An apparatus for dermal treatment of an active substance having certain physical properties having a flexible, wearable patch conformable to the contour of a skin surface and having: a first electrode adapted to communicate the active substance into the skin by application of an electrical current on the skin surface, a second electrode capable of closing an electrical circuit with the skin surface, a power source for providing a current and voltage connected through a conductive media to the first and second electrode, and an apparatus for substantially controlling penetration depth of the active substance by selecting at least one variable from a plurality of variables.