Did you know... human hair has several stages.. hair cycle

Hair has a dynamic growth structure that includes continuous elongation, thinning and fall out phases. Each hair fiber is independent from each other and might be found in a particular phase of its life cycle.

Anagen is the phase of hair growth which is from 2 to 8 years long. During this period the cells in hair papillas divide themselves continually and this way they build the stalk of a hair. A stalk becomes hardened with keratine while gradual growing out of the cells into the skin pores. At the same time the cell is growing into deeper layers of skin to get nutrition.

Catagen is the next phase which is relatively short because it lasts for only 2 to 4 weeks and it the phase of a hair renewal. The hair follicle stops growing thus becomes degenerated but it does not fall out right away. It shrinks to around one sixth of its normal width. Its bottom part becomes destroyed and a hair papilla gets separated from its follicle. A hair bulb is separated from the blood nutrition and, as a result, the whole stalk becomes pulled outside when a hair follicle gets disintegrated.

Telogen is the last phase of a rest which lasts from 2 to 4 months. During this period a hair still is not growing, although it is detached to a follicle while its papilla is at rest. If the whole process (cycle) of hair growth is taking a normal course then app. 10 to 15% of hairs remain at this stage. Sometimes, the hair follicles go into a latent state called the Lag phase and the follicles remain dormant for 2 – 5 weeks. Approximately 10 – 15 % of our scalp hair is in telogen phase.

After the Telogen phase the whole cycle is completed and the Anagen phase begins. The new stalk of a hair is being formed and the old one id being pulled out and falls out.

10 % of the hair follicles of an individual, who has a total of 100,000 hair follicles, are theoretically found in telogen phase. Given this, the loss of an average of 100 hair fibers per day – taking into account that a telogen phase that lasts about 90 to 100 days – should be considered as normal.

Important!
When a new hair (new stalk) begins growing out of the hair cell, it has to get rid of the old one first. If that happens to many hair cells at the same time, we can observe the process of casting or losing hair (ecdysis). which means that large amount of hair is falling out at the same time.