In this paper, we studied the potential of thermoelectric generation from human body heat. The main objective is to maximize the thermoelectric productivity while minimizing the volume of the generator incorporating or not a heat sink, with a view to charging an accumulator which itself supplies a consumer electronic device such as a communicating sensor. The sizing of such a device should be done with a system-level approach where the thermal coupling with the environment, and the electrical coupling with the DC-DC converter (including losses) are taken into account. The advantage of such an approach is presented in this article. The dual thermal and electrical matching that maximize energy harvesting will also be studied.