What Is PT-141 (Bremelanotide)?

Short definition

PT-141 is the development name of a synthetic cyclic heptapeptide. The generic name of that same active molecule is bremelanotide. ClinicalTrials.gov also lists BMT and PT-141 as names for bremelanotide. That naming relationship describes a research object. It does not describe a finished drug.^3,1

This page answers “what is it” in scientific and regulatory nomenclature. It does not independently verify the contents of a Peptra commercial vial. It is not human-use guidance and it does not turn a drug approval into a claim about a research material.

Structure, at a high level

The peptide contains seven residues in a cyclic structure. A bridge between aspartic acid and lysine closes the ring. The amino terminus is acetylated and the carboxyl terminus is a free acid. That is a chemical-identity description. It is not a laboratory recipe and not a reconstitution instruction.¹

Current labeling reports the free-base molecular weight as approximately 1025.2. The active-moiety UNII is 6Y24O4F92S. Bremelanotide acetate has a different UNII: PV2WI7495P. Two identity records are not two separate approvals, but they are two forms that should not be casually collapsed.^1,3,4

Melanocortin receptor agonism

The label describes bremelanotide as a melanocortin receptor agonist. It activates several subtypes. At approved-product exposure, FDA identifies MC1R and MC4R as particularly relevant. MC4R-expressing neurons are present across multiple central-nervous-system regions.¹

The same label states that the exact mechanism by which Vyleesi improves HSDD is unknown. This page does not say that PT-141 “switches on desire,” and it does not claim a fully closed central pathway.¹

Development history

Early literature used the code PT-141 in human pharmacology, including research in men with erectile-response measures. Later, the HSDD clinical program and the approved product used the generic name bremelanotide. The name change does not erase those studies. It also does not turn them into the current indication.^7,5

On June 21, 2019, FDA approved the drug product Vyleesi, containing bremelanotide, under NDA 210557. That date approves a product. It does not approve “PT-141 for all uses.”²

What Vyleesi is

Vyleesi is the approved pharmaceutical product. Current labeling describes it as bremelanotide injection for subcutaneous use. The marketed form is a bremelanotide acetate formulation, sterile, in an autoinjector. That is a finished drug, with manufacturing controls and a written indication.¹

A lyophilized research vial labeled PT-141 does not inherit that formulation, that pharmaceutical sterility, or that indication. Active-ingredient evidence is not product equivalence.

Approved versus investigated uses

The approved indication is treatment of premenopausal women with acquired, generalized HSDD, when 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 drug.¹

Vyleesi is not indicated in postmenopausal women, is not indicated in men, and is not indicated to enhance sexual performance. Those limitations belong to the label. They are not erased because human research in men exists.^1,8

Current evidence map

There is a Phase 2 dose-finding trial in premenopausal women and two randomized Phase 3 trials (RECONNECT). Those trials measured desire and distress as co-primary endpoints. The number of satisfying sexual events, a secondary endpoint, did not show a significant difference versus placebo.^6,5,1

In men there is early human pharmacology and a randomized trial of 342 participants. That is published research. It is not an approved indication.^7,8

The Peptra-material distinction

Peptra sells a research-use-only material. A lot certificate can report a sample name, a chromatographic purity, and a mass comparison. That does not show that the vial is bremelanotide acetate, or Vyleesi, or a sterile pharmaceutical injectable.

The current certificate for the 10 mg presentation names the sample PT-141 10mg. It reports HPLC-UV and intact-mass identification. It prints the cyclic sequence and a CAS. HPLC is not a sequence determination. A mass near 1025.19 can be consistent with the bremelanotide active moiety. Consistent is not equivalent. Salt, formulation, finished-product sterility, and bioequivalence are not inferred.

That distinction matters because the literature and the label speak of a development object and a medicine. The catalog speaks of a lyophilizate. Mixing those voices produces the false sentence that “PT-141 is approved.” What was approved is Vyleesi, for a concrete indication. The rest remains research, historical pharmacology, or analytical documentation.^2,1

A reader who arrives with the question “what is it” needs three anchors: the development name, the generic name, and the approved product. That reader also needs to see what does not enter the definition: an indication in men, a performance promise, a laboratory vial turned into a medicine, and a mechanism already closed. Those exclusions are not an appendix. They are part of the definition.

The name history helps when reading older papers. A 2004 article may say PT-141. A 2019 trial may say bremelanotide. A pharmacy label may say Vyleesi. Three labels, two substance objects, and one product. If they fuse, the reader believes a lyophilizate inherits an indication. This page exists so that fusion does not happen in the first paragraph.^7,5,1

Next reading

• Compare PT-141, bremelanotide, and Vyleesi
• See the HSDD trials in women
• See the research in men
• Back to the research hub
• Certificate of analysis archive
• Research-material specifications