Research ledger · Melanocortin agonist
PT-141 is the melanocortin agonist whose recent trials measured a real but modest effect on sexual desire.
A balanced, cited account of bremelanotide: the two Phase 3 trials in 1,267 women, the 2019 FDA approval, the half-life on the label, and the honest qualifications kept in their own ruled lines.
The short version
PT-141 (the lab name for the drug bremelanotide) is a small synthetic peptide that acts on the brain to influence sexual desire. It copies a natural signaling molecule called alpha-MSH (a hormone the body makes), and it switches on receptors called melanocortin receptors (cell switches in the brain that, among other jobs, help regulate sexual motivation and appetite). It does not work on blood flow the way the older erectile-dysfunction pills do — it works in the brain's wiring, not in the plumbing.
In 2019 the FDA approved PT-141, under the name bremelanotide, for one specific use: low sexual desire that causes distress in women who have not yet reached menopause [7]. The trials behind that approval found a real but modest improvement [3]. The most common downside was nausea [4]. Every other use you may read about — men, postmenopausal women, or "performance" — is off-label or research-grade, not an approved use [7]. What people report, including the downsides, is on PT-141 effects.
What is PT-141
PT-141 is a synthetic cyclic heptapeptide (a ring-shaped chain of seven amino acids) and the research-community name for the drug bremelanotide [1]. Its molecular weight is 1025.2 Da and its formula is C50H68N14O10; it carries the CAS number 189691-06-3 and was approved under NDA 210557 [7]. It is a structural relative of an older melanocortin compound, redesigned with a stabilizing ring so it survives longer in the body [1].
The compound is an agonist (an activator) at the melanocortin-3 and melanocortin-4 receptors — MC3R and MC4R — which sit mostly in the central nervous system [1]. That central location is the whole story: it is why PT-141 influences desire through brain circuits rather than through the vascular smooth muscle that erectile-dysfunction tablets target [1]. The most authoritative figures on this page come from the 2019 US prescribing information and the peer-reviewed trial record, both cited on PT-141 references.
What the recent trials measured
The two pivotal Phase 3 trials, run as a matched pair under the program name RECONNECT, enrolled 1,267 premenopausal women with hypoactive sexual desire disorder (HSDD) [3]. Bremelanotide 1.75 mg, given subcutaneously as needed, improved sexual desire on the FSFI-desire scale by an integrated +0.35 (P<.001) and reduced desire-related distress on the FSDS-DAO scale by an integrated −0.33 (P<.001) over 24 weeks, against placebo [3]. Both coprimary endpoints were met in both trials [3].
A 52-week open-label extension in 684 women found the improvement was sustained, with no new safety signals; the most common drug-related effects were nausea (40.4%), flushing (20.6%), and headache (12.0%) [4]. A 2022 mechanistic fMRI study in 31 women added the picture from inside the brain: MC4R activation raised reported desire for up to 24 hours and changed how the brain processed erotic stimuli, including stronger amygdala–insula connectivity [5]. The full quantified record lives on PT-141 results.
The honest qualifications
A balanced ledger carries its debits in plain sight. Independent re-analyses (Spielmans 2021, 2024) argue the measured effects on desire and distress, while statistically significant, are small, and they question how clinically meaningful the outcomes are [11][12]. Nausea is the principal tolerability issue and a real driver of discontinuation [4]. The label warns of transient blood-pressure increases and contraindicates use in uncontrolled hypertension or known cardiovascular disease [7].
The scope of approval matters most. PT-141 is approved only for premenopausal women with HSDD — not for men, not for postmenopausal women, and not to enhance performance [7][9]. A 2024 program to test bremelanotide alongside a PDE-5 inhibitor for male erectile dysfunction is investigational Phase 2, not an approval [8]. And material sold as a "PT-141 research chemical" sits entirely outside the pharmaceutical framework, with no oversight of identity, purity, or concentration [7].
How to read this site
This is an editorial digest, organized as a ledger. The measured human-data findings — the trial figures, the label pharmacokinetics — read as cited entries in the credit column. The qualifications — the small-effect critique, the nausea rate, the blood-pressure warning, the premenopausal-only boundary — read as clearly marked entries in the debit column. Nothing here is a recommendation, and no dose on this page is advice for any individual.
The PT-141 research page covers mechanism and the key studies. PT-141 results collects the quantified outcomes. The dosage page sets out the label's pharmacokinetics in research context. Is PT-141 fda-approved walks the regulatory status in detail, and PT-141 effects covers reported benefits, side effects, and cited safety cautions.