In which phase of hair growth does a new cycle begin?

The phase of hair growth in which a new cycle begins is the anagen phase. This is the active growth phase where the hair follicles are producing new cells rapidly, leading to the lengthening of the hair strand. During the anagen phase, hair can grow for several years, and this duration varies widely among individuals and different hair types.

In contrast, the other phases play different roles in the hair growth cycle. The telogen phase is a resting phase where the hair is not actively growing but is prepared to shed. The catagen phase is a transitional period where the hair stops growing and detaches from the blood supply, preparing for the shedding that occurs in the telogen phase. Hypertrichosis, on the other hand, refers to excessive hair growth in areas where hair is normally present, but it does not represent a phase of the hair growth cycle.

Thus, the anagen phase is critical as it marks the beginning of a new growth cycle for hair, setting the foundation for healthy hair development.