PT-141 (Bremelanotide)

Updated June 29, 2026

PT-141, chemically known as bremelanotide, is a cyclic heptapeptide melanocortin receptor agonist. It was originally derived from Melanotan II — a tanning peptide — after researchers noticed that subjects in tanning trials experienced spontaneous erections. Unlike sildenafil (Viagra) and other PDE5 inhibitors that work peripherally by increasing blood flow to genital tissue, PT-141 acts centrally in the brain, primarily activating melanocortin receptor subtypes MC3R and MC4R in the hypothalamus and limbic system. This central mechanism produces genuine desire and arousal rather than mechanical vasodilation, making it effective in cases where psychological or central factors underlie sexual dysfunction.

PT-141 received FDA approval in 2019 under the brand name Vyleesi for the treatment of hypoactive sexual desire disorder (HSDD) in premenopausal women — a condition characterised by low sexual desire causing personal distress. The pivotal clinical trials showed significant improvements in satisfying sexual events, desire scores, and distress measures compared to placebo. This approval is notable as it was the first pharmacological treatment approved for HSDD in premenopausal women and specifically for central (desire-based) rather than peripheral (arousal-based) dysfunction.

In men, PT-141 has been studied for erectile dysfunction not responding to PDE5 inhibitors, with phase II clinical trials showing dose-dependent improvements in erectile function. The central mechanism means it can work where PDE5 inhibitors fail — in cases with neurological or psychological components, or simply where genuine desire is the missing element. Off-label use in healthy individuals typically targets enhanced desire and arousal rather than treatment of dysfunction.

The onset is slower than PDE5 inhibitors — effects typically begin 30 to 90 minutes after administration and last 6 to 12 hours. Administration is subcutaneous injection (research use) or nasal spray (the approved Vyleesi formulation). Common side effects include transient nausea (the most frequent, occurring in roughly 40 percent of users), flushing, and a modest transient increase in blood pressure. Nausea is dose-dependent and manageable with antiemetics or by reducing dose. Blood pressure elevation of 6 to 8 mmHg typically resolves within 12 hours.

The approved dose in the Vyleesi formulation is 1.75 mg subcutaneously. Research protocols typically use 0.5 to 2 mg. It is contraindicated in people with cardiovascular disease due to the blood pressure effect, and should not be used more than once every 24 hours. This is general information, not medical advice — medical supervision is appropriate for any use of PT-141.