What are the stages of hair growth?

The stages of hair growth consist of anagen, catagen, and telogen.

In the anagen phase, which is the active growth stage, hair follicles are busy generating new hair cells, leading to the lengthening of the hair. This phase can last from several years, depending on individual genetics and health factors, and is crucial for determining the ultimate length of the hair.

The catagen phase follows, marking a transitional period where hair growth stops, and the hair strand detaches from its blood supply and begins to shrink. This stage is relatively short, lasting a few weeks, during which the hair follicle begins to undergo apoptosis, or programmed cell death.

Finally, the telogen phase is the resting phase of the hair cycle. During this time, the hair is fully formed but is not growing. The hair may eventually shed during this phase as a new anagen phase begins for a new hair strand.

This triphasic structure of hair growth highlights the intricate cycle involved in hair development, while the other options do not accurately describe these stages.