In which hair growth phase can hair be damaged by lasers?

The correct answer is the anagen phase, which is the active growth phase of hair. During this period, hair follicles are engaged in producing new hair, and the hair shaft is firmly anchored in the follicle. Laser hair removal treatments target the pigment in the hair shaft and the surrounding follicle, making them most effective in this phase. The anagen phase is crucial because the hair is actively growing and has the most melanin, which absorbs the laser energy effectively.

In contrast, the telogen phase is where hair is resting and not growing, meaning it is less susceptible to damage from laser treatments. Similarly, the catagen phase marks the transition between active growth and the resting phase and does not offer the same potential for laser harm as the actively growing anagen phase. The exogen phase involves hair shedding, which further diminishes the potential for effective laser treatment. Understanding these phases is essential for effective laser hair removal, as treating hair in the wrong phase can lead to insufficient results.