This absolutely does work. It's just small so it's tedious to go through the body parts you want (i.e.: lower leg, for example).
Also depending on the level you put it on 1-5 (1 being lowest, 5 most powerful) will also determine how quickly it works. Depending on the spot of your body you do it, sometimes you don't feel it and other times it's definitely a sharp pain (on shin bone, for example)