Wisconsin Esthetics State Board Practice Test

What phase of hair growth is laser hair removal most effective?

1. Catagen phase

2. Telogen phase

3. Anagen phase

4. Exogen phase

The correct answer is: Anagen phase

Laser hair removal is most effective during the anagen phase of hair growth. This is the active growth phase when hair follicles are producing new hair. During this phase, the hair is firmly anchored in the follicle, which allows the laser to target the melanin in the hair shaft and effectively disable the follicle. The energy from the laser is absorbed by the pigment in the hair, resulting in the destruction of the hair follicle and preventing future hair growth. In contrast, during the catagen phase, which is a transitional phase of hair growth, the hair follicles shrink and detach from the dermal papilla, making it less effective for laser treatment since the hair is not as firmly rooted. The telogen phase is when hair is resting and not growing actively, resulting in even less efficacy for laser interventions. Meanwhile, during the exogen phase, which is considered an extended part of the telogen phase where shedding occurs, hair doesn't contain sufficient pigment for the laser to effectively target. Thus, the anagen phase is critical for successful laser hair removal, as it maximizes the treatment's potential to reduce hair growth.