Melanotan II guide
This melanotan II guide has to start with a naming problem, because almost every confident claim made about this compound is really a claim about a different one. Melanotan I, melanotan II and bremelanotide are three separate molecules. Two of them are approved medicines. Melanotan II is not78921.
The short answer
- What it is: a synthetic ring-shaped peptide that switches on the same receptors as a natural pigment hormone, but not selectively, which is why it does so many unrelated things at once.
- Approved? Nowhere. Regulators in the United States, Australia, the United Kingdom and Denmark have all acted against it12457.
- Human tanning evidence: three volunteers, in 1996, two of whom pigmented. That is all of it10.
- Best-evidenced effect: erections, from two placebo-controlled trials of ten men each13149.
- Does it protect against sun damage? No study says so, and regulators say no tan of any kind does316.
- What is in the vial: not what the label says, according to both independent laboratories and a regulator’s own testing21220.
Three molecules, constantly confused
Melanotan I is afamelanotide, and it is an approved medicine. It was approved in October 2019 as a bioresorbable implant that a clinician places every two months, for adults with a rare inherited condition that makes sunlight painful. It has a different formula and a different structure from melanotan II78921.
Bremelanotide is an approved injection for a sexual desire disorder in premenopausal women, with a label that limits it to one dose in 24 hours. It came out of the melanotan II research programme, which is how this drug family’s sexual effects came to be studied at all13149.
Melanotan II is neither. It has a registry identifier and a chemical formula, and the agency that issues those identifiers notes on the same page that having one implies no regulatory review or approval12457.
This matters in a specific, checkable way. The tanning studies people cite for melanotan II — including the widely-quoted finding about fewer sunburn cells after ultraviolet exposure — tested melanotan I8. Attributing those results to melanotan II is the single most common error made about this compound.
What has actually been tested in people
For tanning: three men, for two weeks, in a 1996 first-in-human pilot. Two of the three showed increased pigmentation. The same study recorded drowsiness, fatigue, mild nausea, and a stretching and yawning response that coincided with spontaneous erections10. No larger, longer or controlled tanning study of melanotan II has been published in the thirty years since.
For erections, the evidence is genuinely better. Two double-blind placebo-controlled crossover trials, ten men each, found clear effects: rigidity above 80 per cent lasting roughly 38 to 45 minutes against 2 to 3 minutes on placebo, with sexual desire also rising13149. Severe nausea followed about one injection in five in the second trial, which is worth putting next to the benefit.
For appetite, nothing. Loss of appetite appears in the record only as an unwanted effect, reported in the trials and listed by regulators. No human trial has tested this compound for appetite or weight133.
One phase 2 trial is registered, at a single hospital, testing melanotan II alongside ultraviolet phototherapy for vitiligo. It has no results, vitiligo is not why anyone buys this, and the registration itself does not hold up: it belongs to a cluster of eight entries from one sponsor, one of which is titled a mock study and another of which copies a trial a different company published years ago22. Registries do not check what sponsors submit to them.
The harm literature, and what it can and cannot show
Everything in this section is individual case reports. They establish that something happened after an exposure. They cannot establish that the exposure caused it, and several of the authors are careful to say so in their own papers. That caveat is real, and it does not make the reports uninformative.
Acute systemic reactions. Two hours after injecting melanotan II bought online, a previously healthy man arrived at hospital sweating, shaking, with dilated pupils and a racing heart. Muscle-breakdown markers rose roughly tenfold over twelve hours and his kidneys began failing; he spent three days in intensive care1115. A second previously healthy man lost the blood supply to about half of one kidney, with normal arteries, no source of a clot and normal clotting studies, and was left with new high blood pressure1115.
In both of those cases the patient’s own product was sent for laboratory analysis and confirmed to be melanotan II, with nothing else in it1115. That closes off the comfortable explanation that serious harm only comes from fakes.
Priapism. A prolonged painful erection after injection failed to respond to drainage, irrigation and injected medication, and required surgery. In another published case the patient had not recovered erectile function four weeks later17. This is the same pharmacology as the desired sexual effect, not a separate quirk.
Moles. This is the most frequently reported problem by some distance: new moles appearing in crops, existing moles darkening and beginning to grow, and lesions changing enough that dermatologists reported difficulty telling them apart from melanoma162118. In one instructive case, a man with a previous melanoma grew crops of atypical lesions that lightened and stopped growing after he stopped. His dermatologists concluded that these peptides can drive proliferation of neoplastic melanocytic cells in people already predisposed — the opposite of the protective effect this compound is sold on316.
Melanoma. Melanoma has been reported after melanotan use several times, including in a 20-year-old woman three months after a short course, and a mucosal melanoma in the upper jaw of a 22-year-old who had used the nasal spray181921. Read these honestly: users very often also use sunbeds, the case authors flag that confounder themselves, and no cohort or registry study has ever measured whether melanotan users get melanoma more often than anyone else. The accurate statement is that the risk is mechanistically plausible and repeatedly reported, not that it is established.
Why one peptide causes so many unrelated effects
Melanotan II does not act only on the receptor that controls skin pigment. It activates all five receptors in that family, and those receptors sit in the skin, the adrenal glands, the brain, the nervous system and the glands. Nausea, flushing, yawning and stretching, appetite loss, spontaneous erections and sympathetic overstimulation all follow from where those receptors are1013143. The unwanted effects are not contaminants or bad batches; they are the drug working as designed on tissues nobody was aiming at.
There is also no published human pharmacokinetic data at all. No study has measured what happens to melanotan II in the body after a dose, and the half-life figures that circulate for it are either unsourced or are melanotan I data attached to the wrong molecule[unverified].
What is in the products people actually buy
This is among the best-evidenced claims on this page, because a regulator did the testing itself. Australia’s medicines regulator analysed five nasal spray bottles from one product line, all labelled 30 mg, and found between 22 mg and 54 mg in them. It noted that the inconsistency alone raises the chance of an adverse event21220.
Independent laboratories found the same pattern from the other direction. Vials from three online shops, all claiming 10 mg, held between 4.32 and 8.84 mg, with unknown impurities making up four to six per cent of the contents in two shops’ vials. A separate forensic analysis put a batch at 30 per cent purity21220.
The practical consequence is simple: the number on the label does not tell you the amount in the vial, in either direction.
What regulators have on record
The United Kingdom’s regulator received 13 suspected adverse reaction reports associated with melanotan II between 2011 and 2021 through its voluntary scheme, and says it has repeatedly acted to remove these products from sale for over a decade. It attaches two caveats that should travel with the number: a report does not mean the drug caused the event, and the scheme has unknown and variable under-reporting415. Sweden’s poisons centre logged 215 enquiries about melanotan II side effects between 2008 and 2019. Neither figure has a denominator, so neither is a rate.
Denmark warned in 2008 and again in 2011 that the effect is undocumented and that no studies of its potential side effects exist105. Australia states that supplying these products without a prescription is illegal in any form, spray or injection or cream, and that advertising them to the public, including by influencers, is illegal too12457.
In sport, melanotan II is not a named entry on the 2026 prohibited list. The list itself says that absence from it does not mean a substance is permitted, because its categories give examples rather than complete lists6. Anyone subject to testing should treat this as unresolved rather than allowed.
The honest summary
The compound does what its pharmacology predicts: it pigments skin and it produces erections. The human evidence for the first is three people and for the second is twenty. Against that sits a case literature of acute toxicity, kidney injury, emergency priapism and repeated melanocytic change, a complete absence of long-term safety data, and laboratory evidence that the products sold are not reliably what they claim to be.
No trial of melanotan II has run longer than two weeks or enrolled more than ten people in a group105. That is the whole foundation.
Where the rest of the detail lives
The interactive library on the homepage carries the fuller reference entry for melanotan II, including the amounts and handling notes it holds for every compound. That is general reference information, the same for every visitor.
References
These are the sources behind this page, listed so you can read them yourself rather than take our word for it. Animal and laboratory findings do not establish that something works or is safe in people. Doses and protocols shown on a study card are that study's research parameters, not recommendations. PepCaddie does not sell peptides and does not choose a dose for anyone; this is educational material and it does not replace a qualified healthcare professional.
The entire human tanning evidence: three volunteers
1996Human observational study
The dose above is the amount used in this study. It is research information, not a recommended dose, and PepCaddie does not convert study doses into human doses.
Two of three volunteers showed increased pigmentation in the face, upper body and buttock over two weeks. The investigators also recorded a stretching and yawning response that appeared to coincide with spontaneous erections, along with drowsiness, fatigue and mild nausea. This is the whole of the published human evidence that melanotan II tans human skin.
Limitation: Three people, two weeks, no control group. It was a first-in-human dose-finding exercise with pharmaceutical-grade compound under medical supervision, which is nothing like the product and setting people actually use.
Single-blind pilot phase 1 studyView study: The entire human tanning evidence: three volunteers
Rhabdomyolysis and kidney injury after one injection
2012Case report or case series
The dose above is the amount used in this study. It is research information, not a recommended dose, and PepCaddie does not convert study doses into human doses.
Two hours after injecting melanotan II bought online, a previously healthy man arrived with body aches, sweating, a racing heart, dilated pupils and tremor. Muscle breakdown markers rose roughly tenfold over twelve hours and kidney function deteriorated, requiring three days of intensive care with fluids. What makes this case unusually informative is that the substance he injected was analysed by mass spectrometry against a reference standard and confirmed as melanotan II, so the harm cannot be attributed to a counterfeit.
Limitation: A single case. It establishes that this happened after an injection, not how often it happens or in whom. The amount injected was several times what the patient understood to be a starting amount.
Case report with laboratory confirmation of the injected substanceView study: Rhabdomyolysis and kidney injury after one injection
What was actually in vials bought from three shops
2015Laboratory or in-vitro studyNot human evidence
The dose above is the amount used in this study. It is research information, not a recommended dose, and PepCaddie does not convert study doses into human doses.
Every shop claimed its vials held 10 mg. The measured content was between 4.32 and 8.84 mg, so no vial held what its label said. Vials from two of the three shops carried unknown impurities making up between 4.1 and 5.9 per cent of the contents. The authors concluded that buyers of these products face a range of potential harms simply because of how they are made and supplied.
Limitation: A snapshot of three sellers at one point in time. It cannot describe any other seller, and it does not identify what the impurities were.
Validated laboratory analysis of purchased productsView study: What was actually in vials bought from three shops
Placebo-controlled trial in erectile dysfunction
1998Human randomised trial
The dose above is the amount used in this study. It is research information, not a recommended dose, and PepCaddie does not convert study doses into human doses.
Eight of ten men developed clinically apparent erections on melanotan II. Rigidity above 80 per cent lasted a mean of 38 minutes against 3 minutes on placebo. Reported effects included nausea, stretching, yawning and decreased appetite. This is the best-designed human evidence that exists for this compound, and it is about erections rather than tanning.
Limitation: Ten men, a crossover design, and nearly thirty years old. It was conducted with pharmaceutical-grade compound under supervision, and the effect it demonstrates now has an approved medicine of its own.
Double-blind, placebo-controlled crossover trialView study: Placebo-controlled trial in erectile dysfunction
Second placebo-controlled trial in erectile dysfunction
2000Human randomised trial
The dose above is the amount used in this study. It is research information, not a recommended dose, and PepCaddie does not convert study doses into human doses.
Melanotan II produced reported erections after 12 of 19 injections against 1 of 21 placebo doses, with rigidity above 80 per cent lasting 45 minutes against under 2 minutes. Sexual desire also rose significantly. Severe nausea followed 4 of the 19 injections, which is a useful counterweight to how the effect is usually described.
Limitation: Ten men again, and the same research group as the earlier trial. Severe nausea in roughly one injection in five is a substantial burden for the effect obtained.
Double-blind, placebo-controlled crossover trialView study: Second placebo-controlled trial in erectile dysfunction
Kidney infarction in a healthy man
2020Case report or case series
The dose above is the amount used in this study. It is research information, not a recommended dose, and PepCaddie does not convert study doses into human doses.
A previously healthy 45-year-old man lost blood supply to about half of one kidney. His renal arteries were normal, no source of a clot was found on scans or echocardiography, and his clotting studies were normal. His own product was analysed at a forensic centre and contained melanotan II and nothing else. He was left with new high blood pressure and reduced kidney function two months later. The same paper records that Sweden’s poisons centre logged 215 enquiries about melanotan II side effects between 2008 and 2019.
Limitation: The authors themselves say the infarction was most likely attributed to melanotan II rather than proven to be caused by it, and note that no blood concentration was measured. The poisons centre figure is a count of enquiries with no denominator.
Case report with forensic analysis of the patient’s own productView study: Kidney infarction in a healthy man
New atypical moles that faded after stopping
2009Case report or case series
A man with a previous melanoma and many atypical moles grew crops of new pigmented lesions, several of which looked and behaved abnormally under the microscope, while his existing moles darkened and started growing. After he stopped, the lesions lightened and stopped growing. The authors concluded that these peptides can drive proliferation of neoplastic melanocytic cells in predisposed people, which directly contradicts the idea that they protect against skin cancer.
Limitation: One patient, already at high risk. The reversal on stopping strengthens the temporal link but a single case cannot establish how often this happens or in whom.
Case report with histopathologyView study: New atypical moles that faded after stopping
Priapism needing surgery
2021Case report or case series
A prolonged painful erection after injecting melanotan II failed to respond to drainage, irrigation and injected medication, and required an operation. Ischaemic priapism is a urological emergency: left untreated it damages tissue permanently. In a separate published case the patient had still not recovered erectile function four weeks later.
Limitation: A single case, and the authors note only two previous reports existed at the time. The sexual effect and this complication are the same pharmacology, which is why the risk is not incidental.
Case reportView study: Priapism needing surgery
Melanoma after a self-injected course
2014Case report or case series
A 20-year-old woman with fair skin developed a suspicious dark lesion three months after a three to four week course of self-injections taken to boost sunbed tanning. Excision confirmed melanoma. The authors are careful with their language: the melanocyte stimulation coincided with the melanoma, and the case brings attention to potential risk.
Limitation: She was also using sunbeds, which is itself a melanoma risk, and the authors say so. One case with two exposures cannot separate them.
Case report with excision histologyView study: Melanoma after a self-injected course
Mucosal melanoma after nasal spray use
2025Case report or case series
A 22-year-old woman who had been using melanotan II nasal spray for tanning developed a mass in the upper jaw that proved to be a mucosal malignant melanoma. The report is included here because nasal sprays are often presented as the gentler option, and because mucosal melanoma is not a sun-exposure cancer.
Limitation: The authors themselves frame this as a question rather than a finding, and one case cannot answer it. Mucosal melanoma is rare and its causes are poorly understood.
Case report with histologyView study: Mucosal melanoma after nasal spray use
Forensic analysis finding 30 per cent purity
2024Laboratory or in-vitro studyNot human evidence
Vials labelled melanotan II were confirmed to contain it, at 30 per cent purity. The authors also note that the molecule is heavy enough, and carries enough charge, to slip past routine forensic screening methods, which they suggest is part of why it circulates so freely.
Limitation: A forensic case analysis, not a survey of the market. It describes the samples examined and no others.
Forensic laboratory analysis by several mass spectrometry methodsView study: Forensic analysis finding 30 per cent purity
Dermatology review of the harm literature
2017Narrative review
This review gathers the case literature and concludes that a growing number of reports link unregulated use of both melanotan I and melanotan II to skin complications, particularly changes in moles, including newly dysplastic lesions and melanomas. It draws the same line this page draws, between the illegal melanotans and afamelanotide as the one approved analogue.
Limitation: A narrative review of case reports, not a systematic review and not an incidence study. It inherits every limitation of the cases it summarises.
Narrative reviewView study: Dermatology review of the harm literature
The only registered trial, and it does not stand up
2026Registered clinical trial
This is the only melanotan study the trial registry returns. It is registered as recruiting from February 2026 at a single hospital, testing melanotan II alongside narrowband ultraviolet phototherapy for vitiligo, a pigment-loss condition rather than tanning.
Limitation: No results, no stated dose or route, and a condition that is not why anyone buys this compound. There is also a larger problem with the record. This registration needs more scepticism than a registry entry usually gets. The same sponsor has registered eight studies, all at one hospital, nearly all recording the same start date and all the same completion date, covering most of the compounds in this library. One of them carries the words "Mock Study" in its own title, and another reuses the title and internal study code of a large trial a different company completed and published years earlier. Registry entries come from sponsors and are not checked by the registry, so this record is reported here but is not treated as evidence that a trial is really running.
Phase 2, randomised, double-blind, placebo-controlledView study: The only registered trial, and it does not stand up
Notice of opportunity for hearing: Manookian, Edward. U.S. Food and Drug Administration; 2016.
Official regulatory sourceChecked 2026-09-21
Read FDA's position: an unapproved new drug at the sourceMelanotan II tanning peptide products found to be inconsistently dosed. Therapeutic Goods Administration, Australia; 2026.
Official regulatory sourceChecked 2026-09-21
Read Australian regulator laboratory testing at the sourceDon’t risk using tanning products containing melanotan. Therapeutic Goods Administration, Australia; 2025.
Official regulatory sourceChecked 2026-09-21
Read Australian regulator consumer advice at the sourceMHRA freedom of information response 21/1237: melanotan adverse drug reaction reports. Medicines and Healthcare products Regulatory Agency, United Kingdom; 2021.
Official regulatory sourceFOI 21/1237Checked 2026-09-21
Read UK adverse reaction reports, released under FOI at the sourceWarning against the tanning product Melanotan. Danish Medicines Agency; 2011.
Official regulatory sourceChecked 2026-09-21
Read Danish regulator warning at the sourceThe 2026 Prohibited List. World Anti-Doping Agency; 2026.
Official regulatory sourceChecked 2026-09-21
Read WADA's 2026 Prohibited List at the sourceFDA Global Substance Registration System: melanotan II. U.S. Food and Drug Administration; 2026.
Official regulatory sourceUNII UPF5CJ93X7Checked 2026-09-21
Read FDA's substance registry entry at the sourceSCENESSE (afamelanotide) implant, for subcutaneous use: prescribing information. DailyMed, U.S. National Library of Medicine; 2024.
Approved prescribing informationNDA 210797Checked 2026-09-21
Read Approved label for afamelanotide, the other melanotan at the sourceVYLEESI (bremelanotide) injection, for subcutaneous use: prescribing information. DailyMed, U.S. National Library of Medicine; 2026.
Approved prescribing informationNDA 210557Checked 2026-09-21
Read Approved label for bremelanotide at the sourceDorr RT, Lines R, Levine N, et al.. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sciences; 1996.
Human observational studyPMID 8637402Checked 2026-09-21
Read The entire human tanning evidence: three volunteers at the sourceNelson ME, Bryant SM, Aks SE. A case of melanotan-associated rhabdomyolysis and systemic toxicity after subcutaneous injection. Clinical Toxicology; 2012.
Case report or case seriesPMID 23121206 · DOI 10.3109/15563650.2012.740637Checked 2026-09-21
Read Rhabdomyolysis and kidney injury after one injection at the sourceBreindahl T, Evans-Brown M, Hindersson P, et al.. Identification and characterization by mass spectrometry of melanotan II in products sold over the internet. Drug Testing and Analysis; 2015.
Laboratory or in-vitro studyPMID 24771717 · DOI 10.1002/dta.1655Checked 2026-09-21
Read What was actually in vials bought from three shops at the sourceWessells H, Fuciarelli K, Hansen J, et al.. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: a double-blind, placebo controlled crossover study. Journal of Urology; 1998.
Human randomised trialPMID 9679884Checked 2026-09-21
Read Placebo-controlled trial in erectile dysfunction at the sourceWessells 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.
Human randomised trialPMID 11018622Checked 2026-09-21
Read Second placebo-controlled trial in erectile dysfunction at the sourcePeters B, Hadimeri H, Wahlberg R, Afghahi H. A case of renal infarction related to Melanotan II. CEN Case Reports; 2020.
Case report or case seriesPMID 31953620 · DOI 10.1007/s13730-020-00447-zChecked 2026-09-21
Read Kidney infarction in a healthy man at the sourceCardones AR, Grichnik JM. alpha-Melanocyte-stimulating hormone-induced eruptive nevi. Archives of Dermatology; 2009.
Case report or case seriesPMID 19380666 · DOI 10.1001/archdermatol.2008.623Checked 2026-09-21
Read New atypical moles that faded after stopping at the sourceMallory CW, Lopategui DM, Cordon BH. Melanotan II: a possible cause of priapism. Sexual Medicine; 2021.
Case report or case seriesPMID 33460908 · DOI 10.1016/j.esxm.2020.100298Checked 2026-09-21
Read Priapism needing surgery at the sourceHjuler KF, Lorentzen HF. Melanoma associated with the use of melanotan-II. Dermatology; 2014.
Case report or case seriesPMID 24355990 · DOI 10.1159/000356389Checked 2026-09-21
Read Melanoma after a self-injected course at the sourceYassin Alsabbagh A, Bhujel N, Singh RP. Oral mucosal melanoma following the use of Melanotan II nasal spray: a possible risk factor?. International Journal of Oral and Maxillofacial Surgery; 2025.
Case report or case seriesPMID 40210573 · DOI 10.1016/j.ijom.2025.03.014Checked 2026-09-21
Read Mucosal melanoma after nasal spray use at the sourceDeville M, Charlier C. Melanotan II: identification and quantification in a forensic context. Journal of Forensic Sciences; 2024.
Laboratory or in-vitro studyPMID 39302005 · DOI 10.1111/1556-4029.15633Checked 2026-09-21
Read Forensic analysis finding 30 per cent purity at the sourceHabbema L, Halk AB, Neumann M, Bergman W. Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review. International Journal of Dermatology; 2017.
Narrative reviewPMID 28266027 · DOI 10.1111/ijd.13585Checked 2026-09-21
Read Dermatology review of the harm literature at the sourceA randomized, double-blind, placebo-controlled phase 2 study of melanotan II as an adjunct to narrowband UV-B phototherapy in adults with stable nonsegmental vitiligo. ClinicalTrials.gov (sponsor: Hudson Biotech); 2026.
Registered clinical trialNCT07437560Checked 2026-09-21
Read The only registered trial, and it does not stand up at the source