PT-141 (Bremelanotide): Clinical Evidence, Vyleesi & Melanocortin Receptors

Overview

PT-141 and bremelanotide name, in the literature and on ClinicalTrials.gov, the same development active molecule. Vyleesi is a different category: an approved pharmaceutical product that contains bremelanotide. Peptra sells a research-use-only material labeled PT-141. Those three sentences are not collapsed.

This hub orients evidence. It is not a pharmaceutical product monograph, not human-use guidance, and it does not turn a drug approval into a claim about a laboratory vial.

PT-141 and bremelanotide

PT-141 is the development name. Bremelanotide is the generic name of that same active moiety. Trial registries also use BMT. That name relationship is useful when an older paper says PT-141 and a later paper says bremelanotide.^3,2

FDA labeling describes bremelanotide as a synthetic cyclic heptapeptide: Ac-Nle-cyclo-(Asp-His-D-Phe-Arg-Trp-Lys-OH). The free-base molecular weight is reported as approximately 1025.2. The active-moiety UNII is 6Y24O4F92S. The acetate has a different UNII: PV2WI7495P.^2,3,4

What Vyleesi is

Vyleesi is the approved pharmaceutical product. FDA approved that product, containing bremelanotide, on June 21, 2019, under NDA 210557. The current marketed form is a bremelanotide acetate formulation, not a lyophilized research powder.^1,2

Approval covers the application, the formulation, the manufacturing controls, the route, the delivery system, and the product specifications. It does not automatically extend to a third-party vial labeled PT-141. Active-ingredient evidence is not pharmaceutical-product equivalence.

What is actually approved

The current indication is treatment of premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD), where low sexual desire causes marked distress or interpersonal difficulty and is not due to a co-existing medical or psychiatric condition, relationship problems, or the effects of a medication or other drug.²

That cut-off is the labeled population. A finding inside that cut-off is not turned into a claim about “desire” in general.

What is NOT approved

• Vyleesi is not indicated for postmenopausal women.
• Vyleesi is not indicated for men.
• Vyleesi is not indicated to enhance sexual performance.
• Peptra RUO material is not Vyleesi and does not inherit that indication.

Those limitations belong to the label. They stay visible even though human research in men exists and even though the name PT-141 appears in older papers.²

Evidence map

What the Phase 3 trials showed

The two RECONNECT Phase 3 trials were randomized, double-blind, and placebo-controlled. The randomized total was 1,267 women. The co-primary endpoints measured sexual desire and distress related to low sexual desire. The label reports a statistically significant difference on both.^7,2

The same label states that there was no significant difference versus placebo in the change in the number of satisfying sexual events. That third fact is not omitted. A summary that says “broad improvement in sexual outcomes” without that nuance is a cut.²

Statistical significance is not, by itself, a large clinical effect. A later independent analysis questions magnitude and measurement. That critique does not overturn approval. It distinguishes the primary trial from a later methodological reading.¹⁰

Research in men

Published human research in men exists. The 2004 studies measured pharmacology and erectile response by an intranasal and a subcutaneous route. A 2005 crossover enrolled 19 men. A 2008 trial randomized 342 men. That is published response evidence. It is not an approved indication.^12,13,14,15

Vyleesi is not FDA-indicated for men. It is also not indicated to enhance sexual performance. Those limitations are not erased because older erectile-dysfunction trials exist.²

Melanocortin mechanism

The label describes bremelanotide as a melanocortin receptor agonist. It activates several subtypes. At approved-product exposure, it identifies MC1R and MC4R as particularly relevant. Neurons expressing MC4R are present in multiple central-nervous-system regions.²

MC1R is expressed on melanocytes and is connected with melanin expression. That belongs in the hyperpigmentation context, not in a cosmetic claim. The same label states that the exact mechanism by which Vyleesi improves HSDD is unknown. This hub does not write that PT-141 “switches on desire.”²

Vyleesi versus RUO material

Vyleesi is a finished drug. Peptra material is a research lyophilizate. A lot certificate can report the sample name PT-141 10mg, an HPLC-UV purity, and an intact mass near 1025.19. That can be consistent with the bremelanotide active moiety. It does not demonstrate acetate, finished-product sterility, bioequivalence, or equivalence to Vyleesi.

A “research use only” label does not protect the surrounding context. If content around a peptide demonstrates intended human use, the frame is no longer documentary. That is why this hub and the commercial listing stay separate.¹⁶

What we do not know

• We do not know the exact mechanism by which the approved product improves HSDD.
• We do not know that Phase 3 showed a difference in satisfying sexual events: the label says it did not.
• We do not know that research in men creates an approved indication.
• We do not know that the Peptra vial is bremelanotide acetate or Vyleesi.
• We do not infer a COFEPRIS status from FDA.
• We do not assign a WADA status: the exact name was not identified in the official list reviewed.

Explore Research

• What PT-141 (bremelanotide) is
• MC4R, melanocortin, and what remains unknown
• HSDD trials in women, with all three outcomes
• Research in men, kept separate from the indication
• PT-141 versus Vyleesi
• FDA status, limits, and labeled safety

Analytical Documentation

• PT-141 certificate of analysis archive
• Research-material specifications
• How to read a certificate of analysis
• What distinguishes HPLC from LC-MS