Bremelanotide · Vyleesi · Melanocortin Receptor Agonist
A synthetic melanocortin receptor agonist and the first FDA-approved treatment for hypoactive sexual desire disorder (HSDD) in premenopausal women. PT-141 acts directly on the central nervous system through melanocortin receptors to increase sexual desire — a fundamentally different mechanism to PDE5 inhibitors (Viagra) which work peripherally on blood flow.
PT-141 (bremelanotide, brand name Vyleesi) is a cyclic heptapeptide analogue of alpha-melanocyte stimulating hormone (α-MSH) that acts as a non-selective agonist of melanocortin receptors MC1R, MC3R and MC4R. It received FDA approval in 2019 for the treatment of hypoactive sexual desire disorder (HSDD) in premenopausal women — making it the first centrally-acting sexual dysfunction treatment approved for women.
The key distinction between PT-141 and conventional sexual dysfunction treatments (PDE5 inhibitors like sildenafil) is the mechanism. PDE5 inhibitors work peripherally — they increase blood flow to genital tissue but do not address desire or libido at the neurological level. PT-141 acts centrally through MC4R receptors in the hypothalamus and limbic system — directly activating the neural pathways associated with sexual desire, arousal and motivation. This central mechanism makes it effective for both desire and arousal across sexes.
While FDA-approved only for women, PT-141 has been extensively studied and used in men. Research has demonstrated significant improvements in erectile function including in men who did not respond to PDE5 inhibitors — suggesting complementary mechanisms. The central desire-enhancing effect is relevant regardless of sex, and PT-141 is commonly used by men seeking both the central desire effects and the peripheral arousal enhancement that results from the CNS activation.
The most common side effect is nausea, occurring in approximately 40% of users — typically mild to moderate and resolving within 2-4 hours. Transient increases in blood pressure have been documented, making PT-141 contraindicated in individuals with cardiovascular disease. Facial flushing is also common. Pre-treatment with an antiemetic (e.g. ondansetron) significantly reduces nausea.