PT-141 · UK research stock

It is studied for the part central melanocortin receptors play in sexual function. It is an agonist at melanocortin receptors including MC3R and MC4R, which are expressed mainly in the brain, and in rats it activated neurons in the hypothalamus ^[4]. In female rats it selectively increased sexual solicitation without changing lordosis, pacing or general motor activity, reported as the first selective drug effect on appetitive sexual behaviour in that model ^[5]. Early studies in healthy men and in men with erectile dysfunction reported a rapid, dose-dependent increase in erectile activity ^[4].

Unlike most research peptides, it reached a licensed medicine. As Vyleesi, bremelanotide was approved by the US Food and Drug Administration on 21 June 2019 for acquired, generalised hypoactive sexual desire disorder in premenopausal women ^[6]. That approval rests on two identical phase 3 trials, RECONNECT, in 1,267 women over 24 weeks, which reported statistically significant improvements in desire and related distress against placebo ^[7]. Across roughly 3,500 people in the development programme the commonest adverse events were nausea, flushing and headache, with small, transient rises in blood pressure and focal hyperpigmentation that became common with consecutive daily use ^[8].

The approval is a US one and does not extend to the UK. The peptide listed here is a research reagent, not that medicine.