PT-141

PT-141 (Bremelanotide) is a synthetic cyclic heptapeptide derived from Melanotan II through selective modification that enhances selectivity for the melanocortin-4 receptor (MC4R) while reducing melanogenic activity. Unlike phosphodiesterase type 5 (PDE5) inhibitors that act peripherally on vascular smooth muscle, PT-141 acts through central nervous system melanocortin pathways, specifically activating MC4R and MC3R in the hypothalamus and limbic system to modulate sexual arousal pathways. This central mechanism of action makes it effective regardless of peripheral vascular status. PT-141 has undergone extensive clinical evaluation, resulting in FDA approval for hypoactive sexual desire disorder (HSDD). Research applications include detailed studies of melanocortin receptor signaling in the CNS, neuroendocrine modulation of sexual function, MC4R-mediated autonomic nervous system effects, and investigation of the melanocortin system's role in reward circuitry and motivated behavior. The compound's unique mechanism also makes it valuable for studying the neurobiology of desire versus arousal and the intersection of melanocortin and oxytocin signaling.