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PT-141 vs Melanotan II

A Bremelanotide Melanocortin receptor agonist, high affinity for MC4R FDA-approved (Vyleesi) · Prescription C Melanotan II Non-selective melanocortin-receptor agonist; pigmentation via MC1R Not FDA-approved · FDA compounding nomination withdrawn

Residue Editorial Team · updated

In brief

PT-141 (bremelanotide) and Melanotan II are closely related: PubChem lists the same seven-residue sequence for both1PubChemPubChem compound record: Bremelanotide. C50H68N14O10 · MW 1025.2 g/mol.,2PubChemPubChem compound record: melanotan-II. C50H69N15O9 · MW 1024.2 g/mol.. Bremelanotide was developed for sexual function, tested in phase 3 trials of 1,267 women, and approved as Vyleesi in 20193PubMedBremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. Kingsberg SA et al. Obstet Gynecol. 2019.,4FDADrugs@FDA: VYLEESI (AUTOINJECTOR) (NDA210557). COSETTE; original approval 2019-06-21; Prescription.. Melanotan II was developed for tanning, caused erections in two 10-man studies, and was never approved5PubMedSynthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study. Wessells H et al. J Urol. 1998.,6PubMedEffect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction. Wessells H et al. Urology. 2000.,7FDACertain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. U.S. FDA, content current as of 04/22/2026..

How do Bremelanotide and Melanotan II compare at a glance?

Table 1. Bremelanotide and Melanotan II on the dimensions that matter most; every entry is cited.
DimensionBremelanotideMelanotan II
Sequence (PubChem)XDHFRWK; C50H68N14O101XDHFRWK; C50H69N15O92
Receptor emphasisHigh affinity for MC4R8PubMedBremelanotide: First Approval. Dhillon S & Keam SJ Drugs. 2019.Non-selective melanocortin agonist9PubMedMelanotan II: a possible cause of renal infarction: review of the literature and case report. Peters B et al. CEN Case Rep. 2020.
Main use studiedLow sexual desire (HSDD) in premenopausal women3Tanning; erectile dysfunction in men10PubMedEvaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Dorr RT et al. Life Sci. 1996.,5
Largest trialTwo phase 3 RCTs, 1,267 women310-man crossover studies5,6
Trial dose1.75 mg SC as needed30.025 mg/kg SC5
Common side effectsNausea 40%, flushing 20%, headache 11%11PubMedSafety Profile of Bremelanotide Across the Clinical Development Program. Clayton AH et al. J Womens Health (Larchmt). 2022.Nausea, yawning, reduced appetite5
FDAApproved: Vyleesi, 20194Not approved; withdrawn compounding nomination7
Evidence gradeAC

Written by Residue Editorial Team

Reviewed by Residue Editorial Team · source-by-source check,

First published

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Registry data · How we grade · Markdown + sources

Figure 1. Size of the research record, from PubMed and ClinicalTrials.gov at the data edition. Bars are scaled to the larger value in each row; volume is not quality.
PubMed records 113 625
Trial publications 16 5
Registered studies 10 1
Phase 3 studies 3 0

Bremelanotide Melanotan II

Bremelanotide is a synthetic analog of α-MSH with high affinity for the melanocortin type 4 receptor8. Melanotan II is a non-selective melanocortin-receptor agonist9. PubChem gives both the sequence XDHFRWK, with formulas differing by one nitrogen, one hydrogen and one oxygen1,2.

What is the evidence for bremelanotide?

The RECONNECT phase 3 program randomized 1,267 premenopausal women with hypoactive sexual desire disorder to 1.75 mg as needed or placebo for 24 weeks; desire rose and distress fell versus placebo3. A 2024 reanalysis judged the benefits statistically modest12PubMedSmall Effects, Questionable Outcomes: Bremelanotide for Hypoactive Sexual Desire Disorder. Spielmans GI & Ellefson EM J Sex Res. 2024.. Vyleesi was approved in June 20194.

What is the evidence for Melanotan II?

In ten men with psychogenic erectile dysfunction, eight developed erections after 0.025 mg/kg5; in ten men with organic risk factors, erections followed 12 of 19 injections versus 1 of 21 placebo doses6. Case reports since describe melanoma, rhabdomyolysis and priapism13PubMedMelanoma associated with the use of melanotan-II. Hjuler KF & Lorentzen HF Dermatology. 2014.,14PubMedMelanotan II injection resulting in systemic toxicity and rhabdomyolysis. Nelson ME et al. Clin Toxicol (Phila). 2012.,15PubMedMelanotan Tanning Injection: A Rare Cause of Priapism. Mallory CW et al. Sex Med. 2021..

How should this evidence be read?

Bremelanotide's approval covers premenopausal women with HSDD only8. Melanotan II's controlled evidence is 23 people in three studies10,5,6, and FDA records serious adverse-event reports7.

Two identical glass beakers, one holding pale amber liquid and one clear, standing either side of a brass balance

Why do they get these evidence grades?

A Bremelanotide
FDA-approved (Vyleesi, NDA 210557) for acquired, generalized hypoactive sexual desire disorder in premenopausal women, on the basis of two randomized phase 3 trials. Other uses are graded separately. Grade A: Approved / regulatory-grade.
C Melanotan II
Two double-blind, placebo-controlled crossover studies of 10 men each and a 3-man phase I pilot; the abstracts do not report randomization. Later literature is mainly case reports. Grade C: Limited / early human data.

Questions readers ask

Is PT-141 the same as Melanotan II?

No, though they are closely related; PubChem lists the same sequence with different formulas1,2. Bremelanotide is an approved drug4; Melanotan II is not7.

Which works better for libido?

No trial has compared them. Bremelanotide improved desire scores modestly versus placebo in women3,12; Melanotan II raised self-reported desire in one 10-man study6.

Does PT-141 cause tanning like Melanotan II?

Focal hyperpigmentation was rare at labeled bremelanotide dosing but occurred in more than a third of people given up to 16 consecutive daily doses11. Melanotan II was developed to tan10.

References

Every source below was retrieved from its official API or page and cached on the data-edition date. Numbers match the margin notes.

  1. 1 PubChem PubChem compound record: Bremelanotide. C50H68N14O10 · MW 1025.2 g/mol.
  2. 2 PubChem PubChem compound record: melanotan-II. C50H69N15O9 · MW 1024.2 g/mol.
  3. 3 PubMed 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. PMID 31599840; doi:10.1097/AOG.0000000000003500.
  4. 4 FDA Drugs@FDA: VYLEESI (AUTOINJECTOR) (NDA210557). COSETTE; original approval 2019-06-21; Prescription.
  5. 5 PubMed 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. J Urol 1998. PMID 9679884.
  6. 6 PubMed Wessells H, Gralnek D, Dorr R, et al. Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction. Urology 2000. PMID 11018622; doi:10.1016/s0090-4295(00)00680-4.
  7. 7 FDA Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. U.S. FDA, content current as of 04/22/2026.
  8. 8 PubMed Dhillon S, Keam SJ. Bremelanotide: First Approval. Drugs 2019. PMID 31429064; doi:10.1007/s40265-019-01187-w.
  9. 9 PubMed Peters B, Hadimeri H, Wahlberg R, et al. Melanotan II: a possible cause of renal infarction: review of the literature and case report. CEN Case Rep 2020. PMID 31953620; doi:10.1007/s13730-020-00447-z.
  10. 10 PubMed Dorr RT, Lines R, Levine N, et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sci 1996. PMID 8637402; doi:10.1016/0024-3205(96)00160-9.
  11. 11 PubMed Clayton AH, Kingsberg SA, Portman D, et al. Safety Profile of Bremelanotide Across the Clinical Development Program. J Womens Health (Larchmt) 2022. PMID 35147466; doi:10.1089/jwh.2021.0191.
  12. 12 PubMed Spielmans GI, Ellefson EM. Small Effects, Questionable Outcomes: Bremelanotide for Hypoactive Sexual Desire Disorder. J Sex Res 2024. PMID 36809187; doi:10.1080/00224499.2023.2175192.
  13. 13 PubMed Hjuler KF, Lorentzen HF. Melanoma associated with the use of melanotan-II. Dermatology 2014. PMID 24355990; doi:10.1159/000356389.
  14. 14 PubMed Nelson ME, Bryant SM, Aks SE. Melanotan II injection resulting in systemic toxicity and rhabdomyolysis. Clin Toxicol (Phila) 2012. PMID 23121206; doi:10.3109/15563650.2012.740637.
  15. 15 PubMed Mallory CW, Lopategui DM, Cordon BH. Melanotan Tanning Injection: A Rare Cause of Priapism. Sex Med 2021. PMID 33460908; doi:10.1016/j.esxm.2020.100298.