It depends on several factors. Thick hair responds better than thin hair and darker hair responds faster than the lighter ones. Six sessions of laser treatment for dark thick hair may induce about 75% to 85% of hair reduction. Legs are an example of dark thick hairs. The most responsive areas of the body for laser hair removal are the legs, underarms, and bikini area for both men and women. The male back and female face are more challenging and can take a few additional treatments. Of course results can vary from person to person and some get better results than others.