If you have more hair above the skin surface most of the laser light will reach the portions of hair above the skin and not the deeper hair follicles. As the laser light goes deeper more effective will be the results. So it is recommended to do shaving to remove the hair above skin before laser treatment to allow more light into the hair root. To treat your hair with tria beauty, press it on the treatment area where you want to remove hair and have contact on that skin. You will hear a beep that indicates that the device is treating the area.