Melanotan II: What the Record Actually Shows
Melanotan II is the most legally troubled compound covered on this site. It has no approval in any country, its US distribution ended in a criminal conviction and a permanent debarment order, and the UK regulator has shut down more than a hundred websites selling it. It is also one of the few research compounds where the case-report literature is substantial enough to describe specific harms rather than theoretical ones.
What it is, and what it does by accident
Melanotan II is a cyclic synthetic analogue of α-melanocyte-stimulating hormone. Unlike PT-141, which was later engineered for selectivity, it activates the melanocortin receptors indiscriminately — MC1R, which drives pigmentation, and MC3R and MC4R in the central nervous system, which govern sexual arousal and appetite.
That non-selectivity is the whole story of the compound. Its intended effect and its most famous side effect come from different receptors being hit at the same time, and there is no dose that separates them.
The trials that did happen
Melanotan II reached controlled human trials, but for erectile dysfunction rather than tanning. A double-blind placebo-controlled crossover study in psychogenic erectile dysfunction and a randomised trial in organic erectile dysfunction both reported effects on erection.
Development then moved away from it, toward the selective analogue. That is the informative part: the people who understood the molecule best chose to build a cleaner version rather than pursue this one, and the reason was the side-effect burden that comes with hitting every melanocortin receptor at once.
There has never been a controlled trial of Melanotan II for cosmetic tanning — the use that accounts for essentially all of its consumption.
The documented harms
These are case reports, not trial incidence rates, and that distinction matters: they tell you what can happen, not how often. They are also published in peer-reviewed journals rather than forum anecdote, which puts them a tier above most safety discussion in this space.
| Event | What was reported |
|---|---|
| Rhabdomyolysis | 39-year-old man injected 6 mg — roughly six times a typical starting dose. Sympathomimetic toxicity, creatine kinase peaking at 17,773 IU/L, intensive care admission. |
| Posterior reversible encephalopathy syndrome | A neurological syndrome confirmed on MRI following melanotan use, reported in Annals of Internal Medicine. |
| Priapism | At least three published cases. One required surgical penoscrotal decompression after aspiration and phenylephrine both failed. |
| Renal infarction | Case report with literature review. |
| Eruptive melanocytic naevi | The most consistent signal: at least five separate reports across four countries of moles darkening, enlarging and appearing in numbers after use. |
The melanoma question, answered precisely
This is where most writing on Melanotan II goes wrong in one direction or the other. Vendors say there is no evidence it causes cancer, which is technically true. Critics say it causes melanoma, which is not established.
Here is the accurate version. Melanoma cases in melanotan users are published — five primary melanomas in situ in one patient, an oral mucosal melanoma in a 22-year-old after nasal spray use. But the confounders are severe enough to be named in the titles of the papers themselves: concurrent tanning-bed use, anabolic hormone use. No causal link has been demonstrated, and with this kind of evidence none can be.
Melanotan I is a different drug
Search results conflate these constantly, usually to the benefit of the unapproved one.
| Melanotan I (afamelanotide) | Melanotan II | |
|---|---|---|
| Status | Approved — EU (SCENESSE, December 2014) and FDA | Not approved anywhere |
| Indication | Preventing phototoxicity in erythropoietic protoporphyria | None |
| Form | 16 mg subcutaneous implant every two months, administered by a physician | Self-injected powder from research suppliers |
| Cosmetic tanning use | Not approved, anywhere | Not approved, anywhere |
Note the last row. Neither compound is approved for tanning in any jurisdiction. The existence of an approved melanocortin drug for a rare light-sensitivity disease says nothing about the safety of injecting a different, non-selective analogue for a suntan.
Legal status
United States. The FDA treated Melanotan II as an unapproved new drug that could not lawfully be introduced into interstate commerce. Warning letters went out in 2007, a criminal conviction for conspiracy was entered in 2015, and a permanent debarment order was published in the Federal Register effective November 2016.
United Kingdom. The MHRA treats melanotan as a medicinal product under the Human Medicines Regulations. No melanotan product holds a UK marketing authorisation, so advertising, sale and supply all breach the regulations. The agency reported suspending more than 100 websites in a twelve-month period, and as of mid-2014 had received 22 adverse drug reaction reports describing 93 separate reactions.
Anti-doping. Melanotan II is not named in the 2026 WADA Prohibited List. As a substance with no regulatory approval anywhere for human use, it would be captured by the S0 catch-all class — that is a reading of the rule rather than an explicit listing, and anyone subject to testing should confirm with their own authority.
Dosing references
No approved dose exists. Protocols in circulation use a loading phase of 250–500 mcg daily until the desired pigmentation appears, then a maintenance dose once or twice weekly. The 6 mg single dose that produced the rhabdomyolysis case sits far above that range — which is the practical argument for the calculator below rather than eyeballing a syringe.
| Vial | Water | Concentration | 250 mcg | 500 mcg | Doses (250 mcg) |
|---|---|---|---|---|---|
| 10 mg | 2 ml | 5,000 mcg/ml | 5 units | 10 units | 40 |
| 10 mg | 2.5 ml | 4,000 mcg/ml | 6.25 units | 12.5 units | 40 |
| 10 mg | 5 ml | 2,000 mcg/ml | 12.5 units | 25 units | 40 |
Formula: concentration = peptide (mcg) ÷ water (ml). Volume = dose ÷ concentration. One unit on a U-100 insulin syringe = 0.01 ml. Values are for laboratory reference only.
Nausea and flushing are near-universal early on and are dose-related, which is why protocols start low. Neither is a sign the compound is working; both are the melanocortin system being activated indiscriminately.
Melanotan II — 10 mg — American Peptides
Not approved in any country, and subject to enforcement action in the US and UK. If you are sourcing it, batch purity documentation is the only quality signal available. Research use only.
We may earn a commission if you buy through this link (at no extra cost to you). Sold for research purposes only.
Frequently asked questions
Does Melanotan II cause melanoma?
That has never been established. Case reports of melanoma in melanotan users exist, but the published cases carry heavy confounders — concurrent tanning-bed use, anabolic steroid use, existing sun damage. The claim that is well supported is different and still serious: melanotan reliably causes existing moles to darken, enlarge and multiply, which makes early melanoma harder to spot against a background of changing lesions.
What is the difference between Melanotan I and Melanotan II?
They are different molecules with very different regulatory status, and the two get conflated constantly. Melanotan I is afamelanotide, approved in the EU as SCENESSE and by the FDA — but only for preventing phototoxicity in erythropoietic protoporphyria, a rare light-sensitivity disease. Melanotan II is not approved anywhere for anything. Citing the first to imply legitimacy for the second is the most common sleight of hand in this category.
Why does Melanotan II cause erections?
It is a non-selective melanocortin agonist. Tanning comes from MC1R; the sexual effect comes from MC3R and MC4R in the central nervous system. That effect was discovered by accident — in the first human study, two of three volunteers had spontaneous erections lasting one to five hours, which nobody had set out to produce.
What are the documented serious side effects?
Published case reports include rhabdomyolysis with a creatine kinase peak of 17,773 IU/L after a 6 mg dose, posterior reversible encephalopathy syndrome confirmed on MRI, priapism requiring surgical decompression after drug treatment failed, and renal infarction. These are individual case reports rather than trial rates, but they are documented in peer-reviewed journals.
Is Melanotan II legal?
It has no approval anywhere. In the United States the FDA treated it as an unapproved new drug, issued warning letters, and the matter ended in a criminal conviction and a permanent debarment order published in the Federal Register. In the UK the MHRA classes it as a medicinal product with no licence, and has suspended more than a hundred websites selling it.
Sources
- Dorr RT et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sciences, 1996;58(20):1777–84. PubMed
- Wessells H et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: a double-blind, placebo controlled crossover study. Journal of Urology, 1998;160(2):389–93. PubMed
- Wessells H et al. Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction. Urology, 2000;56(4):641–6. PubMed
- Hadley ME, Dorr RT. Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization. Peptides, 2006;27(4):921–30. PubMed
- Nelson ME, Bryant SM, Aks SE. Melanotan II injection resulting in systemic toxicity and rhabdomyolysis. Clinical Toxicology, 2012;50(10):1169–73. PubMed
- Kaski D et al. Melanotan and the posterior reversible encephalopathy syndrome. Annals of Internal Medicine, 2013;158(9):707–8. PubMed
- Mallory CW, Lopategui DM, Cordon BH. Melanotan Tanning Injection: A Rare Cause of Priapism. Sexual Medicine, 2021;9(1):100298. PubMed
- Peters B et al. Melanotan II: a possible cause of renal infarction — review of the literature and case report. CEN Case Reports, 2020;9(2):159–161. PubMed
- Cousen P, Colver G, Helbling I. Eruptive melanocytic naevi following melanotan injection. British Journal of Dermatology, 2009;161(3):707–8. PubMed
- Langan EA et al. Change in moles linked to use of unlicensed "sun tan jab." BMJ, 2009;338:b277. PubMed
- Cardones AR, Grichnik JM. α-Melanocyte-stimulating hormone-induced eruptive nevi. Archives of Dermatology, 2009;145(4):441–4. PubMed
- Vadner DJ, Smith S. Five primary melanomas in situ in a patient with recent tanning bed use, melanotan exposure, and anabolic hormone use. JAAD Case Reports, 2026;73:111–114. PubMed
- Alsabbagh AY, Bhujel N, Singh RP. Melanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma? International Journal of Oral and Maxillofacial Surgery, 2025;54(9):806–808. PubMed
- FDA. Debarment order, 81 FR 79501–79502 — documents the warning letters, conviction and permanent debarment. Federal Register
- European Medicines Agency. SCENESSE (afamelanotide) — the approved Melanotan I product, for erythropoietic protoporphyria only. EMA
Related guides
- PT-141 (bremelanotide): the selective analogue that reached approval
- Are peptides safe? Side effects by class
- Peptide reconstitution calculator