Which phase in the hair growth cycle is known as the active phase?

The active phase of the hair growth cycle is known as the anagen phase. During this phase, hair follicles are actively producing hair, and it can last for several years, depending on genetic and individual factors. This phase is characterized by rapid cell division and the lengthening of the hair shaft, contributing to significant hair growth.

Understanding the anagen phase is essential because it is the only phase where the hair is actively attached to the hair follicle, allowing it to grow and thrive. This contrasts with other phases. For instance, the catagen phase marks a transition where hair growth slows down and the hair follicle begins to shrink. The telogen phase is a resting phase where the hair is not actively growing and can eventually lead to hair shedding. Exogen is often considered a sub-phase or process during which the hair is shed from the follicle, signaling the end of the hair growth cycle. Therefore, recognizing the anagen phase as the active growth phase is fundamental to understanding hair biology and the lifecycle of hair.