A different mechanism
Unlike erectile-dysfunction drugs that work on blood flow, PT-141 (bremelanotide) is a melanocortin-receptor agonist — it acts on brain pathways involved in sexual desire itself. It's used as-needed, not daily.
The trials
Two large Phase 3 trials — together called RECONNECT, published in Obstetrics & Gynecology in 2019 — enrolled more than 1,200 premenopausal women with hypoactive sexual desire disorder.
Bremelanotide produced statistically significant increases in sexual desire and reductions in the distress around it, versus placebo. On that evidence, the FDA approved it as Vyleesi.
Honest about the size
Two caveats the data is clear on. The average improvement was real but modest, not dramatic. And side effects were common — nausea, flushing and headache, with nausea in roughly 40% of users. It was studied in premenopausal women, not the broader population now using it off-label.
A genuinely FDA-approved peptide with real Phase 3 evidence for desire in women — with a modest effect size and a notable nausea rate. Strong proof it does something; temper expectations on how much.