A microcurrent treatment device has one or more electrodes or emitters configured for electrical communication with the surface of a subject's skin. A voltage or current supply is adapted to generate an electrical waveform or other energetic waveform for application to the skin surface, via the one or more electrodes or emitters, and a controller is configured to modulate the waveform. The controller can modulate consecutive pulses of the waveform so that the pulse width, period, frequency, amplitude or integrated amplitude of the consecutive pulses varies in a predefined, random, pseudorandom, or other aperiodic manner, or so that the pulses exhibit a degree of statistical randomness, over a predefined period. The period can cover a set of consecutive pulses defining a treatment cycle, or a continuous subset of consecutive pulses defining one or more phases of a treatment cycle.