At what stage does hair growth occur?

Hair growth occurs predominantly during the anagen phase, which is the active growth phase of the hair follicle. During this stage, the cells in the hair bulb divide rapidly, causing the hair to grow longer. This phase can last for several years, depending on individual genetics and health factors, and is characterized by the production of new hair cells, resulting in the elongation of the hair shaft.

The other phases mentioned do not contribute to hair growth. The telogen phase is essentially a resting period where the hair is not actively growing and is preparing to shed. The catagen phase is a transitional phase that represents the end of active growth, where the hair follicle shrinks and detaches from the hair bulb. The exogen phase involves the shedding of hair, which signifies the end of the hair cycle, as old hairs fall out to make way for new hair growth in the anagen phase.