This paper explores the heat generated by the human body and the capabilities of wearable thermoelectric generators in harvesting the thermal energy for practical uses. The wearable thermoelectric generator (WTEG) has shown great potential for use in this field, as such small-scale devices consume little power. While batteries are cheap and reliable sources of power, they have the unavoidable limitation of needing to be changed or charged periodically, WTEGs could significantly cut down the size of the batteries required for many devices and in some cases eliminate them altogether. WTEGs also have the distinct advantage of being solid state and maintenance-free. These factors have also made them lucrative options for implantable biomedical devices, which must have surgical procedures performed to replace batteries or conduct maintenance. From these possibilities, an enormous amount of research has surfaced in a short period of time. When analyzing thermoelectric generators, there are several limitations that have to be examined in order to understand maximum power outputs, maximum temperature differences, and thermal matching. This paper provides an in-depth explanation of heat recovery from the human body, including the thermoelectric capabilities of some thermoelectric materials, as well as the true "wearability" of a TEG for everyday use. (C) 2019 Elsevier Ltd. All rights reserved.