Which type of hair is typically not effectively treated by lasers?

Laser hair removal relies on the contrast between the pigmentation in the hair and the surrounding skin. The laser targets the dark pigment (melanin) in the hair follicles to effectively destroy them. Therefore, hair that has little to no pigment, such as blonde, gray, or white hair, is often not effectively treated by lasers. This is because the laser has difficulty detecting the hair follicle due to the lack of pigment, reducing its efficacy.

While thick hair may be more effectively targeted than fine hair, and curly hair doesn't inherently affect laser treatment efficacy, light-colored hair also poses challenges but can sometimes be treated depending on its pigmentation. The key factor here is the absence of pigment, which directly affects the laser's ability to hone in on and effectively treat the hair follicles.