The Laser will get the thick dark hairs, but if you have any gray, white, or blond hairs it will not. And if by chance you Google and find a substance called Melamine, a follicle coloring agent for just such a situation, no one except IMAJ Institute will use it. An Electrolysis Pro told me recently that the hair has to be just long enough to be grabbed with a tweezer. Light hair stubble is hard to see, so do it on a weekend.
Here's some more tips, the Laser will remove the dark hairs permanently if...1)Most important is to prep the skin by cleaning it well. So shave as close as possible several hours before the treatment. I also use a Clarsonic after I shave to remove any debris, because debris on the skin will attenuate the Laser energy away from the hair. (2) The Tech is using the correct settings for your skin based on the Fitzpatrick Scale for Skin Type. (3) At least 4 - 6 treatments, try for at least 5....then just suck up the rest!