Homeothermy represents a remarkable step in animal evolution, albeit at a very high cost in terms of metabolic demand. The maintenance of core body temperature in mammals represents one of the prominent physiological components contributing to the basal metabolic rate. Homeostatic thermoregulation is coordinated by the central nervous system by means of different strategies, spanning from behavioral modifications, aimed at finding a better environment, to the activation or inhibition of key regulatory mechanisms, that are mainly driven by the autonomic nervous system. The hypothalamic neuropeptide MCH plays a pivotal role in regulating basal metabolism, and the activation of this system results in a slowing down of the metabolic rate, and also stimulates food intake. On the contrary, blocking the MCH system, in animal models, promotes a lean phenotype with higher body temperature. Even though MCH is not involved in thermoregulatory processes, modifying MCH activity induces metabolic rate modifications and thermoregulation is modified accordingly. The activation of the MCH system also leads to the dampening of the normal daily oscillation of body temperature. The well-known involvement of MCH in wake sleep cycle regulation, by stabilizing sleep, and in particular REM sleep, reinforces the hypothesis that the functions of metabolism, thermoregulation, and sleep regulation are closely linked.