A skin treatment patch has a substrate 11, optionally of polyurethane film, on which are mounted: a cathode 22, formed of a first material 53 having a first standard potential； and an anode 21 comprising a first layer 51 of the first material and a second, outer layer of a second material 52 having a different standard potential. The cathode and anode form a galvanic couple to deliver a microcurrent through the skin of a user. The metal electrodes are spaced apart and may be covered by a layer 54 of conductive adhesive and a release paper 56. Optionally a line 55 of the conductive adhesive may be located between the electrodes. The first material may be silver chloride and the second material may be zinc, applied to the substrate in conductive inks. In the anode, the second material may completely surround the first material. The patch may deliver a microcurrent of 70-100 mA through a users skin.
