Disclosed herein are systems, devices, and methods for transdermal delivery of a therapeutic agent (for example, a molecule or molecules) to a therapy site. The systems, devices, and methods described herein are flexible and able to conform to the contours of a therapy site, such as the shape of a user's face. In certain approaches, the devices and systems described herein include an integrated power supply for standalone application to the therapy site. The devices, systems, and methods include flexible electrodes with integrated conductance layers and interface layers for improved stability and current distribution. In practice, the device includes at least two electrodes which are coupled to the therapy site. When the electrodes are placed at the therapy site, they are electrically coupled, thereby drawing a current from the power supply to deliver the therapeutic agent to the therapy site.