PT-141 (bremelanotide) is an FDA-approved melanocortin agonist studied for sexual desire

The short version

PT-141 is the research name for bremelanotide, a lab-made copy of a natural body signal (the hormone alpha-MSH) that flips brain switches involved in sexual desire. The U.S. FDA approved it in June 2019, but for exactly one thing: acquired, generalized HSDD (hypoactive sexual desire disorder — persistent low sexual desire that causes real personal distress) in premenopausal women, given as a small injection just under the skin ^[3][6]. It works in the brain, not by changing blood flow the way erection pills do. Every other use — in men, for erectile problems, in postmenopausal women — is off-label and still being studied. This page summarizes that published record; it sells nothing and recommends no dose.

PT-141 peptide: a synthetic melanocortin agonist

PT-141 is a synthetic cyclic heptapeptide — a ring of seven amino acids — built as an analogue of alpha-MSH (alpha-melanocyte-stimulating hormone), an endogenous signaling peptide the body cleaves from a larger precursor protein called POMC ^[1]. Its full sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH, with a lactam bridge (a stabilizing chemical clasp) tying two side chains into a ring; that ring makes it sturdier than the linear melanocortin peptides it descends from. It is a close structural relative of melanotan II, with the C-terminal end changed from an amide to a carboxylic acid. The molecule weighs roughly 1025 Da, carries CAS number 189691-06-3, and is catalogued under the INN "bremelanotide." Sold as a finished pharmaceutical it is a regulated drug; sold as a "research chemical" it is laboratory material outside that approval.

What a melanocortin receptor agonist is

A melanocortin receptor agonist is a molecule that switches on the melanocortin receptors — a family of five G-protein-coupled receptors (MC1R through MC5R) that normally respond to alpha-MSH and related peptides. PT-141 chiefly activates the central subtypes MC4R and, secondarily, MC3R ^[1]. These sit in the brain, concentrated in the hypothalamus and limbic system, where they help regulate sexual motivation and appetite. This is the key distinction from PDE-5 inhibitors (the class that includes sildenafil and tadalafil): those act peripherally on vascular smooth muscle to improve erectile blood flow, while a melanocortin agonist acts centrally on the neural circuitry of desire itself. Activation of the peripheral MC1R subtype is the reason repeated dosing can darken skin and gums — a point the PT-141 side effects page returns to.

PT-141 for women: the approved HSDD indication

The single FDA-approved use for PT-141 (bremelanotide) is acquired, generalized HSDD in premenopausal women ^[3][6]. That approval rests on two identical Phase 3 randomized controlled trials — the RECONNECT program — which together enrolled 1,267 premenopausal women with HSDD. Over 24 weeks, bremelanotide 1.75 mg given subcutaneously (injected just under the skin) on an as-needed basis met both coprimary endpoints: it improved sexual desire (integrated FSFI-desire score +0.35 versus placebo, P<.001) and reduced the distress that low desire caused (integrated FSDS-DAO item-13 score −0.33, P<.001) ^[3]. FSFI and FSDS are the standard validated questionnaires trials use to score sexual desire and the distress low desire causes. The effect is statistically real and was sustained in a 52-week extension ^[4] — and, as the PT-141 in the research literature section details, it is also clinically modest, a characterization independent re-analysts have pressed ^[12].

How PT-141 works, in the brain

PT-141 acts on the brain, not on blood vessels. By stimulating MC4R in hypothalamic circuits — notably the medial preoptic area (mPOA), a region central to sexual motivation — it is thought to engage dopaminergic signaling pathways that govern appetitive, desire-driven sexual behavior ^[1]. The preclinical record is consistent with that central mechanism: in rats and nonhuman primates, systemic PT-141 produced erections and lit up hypothalamic neurons (measured as increased c-Fos), and in female rats it selectively increased solicitational, desire-type behaviors without changing reflexive ones ^[1][2]. A 2022 placebo-controlled fMRI study in 31 women with HSDD added direct human mechanistic evidence: MC4R agonism increased sexual desire for up to 24 hours and altered how the brain processed erotic stimuli, enhancing amygdala-insula connectivity ^[5]. Curiosity about the mechanism continues — a 2025 hamster study found the drug did not act on the brain's reward circuit, a nuanced negative finding ^[13].

PT-141 mechanism of action

PT-141's mechanism of action is central MC4R (and secondary MC3R) agonism in hypothalamic and limbic circuits linked to sexual desire ^[1]. By activating MC4R in regions such as the medial preoptic area, it is thought to recruit dopaminergic pathways that drive sexual motivation ^[5]. It does not work through blood flow and does not act on the HPG (reproductive-hormone) axis.

Is PT-141 the same as bremelanotide?

Yes. PT-141 is the research designation for bremelanotide, the international nonproprietary name (INN) of this melanocortin receptor agonist ^[6]. The two names refer to the same molecule; "PT-141" is the development code, "bremelanotide" the official drug name carried on the FDA-approved injection.

Is PT-141 FDA-approved, and is it legal?

PT-141 (bremelanotide) is FDA-approved, but its approval is narrow — and that scope is the most important fact on this site.

Is PT-141 FDA-approved?

Yes, but only for one indication. Bremelanotide injection was approved on June 21, 2019 (NDA 210557) solely for acquired, generalized HSDD in premenopausal women ^[3][6]. Use in men, in postmenopausal women, for erectile dysfunction, or for sexual "performance" is off-label and not covered by that approval. Material sold as "PT-141 research chemical" sits outside the approved finished-drug product, with no regulatory oversight of its identity, purity, or concentration.

Is PT-141 legal in the US?

Bremelanotide is an FDA-approved prescription drug for HSDD in premenopausal women; it is not a U.S. controlled or scheduled substance ^[6]. The "PT-141" research-chemical form is laboratory material only and is not the approved finished drug. For competitive athletes, melanocortin agonists fall under WADA's non-approved-substances framework (S0); anyone affected should consult current WADA guidance directly.

What is PT-141?

PT-141 is the research designation for bremelanotide, a synthetic cyclic heptapeptide analogue of the hormone alpha-MSH that activates central melanocortin MC3R/MC4R receptors ^[1]. Its approval and regulatory status defines what it is cleared to treat.

What is bremelanotide?

Bremelanotide is a synthetic cyclic heptapeptide melanocortin (MC3R/MC4R) agonist; the FDA approved it in June 2019 as a subcutaneous injection for acquired, generalized HSDD in premenopausal women ^[3][6].

What is PT-141 used for?

Its single FDA-approved use is acquired, generalized HSDD in premenopausal women ^[3]. It has also been studied off-label and investigationally for male erectile dysfunction ^[11] and was examined in early female-arousal and metabolic research ^[7].