A closed-loop wearable device or platform integrates sensors, actuators, and microcontroller on board. The device is applied directly to the skin using stretchable epidermal electronics. It can sense a variety of signals from the human body, thus collecting medically relevant information, and can activate delivery of a therapeutic upon detection of an abnormal condition. The therapeutic can be delivered at a personalized dosage and/or with a unique combination of drugs or other agents based on the individual's metabolism as tracked by various sensor modules integrated with the medical device.