Abstract: Melanocortin-4 receptor(MC4R) is a G-protein-coupled receptor involved in central regulation, which mainly exists in cortex, thalamus, hypothalamus and brain stem. Activation of MC4R can produce a variety of physiological functions, so the recent discovery of exogenous MC4R agonists RM-493, RO27-3225 and PT-141 as well as their physiological functions and research progress are reviewed in this paper to reference evidence for future clinical use.