PT-141 activated melanocortin receptors in the brain and changed the research conversation on sexual desire — 43 trials, 3,500 subjects, one central mechanism.
A clinical-but-approachable reading room for the bremelanotide literature: mechanism, RECONNECT trial data, Phase 2 ED findings, pharmacokinetics, and safety — every claim sourced.
What Is PT-141?
A cyclic heptapeptide melanocortin receptor agonist with a central mechanism unlike any prior approach to sexual dysfunction pharmacology.
PT-141 is a cyclic heptapeptide — seven amino acids arranged in a ring — also known by its international nonproprietary name, bremelanotide. Molecular formula C50H68N14O10, molecular weight 1025.2 Da, CAS 189691-06-3. It is a synthetic analogue of alpha-melanocyte-stimulating hormone (alpha-MSH), derived from melanotan II by removal of the C-terminal amide.
PT-141 is not a vascular drug. It does not act on smooth muscle or change blood flow directly. Instead, it binds to melanocortin receptors — primarily MC3R and MC4R — in the hypothalamus and limbic system, activating central neural pathways associated with sexual desire and arousal. That central mechanism is what distinguishes it from every prior approach to sexual dysfunction pharmacology.
Bremelanotide (the approved pharmaceutical form) received FDA approval in June 2019 under the trade name Vyleesi for the treatment of hypoactive sexual desire disorder (HSDD) in premenopausal women. The approval was based on two identically designed Phase 3 randomized controlled trials, the RECONNECT program, in which bremelanotide at 1.75 mg subcutaneous demonstrated statistically significant improvements in desire scores and sexual distress measures versus placebo [5] [6].
This site covers the published research on PT-141 and bremelanotide: the mechanism, the clinical trial record, the pharmacokinetics, the side-effect profile, and the open questions. It does not sell, recommend, or prescribe.
PT-141: A Synthetic Melanocortin Peptide
Central MC4R agonism — not vascular smooth muscle — is what makes PT-141 structurally distinct from every prior sexual-dysfunction compound.
What sets PT-141 apart from earlier sexual-dysfunction compounds is its point of action: the brain, not the genitals. Sildenafil and related PDE-5 inhibitors act peripherally — they prevent the breakdown of cyclic GMP in vascular smooth muscle, increasing blood flow to erectile tissue. PT-141 acts upstream. It targets MC4R in the medial preoptic area (mPOA) of the hypothalamus, a region critical for sexual motivation in both males and females, and enhances presynaptic dopamine release [10] [15].
The result is a compound that addresses desire initiation — not just the vascular mechanics of sexual response. In rat models, peripheral or direct mPOA infusion of bremelanotide selectively increased solicitation (appetitive) sexual behaviors without affecting consummatory behaviors or locomotion [10]. In human neuroimaging at 1.75 mg SC, bremelanotide enhanced cerebellar and supplementary motor area activity during erotic stimulus processing, reduced secondary somatosensory cortex activity, and enhanced amygdala-insula functional connectivity — consistent with top-down inhibition theory of HSDD pathophysiology [17].
PT-141's cyclic structure confers greater metabolic stability than linear melanocortin peptides. It binds MC4R with high affinity but is non-selective — it also activates MC3R (secondary pathway) and at higher doses MC1R, the receptor governing melanogenesis, which underlies the hyperpigmentation adverse event seen at high-frequency dosing [9].
What Does PT-141 Do?
PT-141 (bremelanotide) is a synthetic analogue of alpha-MSH that acts as an agonist at MC3R and MC4R receptors in the central nervous system, activating neural pathways associated with sexual arousal and desire. The evidence base now spans 43 clinical studies across approximately 3,500 subjects [9].
In premenopausal women with HSDD, the RECONNECT Phase 3 program demonstrated statistically significant increases in satisfying sexual events per month and reductions in sexual distress scores (FSDS-DAO) versus placebo, with response rates approximately 58% bremelanotide versus 36% placebo [5]. A 52-week open-label extension showed sustained efficacy with no new safety signals through 76 weeks of total exposure [14].
In men, Phase 2 trials showed PT-141 produced dose-dependent erectile responses in healthy subjects and in men who did not respond adequately to sildenafil, at intranasal doses above 7 mg and at subcutaneous doses of 4–6 mg [1] [2]. The male indication has not progressed to Phase 3; it is not FDA-approved for this use.
PT-141 Regulatory Status
Bremelanotide received FDA approval on June 21, 2019 (NDA 210557) as Vyleesi — a 1.75 mg SC auto-injector for treatment of acquired, generalized HSDD in premenopausal women. The FDA-labeled dose is one 1.75 mg subcutaneous injection administered at least 45 minutes before anticipated sexual activity, with a maximum of one dose per 24 hours and eight doses per month [6].
The drug is contraindicated in subjects with uncontrolled hypertension or known cardiovascular disease, due to transient blood pressure effects documented in the clinical program [8]. Post-menopausal women and men are not approved populations.
PT-141 as a research compound (outside the pharmaceutical approval framework) is a separate regulatory category. This site covers the published research literature only and does not address that regulatory context.
Availability and Regulatory Status of PT-141
Bremelanotide as Vyleesi requires a prescription in the United States. The approved indication is specifically HSDD in premenopausal women; the prescription is based on diagnosis and clinical evaluation. PT-141 as a research chemical is handled under different regulatory frameworks. This site covers published research only and does not address sourcing, prescribing, or supply.
What Is PT-141 Used for in Research?
Research has focused on two primary areas: (1) sexual desire disorders in both sexes — particularly HSDD in premenopausal women (the approved indication) and erectile dysfunction in men (Phase 2 data, not approved) — and (2) the central melanocortin signaling pathway as a pharmacological target for CNS-mediated arousal and desire. A secondary research area, emerging from Phase 1 data, is the compound's effect on caloric intake and body weight via the same MC4R satiety circuits [19]. The overlap between the sexual-desire and metabolic pathways at MC4R is an active area of mechanistic research [18].
For a complete indexed summary of the trial record, see the PT-141 research page. For dosing data from published studies, see the PT-141 dosage page. For the adverse-event profile, see PT-141 side effects.