PT-141 (bremelanotide) is a synthetic cyclic heptapeptide analogue of α-melanocyte-stimulating hormone (α-MSH) and a non-selective agonist at melanocortin receptors.1 It is the C-terminal-deamidated active metabolite of melanotan II, the experimental tanning peptide.6Important framing note: although it is listed here under a cosmetic/skin category, PT-141 is not approved or used as a cosmetic or skin-pigmentation agent. It is approved by the U.S. FDA as Vyleesi (June 2019) for hypoactive sexual desire disorder (HSDD) in premenopausal women.2 Any skin-tanning association derives from its parent compound melanotan II (an MC1R-active peptide), not from established PT-141 use.6 All material below is provided for research-use-only reference; it is not usage guidance.
Sequence & identity
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH · C₅₀H₆₈N₁₄O₁₀ · 1025.2 g/mol
Cyclic heptapeptide lactam; identity confirmed against PubChem CID 9941379, InChIKey FFHBJDQSGDNCIV-MFVUMRCOSA-N.1
Mechanisms studied
Researchers reported that PT-141 acts as a non-selective agonist at melanocortin receptors, with activity at MC3R and MC4R expressed primarily in the central nervous system.3 In animal and early human studies, investigators observed that activation of hypothalamic melanocortin pathways (paraventricular nucleus and medial preoptic area) was associated with rapid, dose-dependent increases in erectile activity, a central mechanism distinct from the vascular action of PDE5 inhibitors.34 The FDA prescribing label states that, while PT-141 activates melanocortin receptors, the precise mechanism by which it improves sexual desire and related distress in HSDD is unknown.2 The reported elimination half-life is approximately 2.7 hours (range 1.9-4.0 h) for the approved subcutaneous formulation.2
Dosing in the research literature
The figures below summarise regimens as reported in published research — they are not recommendations or directions for use.
| Source / model | Regimen reported | Notes |
|---|---|---|
| FDA Vyleesi prescribing information (210557)2 | 1.75 mg subcutaneous injection (abdomen or thigh), administered at least 45 minutes before anticipated sexual activity; no more than one dose per 24 hours and no more than eight doses per month. | Approved human regimen for HSDD in premenopausal women. Listed for reference only — not usage direction. |
| RECONNECT Phase 3 trials (Kingsberg 2019)5 | 1.75 mg subcutaneous, as-needed, over 24 weeks in two randomized, double-blind, placebo-controlled studies. | The regimen on which FDA approval was based; reflects study design, not a recommendation. |
| Early-phase subcutaneous PK/PD study (Rosen 2004)4 | Single subcutaneous doses evaluated in healthy men and in men with an inadequate response to sildenafil. | Dose-ranging pharmacology; study-reported only. |
Effects observed in research
In two Phase 3 trials (RECONNECT), researchers reported that bremelanotide produced statistically significant improvements versus placebo in the Female Sexual Function Index-desire domain (integrated change +0.35, p<.001) and significant reductions in low-desire-related distress on the Female Sexual Distress Scale (integrated change −0.33, p<.001) in premenopausal women with HSDD.5 Earlier studies in men observed dose-dependent increases in erectile response, including in men who had responded inadequately to sildenafil.34 The most frequently reported adverse events were nausea, flushing, and headache (each ≥10% in both Phase 3 studies); transient increases in blood pressure and decreases in heart rate were also observed.25 No established cosmetic or skin-pigmentation effect has been demonstrated for PT-141 itself.
Strength of evidence
Grade A. PT-141 (bremelanotide) is supported by multiple randomized controlled human trials and is an FDA-approved drug (Vyleesi, 2019) for HSDD in premenopausal women.25 However, this high grade applies to its sexual-desire indication, not to any cosmetic or skin application. For skin/tanning effects, evidence pertains to the related peptide melanotan II rather than PT-141, and is far weaker (largely uncontrolled and associated with safety concerns).6 The categorization of PT-141 as a “cosmetic / skin” agent is therefore not supported by the primary literature. Limited published data exist for any dermatological or pigmentation use of bremelanotide itself.
Reconstitution & storage
Reconstitute with bacteriostatic water for laboratory handling. Store lyophilised material frozen and reconstituted material refrigerated. Use Peptigo’s reconstitution calculator and storage cheat sheet for working figures.
References
- Bremelanotide, PubChem Compound CID 9941379. National Center for Biotechnology Information. https://pubchem.ncbi.nlm.nih.gov/compound/9941379 (CAS 189691-06-3; C50H68N14O10; 1025.2 g/mol; InChIKey FFHBJDQSGDNCIV-MFVUMRCOSA-N).
- VYLEESI (bremelanotide injection) Prescribing Information, U.S. FDA, NDA 210557, June 2019. https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/210557s000lbl.pdf
- 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, a melanocortin receptor agonist, in healthy males and patients with mild-to-moderate erectile dysfunction. Int J Impot Res. 2004;16(1):51-59. doi:10.1038/sj.ijir.3901139.
- Rosen RC, Diamond LE, Earle DC, Shadiack AM, Molinoff PB. Evaluation of the safety, pharmacokinetics and pharmacodynamic effects of subcutaneously administered PT-141, a melanocortin receptor agonist, in healthy male subjects and in patients with an inadequate response to Viagra. Int J Impot Res. 2004;16(2):135-142. doi:10.1038/sj.ijir.3901172. PMID 14999221.
- 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. doi:10.1097/AOG.0000000000003500. PMID 31599840.
- Bremelanotide. Wikipedia / DrugBank summary (pharmacokinetics: t1/2 ~2.7 h; relationship to melanotan II). https://en.wikipedia.org/wiki/Bremelanotide