In hair removal, which phase is most susceptible to damage?

The active phase of hair growth, also known as the anagen phase, is the most susceptible to damage during laser hair removal. This is because the hair follicle is in its growth stage, and the hair shaft is still attached to the follicle, making it more vulnerable to the effects of the laser. During this phase, the hair is actively receiving nutrients and undergoing cell division, which means that the targeted melanin within the hair is more abundant and effectively absorbs the laser's energy. This absorption of energy leads to the destruction of the hair follicle, preventing future hair growth.

In contrast, the telogen phase involves hair that is at rest and not actively growing, making it less responsive to laser treatment. The catagen phase is a transitional stage where the hair follicle begins to shrink and detach from the hair, and the resting phase also signifies a lack of hair growth activity. Therefore, these phases do not present the same level of susceptibility to laser damage as the active phase does.