The invention concerns an electrostimulation and/or iontophoresis device comprising a patch (10) suitable for application to a user's skin (12) and a voltage generator (22) suitable for applying a low intensity current through the user's skin by a system of electrodes located in said patch; This device is characterized in that it comprises a self-regulator (16) that varies the voltage supplied by the voltage generator as a function of the continuous measurement of the resistivity of the user's skin beneath said patch The resistance value of the skin provided by an element for measuring the resistance of the skin (24) yields the resistivity measurement.