An implant system comprising a functional implant (5, 6) that fulfills a medical function, particularly a bone implant, which is formed at least in part of a metal material that can be degraded by the body (2) of the implant wearer, as well as a control device (7) for controlling the degradation behavior of the functional implant (5, 6). The control device (7) has a counter-electrode (10) to the functional implant (5, 6), and a voltage source (8) for making available a polarization voltage (ΔU) between functional implant (5, 6, 15) and counter-electrode (10), to control the degradation behavior of the functional implant (5, 6).