PT-141: Research, Handling and Batch Documentation

Identity and research status

Also referred to as

Bremelanotide, Vyleesi

Generic Name

Bremelanotide

Sequence

Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH

Peptide Class

Cyclic heptapeptide, Asp1 to Lys7 side-chain lactam bridge

Molecular Formula

C50H68N14O10 (free base)

Molecular Weight

1,025.2 g/mol (free base)

CAS Number

189691-06-3 (free base)

PubChem CID

9941379

InChIKey

FFHBJDQSGDNCIV-MFVUMRCOSA-N

UNII

6Y24O4F92S

Parent Compound

Melanotan II, C50H69N15O9, 1,024.2 g/mol, PubChem CID 92432

Receptor Targets

MC1R, MC4R, MC3R, MC5R, MC2R (in descending order of potency)

Plasma Half-Life

2.7 hours (reported range 1.9 to 4.0 hours)

Physical Form

White to off-white lyophilised powder, typically supplied as the acetate salt

CAS number

189691-06-3

Mechanism, in brief

PT-141 is a non-selective melanocortin agonist, not an MC4R-specific ligand. Ranked by potency in receptor panels it engages MC1R first, then MC4R, MC3R, MC5R and MC2R. What makes MC4R the pharmacologically interesting receptor is not selectivity but exposure: at the plasma concentrations reached in the clinical programme, MC4R is the subtype considered most relevant, and MC4R is densely expressed in the medial preoptic area of the hypothalamus.

1. Melanocortin receptor engagement. Binds as an alpha-MSH mimic across the melanocortin family, with potency ranked MC1R, then MC4R, MC3R, MC5R and MC2R. Non-selective, not MC4R-specific.
2. Hypothalamic activation. Systemic administration in rats raised c-Fos immunoreactivity in hypothalamic neurons, marking the medial preoptic area as the site of action (Molinoff, 2003).
3. Central to peripheral circuit. The activated hypothalamic region is the same one labelled by pseudorabies virus delivered to the rat corpus cavernosum, tracing a descending pathway to peripheral tissue.
4. Proposed dopaminergic step. Presynaptic MC4R activation in the medial preoptic area is hypothesised to increase dopamine release. Reviewed, not directly demonstrated in humans.
5. Circuit boundary. In female Syrian hamsters, bremelanotide changed no melanocortin receptor mRNA in the VTA to nucleus accumbens pathway and did not enhance sexual conditioned place preference, arguing against a mesolimbic reward mechanism (Borland, 2025).
6. Peripheral melanocortin signalling. MC1R agonism is not silent. It underlies both the pigmentation observed under repeated daily exposure and the rationale for the renal podocyte research programme.

The full research write-up, including the findings behind each claim and the model each came from, is on the PT-141 10mg 10mg page.

Vial sizes available

Every size of PT-141 Volta lists, in stock or not. Each is a separate catalogue page with its own batch number and specification table.

• PT-141 10mg 10mgBatch #: VPPT10100
  Restocking

Purity and batch documentation

Volta's release specification is >99% (HPLC). That is a threshold we set. >99% is the specification every batch is released to. The figure on a certificate is what a laboratory measured for one lot.

No third-party certificate has been published for PT-141yet. The certificates Volta does publish, with the laboratory's own verification link on each, are in the certificate archive.

Research on PT-141

Handling and stability

Regulatory context

United States

FDA-approved (Vyleesi, 2019) for HSDD in premenopausal women. 1.75 mg SC on-demand, max 8 doses/month.

Canada

Not approved by Health Canada.

United Kingdom

Not MHRA-approved.

• the legal status of research peptides in Canada
• Health Canada's regulatory position

Primary sources

1. Kingsberg SA, Clayton AH, Portman D, et al.. Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. Obstetrics & Gynecology (2019). doi:10.1097/AOG.0000000000003500
2. Simon JA, Kingsberg SA, Portman D, et al.. Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder. Obstetrics & Gynecology (2019). doi:10.1097/AOG.0000000000003514
3. White WB, Myers MG, Jordan R, Lucas J. Usefulness of ambulatory blood pressure monitoring to assess the melanocortin receptor agonist bremelanotide. Journal of Hypertension (2017). doi:10.1097/HJH.0000000000001221
4. Clayton AH, Kingsberg SA, Portman D, et al.. Safety Profile of Bremelanotide Across the Clinical Development Program. Journal of Women's Health (2022). doi:10.1089/jwh.2021.0191
5. Clayton AH, Althof SE, Kingsberg S, et al.. Bremelanotide for female sexual dysfunctions in premenopausal women: a randomized, placebo-controlled dose-finding trial. Women's Health (London) (2016). doi:10.2217/whe-2016-0018
6. Molinoff PB, Shadiack AM, Earle D, Diamond LE, Quon CY. PT-141: a melanocortin agonist for the treatment of sexual dysfunction. Annals of the New York Academy of Sciences (2003). doi:10.1111/j.1749-6632.2003.tb03167.x
7. 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 sildenafil. International Journal of Impotence Research (2004). doi:10.1038/sj.ijir.3901200
8. 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. International Journal of Impotence Research (2004). doi:10.1038/sj.ijir.3901139
9. Diamond LE, Earle DC, Garcia WD, Spana C. Co-administration of low doses of intranasal PT-141, a melanocortin receptor agonist, and sildenafil to men with erectile dysfunction results in an enhanced erectile response. Urology (2005). doi:10.1016/j.urology.2004.10.060
10. Spana C, Jordan R, Fischkoff S. Effect of bremelanotide on body weight of obese women: Data from two phase 1 randomized controlled trials. Diabetes, Obesity and Metabolism (2022). doi:10.1111/dom.14672
11. Pfaus JG, Sadiq A, Spana C, Clayton AH. The neurobiology of bremelanotide for the treatment of hypoactive sexual desire disorder in premenopausal women. CNS Spectrums (2022). doi:10.1017/S109285292100002X
12. Borland JM, Kohut-Jackson AL, Peyla AC, et al.. Female Syrian hamster analyses of bremelanotide, a drug approved for the treatment of female hypoactive sexual desire disorder. Neuropharmacology (2025). doi:10.1016/j.neuropharm.2025.110299
13. Suzuki S, Kitanaka C, Okada M. Melanocortin Receptor Agonist Bremelanotide Induces Cell Death and Growth Inhibition in Glioblastoma Cells via Suppression of Survivin Expression. Anticancer Research (2024). doi:10.21873/anticanres.17214
14. Mestria S, Odoardi S, Frison G, Strano Rossi S. LC-HRMS characterization of the skin pigmentation and sexual enhancers melanotan II and bremelanotide sold on the black market of performance and image enhancing drugs. Drug Testing and Analysis (2021). doi:10.1002/dta.2986
15. Wessells H, Fuciarelli K, Hansen J, et al.. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study. Journal of Urology (1998). PMID 9679884
16. Lindskog A, Ebefors K, Johansson ME, et al.. Melanocortin 1 receptor agonists reduce proteinuria. Journal of the American Society of Nephrology (2010). doi:10.1681/ASN.2009101025
17. Cipriani S, Alfaroli C, Maseroli E, Vignozzi L. An evaluation of bremelanotide injection for the treatment of hypoactive sexual desire disorder. Expert Opinion on Pharmacotherapy (2023). doi:10.1080/14656566.2022.2132144
18. Spielmans GI. Re-Analyzing Phase III Bremelanotide Trials for Hypoactive Sexual Desire Disorder in Women. Journal of Sex Research (2021). PMID 33678061
19. Simon JA, Kingsberg SA, Portman D, et al.. Prespecified and Integrated Subgroup Analyses from the RECONNECT Phase 3 Studies of Bremelanotide. Journal of Women's Health (2022). doi:10.1089/jwh.2021.0225
20. Ultra-sensitive quantification of the therapeutic cyclic peptide bremelanotide utilizing UHPLC-MS/MS for evaluation of its oral plasma pharmacokinetics. Journal of Pharmaceutical and Biomedical Analysis (2020). PMID 32353679
21. Bremelanotide, PubChem Compound Summary CID 9941379. PubChem, National Library of Medicine
22. Phase 3 Trial to Evaluate the Efficacy and Safety of Subcutaneous Bremelanotide in Premenopausal Women With Hypoactive Sexual Desire Disorder (RECONNECT 301). ClinicalTrials.gov (2019)
23. A Phase IIb, Multicenter, Open-Label, Prospective Study of Bremelanotide in Diabetic Kidney Disease. ClinicalTrials.gov (2024)
24. A Phase II Study Evaluating the Co-Administration of Bremelanotide With Tirzepatide in Obesity. ClinicalTrials.gov (2024)