It is anecdotally said that hot peppers help people in the tropics “cool off.” This theory is consistent with the peripheral vasodilatory effect of capsaicin that has been shown to lower skin temperature in humans exposed to a hot environment. Capsaicin feels hot in the mouth because it activates sensory receptors on the tongue otherwise used to detect thermal heat. This receptor is called Transient Receptor Potential Vanilloid 1 (TRPV1). TRPV1 receptors are also located in the gut and in other organs. Stimulation of TRPV1 receptors is known to bring about activation of the sympathetic nervous system (SNS). Capsaicin has been shown to increase fat burning in humans and animals through stimulation of the SNS.
Like capsaicin, capsinoids activate TRPV1 receptors, although they are not hot in the mouth. Capsinoids cannot reach the TRPV1 oral cavity receptors, located slightly below the surface in the mouth, because of structural differences from capsaicin. On the other hand, both capsaicin and capsinoids activate TRPV1 receptors in the same manner. Research has indicated that the TRPV1 receptors in the gut are important for the metabolic effects of capsaicin and capsinoids.
Both energy metabolism  and body temperature  increases are observed in humans following extracted capsinoids or CH-19 Sweet administration. Animal studies also demonstrate these increases, as well as suppressed in body fat accumulation following capsinoids intake. The exact mechanisms and the relative importance of each remain under investigation, as are the effects of capsinoids on appetite and satiation.