A method of operating a flashlamp (2) in a skin treatment system (1) comprises the steps of establishing a conductive path between the flashlamp (2) and a charged capacitor (4) causing a free discharge within the flashlamp, and interrupting said conductive path so as to cut off the current through the lamp when the current density drops below a predetermined current density threshold level (Ix) or when the energy applied to the skin reaches a certain maximum (EM).