PT-141

What PT-141 Is

PT-141 (bremelanotide) is a 7-residue cyclic heptapeptide (Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH, Asp-Lys lactam cyclization; molecular formula C₅₀H₆₈N₁₄O₁₀; MW 1025.18 Da; CAS 32780-32-8; DrugBank DB11580; PubChem CID 9941379; ChEMBL CHEMBL2104995; Wikidata Q4960543). It is derived from the active core of α-melanocyte-stimulating hormone (α-MSH) and acts as a selective MC3R/MC4R melanocortin-receptor agonist within central nervous system melanocortin signaling pathways.

Important Regulatory Disambiguation

Artemis Labs PT-141 is NOT Vyleesi®. Vyleesi® (bremelanotide injection, Palatin Technologies / Cosette Pharmaceuticals) was approved by the U.S. FDA in June 2019 for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women — this is cited solely as a fact of regulatory record. Artemis Labs does NOT offer, substitute for, or reference clinical indications of the Vyleesi product. Our PT-141 is a research-grade lyophilized reference compound for in vitro and IACUC-approved animal research workflows. The FDA has reminded compounders that compounded bremelanotide is not the FDA-approved product; Artemis Labs PT-141 is supplied strictly as a research reagent — not as a Vyleesi substitute, not as a compounded pharmaceutical.

Why It Is Studied — 2024-2026 Research Refinements

The 2024-2026 peer-reviewed literature substantially refined the PT-141 research narrative beyond the early 2000s sexual-arousal framing:

• Central reward-circuit mapping — Borland et al. 2025 (PMID 39793696): female Syrian hamster models localized bremelanotide effects within MC-receptor-mediated sexual-reward circuitry, refining earlier MPOA-dopamine-centric models.
• Pharmacogenomic response variability — Bardhan et al. 2025 (PMID 41002740): MC1R/MC3R/MC4R coding-variant associations with differential bremelanotide response — opens a pharmacogenomic research dimension.
• Novel oncology axis — Suzuki et al. 2024 (PMID 39197897): bremelanotide induces glioblastoma cell death and growth inhibition via survivin suppression — first documented oncology mechanism entirely distinct from sexual-arousal pharmacology.
• Delivery-route innovation — Krupke et al. 2025 (PMID 40513668): biodegradable transbuccal suction patch achieved ~26% relative bioavailability vs subcutaneous bremelanotide — first non-injectable PK demonstration with usable numbers.
• 2026 meta-analysis — Toledo et al. 2026 (PMID 40543759): systematic review and meta-analysis of female sexual desire/arousal/orgasmic dysfunctions including bremelanotide pooled efficacy.
• Male sexual-arousal re-evaluation — Pfaus et al. 2026 (PMID 41960633): mechanistic separation of bremelanotide from PDE5-inhibitor mechanisms in male sexual arousal/desire research.

How Artemis Labs Sources and Verifies PT-141

Each lot is supplied as a sterile lyophilized peptide powder, analytically verified by reverse-phase HPLC to ≥99% peptide purity, with identity confirmed by mass spectrometry. The compound shipped is the canonical 7-mer cyclic sequence with Asp-Lys lactam cyclization. A third-party Certificate of Analysis with residual-solvent and endotoxin testing is available on request.

Honest Limitations of the PT-141 Evidence Base

(1) Pharmacogenomic response variability. Bardhan 2025 (PMID 41002740) demonstrates MC1R/MC3R/MC4R polymorphism-driven response heterogeneity — broad efficacy claims are pharmacogenomically fragile. (2) Cardiovascular safety pool signal. Across the ~3,500-subject development program, transient SBP/DBP rise of ~2-3 mmHg appeared 0-4h post-dose and resolved by 8-10h. Documented in published safety pool. (3) Non-injectable PK ceiling. The Krupke 2025 transbuccal patch (PMID 40513668) achieved only ~26% relative bioavailability vs subcutaneous — non-injectable delivery remains a research-development frontier, not a solved problem. (4) No FDA approval beyond Vyleesi® HSDD indication. Bremelanotide is not approved for male sexual dysfunction, oncology, or any other indication despite preclinical-research signals.

Class Positioning

Unlike Melanotan-2 (non-selective MC1R-MC5R agonist with prominent pigmentary effects), PT-141 selectively targets MC3R/MC4R. Unlike oxytocin (OXTR-acting hypothalamic nonapeptide), PT-141 acts on melanocortin reward circuitry. Bardhan 2025 treats PT-141 as the clinically validated MC-selective comparator within the melanocortin family. See VIP for autonomic-research context and Semax for ACTH(4-10)-derived neuropeptide research.

Regulatory and Compliance Framing

Vyleesi® (injectable bremelanotide) is FDA-approved (June 2019) for HSDD in premenopausal women. No FDA approval exists for any other indication. Not DEA-scheduled. Not on the WADA Prohibited List 2026. No EMA or MHRA approval. Artemis Labs explicitly does NOT make sexual-function, HSDD, oncology, or any other therapeutic claims for the product given the limited pharmacogenomically-modulated evidence base. Research-use-only framing applies to all commercial supply. These statements have not been evaluated by the FDA. Not for human consumption, therapeutic use, or veterinary use.

Science & Research

Mechanism of Action — MC3R/MC4R Selective Agonism

PT-141 binds the MC3 and MC4 melanocortin receptors, both Gs-coupled G-protein-coupled receptors, with selectivity that distinguishes it from the non-selective melanocortin agonist melanotan-2 (which binds MC1R-MC5R). Receptor activation drives adenylyl-cyclase/cAMP signaling cascades. MC3R and MC4R are expressed in brain regions associated with reward, arousal, and energy homeostasis — including the medial preoptic area (MPOA), paraventricular nucleus (PVN), and ventral tegmental area (VTA).

2024-2026 Research Refinements (Scout 3 verified, 2026-05-20)

Borland et al. 2025 (PMID 39793696) used female Syrian hamster models to map bremelanotide effects within MC-receptor-mediated sexual-reward circuitry, refining earlier MPOA-dopamine-centric models. Bardhan et al. 2025 (PMID 41002740) reported MC1R/MC3R/MC4R coding-variant associations with differential bremelanotide response — opening a pharmacogenomic research dimension that constrains broad efficacy generalization.

Suzuki et al. 2024 (PMID 39197897) reported bremelanotide induces glioblastoma cell death and growth inhibition via survivin suppression — the first documented oncology mechanism, entirely distinct from sexual-arousal pharmacology. Krupke et al. 2025 (PMID 40513668) demonstrated a biodegradable transbuccal suction patch achieving ~26% relative bioavailability vs subcutaneous bremelanotide — the first non-injectable PK with practical numbers.

Pooled Cardiovascular Safety Findings

Across 43 studies in the development program (~3,500 subjects pooled), serious cardiovascular events were extremely rare. A transient SBP/DBP rise of ~2-3 mmHg appeared 0-4 hours post-dose and resolved by 8-10 hours. This is cited as a documented finding from the published safety pool, not as an Artemis Labs safety claim for any indication.

2024-2026 Clinical-Adjacent Research

• Toledo RG et al. 2026 (PMID 40543759) — systematic review + meta-analysis: bremelanotide pooled efficacy across female sexual desire/arousal/orgasmic dysfunctions.
• How A et al. 2025 (PMID 39846877) — comparative review of flibanserin and bremelanotide for female sexual dysfunction.
• Pfaus JG et al. 2026 (PMID 41960633) — re-evaluation of bremelanotide for male sexual arousal/desire disorders; mechanistic separation from PDE5 inhibitors.
• Mihulka O et al. 2025 (PMID 41419078) — bremelanotide review for sexual-health management after breast/gynecologic cancer.
• Bhinder JK et al. 2025 (PMID 40518469) — survivorship-guideline comparison citing bremelanotide for cancer-survivor low desire.
• Fuhrman J et al. 2025 (PMID 41088800) — vasomotor + sexual-symptom management in breast-cancer survivors; emerging libido agents including bremelanotide.
• Renke G et al. 2026 (PMID 42123471) — therapeutic peptides across aesthetic/metabolic/endocrine medicine; bremelanotide positioning.
• Ila V et al. 2025 (PMID 40069591) — IV peptides + amino acids for ED research including PT-141 future directions.
• Gollapudi M et al. 2024 (PMID 39036127) — PMDD/FSD overlap; bremelanotide + flibanserin pharmacotherapy context.
• Barakeh D et al. 2025 (PMID 38767282) — pharmacotherapy review confirming bremelanotide + flibanserin as FDA-approved HSDD agents.

Entity Disambiguation

Quality and Specifications

• Purity: ≥99% by RP-HPLC; identity confirmed by mass spectrometry
• Form: Lyophilized white powder, 10 mg/vial
• Storage: Lyophilized ≤ -20°C, desiccated, protected from light; reconstituted 2-8°C
• Documentation: Batch-specific Certificate of Analysis with HPLC chromatogram, MS ID, residual-solvent assay, and endotoxin testing

Honest Limitations

• Pharmacogenomic response heterogeneity — Bardhan 2025 (PMID 41002740): MC-receptor polymorphisms drive differential response; broad efficacy claims are fragile.
• Cardiovascular safety pool signal — transient SBP/DBP rise (~2-3 mmHg, 0-4h post-dose) documented across the published safety pool.
• Non-injectable PK ceiling — Krupke 2025 (PMID 40513668) achieves only ~26% relative bioavailability vs subcutaneous; non-injectable delivery remains research-development frontier.
• No FDA approval beyond Vyleesi® HSDD indication — bremelanotide is not approved for male sexual dysfunction, oncology, or any other indication despite preclinical signals.
• NOT Vyleesi® — Artemis Labs PT-141 is a research-grade reference compound, not a substitute for any FDA-approved bremelanotide product.

References (14 PubMed-Verified)

1. Suzuki S et al. (2024). Anticancer Research. PMID 39197897
2. Gollapudi M et al. (2024). Cureus. PMID 39036127
3. Borland JM et al. (2025). Neuropharmacology. PMID 39793696
4. How A et al. (2025). Clin Obstet Gynecol. PMID 39846877
5. Ila V et al. (2025). Expert Opin Pharmacother. PMID 40069591
6. Krupke H et al. (2025). J Control Release. PMID 40513668
7. Bhinder JK et al. (2025). Support Care Cancer. PMID 40518469
8. Toledo RG et al. (2026). J Minim Invasive Gynecol. PMID 40543759
9. Barakeh D et al. (2025). Ann Pharmacother. PMID 38767282
10. Bardhan M et al. (2025). Diseases. PMID 41002740
11. Fuhrman J et al. (2025). Expert Rev Clin Pharmacol. PMID 41088800
12. Mihulka O et al. (2025). J Minim Invasive Gynecol. PMID 41419078
13. Pfaus JG et al. (2026). J Clin Psychopharmacol. PMID 41960633
14. Renke G et al. (2026). Int J Mol Sci. PMID 42123471

Research Stacks

Stacking rationale below is mechanistic only. No dosing, frequency, duration, route, protocol, or human-use guidance is provided. Researchers design protocols against their own IACUC / institutional review, not against vendor copy. PT-141 is not combined with any FDA-approved drug, PDE5 inhibitor, or pharmaceutical product in any Artemis Labs research framing.

PT-141 × Melanotan-2

Both are melanocortin agonists. PT-141 is MC3R/MC4R-selective; Melanotan-2 is non-selective MC1R-MC5R. Useful mechanism-comparison research model for dissecting selective MC3R/MC4R signaling vs broader pan-MC engagement. Inozemtseva et al. 2024 explicitly compared MT-II with Semax across the melanocortin family; PT-141 serves as the MC-selective comparator in such designs.

PT-141 × Oxytocin

Orthogonal receptor systems: PT-141 acts on MC3R/MC4R; oxytocin acts on OXTR. Both are CNS-acting neuropeptides studied within central arousal/social-bonding research contexts. Mechanistically orthogonal, useful research-model pairing for dissecting melanocortin vs OXTR contributions.

PT-141 × VIP

Vasoactive intestinal peptide × PT-141 pairing studied in preclinical autonomic and vascular research models with a central-arousal counterpart. Different receptor systems with convergent autonomic effects in research designs.

PT-141 × BPC-157 / TB-500

Tissue-repair pairing studied in genitourinary preclinical models. Mechanism rationale only: central arousal axis (PT-141) combined with documented preclinical tissue-repair mechanism research compounds. No human protocols implied.

PT-141 × Semax

Melanocortin / neuropeptide research-model pairing. Semax is an ACTH(4-10)-derived BDNF-axis neuropeptide; PT-141 is an alpha-MSH-derived MC3R/MC4R agonist. Both have melanocortin-family origins but act on different receptor systems. Useful comparative model for melanocortin-family research designs.

Related Compounds in Catalogue

For broader melanocortin-axis research see Melanotan 2. For CNS neuropeptide research see Oxytocin, Semax, Selank. For autonomic / vascular research see VIP.