Melanotan II

Melanotan II at a Glance

Melanotan-II is a synthetic, cyclic analogue of α-MSH that activates melanocortin receptors broadly, triggering melanin production and darkening skin without UV exposure. Because it hits several receptor subtypes at once it also produces the sexual arousal, nausea and flushing that led to PT-141 being developed from it. It was never approved anywhere and is injected on the grey market as a tanning and libido peptide.

History & Development

Melanotan-II came out of the same Arizona programme as its predecessor, and it is the compound whose side effect turned out to be more commercially interesting than its intended purpose.

First described	Developed at the University of Arizona in the late 1980s-early 1990s, following the 1980 alpha-MSH analogue work 29Reference 29Sawyer et al. · 1980Sawyer, T. K., Sanfilippo, P. J., Hruby, V. J., Engel, M. H., Heward, C. B., Burnett, J. B., & Hadley, M. E. (1980). 4-Norleucine, 7-D-phenylalanine-alpha-melanocyte-stimulating hormone: a highly potent alpha-melanotropin with ultralong biological activity. Proceedings of the National Academy of Sciences, 77(10), 5754-5758. https://pubmed.ncbi.nlm.nih.gov/6777774/View study →
Discovered / synthesised by	The Hadley and Hruby melanocortin programme 29,30Reference 29Sawyer et al. · 1980Sawyer, T. K., Sanfilippo, P. J., Hruby, V. J., Engel, M. H., Heward, C. B., Burnett, J. B., & Hadley, M. E. (1980). 4-Norleucine, 7-D-phenylalanine-alpha-melanocyte-stimulating hormone: a highly potent alpha-melanotropin with ultralong biological activity. Proceedings of the National Academy of Sciences, 77(10), 5754-5758. https://pubmed.ncbi.nlm.nih.gov/6777774/View study →Reference 30Arizona Daily StarUA-developed synthetic hormones speed a tanView study →
Institution	University of Arizona 29,30Reference 29Sawyer et al. · 1980Sawyer, T. K., Sanfilippo, P. J., Hruby, V. J., Engel, M. H., Heward, C. B., Burnett, J. B., & Hadley, M. E. (1980). 4-Norleucine, 7-D-phenylalanine-alpha-melanocyte-stimulating hormone: a highly potent alpha-melanotropin with ultralong biological activity. Proceedings of the National Academy of Sciences, 77(10), 5754-5758. https://pubmed.ncbi.nlm.nih.gov/6777774/View study →Reference 30Arizona Daily StarUA-developed synthetic hormones speed a tanView study →
Origin	Cyclic synthetic analogue of the endogenous hormone alpha-MSH
Key patent	Not established in the sources consulted for this section
Assignee	n/a
Development status	Never approved in any jurisdiction; no completed development programme

Discovery

The Arizona group’s founding work produced a superpotent, degradation-resistant alpha-MSH analogue in 1980 ^{29Reference 29Sawyer et al. · 1980Sawyer, T. K., Sanfilippo, P. J., Hruby, V. J., Engel, M. H., Heward, C. B., Burnett, J. B., & Hadley, M. E. (1980). 4-Norleucine, 7-D-phenylalanine-alpha-melanocyte-stimulating hormone: a highly potent alpha-melanotropin with ultralong biological activity. Proceedings of the National Academy of Sciences, 77(10), 5754-5758. https://pubmed.ncbi.nlm.nih.gov/6777774/View study →}. Melanotan-II followed as a cyclic analogue - a ring structure conferring further stability - developed as a candidate chemopreventive agent on the same reasoning: that inducing melanogenesis without ultraviolet exposure might reduce UV-driven DNA damage and skin cancer risk ^{30Reference 30Arizona Daily StarUA-developed synthetic hormones speed a tanView study →}.

The compound is less selective than melanotan-I, activating several melanocortin receptor subtypes rather than MC1 alone. That breadth is the origin of everything else about it. During early human testing the compound produced spontaneous erections and sexual arousal in male subjects - an unintended finding that redirected an entire line of research and led to PT-141 ^{30Reference 30Arizona Daily StarUA-developed synthetic hormones speed a tanView study →}.

Development & ownership

Melanotan-II itself was never developed into a medicine. No company took it through a registered clinical programme, and it has never been approved anywhere. Its pharmacology instead produced two descendants that did reach approval by separating out one receptor effect each: afamelanotide for pigmentation, and bremelanotide for sexual desire.

The patent position and any assignee for melanotan-II specifically were not established in the sources consulted for this section.

How it reached the market

Melanotan-II reached consumers entirely outside pharmaceutical channels. It circulates as an unapproved injectable sold for tanning and libido, typically as lyophilised powder for self-reconstitution, and its non-selectivity means users encounter the nausea, flushing and spontaneous erections that were originally recorded as trial side effects. It is one of the clearest cases here of a research compound reaching the public without any development programme at all.

What It's Used For

Melanotan II (MT-II) is a synthetic, cyclic lactam-bridged analogue of α-melanocyte-stimulating hormone (α-MSH) that acts as a non-selective agonist across the melanocortin receptors — MC1R on melanocytes (skin darkening) and MC3R/MC4R in the hypothalamus (erection, appetite) ^{1,2Reference 1Dorr RT et al. · 1996Clinical trialEvaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study — human (phase I, n=3)View study →Reference 2Hadley ME et al. · 1998ReviewDiscovery and development of novel melanogenic drugsView study →}.

Its evidence posture is unusual and worth stating plainly. MT-II does have a small, genuine human controlled-trial record from the 1990s — double-blind, placebo-controlled crossover studies of erectile response and a three-person phase I tanning pilot — but it was never taken through approval in any jurisdiction, and development pivoted instead to two relatives that were approved: melanotan I / afamelanotide (Scenesse, for erythropoietic protoporphyria) and PT-141 / bremelanotide (Vyleesi, an MT-II metabolite approved for hypoactive sexual desire disorder) ^{7,8Reference 7Molinoff PB et al. · 2003Clinical trialPT-141: a melanocortin agonist for the treatment of sexual dysfunction — human (clinical trial)View study →Reference 8Kingsberg SA et al. · 2019RCTBremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials — human (RCT, phase III)View study →}.

MT-II is the unapproved, non-selective one in the middle. Everything beyond tanning and erection is rodent-only. Route is load-bearing: it is a peptide with negligible oral bioavailability, so it is injected subcutaneously (an illicit nasal spray also circulates). The decisive asymmetry here is that the most informative recent human literature about MT-II is not efficacy data at all — it is a run of adverse-event case reports: melanoma and eruptive atypical naevi, priapism, rhabdomyolysis, posterior reversible encephalopathy syndrome, and renal infarction ^{14,15,16,17,18,19,21,26,27,28Reference 14Mallory CW et al. · 2021Case reportMelanotan tanning injection: a rare cause of priapism — human (case report)View study →Reference 15Dreyer BA et al. · 2019Case reportMelanotan-induced priapism: a hard-earned tan — human (case report)View study →Reference 16Nelson ME et al. · 2012Case reportMelanotan II injection resulting in systemic toxicity and rhabdomyolysis — human (case report)View study →Reference 17Hjuler KF et al. · 2014Case reportMelanoma associated with the use of melanotan-II — human (case report)View study →Reference 18Paurobally D et al. · 2011Case reportMelanotan-associated melanoma — human (case report)View study →Reference 19Reid C et al. · 2013Case reportAtypical melanocytic naevi following melanotan injection — human (case report)View study →Reference 21Yassin Alsabbagh A et al. · 2025Case reportMelanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma? — human (case report)View study →Reference 26Kaski D et al. · 2013Case reportMelanotan and the posterior reversible encephalopathy syndrome — human (case report)View study →Reference 27Peters B et al. · 2020Case reportMelanotan II: a possible cause of renal infarction — review of the literature and case report — human (case report + review)View study →Reference 28Devlin J et al. · 2013Case reportMelanotan II overdose associated with priapism — human (case report)View study →}.

Evidence by IndicationStrength of support · Beta

Support is an experimental score I’m building — a composite weighted by study type (human > animal > in vitro > review) and study volume. It’s a beta: a fast way to rank strength of evidence at a glance, not a validated metric. Each application links down to its write-up.

01Erectile / sexual functionPromising58%Several small human double-blind placebo-controlled crossover trials (n≈10–20, 1996–2000), then development abandoned in favor of PT-141. No phase III, no approval.

02Skin tanning (melanogenesis)Promising45%MC1R mechanism certain and universally confirmed in real-world use, but formal human efficacy = one 3-person phase I pilot. No dose-response or safety trial.

03Appetite suppression & weight lossShaky28%Rodent only. MC4R pathway is human-validated via the different, selective drug setmelanotide; no human MT-II trial exists.

04Insulin sensitivity & glucoseShaky22%One rat strain (OLETF), one lab, confounded by weight loss. No human data.

05Peripheral nerve regenerationShaky14%Single rat sciatic-nerve study from one group. No replication, no human data.

Mechanisms

MT-II is deliberately non-selective, and that breadth is the whole story: one molecule tans, erects and suppresses appetite because it hits four receptor subtypes at once — and the same non-selectivity is why the side-effect profile (nausea, blood-pressure change, priapism) tracks its central melanocortin activity rather than being separable from its cosmetic effect.

Pharmacokinetics

MT-II is a peptide with negligible oral bioavailability, so it is given subcutaneously; an illicit nasal-spray route also circulates ^{21Reference 21Yassin Alsabbagh A et al. · 2025Case reportMelanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma? — human (case report)View study →}. This is load-bearing rather than incidental — oral “melanotan” products cannot deliver intact peptide, and every rodent finding above was produced by injection or direct central administration. Human pharmacokinetics are essentially unpublished. The only formal PK study is preclinical: an LC-MS/MS characterization of MT-II disposition after intravenous dosing in rats ^{13Reference 13Mock S et al. · 2002AnimalDetermination of melanotan-II in rat plasma by liquid chromatography/tandem mass spectrometry: pharmacokinetic parameters following intravenous administration — animal (rat, PK)View study →}. By class, and by the hours-long duration of the erectile and flushing effects reported in the human trials ^{3,4,5Reference 3Wessells H et al. · 1998RCTSynthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study — human (RCT, crossover)View study →Reference 4Wessells H et al. · 2000RCTEffect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction — human (RCT, crossover)View study →Reference 5Wessells H et al. · 2000Clinical trialMelanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II — human (controlled clinical trial)View study →}, the plasma half-life is short — its approved metabolite bremelanotide has a human t½ of roughly 2.7 hours — but no verified human half-life or bioavailability figure for MT-II exists. Gray-market material is supplied as lyophilized powder requiring reconstitution (typically with bacteriostatic water) before injection; stability and sterility after reconstitution are entirely user-dependent and undocumented.

Clinical & regulatory status

Melanotan II has never been approved as a medicine or a dietary supplement in any jurisdiction. Its entire human clinical record is a handful of small investigator-led studies from 1996–2000 that predate modern trial registration ^{1,3,4,5Reference 1Dorr RT et al. · 1996Clinical trialEvaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study — human (phase I, n=3)View study →Reference 3Wessells H et al. · 1998RCTSynthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study — human (RCT, crossover)View study →Reference 4Wessells H et al. · 2000RCTEffect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction — human (RCT, crossover)View study →Reference 5Wessells H et al. · 2000Clinical trialMelanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II — human (controlled clinical trial)View study →}; the program was then discontinued, with the sexual-function thread continuing as bremelanotide/PT-141 (FDA-approved 2019 for HSDD) and the pigmentation thread as afamelanotide/Scenesse (approved for erythropoietic protoporphyria) ^{7,8Reference 7Molinoff PB et al. · 2003Clinical trialPT-141: a melanocortin agonist for the treatment of sexual dysfunction — human (clinical trial)View study →Reference 8Kingsberg SA et al. · 2019RCTBremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials — human (RCT, phase III)View study →}. There are no ongoing registered MT-II efficacy trials, and the contemporary human literature is dominated by adverse-event case reports rather than efficacy data. The UK MHRA has publicly warned against melanotan products and their sale for human use is unlawful in the UK; dermatology bodies and public-health authors have made the same call, framing it as an unlicensed injectable of unknown purity used cosmetically ^{24Reference 24Evans-Brown M et al. · 2009Use of melanotan I and II in the general population — editorialView study →}.

*Four small investigator-led human studies (1996–2000) exist but were never entered in trial registries ^{1,3,4,5Reference 1Dorr RT et al. · 1996Clinical trialEvaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study — human (phase I, n=3)View study →Reference 3Wessells H et al. · 1998RCTSynthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study — human (RCT, crossover)View study →Reference 4Wessells H et al. · 2000RCTEffect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction — human (RCT, crossover)View study →Reference 5Wessells H et al. · 2000Clinical trialMelanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II — human (controlled clinical trial)View study →}.

Last checked: July 2026.

Sourcing, Route & Legal Status

Regulatory status. MT-II is an unapproved research chemical with no marketing authorization anywhere in the world. Its sale for human consumption is illegal in the UK — where the MHRA has issued explicit warnings — and in many other countries, so it is typically marketed “for research use only / not for human consumption” to sidestep medicines law ^{21,24Reference 21Yassin Alsabbagh A et al. · 2025Case reportMelanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma? — human (case report)View study →Reference 24Evans-Brown M et al. · 2009Use of melanotan I and II in the general population — editorialView study →}. It should not be confused with its approved relatives: afamelanotide (melanotan I / Scenesse), an α-MSH analogue approved for photoprotection in erythropoietic protoporphyria, and bremelanotide (PT-141 / Vyleesi), an MT-II metabolite approved by the FDA in 2019 for hypoactive sexual desire disorder in premenopausal women ^{7,8Reference 7Molinoff PB et al. · 2003Clinical trialPT-141: a melanocortin agonist for the treatment of sexual dysfunction — human (clinical trial)View study →Reference 8Kingsberg SA et al. · 2019RCTBremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials — human (RCT, phase III)View study →}. Approval by association is exactly the error this compound invites: MT-II sits outside all of it. The selective MC4R agonist setmelanotide, approved for rare genetic obesity, is likewise a different drug.

How it’s supplied & administered. Gray-market MT-II is sold as lyophilized powder in vials, reconstituted by the user — usually with bacteriostatic water — for subcutaneous injection; an illicit nasal spray also circulates and has its own reported harm (a 2025 case report describes oral mucosal melanoma after nasal-spray use) ^{21Reference 21Yassin Alsabbagh A et al. · 2025Case reportMelanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma? — human (case report)View study →}. Oral use is pharmacologically pointless. Reconstituted product should be refrigerated, but real-world storage, dosing accuracy and sterility are entirely in the hands of the user.

Sourcing reality (this is a safety issue, not a footnote). MT-II is produced and sold by unregulated vendors with no manufacturing oversight. Forensic analysis of black-market pigmentation and “sexual enhancer” products has characterized MT-II and bremelanotide sold without reference standards and alongside anabolic steroids and other performance-and-image-enhancing drugs — an unverified supply chain by construction ^{23Reference 23Mestria S et al. · 2021LC-HRMS characterization of the skin pigmentation and sexual enhancers melanotan II and bremelanotide sold on the black market — forensic product analysisView study →}. What follows directly: mislabeling and unknown purity, endotoxin and microbial contamination, non-sterile reconstitution, injection-site infection, and dosing error from self-mixed concentrations. There is no meaningful certificate-of-analysis guarantee; where third-party testing exists at all it is vendor-commissioned. No vendors are recommended or linked here.

Safety

Melanotan II has no controlled long-term human safety data at all, and unusually for a research peptide the published human literature that does exist is predominantly a record of harm — melanoma and atypical moles, priapism, and acute systemic toxicity, all from an unregulated injectable.

Safety at a Glance

⚠️ Moderate toxicityCardiac riskOverdose riskDrug interactions

• Case reports of new, changing and eruptive atypical moles — and of melanoma. Mechanism-driven via MC1R; anyone who has used it and notices a changing mole should get dermatological review.
• Priapism is the best-documented serious harm. A urological emergency that risks permanent erectile dysfunction if not treated promptly.
• Rhabdomyolysis, PRES and renal infarction have all been reported. Blood-pressure dysregulation and self-mixed dosing leave a thin margin.
• Contraindicated in pregnancy and breastfeeding. Not assessed — see the box below.
• An unapproved, unregulated gray-market injectable. Regulators including the UK MHRA have warned against it, and identity, purity and sterility are unverifiable.
• Nausea is dose-limiting even at erectogenic doses. Facial flushing, yawning and stretching, and blood-pressure changes are the other common effects.

Full Safety & Interactions Detail

Overall posture. This is the section that carries the page. MT-II has no controlled long-term human safety data of any kind, and unusually for a research peptide it has a real, published case-report harm literature — which is documented below with its citations, not softened.

Adverse effects seen in the human trials. Across the erectile and tanning studies the common effects were nausea, facial flushing, yawning and stretching, and blood-pressure changes, with nausea effectively dose-limiting even at erectogenic doses ^{1,4,5Reference 1Dorr RT et al. · 1996Clinical trialEvaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study — human (phase I, n=3)View study →Reference 4Wessells H et al. · 2000RCTEffect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction — human (RCT, crossover)View study →Reference 5Wessells H et al. · 2000Clinical trialMelanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II — human (controlled clinical trial)View study →}.

Priapism. The best-documented serious harm is priapism — a prolonged, painful, low-flow (ischemic) erection that is a urological emergency requiring cavernosal aspiration/irrigation and intracavernosal phenylephrine, and that risks permanent erectile dysfunction if not treated promptly. It has been reported after subcutaneous MT-II used for tanning ^{14Reference 14Mallory CW et al. · 2021Case reportMelanotan tanning injection: a rare cause of priapism — human (case report)View study →}, in a further indexed case ^{15Reference 15Dreyer BA et al. · 2019Case reportMelanotan-induced priapism: a hard-earned tan — human (case report)View study →}, and specifically in the context of overdose ^{28Reference 28Devlin J et al. · 2013Case reportMelanotan II overdose associated with priapism — human (case report)View study →}.

Rhabdomyolysis and systemic toxicity. A case of systemic sympathomimetic toxicity with rhabdomyolysis was reported after a 6 mg subcutaneous dose — roughly six times the user’s intended starting amount — illustrating how thin the margin is when dosing is self-mixed from a reconstituted powder ^{16Reference 16Nelson ME et al. · 2012Case reportMelanotan II injection resulting in systemic toxicity and rhabdomyolysis — human (case report)View study →}.

Posterior reversible encephalopathy syndrome (PRES). A case of posterior reversible encephalopathy syndrome — a neurological syndrome of headache, seizure, visual disturbance and characteristic imaging changes, typically driven by acute blood-pressure dysregulation — has been reported in association with melanotan use ^{26Reference 26Kaski D et al. · 2013Case reportMelanotan and the posterior reversible encephalopathy syndrome — human (case report)View study →}. This is consistent with the compound’s central melanocortin effects on sympathetic outflow and blood pressure.

Renal injury. Renal infarction has been reported as a possible consequence of MT-II use, published with a review of the literature ^{27Reference 27Peters B et al. · 2020Case reportMelanotan II: a possible cause of renal infarction — review of the literature and case report — human (case report + review)View study →}.

Pigmented lesions and melanoma (mechanism-driven, and the key long-latency concern). Because MT-II directly stimulates melanocytes via MC1R, there are repeated case reports of new or rapidly changing atypical melanocytic naevi, eruptive melanocytic naevi, and cutaneous melanoma temporally associated with use ^{17,18,19,20Reference 17Hjuler KF et al. · 2014Case reportMelanoma associated with the use of melanotan-II — human (case report)View study →Reference 18Paurobally D et al. · 2011Case reportMelanotan-associated melanoma — human (case report)View study →Reference 19Reid C et al. · 2013Case reportAtypical melanocytic naevi following melanotan injection — human (case report)View study →Reference 20Burian EA et al. · 2019ReviewEruptive melanocytic nevi: a review — reviewView study →}, including a mucosal (oral) melanoma following nasal-spray use ^{21Reference 21Yassin Alsabbagh A et al. · 2025Case reportMelanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma? — human (case report)View study →}. These are documented associations rather than proven causation — case reports cannot establish incidence — but the mechanism is exactly the one you would predict causes it, the reports come from multiple independent centers, and melanoma is precisely the kind of long-latency harm that the total absence of controlled trials cannot rule out. The practical rule that dermatologists give is unambiguous: anyone who has used melanotan and notices a new, changing or atypical mole should seek dermatological review, and full-skin examination is prudent regardless.

Injection-specific and sourcing risks. Because the product is a self-injected, self-reconstituted, unregulated powder, add injection-site reactions, non-sterile technique, contamination and endotoxin exposure, and unknown purity and dose to everything above (see Sourcing) ^{23Reference 23Mestria S et al. · 2021LC-HRMS characterization of the skin pigmentation and sexual enhancers melanotan II and bremelanotide sold on the black market — forensic product analysisView study →}.

Interactions. No formal interaction studies exist for MT-II. Mechanistically, co-use with PDE5 inhibitors (sildenafil and relatives) is a plausible additive erectile and hypotensive hazard — the related melanocortin PT-141 showed enhanced erectile response combined with low-dose sildenafil, and blood-pressure monitoring was a live concern in that program ^{6Reference 6Shadiack AM et al. · 2007ReviewMelanocortins in the treatment of male and female sexual dysfunction — reviewView study →}. Treat any vasodilator or antihypertensive co-use as an unassessed hazard, not a cleared one.

Who should avoid it. Anyone with a personal or family history of melanoma, atypical-mole syndrome, or a high naevus count; anyone with cardiovascular disease or uncontrolled blood pressure; anyone predisposed to priapism (including sickle-cell disease); and — given the status — anyone who wants an approved, tested product, because this is not one.

Scope disclosure (honesty, not a claim):

• Human data? Yes, but limited and old — small double-blind placebo-controlled crossover erection trials (n≤20, 1996–2000) and a three-person tanning pilot. No approved-indication RCT and no long-term human data. All non-sexual, non-tanning applications are preclinical only.
• Interactions assessed? No. One mechanistically relevant class is flagged (PDE5 inhibitors, by read-across from the PT-141 program) and it is inferred, not tested.
• Pregnancy / lactation assessed? No — not assessed, not established.
• Long-term safety established? No. There is no controlled long-term safety data whatsoever. The melanoma and atypical-naevi signal is exactly the long-latency harm that the absence of trials cannot exclude.

Never imply safety from silence. Where MT-II has not been studied — interactions, pregnancy, long-term use, gray-market product purity — the correct statement is “not assessed,” not “safe.” And here the silence is not even neutral: the published human literature that does exist is predominantly a record of harm.

Pregnancy & Lactation

⚠ Avoid in pregnancy⚠ Avoid while breastfeeding

Not assessed / not established. There are no human pregnancy or lactation data and no accessible animal reproductive-toxicity data for MT-II. Treat as contraindicated in pregnancy and breastfeeding.

Dosage

There is no established human dose for Melanotan II, and none is recommended here. It has never been approved anywhere, no dose-finding study exists, and this is documentation of a widely used unapproved compound, not a protocol.

For context only: the 1990s human studies dosed MT-II subcutaneously at roughly 0.025 mg/kg, with nausea dose-limiting at or near the erectogenic dose ^{3,4,5Reference 3Wessells H et al. · 1998RCTSynthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study — human (RCT, crossover)View study →Reference 4Wessells H et al. · 2000RCTEffect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction — human (RCT, crossover)View study →Reference 5Wessells H et al. · 2000Clinical trialMelanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II — human (controlled clinical trial)View study →}, and the phase I tanning pilot used daily subcutaneous injection in three volunteers ^{1Reference 1Dorr RT et al. · 1996Clinical trialEvaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study — human (phase I, n=3)View study →}. Community “loading” and “maintenance” protocols circulate widely in milligram amounts, but those numbers come from vendor copy and forum practice, not from controlled human dose-finding — they are not reproduced here, and the overdose literature shows what happens when a self-mixed dose is wrong by a factor of a few ^{16,28Reference 16Nelson ME et al. · 2012Case reportMelanotan II injection resulting in systemic toxicity and rhabdomyolysis — human (case report)View study →Reference 28Devlin J et al. · 2013Case reportMelanotan II overdose associated with priapism — human (case report)View study →}. Oral products cannot deliver intact peptide regardless of the number on the label (see Pharmacokinetics). Informational only — not an endorsement and not medical advice.

References

1. Dorr RT, et al. (1996). Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study — human (phase I, n=3). Life Sciences. https://pubmed.ncbi.nlm.nih.gov/8637402/
2. Hadley ME, et al. (1998). Discovery and development of novel melanogenic drugs. Melanotan-I and -II — review. Pharmaceutical Biotechnology. https://pubmed.ncbi.nlm.nih.gov/9760697/
3. Wessells H, et al. (1998). Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study — human (RCT, crossover). Journal of Urology. https://pubmed.ncbi.nlm.nih.gov/9679884/
4. Wessells H, et al. (2000). Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction — human (RCT, crossover). Urology. https://pubmed.ncbi.nlm.nih.gov/11018622/
5. Wessells H, et al. (2000). Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II — human (controlled clinical trial). International Journal of Impotence Research. https://pubmed.ncbi.nlm.nih.gov/11035391/
6. Shadiack AM, et al. (2007). Melanocortins in the treatment of male and female sexual dysfunction — review. Current Topics in Medicinal Chemistry. https://pubmed.ncbi.nlm.nih.gov/17584134/
7. Molinoff PB, et al. (2003). PT-141: a melanocortin agonist for the treatment of sexual dysfunction — human (clinical trial). Annals of the New York Academy of Sciences. https://pubmed.ncbi.nlm.nih.gov/12851303/
8. Kingsberg SA, et al. (2019). Bremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials — human (RCT, phase III). Obstetrics & Gynecology. https://pubmed.ncbi.nlm.nih.gov/31599840/
9. Giuliano F, et al. (2006). Melanotan-II: investigation of the inducer and facilitator effects on penile erection in anaesthetized rat — animal (rat). Neuroscience. https://pubmed.ncbi.nlm.nih.gov/16360286/
10. Raposinho PD, et al. (2003). The melanocortin agonist Melanotan-II reduces the orexigenic and adipogenic effects of neuropeptide Y in the male rat — animal (rat). Journal of Neuroendocrinology. https://pubmed.ncbi.nlm.nih.gov/12535159/
11. Banno R, et al. (2004). The melanocortin agonist melanotan II increases insulin sensitivity in OLETF rats — animal (rat). Peptides. https://pubmed.ncbi.nlm.nih.gov/15350695/
12. Ter Laak MP, et al. (2003). The potent melanocortin receptor agonist melanotan-II promotes peripheral nerve regeneration and has neuroprotective properties in the rat — animal (rat). European Journal of Pharmacology. https://pubmed.ncbi.nlm.nih.gov/12591111/
13. Mock S, et al. (2002). Determination of melanotan-II in rat plasma by liquid chromatography/tandem mass spectrometry: pharmacokinetic parameters following intravenous administration — animal (rat, PK). Rapid Communications in Mass Spectrometry. https://pubmed.ncbi.nlm.nih.gov/12415547/
14. Mallory CW, et al. (2021). Melanotan tanning injection: a rare cause of priapism — human (case report). Sexual Medicine. https://pubmed.ncbi.nlm.nih.gov/33460908/
15. Dreyer BA, et al. (2019). Melanotan-induced priapism: a hard-earned tan — human (case report). BMJ Case Reports. https://pubmed.ncbi.nlm.nih.gov/30796078/
16. Nelson ME, et al. (2012). Melanotan II injection resulting in systemic toxicity and rhabdomyolysis — human (case report). Clinical Toxicology. https://pubmed.ncbi.nlm.nih.gov/23121206/
17. Hjuler KF, et al. (2014). Melanoma associated with the use of melanotan-II — human (case report). Dermatology. https://pubmed.ncbi.nlm.nih.gov/24355990/
18. Paurobally D, et al. (2011). Melanotan-associated melanoma — human (case report). British Journal of Dermatology. https://pubmed.ncbi.nlm.nih.gov/21564053/
19. Reid C, et al. (2013). Atypical melanocytic naevi following melanotan injection — human (case report). Irish Medical Journal. https://pubmed.ncbi.nlm.nih.gov/23914578/
20. Burian EA, et al. (2019). Eruptive melanocytic nevi: a review — review. American Journal of Clinical Dermatology. https://pubmed.ncbi.nlm.nih.gov/31119650/
21. Yassin Alsabbagh A, et al. (2025). Melanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma? — human (case report). International Journal of Oral and Maxillofacial Surgery. https://pubmed.ncbi.nlm.nih.gov/40210573/
22. Gilhooley E, et al. (2021). Melanotan II user experience: a qualitative study of online discussion forums — human (qualitative). Dermatology. https://pubmed.ncbi.nlm.nih.gov/34464955/
23. Mestria S, et al. (2021). LC-HRMS characterization of the skin pigmentation and sexual enhancers melanotan II and bremelanotide sold on the black market — forensic product analysis. Drug Testing and Analysis. https://pubmed.ncbi.nlm.nih.gov/33245851/
24. Evans-Brown M, et al. (2009). Use of melanotan I and II in the general population — editorial. BMJ. https://pubmed.ncbi.nlm.nih.gov/19224885/
25. Van Hout MC, et al. (2014). An in-depth case examination of an exotic dancer’s experience of melanotan — human (case study). International Journal of Drug Policy. https://pubmed.ncbi.nlm.nih.gov/24280586/
26. Kaski D, et al. (2013). Melanotan and the posterior reversible encephalopathy syndrome — human (case report). Annals of Internal Medicine. https://pubmed.ncbi.nlm.nih.gov/23648958/
27. Peters B, et al. (2020). Melanotan II: a possible cause of renal infarction — review of the literature and case report — human (case report + review). CEN Case Reports. https://pubmed.ncbi.nlm.nih.gov/31953620/
28. Devlin J, et al. (2013). Melanotan II overdose associated with priapism — human (case report). Clinical Toxicology. https://pubmed.ncbi.nlm.nih.gov/23537392/
29. Sawyer, T. K., Sanfilippo, P. J., Hruby, V. J., Engel, M. H., Heward, C. B., Burnett, J. B., & Hadley, M. E. (1980). 4-Norleucine, 7-D-phenylalanine-alpha-melanocyte-stimulating hormone: a highly potent alpha-melanotropin with ultralong biological activity. Proceedings of the National Academy of Sciences, 77(10), 5754-5758. https://pubmed.ncbi.nlm.nih.gov/6777774/
30. Arizona Daily Star. UA-developed synthetic hormones speed a tan. https://tucson.com/news/local/education/college/ua-developed-synthetic-hormones-speed-a-tan/article_1aa2c79c-a216-5579-aead-7d012f7e02da.html

View all 30 references▾