Bremelanotide is a melanocortin receptor (MCR) agonist that nonselectively activates several receptor subtypes with the following order of potency: MC1R, MC4R, MC3R, MC5R, MC2R. The mechanism by which VYLEESI improves HSDD in women is unknown. The MC1R is expressed on melanocytes; binding at this receptor leads to melanin expression and increased pigmentation