untreated follicle
should never be confused with regrowth from an inadequately treated follicle.
The stages of the hair growth cycle are:
- Anagen. (Active hair growth stage).
- Catagen. (Transition to the dormant or resting stage).
- Telogen. (Full resting stage).
- Dormant (no activity).
(Source - 1998 by John E. Fantz. - "Fantz Electrolysis Exam Review".)
The above diagram shows a follicle in anagen on the left, one in catagen in the middle and one in telogen on the right. The telogen follicle shows an electrolysis needle inserted to full anagen depth and the destructive pattern of the electrical current.