# PT-141 vs Melanotan II

- Canonical: https://residue.info/vs/bremelanotide-vs-melanotan-ii/
- Compounds: Bremelanotide (https://residue.info/c/bremelanotide/), Melanotan II (https://residue.info/c/melanotan-ii/)
- Updated: 2026-10-19 · Reviewed by: Residue Editorial Team

PT-141 (bremelanotide) and Melanotan II are closely related: PubChem lists the same seven-residue sequence for both [1][2]. Bremelanotide was developed for sexual function, tested in phase 3 trials of 1,267 women, and approved as Vyleesi in 2019 [3][4]. Melanotan II was developed for tanning, caused erections in two 10-man studies, and was never approved [5][6][7].

## Side by side
| | Bremelanotide | Melanotan II |
|---|---|---|
| Sequence (PubChem) | XDHFRWK; C50H68N14O10 [1] | XDHFRWK; C50H69N15O9 [2] |
| Receptor emphasis | High affinity for MC4R [8] | Non-selective melanocortin agonist [9] |
| Main use studied | Low sexual desire (HSDD) in premenopausal women [3] | Tanning; erectile dysfunction in men [10][5] |
| Largest trial | Two phase 3 RCTs, 1,267 women [3] | 10-man crossover studies [5][6] |
| Trial dose | 1.75 mg SC as needed [3] | 0.025 mg/kg SC [5] |
| Common side effects | Nausea 40%, flushing 20%, headache 11% [11] | Nausea, yawning, reduced appetite [5] |
| FDA | Approved: Vyleesi, 2019 [4] | Not approved; withdrawn compounding nomination [7] |
| Evidence grade | A | C |

## How are they related?

Bremelanotide is a synthetic analog of α-MSH with high affinity for the melanocortin type 4 receptor [8]. Melanotan II is a non-selective melanocortin-receptor agonist [9]. PubChem gives both the sequence XDHFRWK, with formulas differing by one nitrogen, one hydrogen and one oxygen [1][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 placebo [3]. A 2024 reanalysis judged the benefits statistically modest [12]. Vyleesi was approved in June 2019 [4].

## What is the evidence for Melanotan II?

In ten men with psychogenic erectile dysfunction, eight developed erections after 0.025 mg/kg [5]; in ten men with organic risk factors, erections followed 12 of 19 injections versus 1 of 21 placebo doses [6]. Case reports since describe melanoma, rhabdomyolysis and priapism [13][14][15].

## How should this evidence be read?

Bremelanotide's approval covers premenopausal women with HSDD only [8]. Melanotan II's controlled evidence is 23 people in three studies [10][5][6], and FDA records serious adverse-event reports [7].

## Frequently asked questions
**Is PT-141 the same as Melanotan II?**
No, though they are closely related; PubChem lists the same sequence with different formulas [1][2]. Bremelanotide is an approved drug [4]; Melanotan II is not [7].

**Which works better for libido?**
No trial has compared them. Bremelanotide improved desire scores modestly versus placebo in women [3][12]; Melanotan II raised self-reported desire in one 10-man study [6].

**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 doses [11]. Melanotan II was developed to tan [10].


## Sources
[1] PubChem compound record: Bremelanotide. C50H68N14O10 · MW 1025.2 g/mol. https://pubchem.ncbi.nlm.nih.gov/compound/9941379
[2] PubChem compound record: melanotan-II. C50H69N15O9 · MW 1024.2 g/mol. https://pubchem.ncbi.nlm.nih.gov/compound/92432
[3] Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. Kingsberg SA et al. Obstet Gynecol. 2019. https://pubmed.ncbi.nlm.nih.gov/31599840/
[4] Drugs@FDA: VYLEESI (AUTOINJECTOR) (NDA210557). COSETTE; original approval 2019-06-21; Prescription. https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=210557
[5] Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study. Wessells H et al. J Urol. 1998. https://pubmed.ncbi.nlm.nih.gov/9679884/
[6] Effect 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. https://pubmed.ncbi.nlm.nih.gov/11018622/
[7] Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. U.S. FDA, content current as of 04/22/2026. https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
[8] Bremelanotide: First Approval. Dhillon S & Keam SJ Drugs. 2019. https://pubmed.ncbi.nlm.nih.gov/31429064/
[9] Melanotan II: a possible cause of renal infarction: review of the literature and case report. Peters B et al. CEN Case Rep. 2020. https://pubmed.ncbi.nlm.nih.gov/31953620/
[10] Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Dorr RT et al. Life Sci. 1996. https://pubmed.ncbi.nlm.nih.gov/8637402/
[11] Safety Profile of Bremelanotide Across the Clinical Development Program. Clayton AH et al. J Womens Health (Larchmt). 2022. https://pubmed.ncbi.nlm.nih.gov/35147466/
[12] Small Effects, Questionable Outcomes: Bremelanotide for Hypoactive Sexual Desire Disorder. Spielmans GI & Ellefson EM J Sex Res. 2024. https://pubmed.ncbi.nlm.nih.gov/36809187/
[13] Melanoma associated with the use of melanotan-II. Hjuler KF & Lorentzen HF Dermatology. 2014. https://pubmed.ncbi.nlm.nih.gov/24355990/
[14] Melanotan II injection resulting in systemic toxicity and rhabdomyolysis. Nelson ME et al. Clin Toxicol (Phila). 2012. https://pubmed.ncbi.nlm.nih.gov/23121206/
[15] Melanotan Tanning Injection: A Rare Cause of Priapism. Mallory CW et al. Sex Med. 2021. https://pubmed.ncbi.nlm.nih.gov/33460908/

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