PT-141

PT-141 (bremelanotide) is a cyclic heptapeptide melanocortin receptor agonist structurally derived from MT-II. Its pharmacology centers on MC4R activation in the CNS — particularly the hypothalamus and limbic system — which are involved in regulating sexual motivation and arousal through mechanisms distinct from peripheral vasodilatory compounds. This central mechanism has made PT-141 of interest in research on both male and female sexual dysfunction.

Unlike PDE5 inhibitors that enhance vascular response, PT-141 acts centrally on arousal pathways — a mechanism relevant in cases where desire rather than vascular response is the limiting factor. Research in animal models has documented dose-dependent effects on sexual behavior measures, with both male and female subjects showing changes consistent with centrally-mediated arousal pathway activation.

PT-141's clinical development resulted in FDA approval of bremelanotide (Vyleesi) for hypoactive sexual desire disorder in premenopausal women in 2019 — providing a substantial human clinical dataset that researchers can reference alongside preclinical work. Research applications include melanocortin system pharmacology, sexual behavior models, MC4R pathway studies, and comparative pharmacology with MT-II and α-MSH analogues.