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Melanotan II

Studied for skin darkening without UV, erections and arousal and appetite suppression. A cyclic seven-residue analogue of alpha-melanocyte-stimulating hormone synthesised at the University of Arizona in the 1980s and carried no further than a three-subject pilot study.

categoryskin and other
clinical evidencetrials halted
community adoptionhigh
uses graded4
sources12
last reviewed24 Aug 2026
compound file

The answer, first. A cyclic seven-residue analogue of alpha-melanocyte-stimulating hormone synthesised at the University of Arizona in the 1980s and carried no further than a three-subject pilot study. The strongest evidence is for skin darkening without UV, graded C — small or open-label human only.

The only human tanning study dosed three men, two of whom showed increased facial, upper-body and buttock pigment by reflectance a week after dosing ended 1.

Three subjects. Single-blind. 1996. The rest of what it is sold for — appetite suppression, protection from sunburn — grade D or E: animal or mechanism data with no controlled human outcome.

What it is used for

Every use graded on its own evidence, not the compound as a whole. 4 outcomes, ranked by what the human record supports.

#outcome · human · animal · gradewhat the best evidence actually shows
01Skin darkening without UV1 pilot, n=3 · extensivegrade CThe only human tanning study dosed three men, two of whom showed increased facial, upper-body and buttock pigment by reflectance a week after dosing ended 1. Three subjects. Single-blind. 1996.
02Erections and arousal1 crossover trial, n=10 · supportinggrade CIn ten men with psychogenic erectile dysfunction, mean tip rigidity above 80% lasted 38.0 minutes on melanotan II versus 3.0 on placebo [P=0.0045] 2. Ten men, crossover, 1998.
03Appetite suppressionno trial · melanocortin-4 feeding modelsgrade DDecreased appetite was logged as a side effect in the ten-man crossover, more often on melanotan II than placebo 2. No trial has measured weight or body composition.
04Protection from sunburnno trial · none for this endpointgrade DPigment rises, and pigment is protective in principle. No melanotan II study has measured sunburn, DNA damage or minimal erythemal dose. Those endpoints belong to melanotan I 3.
gradewhat it means
ARegulatory approval, or multiple adequately-powered trials agreeing with each other
BAt least one well-powered human randomised trial, with the direction replicated
CSmall or open-label human trials only
DAnimal or mechanism data only, with no controlled human outcome
EA claim the human trials have already killed

How it works

The proposed mechanism, in three steps. A mechanism is a reason to run a trial, never a substitute for one.

1targetBinds melanocortin receptors without selectivity: MC1 on melanocytes drives pigment, MC3 and MC4 in the brain drive arousal and appetite 12.
2signalMC1 activation raises cyclic AMP and tyrosinase. Central MC4 activation acts upstream of erection rather than on genital blood flow 2.
3effectSkin darkens over weeks. Erections, nausea and flushing arrive within hours. The same lack of selectivity produces both 12.

What it does not do

Claims the current record does not support. Worth knowing before you set expectations.

not supported by the evidence

How it is used

What published protocols administered, and what the community reports doing. Descriptive on both counts, and never a recommendation.

routeSubcutaneous injection of reconstituted powder is the sold route. Nasal sprays also circulate and appear in the case-report literature 12.
formatLyophilised powder in 10 mg vials, reconstituted with bacteriostatic water. Nasal spray also sold.
published dosesThe pilot study gave 0.01 mg/kg daily, escalating in 0.005 mg/kg steps to 0.03 mg/kg, five doses a week for two weeks. At 0.03 mg/kg, one of two subjects had grade II somnolence 1. The erection study used a single 0.025 mg/kg dose 2. No human pharmacokinetic study exists.
human pharmacokineticsNo human pharmacokinetic data published.
reported conventionsAs reported on tanning, bodybuilding and physique forums, 2009-2026: a loading run of small daily injections. Then a maintenance dose once or twice a week, with UV exposure alongside. Threads describe dosing at night because nausea and flushing follow within an hour. Convention, not guidance.

This site does not publish protocols to follow. The doses above are what studies administered or what users report, stated as facts about the literature and the market. How protocols are structured, mixing and storage and the reconstitution calculator cover the arithmetic.

What to expect

Where a trial measured it, the trial. Where only the community reports it, that is said out loud.

onsetPigment was measured a week after dosing ended in the three-subject study, after ten doses across two weeks 1. Erections appeared inside the six-hour monitoring window in the crossover study 2. No trial measured time to a cosmetic tan.
most common reportNausea and facial flushing within an hour, spontaneous erections in men, then gradual darkening 12. Freckling and darkening of existing moles is the common dermatology presentation 45.
adverse effectsThe published record is case reports, not rates. Eruptive and changing melanocytic naevi 45, melanoma alongside use 711, priapism 10. One 6 mg injection was followed by rhabdomyolysis with creatine kinase 17,773 IU/L and renal impairment 6.
the stop signalDermatology case series treat a changing or new mole as the reason to stop and be examined 457. The emergency presentations in the toxicology reports followed a single larger-than-usual dose 6.

Approval and status

What regulators and sport bodies have actually said, separately from what the evidence shows.

approvalNever approved anywhere. Development stopped after the 1996 pilot study.
FDANominated for compounding, then withdrawn. FDA cites case reports of melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxidrome and priapism 9.
sport [WADA]Falls under S0, non-approved substances. Prohibited at all times.
sold asresearch chemical

Check the vial

The grade above describes a molecule studied under controlled conditions. It says nothing about the powder in a particular vial.

That gap is the one part of this market a reader can actually close. How to read a certificate of analysis covers the five measures in five minutes, and the 2026 audit grades vendors on the documents they publish against a rubric printed in full.

Questions we get

What is Melanotan II used for?

Tanning, overwhelmingly. It is the melanotan people actually buy, because it darkens skin at low doses and is cheap. A minority buy it for the spontaneous erections that were logged as a side effect in the 1990s studies.

Neither use has ever been through an adequately powered trial. The entire human record is one three-subject dosing study, one ten-man crossover on erections, and roughly two decades of dermatology and toxicology case reports.

How is Melanotan II used?

Described rather than advised. The published studies injected it subcutaneously at 0.01 to 0.03 mg/kg per day, five days a week, over two weeks. As reported on tanning and physique forums since 2009, the pattern is a loading run of small daily injections.

Then a maintenance dose once or twice weekly, with UV exposure alongside. Threads describe dosing at night, because nausea and flushing arrive within an hour. Convention, not guidance.

How long does Melanotan II take to work?

No trial measured it. In the three-subject pilot, increased pigment was recorded a week after dosing ended, following ten doses over two weeks. Erections in the ten-man crossover appeared inside a six-hour monitoring window.

Everything more specific than that comes from forums. Forums cannot distinguish the peptide from the UV exposure people take alongside it, or from the tan they would have developed anyway.

Is Melanotan II an approved drug?

No, and it never was. It is sold as a research chemical. Its development stopped after a pilot study in three volunteers. The derivative that was carried forward, bremelanotide, is a different molecule, approved in 2019 for a different purpose.

Medicines regulators in several countries have warned against melanotan products. Our index grades it trials halted on clinical evidence and high on community adoption, rated separately on purpose.

What are the documented harms of Melanotan II?

Case reports, not rates, because no trial ever counted. The dermatology literature documents eruptive new moles, dermoscopic change in existing ones, and four reported melanomas arising during or shortly after use.

The toxicology literature documents priapism and one confirmed case of systemic toxicity with rhabdomyolysis and renal impairment after a 6 mg injection. FDA lists melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxidrome and priapism in its compounding review.

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;58:1777-84. 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;160:389-93. PMID 9679884
  3. Barnetson RS, et al. [Nle4-D-Phe7]-alpha-melanocyte-stimulating hormone significantly increased pigmentation and decreased UV damage in fair-skinned Caucasian volunteers. J Invest Dermatol. 2006;126:1869-78. PMID 16763547
  4. Cardones AR, Grichnik JM. alpha-Melanocyte-stimulating hormone-induced eruptive nevi. Arch Dermatol. 2009;145:441-4. PMID 19380666
  5. Cousen P, Colver G, Helbling I. Eruptive melanocytic naevi following melanotan injection. Br J Dermatol. 2009;161:707-8. PMID 19575725
  6. Nelson ME, Bryant SM, Aks SE. Melanotan II injection resulting in systemic toxicity and rhabdomyolysis. Clin Toxicol. 2012;50:1169-73. PMID 23121206
  7. Hjuler KF, Lorentzen HF. Melanoma associated with the use of melanotan-II. Dermatology. 2014;228:34-6. PMID 24355990
  8. Breindahl T, et al. Identification and characterization by LC-UV-MS/MS of melanotan II skin-tanning products sold illegally on the Internet. Drug Test Anal. 2015;7:164-72. PMID 24771717
  9. FDA. Certain Bulk Drug Substances for Use in Compounding That May Present Significant Safety Risks. Content current as of 22 April 2026. fda.gov
  10. Mallory CW, et al. Melanotan Tanning Injection: A Rare Cause of Priapism. Sex Med. 2021;9:100298. PMID 33460908
  11. Habbema L, et al. Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review. Int J Dermatol. 2017;56:975-980. PMID 28266027
  12. Yassin Alsabbagh A, et al. Melanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma. Int J Oral Maxillofac Surg. 2025;54:806-808. PMID 40210573

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