Modern societies require a reliable and sustainable energy supply, which can be achieved by solid oxide fuel cells (SOFCs). SOFCs run with a variety of fuels such as methane containing reformates. It is possible to utilize methane directly in SOFCs, but it can cause degradation of the fuel cells anode. However, irreversible degradation can be prevented, when identifying degradation mechanisms at an early stage by online monitoring tools. We used electrochemical impedance spectroscopy and its advanced tool distribution of relaxation times (DRT) method. The operating conditions were varied in order to determine the relevant system behavior as a response to the corresponding methane utilization processes. The tested electrolyte supported cells have an active area of 81cm2 and are tested under different reforming conditions. The holistic approach of this work combines thermal, electrical, electrochemical measurement methods and gas analysis to show the influence of methane utilization on the DRT spectra.