PT-141 (Bremelanotide) is a synthetic peptide analog of alpha-melanocyte stimulating hormone (α-MSH) that acts on the melanocortin receptors, particularly MC3R and MC4R. Unlike other compounds, PT-141 works through the central nervous system rather than the vascular system. Research has focused on its effects on sexual arousal and function in both male and female subjects. The peptide was derived from Melanotan II but modified to eliminate the tanning effects while preserving melanocortin receptor activity. It represents a unique approach to studying sexual function through melanocortin pathway modulation.