Disclosed is a fuel cell system with a control unit (3) for controlling and/or regulating at least one fuel cell unit (1), whereby the fuel cell unit (1) includes at least one membrane monitored by the control unit (3), and an electrical load (4) is provided, in particular an electric drive motor and/or at least one load on the vehicle electrical system, whereby the moistening of the fuel cell membrane is improved. This is achieved according to the present invention by the fact that the control unit (3) includes at least one additional electrical load (5, 7) for an additional power output from the fuel cell unit (1) which is dependent at least on the moistening of the membrane.