It takes about six to eight sessions at four to eight week intervals. The laser only responds to hairs currently growing, and hairs grow on different cycles, so not all are caught in one pass. From the third to fifth session regrowth visibly drops, and arm hair is coarse, so it responds relatively fast.

Hair becomes finer and regrowth drops greatly, but it is not completely permanent. Even when the laser damages the root structure, some survive and become active again over time. Many people top up once every one to two years after finishing the course to hold the state.

It stings about as much as a snapped rubber band, and cooling runs alongside, so it is tolerable. Arm skin is relatively thick, so it feels less intense than the face or bikini line. Waxing or plucking beforehand pulls the root out and reduces the effect, so come having only shaved.