PT-141 is a synthetic peptide derived from melanocortin hormones. It acts as a melanocortin receptor agonist, primarily targeting MC3R and MC4R in the central nervous system. Unlike PDE-5 inhibitors (e.g., Viagra), PT-141 enhances sexual function via neurological pathways rather than directly affecting vascular function. It is administered subcutaneously and is indicated for hypoactive sexual desire disorder (HSDD) and other forms of sexual dysfunction.