Thermogenic means tending to produce heat and is commonly applied to drugs which increase heat through metabolic stimulation[1] or to microorganisms which create heat within organic waste.
In bodybuilding athletes wishing to lose fat use thermogenic drugs to increase the basal metabolic rate, and thereby increasing the energy expenditure. Caffeine and ephedrine are commonly stacked for this purpose, as they have a synergistic effect on fat loss. Both have effects on fat loss through mechanisms not only related to thermogenic effect, but also enhanced utilization of triglycerides for fuel and suppression of appetite. Dinitrophenol/DNP is a very dangerous thermogenic used for fat loss, it will give a dose-dependant increase in body temperature, to the point where it can induce death by hypertermia. It works as a mitochondrial oxidative phosphorylation uncoupler, disrupting the mitochondrial electron transport chain. This stops the mitochondria from produsing adenosine triphosphate, and instead all the energy is released as heat.