Entry 0018Rev 1.0Melanocortin receptor agonist

PT-141

Cyclic heptapeptide · C50H68N14O10

Reviewed

2 Nov 2026

Scientific editor

[Name, PhD]

References

17 sources

PT-141, now called bremelanotide, is a cyclic seven-residue peptide that acts on melanocortin receptors. Palatin Technologies developed it from melanotan II, a tanning peptide made at the University of Arizona.3,4

In 2019 the FDA approved it as Vyleesi for low sexual desire in premenopausal women. The label says the way it works in that condition is unknown.14 It is not authorised in the UK or the EU.

Residues

7, cyclic

Avg mass

1025.2 g/mol

US approval

2019

WADA

Not named

01

Identity

Value
SequenceAc-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH; lactam bridge between Asp2 and Lys7
ReceptorsMelanocortin receptors, MC1R > MC4R > MC3R > MC5R > MC2R
FormulaC50H68N14O10
Avg mass1025.2 g/mol
CAS189691-06-3
DeveloperPalatin Technologies
BrandVyleesi (US)
02

History

  1. Melanotan II, the parent peptide, tested in a phase 1 tanning study.1

  2. Melanotan II found to cause erections in men, pointing to a role in sexual function.2,3

  3. Palatin reports erections in rats and primates with PT-141.4

  4. Erectile dysfunction programme delayed after the FDA raised concerns about rises in blood pressure.15

  5. RECONNECT phase 3 trials published.9

  6. FDA approves Vyleesi for acquired low sexual desire in premenopausal women.13,14

  7. Palatin sells Vyleesi to Cosette Pharmaceuticals.16

03

What the studies measured

StudyPeople or modelWhat was measuredFindingSource
Pfaus 2004Female ratsSexual solicitation, lordosis, activitySolicitation rose selectively; other behaviours unchanged[6]
Molinoff 2003Rats and primatesErections, hypothalamic activationErections in both species[4]
Diamond 2004Healthy men and men with erectile dysfunctionErectile responseSignificant response against placebo; flushing and nausea most common[5]
RECONNECT 20191,267 premenopausal women with low sexual desire, 24 weeks, two trialsDesire score and distress scoreBoth improved against placebo, by small margins; nausea, flushing and headache common[9]
Simon 2019684 women in the open-label extensionSafety over 52 weeksNausea 40.4%, flushing 20.6%, headache 12.0%[10]
Clayton 20223,500 participants across 43 studiesPooled safetyTransient small rises in blood pressure; patchy skin darkening rare under label conditions[11]
04

Regulatory and sport status

As of this revision. General information, not legal advice.

WhereStatus
USApproved in 2019 as Vyleesi, prescription only. Not indicated for men or postmenopausal women.14
UK, EUNot authorised. A European licensing deal ended in 2016.
SportNot named on the 2026 WADA list. As an approved medicine it does not fall under class S0.17
05

Open questions

  1. Whether the effects are clinically meaningful. A 2024 review called them small and questioned how well the trial measures capture the condition.12
  2. How it works in people. The label states the mechanism is unknown.14
  3. Long-term effects of repeated exposure on skin pigmentation and blood pressure.11
06

Common questions

Is PT-141 the same as bremelanotide and Vyleesi?

Yes. PT-141 was the development code; bremelanotide is the generic name and Vyleesi the US brand.

Is PT-141 the same as melanotan II?

No. It was developed from melanotan II and is closely related, but it is a different molecule with its own trials and approval.

What did the trials show?

In two phase 3 trials, desire scores rose and distress fell by small margins against placebo. Nausea affected about 40% of participants.

Is PT-141 approved in the UK?

No. It is approved only in the US among major markets.

Is PT-141 banned in sport?

It is not named on the 2026 WADA list, and as an approved medicine it does not fall under class S0.

—

See also

KPV Entry 0006Metabolic Shelf
07

References

  1. Dorr RT, et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sci. 1996;58(20):1777–1784. PMID 8637402
  2. Wessells H, et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study. J Urol. 1998;160(2):389–393. PMID 9679884
  3. Hadley ME. Discovery that a melanocortin regulates sexual functions in male and female humans. Peptides. 2005;26(10):1687–1689. PMID 15996790
  4. Molinoff PB, et al. PT-141: a melanocortin agonist for the treatment of sexual dysfunction. Ann N Y Acad Sci. 2003;994:96–102. PMID 12851303
  5. Diamond LE, et al. Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141 in healthy males and patients with mild-to-moderate erectile dysfunction. Int J Impot Res. 2004;16(1):51–59. PMID 14963471
  6. Pfaus JG, et al. Selective facilitation of sexual solicitation in the female rat by a melanocortin receptor agonist. Proc Natl Acad Sci USA. 2004;101(27):10201–10204. PMID 15226502
  7. Diamond LE, et al. An effect on the subjective sexual response in premenopausal women with sexual arousal disorder by bremelanotide (PT-141). J Sex Med. 2006;3(4):628–638. PMID 16839319
  8. Clayton AH, et al. Bremelanotide for female sexual dysfunctions in premenopausal women: a randomized, placebo-controlled dose-finding trial. Womens Health. 2016;12(3):325–337. PMID 27181790
  9. Kingsberg SA, 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
  10. Simon JA, et al. Long-term safety and efficacy of bremelanotide for hypoactive sexual desire disorder. Obstet Gynecol. 2019;134(5):909–917. PMID 31599847
  11. Clayton AH, et al. Safety profile of bremelanotide across the clinical development program. J Womens Health. 2022;31(2):171–182. PMID 35147466
  12. Spielmans GI, Ellefson EM. Small effects, questionable outcomes: bremelanotide for hypoactive sexual desire disorder. J Sex Res. 2024;61(4):540–561. PMID 36809187
  13. Dhillon S, Keam SJ. Bremelanotide: first approval. Drugs. 2019;79(14):1599–1606. PMID 31429064
  14. VYLEESI (bremelanotide injection) US prescribing information, NDA 210557. Drugs@FDA.
  15. Palatin Technologies and King Pharmaceuticals. Press release, 30 August 2007. sec.gov
  16. Palatin Technologies. Palatin completes sale of Vyleesi to Cosette Pharmaceuticals. Press release, 20 December 2023. palatin.com
  17. World Anti-Doping Agency. The 2026 Prohibited List (in force 1 January 2026). wada-ama.org

Peptidarium Library. PT-141 (entry 0018), revision 1.0, 2 November 2026. peptidarium.com/library/pt-141

08

Revision history

RevDateChangeBy
1.02 Nov 2026Entry created.[Scientific editor]

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