PT-141 Research Guidebremelanotide · C-terminal acid · not Melanotan II · not Vyleesi

PT-141 is the research code for bremelanotide, a synthetic cyclic lactam heptapeptide analogue of alpha-MSH with the opened PubChem condensed sequence Ac-Nle-Asp(1)-His-D-Phe-Arg-Trp-Lys(1)-OH (CID 9941379; CAS 189691-06-3; UNII 6Y24O4F92S; IUPHAR ligand 10408; INN 8737 bremelanotide). It is a non-selective melanocortin agonist (opened IUPHAR: agonist at human MC1, MC3, MC4, and MC5). A different, regulated product — Vyleesi (bremelanotide injection; NDA 210557; FDA 21 June 2019) — exists as a prescription autoinjector solution. The SRP 10 mg lyophilized vial is research-use-only and is not that approved drug product. It is not Melanotan II, not afamelanotide / Scenesse / Melanotan I, not alpha-MSH, and not KPV. Human efficacy of a research-market 10 mg vial is not established. Research use only. Not medical advice. Not for human use.
CID 9941379
CAS 189691-06-3
UNII 6Y24O4F92S
IUPHAR 10408
INN bremelanotide
Not Melanotan II
Not Vyleesi
Research use only
Educational information only. This page describes an investigational laboratory research peptide. It is not medical advice. Simple Research Peptides (SRP) materials are for laboratory research only and are not for human or veterinary use, consumption, administration, diagnosis, treatment, or therapeutic application. No human dosing, reconstitution, or administration protocol appears on this page. The opened SRP listing is a 10 mg lyophilized research vial (Research Compounds). Sequence, CAS, UNII, CID, C-terminus, salt, and a public COA were not printed on the fetched SRP page. Vyleesi / NDA 210557 is a different finished drug (autoinjector solution), not this vial. Historical IN exposures and autoinjector-product conditions are study / label facts, not instructions.
Sequence and chemical identity (opened registries only)
SRP product and index pages do not print CAS, UNII, PubChem CID, molecular formula, sequence, termini, salt stoichiometry, or a public COA. Identity below is taken only from opened public registries and from primary papers that name PT-141 / bremelanotide.
Opened SRP product page (16 August 2026): title “PT-141 10 mg Melanocortin Research Peptide Vial”. Subhead: “PT-141 (10 mg / 3 mL Vial).” Also Known As: Bremelanotide, PT-141 Acetate. Bullets: 10 mg lyophilized research compound in a 3 mL research vial; COA available for batch verification; Made in the USA; high-purity research material; intended for qualified laboratory and analytical research; securely packaged; For Research Use Only. Not for human or veterinary use. Description: supplied for controlled laboratory evaluation of PT-141 within Research Compounds studies. Research material: PT-141. Listed strength: 10 mg Vial. Research category: Research Compounds. Footer: for laboratory research only; not for human or animal use, consumption, administration, diagnosis, treatment, or therapeutic application. Price printed $60.00. Availability: “5 in stock (can be backordered).” Shipping-box fields: Weight 1 lbs; Dimensions 1 × .5 × 2 in. Reviews (0). Price, stock, and shipping-box fields are vendor listings, not chemistry.
Not printed on the opened product page and therefore not claimed as SRP-verified: cyclic sequence; free-base vs acetate salt stoichiometry; CAS; UNII; CID; a public COA file; a published 10 mg laboratory dose.
Opened SRP index card (compound-research-guides, 16 August 2026): “PT-141 (10 mg Vial)” under Other; tag Evidence profile (not “Dedicated evidence guide”); evidence tier Human clinical evidence; regulated analogue context. Overview: “PT-141 is bremelanotide, a cyclic melanocortin-receptor agonist developed from melanocortin peptide research.” Mechanism: acts centrally through melanocortin receptors involved in sexual response; mechanism differs from vasodilator drugs. Evidence: a regulated prescription bremelanotide product has clinical-trial and labeling evidence for a specific indication; that evidence does not establish equivalence of an unapproved research vial. Quality note: check the current FDA label for the regulated product and distinguish it from research material in formulation, manufacturing, and oversight. Last editorial review printed on that index: August 2026.
Opened dedicated-guide URL http://simpleresearchpeptides.com/research-compound-directory/pt-141-research-guide/ returned HTTP 404 on 16 August 2026. This page is written for that missing standalone listing.
| Identifier | Value on opened page | Source opened |
|---|---|---|
| Common / research names | Bremelanotide; PT-141; PT 141; PT141; PT-141 FREE BASE; Vyleesi (TN) on PubChem synonyms | PubChem CID 9941379; IUPHAR ligand 10408; NCATS UNII 6Y24O4F92S |
| INN / USAN | bremelanotide; INN number 8737 | IUPHAR HTML + /services/ligands/10408; NCATS |
| Peptide class | Cyclic lactam heptapeptide analogue of alpha-MSH; C-terminal carboxylic acid | PubChem biologic; DailyMed description; King 2007 PMID 17584130 |
| IUPAC condensed / HELM | Ac-Nle-Asp(1)-His-D-Phe-Arg-Trp-Lys(1)-OH; sequence XDHFRWK; HELM PEPTIDE1{[ac].[Nle].D.H.[dF].R.W.K}$PEPTIDE1,PEPTIDE1,3:R3-8:R3$$$ | PubChem CID 9941379 biologic description |
| DailyMed printed structure | Ac-Nle-cyclo-(Asp-His-D-Phe-Arg-Trp-Lys-OH) · xCH3COOH (approved-product acetate) | DailyMed VYLEESI label, opened 16 August 2026 |
| PubChem CID | 9941379. Title: Bremelanotide. Create 2006-10-25; Modify 2026-08-15 | PubChem HTML + PUG REST |
| CAS (free base) | 189691-06-3 (ChemIDplus; DrugBank; EPA DSSTox; GSRS; WHO INN on IUPHAR) | PubChem; IUPHAR; ChEBI; NCATS |
| UNII (free base / active moiety) | 6Y24O4F92S | PubChem; NCATS; DailyMed active moiety |
| Formula / MW (free base) | C50H68N14O10; 1025.2 g/mol (PubChem computed). NCATS structure mwt 1025.1647. ChEBI average mass 1025.182 | PubChem PUG; NCATS; ChEBI |
| Exact / monoisotopic mass | 1024.52428442 Da | PubChem PUG; ChEBI monoisotopic 1024.52428 |
| InChIKey (free base) | FFHBJDQSGDNCIV-MFVUMRCOSA-N | PubChem PUG; IUPHAR; NCATS; ChEBI |
| Defined stereocenters | 7 defined / 0 undefined | PubChem; NCATS 7/7 |
| IUPAC (computed) | (3S,6S,9R,12S,15S,23S)-15-[[(2S)-2-acetamidohexanoyl]amino]-9-benzyl-6-[3-(diaminomethylideneamino)propyl]-12-(1H-imidazol-5-ylmethyl)-3-(1H-indol-3-ylmethyl)-2,5,8,11,14,17-hexaoxo-1,4,7,10,13,18-hexazacyclotricosane-23-carboxylic acid | PubChem; IUPHAR; ChEBI |
| ChEBI | CHEBI:177849; bremelanotide; is a oligopeptide; CAS 189691-06-3 | ChEBI HTML, opened 16 August 2026 |
| ChEMBL | CHEMBL2070241 | PubChem; IUPHAR |
| EPA DSSTox | DTXSID40893711 | PubChem; NCATS |
| DrugBank | DB11653 | PubChem; IUPHAR; NCATS |
| KEGG / ATC | D06569 / G02CX05 Bremelanotide | PubChem; ChEBI; WHO ATC on that page |
| IUPHAR / GtoPdb | Ligand 10408; name bremelanotide; type Peptide; approved: true; approvalSource FDA (2019); INN bremelanotide | IUPHAR HTML + /services/ligands/10408 |
| MeSH / Wikidata / NCI / RxCUI | bremelanotide; MeSH Unique ID M0500526; Wikidata Q415353; NCI Thesaurus C77009; RxCUI (free base) 2176312 | PubChem; NCATS |
| Acetate salt (approved-product substance; not automatically the SRP lot) | UNII PV2WI7495P; CAS 1607799-13-2; formula C50H68N14O10·C2H4O2; NCATS MW 1085.2147; InChIKey MAYUSRUHXFWITM-GBRHMYBBSA-N; Orange Book / USAN “BREMELANOTIDE ACETATE” | NCATS drugs.ncats.io/drug/PV2WI7495P; openFDA substance_name BREMELANOTIDE ACETATE; DailyMed |
| ClinicalTrials.gov (bremelanotide as intervention) | query.intr=bremelanotide: totalCount 10 (versionHolder 2026-08-14). All 10 IDs listed in section 04. |
CT.gov API v2 |
| openFDA Drugs@FDA | openfda.generic_name:bremelanotide: 1 result. NDA 210557; brand VYLEESI; sponsor COSETTE; ORIG approved 20190621; Type 1 NME; route SUBCUTANEOUS; product_type HUMAN PRESCRIPTION DRUG |
openFDA API, last_updated 2026-08-14 |
| FDA-approved bremelanotide drug product | Vyleesi (bremelanotide injection), NDA 210557, initial U.S. approval 2019. Cosette packager on opened DailyMed. Not this vial. | openFDA; DailyMed; IUPHAR approved true |
| SRP standalone listing | “PT-141 10 mg Melanocortin Research Peptide Vial”; $60.00; Research Compounds; 10 mg lyophilized; Also Known As Bremelanotide, PT-141 Acetate | SRP product page |
| Adjacent SRP listing (different SKU) | “Melanotan II (10 mg Vial)”; $30.00. Different molecule (C-terminal amide). | SRP Melanotan II product page (prior locked MT-II pass; distinction restated here) |
Critical identity point. CID 9941379 / UNII 6Y24O4F92S is the C-terminal carboxylic acid cyclic lactam. Melanotan II (CID 92432; InChIKey JDKLPDJLXHXHNV-MFVUMRCOSA-N) is the C-terminal carboxamide of the same ring. King 2007 (PMID 17584130; PMC 2694735 opened abstract): “PT-141, which is the carboxylate derivative of MT-II.” Formula C50H68N14O10 vs C50H69N15O9. InChIKeys share the stereo suffix MFVUMRCOSA-N but have different first blocks. An SRP “PT-141 10 mg” lot is not automatically the acetate salt, not Melanotan II, not Vyleesi, and not afamelanotide. Confirm sequence, C-terminus (acid vs amide), stereochemistry (D-Phe), lactam closure, and salt on a COA / LC-MS.
Registry chaos that must not be collapsed.
- SRP prints “Also Known As: Bremelanotide, PT-141 Acetate.” That vendor string is not a COA. PubChem depositor synonym “PT-141 FREE BASE” sits on CID 9941379. NCATS acetate UNII PV2WI7495P / CAS 1607799-13-2 is the approved-product salt record. Neither string proves the SRP lot counter-ion or acetate stoichiometry (DailyMed: 1 ≤ x ≤ 2 acetic acid on the approved product).
- openFDA
uniion the Vyleesi NDA record prints PV2WI7495P (acetate). DailyMed active moiety is 6Y24O4F92S (free base). Both are real. Do not assign the acetate UNII to the free-base CID, or the free-base UNII to the salt. - IUPHAR ligand 10408 is bremelanotide (approved: true). Ligand 1323 is MT-II (approved: false; INN empty). Ligand 1324 is afamelanotide (EMA 2014 / FDA 2019). Ligand 1320 is alpha-MSH (approved: false). Those are four different records.
- Vyleesi approval does not convert a research-market lyophilized vial into NDA 210557.
How PT-141 / bremelanotide is not Melanotan II, not afamelanotide / Scenesse, not alpha-MSH, and not KPV
Catalog “melanocortin research” language does not convert a research cyclic heptapeptide into Vyleesi, Scenesse, Melanotan II, endogenous alpha-MSH, or the KPV tripeptide.
| Identity | What opened sources actually describe | Peptide? | Typical literature role |
|---|---|---|---|
| PT-141 / bremelanotide (this page) | Cyclic lactam heptapeptide, C-terminal acid; CID 9941379; CAS 189691-06-3; UNII 6Y24O4F92S; IUPHAR 10408; INN 8737; C50H68N14O10; MW 1025.2; InChIKey FFHBJDQSGDNCIV-MFVUMRCOSA-N; approved: true (FDA 2019) for a different product | Yes (cyclic heptapeptide, C-acid) | Melanocortin-agonist research ligand. Approved-drug development program exists as Vyleesi. Not this vial. |
| Vyleesi (regulated product; not this SKU) | Bremelanotide injection; NDA 210557; DailyMed: HUMAN PRESCRIPTION DRUG; Cosette; single-dose autoinjector solution (not a 10 mg lyophilized vial); initial U.S. approval 2019 | Same peptide moiety in a formulated drug product | Labeled indication on DailyMed for a specific premenopausal HSDD population, with listed limitations of use. Not the SRP vial. |
| Melanotan II (MT-II) | Cyclic lactam heptapeptide, C-terminal amide; CID 92432; CAS 121062-08-6; UNII UPF5CJ93X7; IUPHAR 1323; C50H69N15O9; MW 1024.2; InChIKey JDKLPDJLXHXHNV-MFVUMRCOSA-N; approved: false | Yes (cyclic heptapeptide, C-amide) | Non-selective MC research ligand. Not an approved drug. Separate SRP 10 mg SKU. |
| alpha-MSH | Endogenous tridecapeptide; IUPHAR ligand 1320; approved: false; INN empty | Yes (13 aa, linear) | Principal endogenous melanocortin peptide. Not PT-141. |
| Melanotan I / NDP-MSH / afamelanotide / Scenesse | Linear [Nle4, D-Phe7]-alpha-MSH. Sawyer 1980 PMID 6777774. IUPHAR 1324; INN afamelanotide; CID 16197727; C78H111N21O19; MW 1646.8; InChIKey UAHFGYDRQSXQEB-LEBBXHLNSA-N; EMA 2014 / FDA 2019 | Yes (13 aa, linear) | Approved alpha-MSH analogue implant in a regulated product for a limited indication. Not this vial. |
| KPV | C-terminal tripeptide of alpha-MSH: Lys-Pro-Val. Opened SRP index: “KPV is the C-terminal tripeptide Lys-Pro-Val derived from alpha-melanocyte-stimulating hormone and studied for anti-inflammatory activity.” Preclinical evidence tag. | Yes (tripeptide) | Preclinical anti-inflammatory fragment literature. Not PT-141. Different SRP 10 mg SKU. |
The standalone vial is not Melanotan II. One atom-level difference: MT-II is the 23-carboxamide; bremelanotide is the 23-carboxylic acid (IUPHAR IUPAC; PubChem condensed -OH vs -NH2). King 2007 (PMID 17584130) and Hadley and Dorr 2006 (PMID 16412534) describe PT-141 as the Palatin carboxylate analogue that entered human sexual-dysfunction development after MT-II. IUPHAR ligand 1323 is approved: false. The opened SRP Melanotan II 10 mg page is a different SKU.
The standalone vial is not Vyleesi. Vyleesi is NDA 210557, a sterile glycerin/water autoinjector solution (DailyMed). The SRP listing is a 10 mg lyophilized research vial with an RUO footer. Formulation, manufacturing, fill, and oversight are not the same. Opened SRP index: regulated-product evidence “does not establish equivalence of an unapproved research vial.”
The standalone vial is not Melanotan I / afamelanotide / Scenesse. Sawyer 1980 (PMID 6777774) made linear [Nle4, D-Phe7]-alpha-MSH. That linear 13-mer is IUPHAR ligand 1324 (afamelanotide; Scenesse; EMA 2014 / FDA 2019). Different sequence length, formula, and InChIKey.
The standalone vial is not alpha-MSH. The parent hormone is the 13-residue linear peptide (IUPHAR 1320). PT-141 is a truncated, Nle4 / D-Phe7, Asp–Lys lactam, C-terminal acid analogue.
The standalone vial is not KPV. KPV is three residues (Lys-Pro-Val) at the C-terminus of alpha-MSH. PT-141 is a cyclic 4–10 fragment analogue. The opened SRP KPV index card is a Recovery / Inflammation Preclinical evidence entry. Do not cite KPV colitis or keratinocyte papers as PT-141 evidence.
Do not equate this vial with alpha-MSH, ACTH, Melanotan I, afamelanotide / Scenesse, Melanotan II, KPV, or the Vyleesi autoinjector. Research use only.
Proposed mechanism (labeled as such)
Opened primary papers and the opened DailyMed label support a non-selective cyclic melanocortin-agonist working model. It is not a treatment claim for this vial. It was not generated with an SRP 10 mg vial. Observed means a measurement in an opened paper or opened label. Proposed means a hypothesis. Not shown means the opened sources did not establish it for a research-market lot.
Al-Obeidi 1989 parent chemistry
Al-Obeidi, Castrucci, Hadley and Hruby 1989 (PMID 2555512; J Med Chem) designed cyclic lactam alpha-MSH4-13 and alpha-MSH4-10 analogues, including Ac-[Nle4,Asp5,D-Phe7,Lys10]-alpha-MSH4-10-NH2 — the amide parent of Melanotan II. PT-141 is the later C-terminal acid of that ring (King 2007). This 1989 paper is amphibian / reptile melanocyte-assay chemistry. Not a human trial. Not Vyleesi. Not this vial.
Human MC1 / MC3 / MC4 / MC5 agonist
Opened IUPHAR /services/ligands/10408/interactions lists bremelanotide as an Agonist (selectivity “Not Determined”) at human:
- MC1: pKi 8.2 (Ki 6.4×10−9); PMID 22335602
- MC3: pKi 7.3 (Ki 5.3×10−8); PMID 22335602
- MC4: pKi 9.6 (Ki 2.5×10−10); PMID 22335602, PMID 31599840
- MC5: pKi 7.8 (Ki 1.7×10−8); PMID 22335602
Assay on those rows: inhibition of 125I-NDP-αMSH binding to membranes from BHK570 cells stably expressing the human receptor (Conde-Frieboes et al. 2012, PMID 22335602). That paper is an MC4-selective analogue chemistry paper that tabulates bremelanotide affinities; it is not a Vyleesi trial and not this vial.
Label language, not this SKU
Opened DailyMed section 12.1: bremelanotide “nonselectively activates several receptor subtypes with the following order of potency: MC1R, MC4R, MC3R, MC5R, MC2R.” At therapeutic dose levels of the approved product, binding to MC1R and MC4R is described as most relevant. “The mechanism by which VYLEESI improves HSDD in women is unknown.” MC1R on melanocytes is linked to melanin expression / pigmentation. That is label language for Vyleesi, not a mechanism proof for an SRP lot.
King 2007 / Hadley 2006
King, Yeh, Guthrie, et al. 2007 (PMID 17584130; Curr Top Med Chem; PMC 2694735 opened abstract) states that PT-141 is the carboxylate derivative of MT-II and reviews melanocortin receptors as emerging erectile-function effectors, with MC4 as a leading candidate. Historical development context. Not a protocol.
Hadley and Dorr 2006 (PMID 16412534; Peptides) review Melanotan I as the linear analogue and Melanotan II as the cyclic analogue, and discuss PT-141 as a related molecule. Secondary identity/history source, not a receptor-affinity table.
Molinoff 2003
Molinoff, Shadiack, Earle, Diamond and Quon 2003 (PMID 12851303; Ann N Y Acad Sci) is the opened first-description paper titled “PT-141: a melanocortin agonist for the treatment of sexual dysfunction.” Title language is historical development framing, not an approval of this vial and not a use instruction.
Pfaus 2004, not a human indication
Pfaus, Shadiack, Van Soest, Tse and Molinoff 2004 (PMID 15226502; PNAS; PMC 454387) reported selective facilitation of sexual solicitation in the female rat by a melanocortin receptor agonist (PT-141 named on that record). Rat behavior. Not a human trial. Not this vial.
DailyMed: HSDD mechanism unknown
DailyMed 12.1 (opened): the mechanism by which the approved product improves HSDD in women is unknown. Do not invent a completed receptor-to-indication story for the research vial.
No vial-level claim
Not shown: equivalence of an SRP 10 mg lyophilized vial to Vyleesi; a sexual-function treatment claim for this SKU; a tanning, pigmentation, or melanoma-prevention use; a human obesity, diabetic-kidney-disease, or lactation protocol (later NCTs exist for the drug substance / approved product, not for this vial); identity of the SRP lot as free base vs acetate, or as DailyMed xCH3COOH stoichiometry.
Where the literature actually sits
SRP index Evidence profile for this SKU: Human clinical evidence; regulated analogue context. That is the house tier. This page does not upgrade a research vial to NDA 210557. PT-141 ≠ Melanotan II ≠ afamelanotide ≠ alpha-MSH ≠ KPV ≠ Vyleesi. Historical language is not a completed therapeutic program for this vial.
| Bucket | What was opened | What it supports | What it does not support |
|---|---|---|---|
| Design / identity | Al-Obeidi 1989 PMID 2555512; King 2007 PMID 17584130; PubChem CID 9941379; NCATS UNII 6Y24O4F92S; IUPHAR 10408; ChEBI CHEBI:177849 | Cyclic 4-10 lactam Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-OH is bremelanotide / PT-141 | That the SRP lot is Vyleesi, acetate-proven, or Melanotan II |
| Receptor table | IUPHAR ligand 10408 interactions; DailyMed 12.1 | Agonist at human MC1/MC3/MC4/MC5 as tabulated by IUPHAR; label lists MC1R>MC4R>MC3R>MC5R>MC2R for the approved product | A completed HSDD mechanism; a claim for this vial |
| Rat behavior | Pfaus 2004 PMID 15226502 | Named PT-141 paper in female rats | A human indication or this SKU |
| Historical IN men / IN women development | Molinoff 2003 PMID 12851303; Diamond 2004 PMID 14963471; NCT00425256 (IN, FSAD, COMPLETED, hasResults false) | Early Palatin IN program existed | Current protocol; approved IN product; this vial |
| Phase 2b SC program | Clayton 2016 PMID 27181790; NCT01382719 COMPLETED hasResults true; n=612 | Dose-finding trial in the drug-development program | Equivalence of a research vial |
| Phase 3 RECONNECT | Kingsberg 2019 PMID 31599840; Simon 2019 PMID 31599847; NCT02333071 (n=723, hasResults true); NCT02338960 (n=714, hasResults true) | Two identical Phase 3 trials of the development product; DailyMed section 14 cites both NCTs | A treatment claim or dose for this SKU |
| Critical appraisal | Spielmans & Ellefson 2024 PMID 36809187 | Opened review questions small effects / outcomes of the HSDD program | Deletion of the NDA; proof this vial works |
| fMRI physiology | Thurston 2022 PMID 36189794; NCT04179734 COMPLETED hasResults true | Phase 4 fMRI crossover of the autoinjector product | This vial; a consumer use |
| Nausea + ondansetron | NCT03973047 COMPLETED hasResults false; DailyMed 6.1 cites a Phase 4 ondansetron pretreatment study | A registered nausea study of the autoinjector product exists | A reconstitution or anti-emetic protocol for this SKU |
| Ethanol coadministration | Clayton 2017 PMID 28189361 | Phase I IN + ethanol in healthy participants (opened title/abstract record) | A drinking protocol; this vial |
| Safety compilation | Clayton 2022 PMID 35147466 | Program-level safety review of the clinical development product | Safety of a research-market lot |
| Later / adjacent NCTs | NCT06565611 obesity + tirzepatide ACTIVE_NOT_RECRUITING; NCT05709444 DKD COMPLETED; NCT04943068 Phase 3 bridging COMPLETED; NCT06867835 lactation COMPLETED | Other bremelanotide-intervention records exist (totalCount 10) | Indications for this vial |
| Regulated product | openFDA NDA 210557; DailyMed VYLEESI; IUPHAR approved true FDA 2019 | A prescription autoinjector solution is approved | That the SRP 10 mg vial is that product |
ClinicalTrials.gov (opened; this molecule as intervention). query.intr=bremelanotide returned totalCount 10 (API v2; versionHolder 2026-08-14). All ten IDs were returned on that list. Those ten records belong to bremelanotide / Vyleesi development or post-approval work. They do not authorize a human-use protocol, a dose, a reconstitution recipe, or a claim that this SRP vial is a sexual-function product.
| NCT | Phase / status | What the opened record is | hasResults |
|---|---|---|---|
| NCT02333071 | PHASE3 COMPLETED; Palatin; n=723 | RECONNECT Study 301. DailyMed and Kingsberg 2019 PMID 31599840 | true |
| NCT02338960 | PHASE3 COMPLETED; Palatin; n=714 | RECONNECT Study 302. Same paper / DailyMed section 14 | true |
| NCT01382719 | PHASE2 COMPLETED; Palatin; n=612 | Premenopausal FSAD and/or HSDD dose-finding. Maps to Clayton 2016 PMID 27181790 | true |
| NCT00425256 | PHASE2 COMPLETED; Palatin; orgStudyId PT-141-2005-53 | Intranasal bremelanotide in postmenopausal FSAD. Early route. | false |
| NCT04179734 | PHASE4 COMPLETED; Imperial College Healthcare NHS Trust; n=40 | MC4R fMRI crossover. Maps to Thurston 2022 PMID 36189794 | true |
| NCT03973047 | PHASE1 COMPLETED; AMAG; n=228 | Nausea ± Zofran after a single autoinjector dose. DailyMed 6.1 discusses ondansetron pretreatment. | false |
| NCT04943068 | PHASE3 COMPLETED | Bridging multicenter SC trial (title opened on the list) | false |
| NCT05709444 | PHASE2 COMPLETED | Open-label DKD (title opened on the list) | false |
| NCT06565611 | PHASE2 ACTIVE_NOT_RECRUITING | Co-administration with tirzepatide for obesity (title opened on the list) | false |
| NCT06867835 | PHASE4 COMPLETED | Single dose of Vyleesi in lactating subjects; breast-milk concentration (title opened on the list) | false |
Not this molecule
Afamelanotide / Scenesse is IUPHAR 1324, a different linear 13-mer. Do not file Scenesse implant trials as PT-141 evidence. Melanotan II intervention search from the locked MT-II pass is a different molecule (C-amide).
NDA 210557 is Vyleesi
openFDA: NDA 210557; brand VYLEESI; sponsor COSETTE; ORIG 20190621. DailyMed: sterile clear solution in a pre-filled syringe / single-dose autoinjector; inactive ingredients 2.5% glycerin, sterile water, HCl or NaOH for pH. That is not a 10 mg lyophilized research vial.
RECONNECT, development product
NCT02333071 (n=723) and NCT02338960 (n=714) are the opened Phase 3 pair. Kingsberg 2019 PMID 31599840 and DailyMed section 14 cite both. Coprimary FSFI-desire and FSDS-DAO item 13; satisfying-sexual-event secondary did not differ. Not a claim for this SKU.
Spielmans 2024
Spielmans & Ellefson 2024 (PMID 36809187) questions small effects / outcomes of the HSDD program. Listed so Phase 3 is not presented as unquestioned. It is not a reason to invent a contrary NCT, and it is not proof this vial works.
Sawyer — linear NDP-MSH
Linear [Nle4, D-Phe7]-alpha-MSH, later afamelanotide / Melanotan I. Distinction only. PMID 6777774.
Al-Obeidi — cyclic lactam amide parent
Asp5–Lys10 23-membered lactam amide. Parent of Melanotan II, not the PT-141 acid. PMID 2555512.
Molinoff — first named PT-141 paper
Investigational-code first description. Title is development language. PMID 12851303.
Diamond IN / Pfaus rat
Historical intranasal evaluation (PMID 14963471) and female-rat solicitation (PMID 15226502). Not this vial.
Hadley / King identity history
MTI linear vs MTII cyclic vs PT-141 carboxylate. PMID 16412534; PMID 17584130.
Conde-Frieboes affinities
Source of the IUPHAR bremelanotide Ki / pKi rows. PMID 22335602.
Phase 2b / RECONNECT / Vyleesi NDA
Development-product program. FDA 21 June 2019 for the autoinjector, not this vial. PMID 27181790; PMID 31599840.
fMRI, safety compilation, critical review
Autoinjector-product physiology and program-level safety; Spielmans questions small effects. PMID 36189794; PMID 35147466; PMID 36809187.
Regulatory and listing status (opened sources only)
Read the “not this vial” column in your head. A regulated autoinjector product exists. That approval does not convert a research-market lyophilized vial into NDA 210557. Historical routes, trial arms, and label strengths are study / product conditions, not instructions.
- IUPHAR ligand 10408: type Peptide; approved: true; approvalSource FDA (2019); INN bremelanotide; INN number 8737.
- openFDA Drugs@FDA: NDA 210557; brand VYLEESI; generic BREMELANOTIDE; sponsor COSETTE; ORIG submission_status_date 20190621; Type 1 NME; route SUBCUTANEOUS; substance_name BREMELANOTIDE ACETATE.
- DailyMed (opened 16 August 2026): VYLEESI-bremelanotide injection; NDC 0713-0897-04 / 0713-0897-06; packager Cosette Pharmaceuticals, Inc.; Category HUMAN PRESCRIPTION DRUG LABEL; Marketing Status New Drug Application; Initial U.S. Approval 2019; revised 3/2024. Indication text is for premenopausal women with acquired, generalized HSDD with listed exclusions and Limitations of Use (not for postmenopausal women or men; not to enhance sexual performance). Contraindication: uncontrolled hypertension or known cardiovascular disease. That is label text for Vyleesi. It is not a treatment claim for this SKU.
- DailyMed description of the approved product: sterile clear solution in a pre-filled syringe / single-dose autoinjector; inactive ingredients 2.5% glycerin, sterile water, HCl or NaOH for pH. That is not a 10 mg lyophilized research vial.
- NCATS UNII 6Y24O4F92S: US Approved Rx (2019); source NDA210557. Acetate UNII PV2WI7495P: separate salt record; CAS 1607799-13-2.
- SRP product page: Research Use Only footer. No public COA on the opened product HTML.
- This SKU is a research-use-only lyophilized vial. It is not Vyleesi and not Scenesse.
What this page does not claim
- No human reconstitution, administration, or dosing protocol.
- No claim that this vial is Vyleesi, a sexual-function product, a tanning product, or a performance product.
- No claim that PT-141 is Melanotan II, afamelanotide / Scenesse, alpha-MSH, or KPV.
- No invented CAS, UNII, CID, NCT, or PMID.
- No use of acetate UNII PV2WI7495P as proof of the SRP lot salt.
- No transcription of DailyMed section 2 as a protocol for this SKU.
- Phase 3 / label outcomes apply to the approved autoinjector product in a defined population. They do not establish efficacy or safety of a research-market 10 mg vial.
- Spielmans 2024 (PMID 36809187) is listed so the Phase 3 program is not presented as unquestioned. It is not a reason to invent a contrary NCT.
Not Vyleesi
Vyleesi is NDA 210557, a prescription autoinjector solution (DailyMed; Cosette; FDA 2019). The SRP listing is a 10 mg lyophilized research vial with an RUO footer. Formulation, manufacturing, fill, and oversight are not the same.
Not a sexual-function treatment claim for this SKU
Opened HSDD / FSAD / ED literature belongs to the development product / approved autoinjector, or to historical IN work, or to rat behavior. It does not authorize a treatment claim, a dose, or a reconstitution recipe for this vial.
Not Melanotan II
Same 23-membered Asp–Lys lactam ring; C-terminal acid (PT-141) versus C-terminal amide (Melanotan II). CID 9941379 vs 92432. IUPHAR 10408 vs 1323. Separate SRP SKUs.
Not afamelanotide / alpha-MSH / KPV
Afamelanotide is a linear 13-mer (IUPHAR 1324; CID 16197727). Alpha-MSH is IUPHAR 1320 (13 aa). KPV is Lys-Pro-Val (separate SRP 10 mg Recovery listing; preclinical index tag).
Key papers as short cards
Each card is a single opened record. Historical routes, trial arms, and label strengths are study / product conditions, not instructions. No reconstitution scheme appears here.
Al-Obeidi et al., 1989 — J Med Chem
Potent and prolonged acting cyclic lactam analogues of alpha-melanotropin. Design of the Asp5–Lys10 23-membered lactam amide parent. Frog / lizard skin bioassay. Not PT-141 acid. Not Vyleesi. PMID 2555512. DOI 10.1021/jm00132a010.
Sawyer et al., 1980 — PNAS
[Nle4, D-Phe7]-alpha-MSH. Linear 13-mer parent of afamelanotide / Melanotan I. Distinction only. PMID 6777774. DOI 10.1073/pnas.77.10.5754. PMC 350149.
Molinoff et al., 2003 — Ann N Y Acad Sci
PT-141: a melanocortin agonist for the treatment of sexual dysfunction. First opened paper that names the investigational code. Title is development language, not an approval of this vial. PMID 12851303. DOI 10.1111/j.1749-6632.2003.tb03167.x.
Diamond et al., 2004 — Int J Impot Res
Double-blind, placebo-controlled evaluation of intranasal PT-141 in healthy males and men with mild-to-moderate ED. Historical IN route. Not the approved autoinjector. Not this vial. PMID 14963471. DOI 10.1038/sj.ijir.3901139.
Pfaus et al., 2004 — PNAS
Selective facilitation of sexual solicitation in the female rat by a melanocortin receptor agonist. Rat. PMID 15226502. DOI 10.1073/pnas.0400491101. PMC 454387.
Hadley & Dorr, 2006 — Peptides
Melanocortin peptide therapeutics: historical milestones. MTI linear vs MTII cyclic vs PT-141. Secondary history. PMID 16412534. DOI 10.1016/j.peptides.2005.01.029.
King et al., 2007 — Curr Top Med Chem
Melanocortin receptors, melanotropic peptides and penile erection. Opened abstract: PT-141 is the carboxylate derivative of MT-II. PMID 17584130. DOI 10.2174/156802607780906564. PMC 2694735.
Conde-Frieboes et al., 2012 — J Med Chem
Long-acting MC4-selective α-MSH analogues. Source of the IUPHAR bremelanotide Ki / pKi rows. Not a Vyleesi trial. PMID 22335602. DOI 10.1021/jm201489a.
Clayton et al., 2016 — Womens Health (Lond)
Bremelanotide for female sexual dysfunctions in premenopausal women: a randomized, placebo-controlled dose-finding trial. Maps to NCT01382719. Development-product Phase 2b. Not this vial. PMID 27181790. DOI 10.2217/whe-2016-0018. PMC 5384512.
Clayton et al., 2017 — Clin Ther
Phase I safety/tolerability of bremelanotide coadministered with ethanol. Opened record. Not a drinking protocol. PMID 28189361. DOI 10.1016/j.clinthera.2017.01.018.
Kingsberg et al., 2019 — Obstet Gynecol
Bremelanotide for HSDD: two randomized Phase 3 trials (RECONNECT). Clinical trial registration: NCT02333071 (Study 301) and NCT02338960 (Study 302). DailyMed section 14 cites the same pair. Coprimary FSFI-desire and FSDS-DAO item 13; satisfying-sexual-event secondary did not differ. Development / approved-product program. Not a claim for this SKU. PMID 31599840. DOI 10.1097/AOG.0000000000003500. PMC 6819021.
Simon et al., 2019 — Obstet Gynecol
Long-term safety and efficacy of bremelanotide for HSDD. Open-label extension companion. PMID 31599847. DOI 10.1097/AOG.0000000000003514. PMC 6819023.
Thurston et al., 2022 — J Clin Invest
MC4R agonism and sexual brain processing in women with HSDD. Maps to NCT04179734. Autoinjector product; fMRI. PMID 36189794. DOI 10.1172/JCI152341. PMC 9525110.
Clayton et al., 2022 — J Womens Health
Safety profile of bremelanotide across the clinical development program. Secondary compilation. PMID 35147466. DOI 10.1089/jwh.2021.0191.
Spielmans & Ellefson, 2024 — J Sex Res
Small effects, questionable outcomes: bremelanotide for HSDD. Critical review of the HSDD program. Listed so Phase 3 is not presented as unquestioned. PMID 36809187. DOI 10.1080/00224499.2023.2175192.
Research-only caution
PT-141 / bremelanotide is an investigational laboratory research peptide on this listing. A different formulated product (Vyleesi) is an FDA-approved prescription autoinjector. This page is educational. It does not provide dosing, reconstitution, administration, or any human-use instructions. The 10 mg mass is a vendor listing, not a published laboratory protocol and not the approved-product fill.
Simple Research Peptides (SRP) materials are for laboratory research only and are not for human or veterinary use, consumption, administration, diagnosis, treatment, or therapeutic application.
Laboratory identity is the first practical issue. Opened registries describe bremelanotide as CID 9941379 / CAS 189691-06-3 / UNII 6Y24O4F92S / Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-OH. SRP product pages do not print sequence, CAS, UNII, C-terminus, salt, or a public COA. A method written for Melanotan II (C-amide), afamelanotide, alpha-MSH, KPV, or Vyleesi is not automatically valid for this vial.
Confirm peptide identity, C-terminus (acid vs amide), stereochemistry (D-Phe), lactam closure, salt, and purity by LC-MS before treating a vial as the literature article or as NDA 210557 material. Independently sourced research peptides are not established as equivalent to Palatin clinical lots or to Cosette Vyleesi. Historical IN exposures and autoinjector-product conditions are study / label facts. They are not a reconstitution scheme.
No reconstitution scheme, no administration route, and no human or veterinary use protocol appears on this page. Research use only.
Common questions
Is PT-141 the same as Melanotan II?
No. Same 23-membered Asp–Lys lactam ring; C-terminal acid (PT-141) versus C-terminal amide (Melanotan II). King 2007 PMID 17584130: PT-141 is the carboxylate derivative of MT-II. CID 9941379 vs 92432. IUPHAR 10408 vs 1323. Separate SRP SKUs.
Is the SRP 10 mg vial the same as Vyleesi?
No. Vyleesi is NDA 210557, a prescription autoinjector solution (DailyMed). The SRP listing is a 10 mg lyophilized research vial with an RUO footer. Opened SRP index: regulated-product evidence does not establish equivalence of an unapproved research vial.
Is bremelanotide FDA-approved?
The INN / active moiety is the approved ingredient of Vyleesi (FDA 21 June 2019; IUPHAR approved true). That approval is for the regulated autoinjector product, not for a research-market vial.
What is Vyleesi indicated for on the opened label?
DailyMed: premenopausal women with acquired, generalized HSDD, with listed exclusions (not due to a co-existing medical or psychiatric condition, relationship problems, or a medication/drug). Limitations of Use: not for postmenopausal women or men; not to enhance sexual performance. That is label text for Vyleesi. It is not a treatment claim for this SKU.
Is PT-141 the same as afamelanotide / Scenesse / Melanotan I?
No. Afamelanotide is a linear 13-mer (IUPHAR 1324; CID 16197727; C78H111N21O19). Different molecule and a different approved product (implant).
Is PT-141 the same as alpha-MSH or KPV?
No. Alpha-MSH is IUPHAR 1320 (13 aa). KPV is the C-terminal tripeptide Lys-Pro-Val (separate SRP 10 mg Recovery listing; preclinical index tag).
Is the SRP lot the acetate salt?
Not established. Vendor line says “PT-141 Acetate.” CID 9941379 is the free base. Approved-product salt is UNII PV2WI7495P / CAS 1607799-13-2. Confirm salt on a COA.
Which NCTs belong to this molecule?
Opened query.intr=bremelanotide totalCount 10. Core development pair: NCT02333071 and NCT02338960 (RECONNECT). Phase 2b: NCT01382719. Early IN: NCT00425256. Others listed in section 04. None of them is a protocol for this vial.
Can these findings be used as dosing or administration instructions?
No. SRP listings are for laboratory research only and are not for human or animal use. This page does not provide reconstitution, administration, or dosing instructions.
Does this page include human dosing?
No. There is no human dosing, reconstitution, or administration protocol on this page. Research use only. Not medical advice. Not for human use.
Citations used on this page
Sources actually opened for the locked draft. Do not add PMIDs or NCTs that are not on the allowed list.
- Al-Obeidi F, Castrucci AM, Hadley ME, Hruby VJ. Potent and prolonged acting cyclic lactam analogues of alpha-melanotropin: design based on molecular dynamics. J Med Chem. 1989;32(12):2555-2561. PMID 2555512. DOI 10.1021/jm00132a010. Cyclic lactam amide parent. Abstract.
- Sawyer TK, Sanfilippo PJ, Hruby VJ, et al. 4-Norleucine, 7-D-phenylalanine-alpha-melanocyte-stimulating hormone: a highly potent alpha-melanotropin with ultralong biological activity. Proc Natl Acad Sci U S A. 1980;77(10):5754-5758. PMID 6777774. DOI 10.1073/pnas.77.10.5754. PMC 350149. Linear NDP-MSH / Melanotan I parent. Distinction.
- Molinoff PB, Shadiack AM, Earle D, Diamond LE, Quon CY. PT-141: a melanocortin agonist for the treatment of sexual dysfunction. Ann N Y Acad Sci. 2003;994:96-102. PMID 12851303. DOI 10.1111/j.1749-6632.2003.tb03167.x. First named PT-141 paper.
- Diamond LE, Earle DC, Rosen RC, Willett MS, Molinoff PB. Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141… Int J Impot Res. 2004;16(1):51-59. PMID 14963471. DOI 10.1038/sj.ijir.3901139. Historical IN. Abstract.
- Pfaus JG, Shadiack A, Van Soest T, Tse M, Molinoff P. Selective facilitation of sexual solicitation in the female rat by a melanocortin receptor agonist. Proc Natl Acad Sci U S A. 2004;101(27):10201-10204. PMID 15226502. DOI 10.1073/pnas.0400491101. PMC 454387. Rat.
- Hadley ME, Dorr RT. Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization. Peptides. 2006;27(4):921-930. PMID 16412534. DOI 10.1016/j.peptides.2005.01.029. MTI vs MTII vs PT-141. Abstract.
- King SH, Mayorov AV, Balse-Srinivasan P, Hruby VJ, Vanderah TW, Wessells H. Melanocortin receptors, melanotropic peptides and penile erection. Curr Top Med Chem. 2007;7(11):1098-1106. PMID 17584130. DOI 10.2174/156802607780906564. PMC 2694735. “Carboxylate derivative of MT-II.” Abstract opened.
- Conde-Frieboes K, Thøgersen H, Lau JF, et al. Identification and in vivo and in vitro characterization of long acting and melanocortin 4 receptor (MC4-R) selective α-MSH analogues. J Med Chem. 2012;55(5):1969-1977. PMID 22335602. DOI 10.1021/jm201489a. IUPHAR affinity source.
- Clayton AH, Althof SE, Kingsberg S, et al. Bremelanotide for female sexual dysfunctions in premenopausal women: a randomized, placebo-controlled dose-finding trial. Womens Health (Lond). 2016;12(3):325-337. PMID 27181790. DOI 10.2217/whe-2016-0018. PMC 5384512. NCT01382719.
- Clayton AH, Lucas J, DeRogatis LR, Jordan R. Phase I randomized placebo-controlled, double-blind study of the safety and tolerability of bremelanotide coadministered with ethanol… Clin Ther. 2017;39(3):514-526.e14. PMID 28189361. DOI 10.1016/j.clinthera.2017.01.018.
- Kingsberg SA, Clayton AH, Portman D, et al. Bremelanotide for the treatment of hypoactive sexual desire disorder: two randomized Phase 3 trials. Obstet Gynecol. 2019;134(5):899-908. PMID 31599840. DOI 10.1097/AOG.0000000000003500. PMC 6819021. NCT02333071 / NCT02338960.
- Simon JA, Kingsberg SA, Portman D, et al. Long-term safety and efficacy of bremelanotide for hypoactive sexual desire disorder. Obstet Gynecol. 2019;134(5):909-917. PMID 31599847. DOI 10.1097/AOG.0000000000003514. PMC 6819023.
- Thurston L, Hunjan T, Mills EG, et al. Melanocortin 4 receptor agonism enhances sexual brain processing in women with hypoactive sexual desire disorder. J Clin Invest. 2022;132(19):e152341. PMID 36189794. DOI 10.1172/JCI152341. PMC 9525110. NCT04179734.
- Clayton AH, Kingsberg SA, Portman D, et al. Safety profile of bremelanotide across the clinical development program. J Womens Health (Larchmt). 2022;31(2):171-182. PMID 35147466. DOI 10.1089/jwh.2021.0191.
- Spielmans GI, Ellefson EM. Small effects, questionable outcomes: bremelanotide for hypoactive sexual desire disorder. J Sex Res. 2024;61(4):540-561. PMID 36809187. DOI 10.1080/00224499.2023.2175192. Critical review.
- ClinicalTrials.gov API v2
query.intr=bremelanotide, opened 16 August 2026, versionHolder 2026-08-14, totalCount 10. IDs: NCT03973047, NCT00425256, NCT04179734, NCT02333071, NCT06565611, NCT05709444, NCT02338960, NCT04943068, NCT01382719, NCT06867835. - PubChem CID 9941379 (Bremelanotide; CAS 189691-06-3; UNII 6Y24O4F92S). https://pubchem.ncbi.nlm.nih.gov/compound/9941379
- PubChem PUG REST CID 9941379 properties, opened 16 August 2026. C50H68N14O10; 1025.2; InChIKey FFHBJDQSGDNCIV-MFVUMRCOSA-N; ExactMass 1024.52428442.
- ChEBI CHEBI:177849 (bremelanotide; CAS 189691-06-3). https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:177849
- IUPHAR/BPS ligand 10408 (bremelanotide; INN 8737; approved FDA 2019). https://www.guidetopharmacology.org/GRAC/LigandDisplayForward?ligandId=10408 and
/services/ligands/10408+/interactions. - NCATS Inxight UNII 6Y24O4F92S (free base) and PV2WI7495P (acetate). https://drugs.ncats.io/drug/6Y24O4F92S ; https://drugs.ncats.io/drug/PV2WI7495P
- openFDA Drugs@FDA
openfda.generic_name:bremelanotide, last_updated 2026-08-14. NDA 210557; VYLEESI; ORIG 20190621. - DailyMed: VYLEESI-bremelanotide injection (Cosette; NDA 210557; revised 3/2024). https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=VYLEESI
- Distinction PUG: CID 92432 melanotan-II C50H69N15O9 InChIKey JDKLPDJLXHXHNV-MFVUMRCOSA-N; CID 16197727 Afamelanotide C78H111N21O19 InChIKey UAHFGYDRQSXQEB-LEBBXHLNSA-N. IUPHAR services 1323 / 1324 / 1320.
- SRP pages (opened 16 August 2026): PT-141 10 mg product http://simpleresearchpeptides.com/product/pt-141-10-mg-vial/ ; index http://simpleresearchpeptides.com/research-compound-directory/compound-research-guides/ . Dedicated guide 404. For laboratory research only. Not for human or animal use.
Allowed PMID list used on this page: 2555512, 6777774, 12851303, 14963471, 15226502, 16412534, 17584130, 22335602, 27181790, 28189361, 31599840, 31599847, 35147466, 36189794, 36809187.
Allowed NCT list used on this page: NCT02333071, NCT02338960, NCT01382719, NCT00425256, NCT04179734, NCT03973047, NCT04943068, NCT05709444, NCT06565611, NCT06867835.
Educational information only. The SRP listing PT-141 10 mg is a research cyclic heptapeptide corresponding, on opened registries, to bremelanotide / Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-OH (CID 9941379; CAS 189691-06-3; UNII 6Y24O4F92S; IUPHAR 10408; INN 8737; C50H68N14O10; 1025.2 g/mol). It is not Melanotan II, not afamelanotide / Scenesse, not alpha-MSH, not KPV, and not Vyleesi. A regulated bremelanotide autoinjector product exists (NDA 210557; FDA 2019). That approval does not convert this vial into that product. Salt of an SRP lot is not printed. Historical IN exposures and autoinjector-product conditions are study / label facts, not instructions. Laboratory research use only; not for human or animal use. Not medical advice. Not for human use. No human dosing protocol. Last source review: 16 August 2026 (America/Indianapolis). Locked draft converted to HTML the same day. For laboratory research only. Not for human or veterinary use.