During which phase is the hair actively growing?

The hair is actively growing during the anagen phase. This phase is characterized by the robust activity of the hair follicles, leading to hair growth. In this stage, cells in the hair bulb divide rapidly, which results in the elongation of the hair strand. Most of the hair on the scalp is typically in the anagen phase at any given time, and this phase can last for several years, depending on various factors including genetics and overall health.

In contrast, during the catagen phase, hair growth slows down and the hair follicle begins to shrink, marking a transition period. The telogen phase is a resting stage where the hair is not actively growing and is eventually shed. While the exogen phase refers to the actual shedding of the hair, it does not involve growth but rather the culmination of the hair's lifecycle. Understanding these phases is crucial for estheticians and anyone involved in hair treatment, as it influences how they approach hair care and treatment strategies.