PT-141 is a central melanocortin peptide studied for sexual desire and erectile response — here is what the trials measured.

The short version

PT-141 is the research name for bremelanotide, a small synthetic peptide that works on the brain rather than on blood flow. It switches on melanocortin MC3R/MC4R receptors (brain switches that influence sexual desire, appetite, and skin pigment) and, through them, nudges the circuits that govern desire and arousal. The US Food and Drug Administration (FDA) approved it in June 2019 for exactly one use: acquired, generalized HSDD (hypoactive sexual desire disorder — persistent low sexual desire that causes real personal distress) in premenopausal women. Every other use — in men, for erectile difficulty, in postmenopausal women — sits outside that approval. This site reads the studies; it sells nothing and recommends nothing.

What the PT-141 literature actually shows

PT-141 has been measured, not just described. In two identical Phase 3 trials known as the RECONNECT program (1,267 premenopausal women with HSDD), bremelanotide 1.75 mg given subcutaneously (injected just under the skin) as needed produced a statistically significant rise in sexual desire and a fall in the distress that low desire causes, against placebo, over 24 weeks ^[3]. The effect was real and it was modest — an integrated FSFI-desire change of +0.35 and an FSDS-DAO item-13 change of -0.33 (the FSFI and FSDS are the standard questionnaires trials use to score sexual desire and the distress it causes) ^[3]. Both coprimary endpoints were met in both trials.

That is the headline, and the honest qualifier rides with it: the benefit is statistically established but clinically small, and independent re-analyses have pressed exactly that point. PT-141's record is unusually well-populated for a peptide of this kind — a 52-week open-label extension ^[4], a mechanistic brain-imaging study ^[5], and the approved prescribing label itself ^[6] all sit in the file. We read each in turn, and we keep the studies behind these findings one click away.

The approval is narrow and worth stating plainly up front, because it is the most misread fact about this molecule. Bremelanotide injection is approved for HSDD in premenopausal women — not for men, not for postmenopausal women, not for sexual "performance." Use outside that window is off-label. See the FDA approval status section for the precise wording.

PT-141 peptide: what the molecule is

The PT-141 peptide is a synthetic cyclic heptapeptide — seven amino acids joined in a closed ring — built as a stable analogue of alpha-MSH (alpha-melanocyte-stimulating hormone), a natural signaling peptide the body makes from a precursor called pro-opiomelanocortin ^[1]. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH, with a lactam bridge closing the ring; that ring is what makes it sturdier than the linear peptides it descends from. It carries a molecular weight of 1025.2 Da, the formula C50H68N14O10, and CAS 189691-06-3.

A point worth keeping straight: "PT-141" and "bremelanotide" are two names for one molecule. PT-141 is the development designation; bremelanotide is the international nonproprietary name (INN) of the approved drug. The finished, approved product is bremelanotide injection. Material sold under the label "PT-141 research chemical" is a laboratory-research compound — it is not the approved finished drug, and nothing about its identity, purity, or concentration is regulated.

How PT-141 works: central melanocortin signaling

PT-141 acts on the brain. It agonizes (switches on) melanocortin MC4R and, secondarily, MC3R receptors concentrated in the central nervous system — chiefly in hypothalamic circuits such as the medial preoptic area, a region tied to sexual motivation ^[1][2]. Stimulating MC4R there is thought to engage dopamine pathways that drive appetitive (desire-led) sexual behavior, rather than the reflexive mechanics of arousal.

This is the line that separates PT-141 from the more familiar erectile drugs. A PDE-5 inhibitor (a class such as sildenafil that acts on the blood vessels of the penis to improve erectile blood flow) works peripherally, on plumbing. PT-141 works centrally, on wanting. In female-rat models a melanocortin agonist selectively increased solicitational behavior without touching general movement — the first agent reported to act on appetitive female sexual behavior ^[2]. In a brain-imaging study of 31 women with HSDD, MC4R agonism raised desire for up to 24 hours and changed how the brain processed erotic cues, strengthening amygdala-insula connectivity ^[5]. The detail lives on the how PT-141 works page, and the PT-141 versus PDE-5 inhibitors contrast is drawn out where the male research sits.

What this notebook is — and is not

This is a reading desk, not a dispensary. We summarize the peer-reviewed literature and the approved label on PT-141, and we keep two layers strictly apart: the cited clinical evidence, and the things people report from outside the trials. The cited layer carries a study number on every quantitative claim. The reported layer — collected on the PT-141 side effects page — is labeled as unverified community observation and is attached to no journal.

The "pharmacy" in the name is a register, not a service. We do not prescribe, compound, fill, or sell. We do not employ clinicians. Dosing decisions belong to a qualified prescriber and to no one reading a web page. From here you can follow PT-141 for men, the PT-141 dosage record as it appears in the trials and label, the PT-141 half-life and pharmacokinetics, or the full reference list.