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Peptides Explained

Melanocortin

Melanotan II

A lab-made tanning drug, approved nowhere. It darkens skin and moles, and can cause erections and sickness.

Not an authorised medicine

At a glance

Is it an approved medicine?
No Not approved as a medicine in the EU, the UK or the US.
Has it been tested in people?
Some Small trials in patients. No large trials published yet.
Is it allowed in sport?
No Banned in sport at all times. Anti-doping list (WADA), section S0
What is the biggest risk?
Moles may darken or change, which makes skin cancer harder to spot. More about the risks

Status checked on . The details and sources are further down this page.

Stop and get help if you notice

  • Erection lasting more than 3 hours, or painful77,61,62
  • Racing heart, shaking, or dark urine63,49,106
  • Sudden severe headache, a fit, or losing sight64,78,107

If it is severe, call your local emergency number.

All warning signs, further down this page Warning signs for any peptide

The 30-second version

About 8 minutes for the short version; 38 with every detail open.

  • Melanotan II is lab-made. It copies a hormone that darkens skin. No country has approved it.
  • It darkens skin and moles. It also acts in the brain: erections, feeling sick, less hunger.
  • Only 23 men took part in the published trials, all before 2001. Long-term safety is unknown.
  • Doctors have seen moles change, long erections and some melanoma. No one knows if it causes melanoma.
  • A tan from melanotan II has not been shown to protect your skin from the sun.
Class
Melanocortin
How it is taken
Injected under the skin; also sold as nasal spray
Published trials
Three small trials, 23 men in all, 1996 to 2000
Approved relatives
Afamelanotide (Scenesse, EU) and bremelanotide (Vyleesi, US)
Developed at
University of Arizona, late 1980s
Status in the EU
Not authorised
Tested in people
Some

Label facts, not dosing advice. Sources are in the sections below.

Last reviewed
Skin under a microscope, stained pink and purple: a thin top layer with brown pigment along its base, and small clusters of pigment cells just below it.
An abnormal mole under a microscope. Melanotan II darkens moles. Its link to skin cancer is unknown. Photo: Nephron (Wikimedia Commons) CC BY-SA 3.0 Image details

Each section starts with the short answer. The rest is folded under “In detail”.

Evidence profile

Four separate questions. Not a score.

Human clinical evidence How far has it been tested in people?
Phase II (dose and early effect)
Preclinical volume How much laboratory and animal research exists?
Extensive
Source independence How many independent groups produced it?
Broadly replicated
Safety characterisation How well do we know the harms in humans?
Partial
In detail Why these grades: the reason for each step
Human clinical evidence
Phase 2, at the very bottom of that range. Two small double-blind, placebo-controlled crossover trials tested erections in 20 men with erectile dysfunction (1998 and 2000), the stage usually called phase 2, after a pilot phase 1 study in 3 healthy men (1996). All came from one University of Arizona group, none studied women, and no further trial has been published since 2000 (one registered trial has no results). Tanning was only observed in the 3-man pilot. This is a judgement call at the floor of the category, pending medical review.
Preclinical volume
Extensive. A PubMed search on 22 October 2026 found 189 non-review records with 'melanotan II' in the title or abstract, and 364 when the abbreviation MTII is counted in melanocortin papers; almost all of those mention animals or cells. Melanotan II became a standard research tool for the brain's melanocortin receptors.
Source independence
Broadly replicated, for the laboratory pharmacology only. The developing group wrote 10 of the 189 records (45 of the 364); independent groups, including Merck and the University of Cincinnati, repeated its effects on appetite in rats. Every published human trial, by contrast, came from the one developing group and has never been repeated by anyone else.
Safety characterisation
Partial. Human exposure in trials is 23 men for two weeks at most. Everything else comes from case reports and regulators' reports of unregulated use (16 UK reports to the MHRA in 2012–2022), which describe serious events but cannot give rates or prove cause. We found no long-term, cancer or pregnancy study.

We never add these up. A compound can have a large animal literature from one laboratory and no human data at all — that is a specific situation, and a single number would hide it. How we grade evidence

In detail The molecule: amino-acid sequence and technical details
Amino-acid sequence7 amino acids

Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2

Read from the N-terminus (start) to the C-terminus (end).

Modifications
position 1: Nle (norleucine), a straight-chain building block not used in human proteins, carries an acetyl group at the start of the chain
position 4: D-Phe: the mirror-image form of phenylalanine
Ring closures
2–7 (lactam)
D-form (mirror-image) amino acid
D-Phe (4)
non-standard amino acid
Nle (1)
Full name
Melanotan II (Ac-[Nle4, Asp5, D-Phe7, Lys10]-cyclo-alpha-MSH(4-10)-NH2, a cyclic lactam analogue of alpha-MSH)
Also called
MT-II, MTII, MT2, Melanotan-2
Class
Melanocortin
Body systems
Skin, Sexual function, Brain and nerves, Heart and blood vessels
Formula
C50H69N15O9
Molecular mass
1,024.2 Da

What it actually is

What is melanotan II?

A lab-made copy of a hormone that tans the skin. No country has approved it.
Melanotan II is not approved anywhere. Two of its close cousins are. Melanotan II and its two closest relatives, checked on 22 October 2026.
Melanotan IIAfamelanotide (Scenesse; once called melanotan I)Bremelanotide (Vyleesi; PT-141)
The molecule sold as melanotan II?Yes A ring of six amino acids with one more at the front.1,2No A longer, straight chain of 13 amino acids.3,4No The same ring, with a different end.5,1
Approved in the EU?No No product in EMA’s medicines data.6Yes Since 22 December 2014, for a rare light-pain disease (EPP).7No No EU product.6
Approved in the US?No Called “an unapproved new drug” by the FDA.8Yes Since 8 October 2019.9Yes Since 21 June 2019, for low sexual desire in some women.10,11
Quality checked by a regulator?No Tested vials held 43–88% of the label amount.12Yes As an authorised medicine.7Yes As an authorised medicine in the US.11

Melanotan II was designed at the University of Arizona in the late 1980s, and first tested in people as a way to tan without sun.13,2 It is sold online as powder in vials, in pens and as nasal sprays.14,15,16 In online forums, people describe using it for a tan before sun holidays or fitness competitions, and sunbed use comes up often.17

In detail The molecule, and how it differs from its two relatives

Melanotan II is a chain of seven amino acids: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2. Its formula is C50H69N15O9 and its mass 1024.2 Da.1 It copies positions 4 to 10 of alpha-MSH, the hormone that darkens skin, with three changes:2,13

  • A ring. The side chains of aspartic acid and lysine are joined by a lactam bond, so six of the seven amino acids form a closed ring. This ring held the molecule in a shape that made it about 90 times as potent as alpha-MSH in a lizard-skin test, with a longer-lasting effect.13
  • A mirror-image building block. Phenylalanine is in its D-form. The developers describe melanotan I and II as resistant to the enzymes that break down the natural hormone.1,4,3
  • Norleucine at the front, capped with an acetyl group, and an amide at the end.1

Afamelanotide, once called melanotan I, is the full 13-amino-acid hormone with two changes and no ring.3,4 In the EU it is an implant for erythropoietic protoporphyria (EPP), a rare disease in which light causes burning pain; it works by increasing dark melanin in the skin, which blocks light.7

Bremelanotide (PT-141) has exactly the same ring as melanotan II, but ends in a free acid instead of an amide.5,1 See PT-141. Its US label is a rough guide to what a molecule this close may do in people, because it was tested in large trials; melanotan II never was.11

In detail Where it came from

In 1989 chemists at the University of Arizona reported a series of ring-shaped alpha-MSH fragments built for potency and long action.13 The developers later wrote that melanotan I might give a “therapeutic tan” that could lower the risk of skin cancer.4 In the first test of melanotan II in people, in 1996, two of three men tanned, and the men also had spontaneous erections.2 One of the developers later wrote that the sexual effects “were discovered accidentally” during the tanning work.18

After two small erection trials (1998 and 2000), development moved on to its free-acid form, PT-141, which became the US medicine Vyleesi in 2019, while tanning work continued with melanotan I, now afamelanotide.19,4,10,7 No further trial of melanotan II itself has been published, and regulators were already warning about products sold under its name in 2010.20

Proposed mechanism

How does it work?

It switches on several receptors. In skin it adds dark pigment; in the brain it causes erections.
One drug, four receptors. Each one leads to a different effect.
ReceptorWhere it isWhat switching it on doesShown for melanotan II in
MC1Pigment cells (melanocytes) in skin, moles and gumsMore dark melanin; more pigment cells in a dishCells; tanning in 2 of 3 men; case reports of darker moles and gums
MC4Brain and spinal cordErections, less hunger; raises blood pressure with related drugsRats and mice; erections in 20 men
MC3BrainAppetite, together with MC4Mice and rats
MC5Many tissues outside the brainNot covered by the studies on this pageCells only

Sources 21, 22, 23, 2, 24, 25, 26, 27

The body’s own hormone, alpha-MSH, works on several melanocortin receptors. Melanotan II is a strong copy that switches on four of them.21 So the effects come as a package: in the first trial, the same men who tanned also felt sick and had spontaneous erections.2

In detail Step by step: the chain and what each step rests on
The proposed causal chain, step by step

Each step is labelled with how well the link from the previous step is established.

  1. Step 1 Binding In cells

    Copies alpha-MSH and fits four receptors

    Melanotan II is a shortened, ring-shaped copy of alpha-MSH, the body's own skin-darkening hormone. In cells carrying cloned receptors it acted on the MC1, MC3, MC4 and MC5 receptors, not only on the skin's MC1 receptor. On the human MC1 receptor it stayed bound for hours: 86% was still attached six hours after the free peptide was washed away.

  2. Step 2 Signal inside the cell In cells

    cAMP rises inside pigment cells

    MC1R is a G-protein-coupled receptor on melanocytes. Switched on, it raises cAMP inside the cell, which increases the enzymes that make dark melanin. In cultured human melanocytes the natural hormone also made the cells multiply. Shown in cells; not measured for melanotan II in human skin.

  3. Step 3 Tissue response In humans

    Skin, moles and gums darken

    In a pilot study of 3 healthy men, two had darker skin on the face, upper body and buttocks a week after two weeks of injections. Case reports describe existing moles darkening and new moles appearing, in one report within 24 hours of a single injection, and brown patches on the gums.

  4. Step 4 Cell response In animals

    Brain and spinal-cord receptors start erections and curb appetite

    In rats, melanotan II caused erections through melanocortin receptors in the brain and the lower spinal cord; injected into the penis it did nothing. In mice, melanotan II placed in the brain reduced eating through MC3 and MC4 receptors. In rats given it into a vein, it also reduced eating, although it barely entered the brain and reached only areas where the blood-brain barrier is open.

  5. Step 5 Effect on the body In humans

    Erections, more desire, nausea and yawning in men

    In two small placebo-controlled crossover trials in 20 men with erection problems, erections followed most melanotan II injections and few placebo injections. Nausea, stretching and yawning were common, and nausea was sometimes severe.

  6. Step 6 Effect on the body Hypothesised

    Blood pressure may rise

    Switching on MC4 receptors raised blood pressure in people given another MC4 agonist, and in women given bremelanotide, melanotan II's free-acid form. It has not been measured in a melanotan II trial.

  7. Step 7 Effect on the body Hypothesised

    Sun protection or cancer risk: not known

    Whether a melanotan II tan protects the skin, or whether pushing pigment cells changes melanoma risk in people in either direction, has never been tested. Case reports raise the question; they cannot answer it. One mouse study found that it slowed an existing melanoma.

Receptors: why one molecule does many things

In cells carrying cloned human or mouse receptors, the MC1, MC3, MC4 and MC5 receptors all responded to melanotan II ; MC2, the receptor for the stress hormone ACTH, responds mainly to ACTH.21 On the human MC1 receptor it let go very slowly: six hours after washing, 86% was still bound, against 25% of alpha-MSH .3 The authors suggest that this slow release helps explain its long-lasting effects. The bremelanotide label states the same pattern for that close relative: it “nonselectively activates several receptor subtypes”, most potently MC1R and then MC4R.11

Pigment cells: darker, and more of them

MC1R is a G-protein-coupled receptor. Switched on, it raises cAMP inside the melanocyte, and the cell makes more melanin and passes it to the surrounding skin cells.22 In cultured human melanocytes, alpha-MSH increased tyrosinase, the enzyme that starts melanin production, by 70–450%, and the number of cells by 50–270%, depending on the donor .23 That second effect matters for the mole question below: the same signal that darkens pigment cells also makes them multiply, at least in a dish. In people, the only tanning data are from the 3-man pilot (see the evidence below).2

Brain and spinal cord: erections, appetite and nausea

In awake rats, melanotan II caused erections whether it was given into the brain, the spinal fluid or a vein; a receptor blocker in the spinal fluid stopped the spinal effect, and injecting it into the penis of anaesthetised rats did nothing . In rats, then, the erection signal starts in the brain and the lower spinal cord, not in the penis.25

In mice, melanotan II placed in the brain reduced eating in four different models of overeating, and a blocker made mice eat more .24 Given into a vein in rats, it still reduced eating, although almost none entered the brain: it reached small areas where the blood-brain barrier is open .28 Rats also learned to avoid a flavour paired with melanotan II, a sign that it makes them feel ill , which fits the nausea seen in men.29,19

Blood pressure: shown for relatives, not measured for melanotan II

In 28 overweight or obese volunteers, a different MC4 receptor agonist given daily for seven days raised blood pressure by about 9 mm Hg systolic and 7 mm Hg diastolic compared with placebo, at the highest dose they tolerated . In the same study, people born with a faulty MC4 receptor had high blood pressure less often than equally overweight people without the fault.27 Bremelanotide raises blood pressure after each dose, by up to 6 mm Hg systolic, peaking 2–4 hours after the dose.11 Melanotan II probably does the same through the same receptor , but no trial measured it.

What the evidence actually shows

Does it work?

It darkened skin and caused erections in small trials of 23 men in all.

Only 23 people took part in all published trials

23 men

in three small trials, all run by one group from 1996 to 2000

Who took part Every published trial of melanotan II: 3 healthy men (1996) and two crossover trials of 10 men with erection problems each (1998, 2000); no women Sources Dorr et al. (1996); Wessells et al. (1998); Wessells et al. (2000)2,30,19 Evidence Humans, limited

Most men in the first controlled trial had an erection

8 of 10

men had an erection after melanotan II, checked for six hours

Who took part Wessells 1998: double-blind, placebo-controlled crossover; 10 men with erection problems of no known physical cause Source Wessells et al. (1998)30 Evidence Human trials

Two of three healthy men tanned

2 of 3

men had darker skin one week after the last injection

Who took part Dorr 1996: pilot phase 1, 3 healthy men, two weeks, single-blind with saline days Source Dorr et al. (1996)2 Evidence Humans, limited

The effects were clear in these small trials, but the evidence is thin. A tan and erections both fit the biology, and a close relative, bremelanotide, went on to large trials and US approval.11 But nobody has tested whether a melanotan II tan protects the skin, how long it lasts, or what months of use do.

In detail Every study in one table

24 studies: 14 in humans, 5 in animals, 3 in cells, 2 reviews or other.

Studies discussed on this page
Study Species n Design Funding Research group What it found What it did not show
Al-Obeidi et al. 1989 13 Cells (lab) not reported Laboratory (cells) (controlled) Government Originating group Seven ring-shaped (cyclic lactam) fragments of alpha-MSH were made; the one now called melanotan II was about 90 times as potent as alpha-MSH at darkening lizard skin, and its effect lasted longer. Frog and lizard skin in a dish, not mammals; potency in frog or lizard skin says nothing about human effects or safety.
Hruby et al. 1995 21 Cells (lab) not reported Laboratory (cells) (controlled) Government Mixed Cells carrying cloned melanocortin receptors showed that MC1, MC3, MC4 and MC5 all respond to melanotan II; changing one building block gave SHU9119, which blocks the brain's MC3 and MC4 receptors but still switches on MC1 and MC5. Cells in a dish; written mainly about the new blockers, with melanotan II as the reference agonist.
Dorr et al. 1996 2 Humans 3 Phase I trial (controlled, blinded) Government Originating group Three healthy men had injections under the skin on alternate weekdays for two weeks, with saline on the other days: two had darker skin a week later; mild nausea was common, one man had moderate sleepiness and tiredness at the highest dose, and yawning came with spontaneous erections. Three men, single-blind, two weeks; tanning was seen in only two of them; no women, no sun-protection or cancer endpoints.
Haskell-Luevano et al. 1996 3 Cells (lab) not reported Laboratory (cells) (controlled) Mixed Mixed Six hours after the peptides were washed away, 86% of melanotan II was still bound to the human MC1 receptor, against 65% of melanotan I and 25% of alpha-MSH. Cells in a dish; slow release from the receptor may explain long-lasting effects, but this was not tested in people.
Fan et al. 1997 24 Mice not reported Animal experiment (controlled) Mixed Mixed Melanotan II injected into the brain's fluid spaces reduced eating in four mouse models of overeating, and a blocker of the same receptors made mice eat more. Mice, with the drug placed directly into the brain; a chemist from the developing group was a co-author, so not fully independent.
Wessells et al. 1998 30 Humans 10 Phase II trial (controlled, blinded) Government Originating group In 10 men with erection problems of no known physical cause, 8 had erections after melanotan II; rigid erections lasted a mean 38.0 minutes against 3.0 with placebo. Nausea, stretching, yawning and less appetite were more frequent than with placebo. Ten men, each tested with melanotan II and placebo, six hours of monitoring per test; the abstract does not say how the order of treatments was decided; never repeated by another group.
Wessells et al. 2000 19 Humans 10 Phase II trial (controlled, blinded) Mixed Originating group In 10 men with erection problems and physical risk factors, erections followed 12 of 19 melanotan II injections against 1 of 21 placebo injections; sexual desire rose; 4 of 19 injections caused severe nausea. Ten men, two test injections of each treatment (19 melanotan II injections in all), each watched for six hours; same group as the 1998 trial; no long-term follow-up.
Benoit et al. 2003 29 Rats not reported Animal experiment (controlled) Not disclosed Independent group Rats given melanotan II, once or for seven days, learned to avoid a flavour paired with it, as they do after a drug that makes them sick; the aversion lasted longer than lithium's. Rats; taste aversion is an indirect sign of feeling ill.
Trivedi et al. 2003 28 Rats not reported Animal experiment (controlled) Industry Independent group Melanotan II given into a vein reduced eating in rats, yet almost none entered the brain; labelled peptide reached only small areas where the blood-brain barrier is open. Rats; short-term feeding only; industry-funded (Merck).
Wessells et al. 2003 25 Rats not reported Animal experiment (controlled) Mixed Originating group In awake rats, melanotan II caused erections when given into the brain, the spinal fluid or a vein; a receptor blocker given into the spinal fluid stopped the spinal effect; injected into the penis of anaesthetised rats it had no effect. Rats; the developing group; numbers of animals and blinding not stated in the abstract.
Cousen et al. 2009 68 Humans not reported Case report (uncontrolled) Not disclosed Independent group A letter reporting many new moles (eruptive naevi) after melanotan injections. One letter without an abstract; details could not be checked; cannot show cause.
Mang et al. 2012 67 Humans 1 Case report (uncontrolled) Not disclosed Independent group A 24-year-old man's moles were filmed with a dermatoscope before and during melanotan II use; the changes made it hard to tell a mole from a melanoma. One person; in German; shows a diagnostic problem, not a cancer risk.
Nelson et al. 2012 63 Humans 1 Case report (uncontrolled) Not disclosed Independent group A man came to hospital two hours after injecting melanotan II with a racing heart, sweating, tremor and anxiety; muscle breakdown and kidney strain followed and he spent three days in intensive care. Lab testing confirmed the product was melanotan II. One person, who injected an unusually large amount and whose urine also tested positive for opiates.
Kaski et al. 2013 64 Humans not reported Case report (uncontrolled) Not disclosed Independent group A letter reporting posterior reversible encephalopathy syndrome (PRES), a swelling in the back of the brain, after melanotan injections. One letter without an abstract; details could not be checked; cannot show cause.
Hjuler & Lorentzen 2014 66 Humans 1 Case report (uncontrolled) Not disclosed Independent group A 20-year-old woman with fair skin used melanotan II for three to four weeks with sunbed tanning; three months later a melanoma was removed from her buttock. One person; sunbed use is itself a melanoma risk; cannot show cause.
Breindahl et al. 2015 12 — not reported Product testing Not disclosed Independent group Vials sold as melanotan II by three online shops all contained melanotan II, but only 43–88% of the amount on the label; vials from two shops held 4.1–5.9% unknown impurities. Three shops; the study tested identity, content and purity only, not sterility or bacterial toxins.
Burian & Jemec 2019 37 Humans 179 Systematic review (uncontrolled) Not disclosed Independent group A systematic search found 179 people with eruptive naevi in 93 papers; immunosuppressants, chemotherapy or melanotan were the suspected cause in 41%; 16% had at least one abnormal (dysplastic) mole and five had a melanoma. Pooled case reports, not only melanotan; the authors state the data cannot estimate the risk of cancer.
Peters et al. 2020 65 Humans 1 Case report (uncontrolled) Not disclosed Independent group A middle-aged man had a kidney infarction (part of a kidney died from a blocked blood supply) that the doctors judged most likely caused by melanotan II. One person; the authors' mechanism (a clotting effect or direct kidney damage) is a suggestion, not tested.
Wu et al. 2020 32 Mice 12 Animal experiment (controlled) Government Independent group In 12 mice with an implanted melanoma (6 per group), melanotan II put on the skin slowed tumour growth. In a dish it did not change how fast melanoma cells divided but made them less invasive; blocking MC1R in the dish removed this effect. Mouse melanoma cells and mice; an existing tumour, not normal moles; the MC1R test was done only in cells; says nothing about whether melanotan II starts or speeds melanoma in people.
Mallory et al. 2021 61 Humans 1 Case report (uncontrolled) Not disclosed Independent group A 55-year-old man arrived after 30 hours of painful erection following a melanotan II injection; drainage and medicine failed, surgery was needed, and 15 weeks later he had new erection problems and scarring. One person; earlier uses had caused only erections of a few minutes, and why this episode was different is not known.
Eijmael MJPM, Janmaat CJ, Briët-Schipper EMN 2022 49 Humans 1 Case report (uncontrolled) Not disclosed Independent group A 27-year-old man came to the emergency department of a hospital in Gouda two hours after injecting melanotan II with sympathomimetic symptoms and was treated with a sedative, potassium and intravenous fluids. One person; in Dutch; product content not reported in the abstract.
Deville & Charlier 2024 15 — not reported Product testing Not disclosed Independent group A Belgian forensic laboratory confirmed melanotan II in vials labelled with that name; the powder was 30% pure. Two vials sent to one laboratory; what the other 70% was is not reported.
Yassin Alsabbagh et al. 2025 16 Humans 1 Case report (uncontrolled) Not disclosed Independent group A 22-year-old woman who had used a melanotan II nasal spray for tanning developed a melanoma inside the mouth, treated with surgery and immunotherapy. One person; mouth melanoma also occurs without any drug; cannot show cause.
Vadner & Smith 2026 60 Humans 1 Case report (uncontrolled) Not disclosed Independent group A 49-year-old man with fair skin and many moles used sunbeds and melanotan II, then melanotan I; within about a week several moles turned black, and five biopsies showed early melanoma (melanoma in situ) in severely abnormal moles. One person with many confounders: sunbeds, a high mole count, a family history of melanoma and testosterone from an unregulated source.

The table covers the lab and animal studies behind the mechanism, every published trial in people, the main case reports of harm and two analyses of products. Case reports describe what happened to one person; they cannot show that melanotan II caused it, and they cannot say how often it happens.

In detail Lab and animal studies

Melanotan II is a common research tool for the brain’s melanocortin system. A PubMed search on 22 October 2026 found 189 non-review records with “melanotan II” in the title or abstract, and 364 when the abbreviation MTII is counted in melanocortin papers; almost all mention animals or cells.31 The developing group at the University of Arizona wrote 10 of the 189 and 45 of the 364.31

That is why the laboratory picture is well replicated. The appetite effect seen in mice in Oregon was repeated in rats by a Merck team and, with a taste-aversion test, by a Cincinnati team .24,28,29 The rat erection work and the receptor studies come from the developing group and its collaborators.25,21,3

What the animal work does not cover matters more for users: a PubMed search for toxicity, cancer and pregnancy studies of melanotan II on 22 October 2026 found none.31 One study in 12 mice with an implanted melanoma found the opposite of a cancer-promoting effect: melanotan II put on the skin slowed the tumour . It tested an existing tumour in mice, not normal moles in people.32

In detail The three trials in people

All three trials come from the University of Arizona group that designed the molecule, and the study table above gives each one’s findings and limits.2,30,19

  • 1996, 3 healthy men, two weeks. Two tanned; mild nausea was common; yawning and stretching came with spontaneous erections .2
  • 1998, 10 men with erection problems of no known physical cause. Eight had erections with melanotan II; rigid erections lasted a mean 38.0 minutes, against 3.0 with placebo .30
  • 2000, 10 men with physical risk factors. Erections followed 12 of 19 melanotan II injections and 1 of 21 placebo injections, and desire rose; 4 of 19 injections caused severe nausea .19

What these trials cannot tell you: anything about women (none took part), repeated use beyond two weeks, how well a tan protects, or any rare harm. Twenty-three people can only reveal common, short-term effects.

In detail Where the evidence is promising, and what the gap costs

The biology behind melanotan II has produced real medicines. Afamelanotide, its straight-chain relative, is authorised in the EU for EPP because the extra melanin it causes lets patients tolerate more light.7 In a randomised trial completed by 65 people, afamelanotide raised skin melanin, and in volunteers who burn easily it more than halved the sunburn cells caused by a standard test dose of UV .33 Bremelanotide is a US medicine, and setmelanotide (Imcivree), an MC4 receptor agonist, has been authorised in the EU since 16 July 2021 for obesity and hunger in some rare genetic and hypothalamic conditions.11,6,34

So the idea of a melanocortin tan is not fantasy, and a tested product for people who burn easily could have value. The cost of the gap is that melanotan II itself stopped at 23 men in 2000, while it kept being sold. Its users now get a strong, unselective version of that biology, from products of uncertain strength and purity, without the trials that would show what it does over years.

In detail The one registered trial

ClinicalTrials.gov lists one trial: a placebo-controlled phase 2 study of melanotan II added to light therapy for vitiligo, a disease in which skin loses its pigment cells. It plans 60 participants at one hospital in Shenzhen, China, and is marked as recruiting.35

What is genuinely unknown

What is still not known?

What longer use does, whether it changes cancer risk, and what is in the vials.
The trials covered two weeks at most. Longer use has never been studied. How long the published trials followed people, in weeks of use.

  • Pilot trial: 3 healthy men

    two weeks

  • Erection trials: 20 men

    test injections, each watched for six hours

  • Use over months or years

    Not known: no safety studies

Sources Dorr et al. (1996); Wessells et al. (1998); Wessells et al. (2000)2,30,19 Checked

In detail All nine open questions, with their sources

As of 22 October 2026, these are specifically unknown:

  • Long-term safety. No trial lasted more than two weeks, and no long-term animal toxicity study was found.2,31
  • Melanoma risk. Case reports describe melanomas during or soon after use, but conclusive evidence of a link is lacking, and the pooled reports cannot estimate a risk.36,37
  • Whether new moles go away. Eruptive moles mostly persist, although fading after stopping has been reported.37,38
  • Sun protection. Whether a melanotan II tan protects the skin has never been measured.2
  • Blood pressure. Never measured in a melanotan II trial, although close relatives raise it.11,27
  • Effects in women. No published trial included women. One of the developers wrote that it also raised desire and arousal in women, but no such trial has been published.2,30,19,18
  • Pregnancy and breastfeeding. No data on melanotan II.31
  • How often harms happen. Case reports and regulator reports cannot give rates; the MHRA notes its reports do not equal the number of people harmed.14
  • What products contain. Tested vials held less than the label amount, or were 30% pure; some products sold as melanotan held insulin.12,15,39

Regulatory status

Is it legal?

It is approved nowhere and banned in sport. European regulators warn against it.
Melanotan II is not an approved medicine in Europe, the UK or the US. Status checked on 22 October 2026.
Netherlands and the EUUnited KingdomUnited States
Approved as a medicine?No No EU or Dutch authorisation.6,40No Unauthorised; the MHRA treats injectable products as medicines.14No The FDA calls it “an unapproved new drug”.8
Legal to sell or supply?No Dutch law forbids supplying a medicine without authorisation; Belgium calls its distribution illegal.41,39No Sale, supply and advertising of unauthorised medicines are not permitted.14,42No A seller was convicted and permanently barred by the FDA.8
Has a regulator flagged its risks?Yes The German (2010) and Belgian regulators warned against it; we found no Dutch warning.20,39Yes “Stop using them immediately” (2024).14Yes The FDA lists serious harms from case reports.43
Allowed in sport?No Not named, but by our reading banned at all times as a non-approved substance (S0).44,45No The same worldwide rule.44No The same worldwide rule.44
In detail Status in each country, and in sport
Regulatory status by jurisdiction
Jurisdiction Status Note Checked
European Union Not authorised Not authorised; no record in EMA's medicines data. Afamelanotide (Scenesse), a different molecule, is authorised for EPP. 48,6
Netherlands Not authorised Not authorised; no CBG record. Supplying an unauthorised medicine is prohibited by the Geneesmiddelenwet. 40,41
Germany Not authorised Not authorised. The BfArM warned against melanotan products in October 2010. 50,20,6
Belgium Not authorised Not authorised; the FAGG calls its distribution illegal and found insulin in products sold as melanotan. 51,39,6
United Kingdom Not authorised Not authorised; the MHRA treats injectable products as medicines and advises users to stop (April 2024). 42,14
United States Not authorised Not FDA-approved. On the agenda of an FDA advisory meeting planned before the end of February 2027. 43,53,55,8
Sport (WADA) Prohibited in sport · S0, at all times Not named on the List; falls under S0 (non-approved substances) by our reading: prohibited at all times. 44,45,46,47

All statuses were checked on 22 October 2026.

Sport (WADA)

Melanotan II is not named on the 2026 or 2027 Prohibited List. By our reading, it falls under S0, which bans at all times any pharmacological substance not covered elsewhere on the List “with no current approval by any governmental regulatory health authority for human therapeutic use”.44,45 No regulator has approved melanotan II. WADA and UK Anti-Doping both stress that a peptide can be prohibited without being named, and the 2027 List adds “peptides” to the S0 examples.46,47

In detail The EU, the Netherlands, Germany and Belgium

European Union

No melanotan II product has been authorised in the EU, and EMA’s medicines data, which also list refused and withdrawn applications, contain no record of it. Afamelanotide (Scenesse) and setmelanotide (Imcivree) are authorised, but they are different molecules.48,6,7

Netherlands

The CBG medicines database lists no melanotan II product.40 Under the Geneesmiddelenwet a product is a medicine if it is presented for treating or preventing disease, or used to change body functions through a pharmacological effect, and selling, supplying or importing a medicine without a marketing authorisation is prohibited, with narrow exceptions.41 We found no specific warning about melanotan from the IGJ or the CBG online. Dutch dermatologists have warned about it in the medical literature, and a Dutch hospital reported a patient with acute symptoms after an injection.36,49

Germany

Finished medicines need a licence (AMG § 21), and melanotan II has none.50,6 On 28 October 2010 the BfArM urgently advised against obtaining melanotan products from unidentifiable internet sources and using them for cosmetic purposes: they are not authorised, their quality, safety and efficacy have not been adequately studied, and the known risks concern the heart and circulation, the digestive tract and unintended changes in skin colour.20

Belgium

A medicine may be placed on the market only with a national or EU authorisation.51 The federal medicines agency (FAGG) calls melanotan, also sold as MT2, an experimental product not authorised as a medicine, so its distribution is illegal. In one of its investigations, products sold as melanotan contained insulin, which can cause a coma.39

In detail The United Kingdom

No melanotan II product is authorised, and supplying an unauthorised medicine is prohibited.42,14 In April 2024 the MHRA wrote that products containing melanotan II are classified as medicines if they are injectable or pens; a nasal spray only if it is sold with medical claims. Its advice to users is to stop using them immediately, see a doctor about side effects and report them through the Yellow Card scheme. It had received 16 suspected side-effect reports from 2012 to 2022, and has removed melanotan products from sale for over ten years.14 In 2021 it had described injectable products as “not automatically medicines”; the 2024 wording is clearer.52

In detail The United States, and the FDA advisory committee

Melanotan II is not FDA-approved. In 2016 the FDA permanently debarred a man convicted of federal felonies for a business that sold melanotan II online as an injectable tanning product; the order calls it “an unapproved new drug”.8

It was once nominated for pharmacy compounding and placed in Category 2, substances that may present significant safety risks; the nomination was withdrawn. The FDA’s page still gives its reasons: possible immune reactions from clumping or impurities, and “serious adverse events including melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxidrome and priapism” in published case reports.43 It is in none of the FDA’s three 503A categories on the list updated 14 May 2026.53

Not part of the July 2026 meeting. Melanotan II was not on the agenda of the FDA’s Pharmacy Compounding Advisory Committee (PCAC) on 23–24 July 2026; that meeting is explained on the US law page.54

What comes next. The FDA has announced a PCAC meeting “before the end of February 2027” to discuss melanotan II together with LL-37, GHK-Cu, dihexa acetate and pegylated mechano growth factor. By 22 October 2026 no date, docket or briefing document had been published.55 Advisory committees give non-binding advice.55 Even if melanotan II were later added to the 503A list by rulemaking, that would only allow pharmacy compounding on prescription in the US; it would not be an approval, would say nothing about efficacy and would change nothing in the EU.56,57,58

Risk profile

What are the risks?

Many feel sick. Doctors have seen moles change, long erections and melanoma. Its role in melanoma is unknown.
Serious harms have been seen in people. No study has counted how often they happen. What trials, case reports and regulators describe, as of 22 October 2026. A case report shows that something happened, not that melanotan II caused it.
Possible harmSeen in people?
Feeling sick, yawning, less appetiteYes Common in the trials; severe nausea after 4 of 19 injections in one.19,30
New moles, or moles that darkenYes In many case reports, once within a day of one injection.37,59
MelanomaUnknown Reported during or soon after use; a link has not been shown.36,60
An erection that will not stop (priapism)Yes In case reports; one man needed surgery and was left with erection problems.61,62
Racing heart, agitation, muscle breakdownYes In case reports, including one from the Netherlands.63,49
Brain swelling (PRES), kidney infarctionYes In single case reports.64,65
Raised blood pressureUnknown Not measured for melanotan II; shown for close relatives.11,27

Most of what is known about harm comes from case reports of people using unregulated products, often together with sunbeds or other drugs.66,60,63 The FDA lists the same serious events.43 Neither can say how often they happen.

In detail Side effects in the trials

In the trials, the common effects were nausea, stretching and yawning, less appetite and spontaneous erections; the investigators’ pooled account puts severe nausea at 12.9% at the dose they studied.2,30,26 In rats, pure melanotan II produces a learned dislike of a flavour paired with it, whichever way it is given: a sign that feeling sick is part of the drug’s own action, not a quirk of one product.29

For comparison, its close relative bremelanotide caused nausea in 40% of women in the large trials behind its US approval, and dark patches on the face, gums or breasts in 1% at occasional use but 38% after eight days of daily use; the patches did not always fade after stopping.11

In detail Moles and melanoma: why the worry makes sense, and why it is unproven

The worry follows a chain that is partly established and partly a hypothesis:

Why melanotan II raises a skin cancer question. The last step has not been tested.
  1. Melanotan II switches on MC1R on every pigment cell, including those in moles (shown in cells).
  2. The cells make more melanin, so moles darken (seen in people: case reports).
  3. The same signal makes pigment cells multiply, at least in a dish; new moles appear (cells; case reports of eruptive moles).
  4. Darker and new moles are harder to judge, so a melanoma may be found later (shown in one dermoscopy case).
  5. Whether this raises the chance of melanoma itself is not known (hypothesis; sunbeds and many moles confuse the picture).

Sources 22, 23, 37, 67, 36

What is seen. Many case reports describe existing moles darkening and new moles appearing during melanotan use , in one report within 24 hours of a single injection.68,59,37 A review of all published eruptive-mole cases found 179 people; immunosuppressant drugs, chemotherapy or melanotan were the suspected trigger in 41%, 16% had at least one abnormal (dysplastic) mole, and five had a melanoma.37 In a German case followed with a dermatoscope, the changes made it difficult to tell a mole from a melanoma.67 Pigment can also appear on the gums and inner cheeks, and in one man the gum colour was still there three months after stopping; he also smoked, which can darken the gums too.69

Melanoma reports. Melanoma has been reported during or shortly after melanotan use in several case reports : a Dutch review counted four by 2017.36 Reported cases include a melanoma in a woman (2011), a melanoma in situ in a young woman (2012), a 20-year-old woman in Denmark who also used sunbeds, a woman whose mouth melanoma followed a melanotan II nasal spray, and in 2026 a 49-year-old man with five early melanomas (melanoma in situ), whose moles had “turned black” within about a week of starting.70,71,66,16,60 A man with a past melanoma had new atypical moles after using a synthetic alpha-MSH peptide, and his moles lightened after he stopped; the authors concluded that such peptides “can drive proliferation” of abnormal pigment cells in predisposed people.38

Why that is not proof. Melanoma is common, and the people in these reports often had other strong risks. In 27 observational studies, people who had ever used sunbeds had about a fifth more melanoma, and nearly twice as much when they started before age 35.72 The 2026 case also had many moles, fair skin, a grandmother with melanoma and unregulated testosterone use. His doctors add that the melanomas may already have been there, and only became visible when the moles darkened.60 The Dutch reviewers conclude that conclusive evidence linking melanotan to melanoma is lacking.36

The argument the other way. MC1R signalling also helps pigment cells repair UV damage to their DNA: in cultured human melanocytes, alpha-MSH reduced UV-induced DNA damage and cell death , and people whose MC1R works poorly are more prone to melanoma.73,22 In 12 mice with an implanted melanoma, melanotan II put on the skin slowed the tumour ; in a dish, blocking MC1R removed its effect on melanoma cells.32 So stimulating MC1R could in theory protect as well as harm. Which effect wins for melanotan II in real use, often with sunbeds, has never been studied.

In detail Why a melanotan tan cannot be counted as sun protection

A tan from melanotan II looks like a sun tan, but nobody has measured what it protects against. On light skin, even a natural tan offers only modest protection .74 In a study of 12 volunteers, tans built with UVA light gave less protection than an SPF of 1.5, and tans built with UVB gave only very modest protection ; the authors called a pre-holiday tan from UVA-rich sunlamps counterproductive.75 How a tan is made changes what it does.

With afamelanotide, a related molecule tested in a randomised trial, the extra melanin did reduce sunburn cells in volunteers who burn easily.33 That has never been tested for melanotan II. In online forums, users often mention sunbeds as well, and sunbeds add UV damage of their own.17,72

In detail Erections that do not stop (priapism)

In rats, melanotan II starts erections from the brain and spinal cord, not from the penis. In men, it caused erections without any sexual stimulation.25,26 In the 1996 pilot, spontaneous erections came and went over 1–5 hours after an injection.2 But several case reports describe priapism, an erection that does not go down, after melanotan injections .62,76,61

In this kind of priapism (“low-flow” or ischaemic), blood is trapped in the penis and its tissue runs short of oxygen, which can lead to scarring. In a Glasgow case, drainage and medicine worked, but erections had not recovered four weeks later.62,61 In a Miami case, a 55-year-old man arrived after 30 hours; medicine failed, he needed surgery, and 15 weeks later he had new erection problems with scarring.61 An erection that lasts more than 3 hours needs emergency care, because delay can cause lasting damage.77

In detail Heart, blood pressure, brain and kidneys

A Chicago man who injected an unusually large amount of melanotan II developed a racing heart, sweating, tremor and anxiety within two hours; his muscle broke down (rhabdomyolysis), his kidney function fell, and he spent three days in intensive care . Testing confirmed the product was melanotan II; his urine also tested positive for opiates.63 A Dutch hospital treated a 27-year-old man for similar “sympathomimetic” symptoms two hours after an injection.49

PRES, a swelling at the back of the brain, has been reported after melanotan injections.64 PRES is linked to swings in blood pressure, among other causes. Mild forms may cause only a headache or a fit; most cases get better, but severe forms can cause bleeding in the brain.78 A rise in blood pressure through MC4 receptors would be a plausible route , because related molecules raise blood pressure in people; this has not been tested.27,11

A man in Sweden had a kidney infarction, part of a kidney dying from a blocked blood supply, which his doctors judged most likely caused by melanotan II.65 The German regulator lists risks to the heart and circulation and to the digestive tract.20

In detail What is in the products

Vials bought from three online shops did contain melanotan II, but only 43–88% of the amount on the label, and vials from two shops held 4.1–5.9% unknown impurities.12 A Belgian forensic laboratory found vials labelled melanotan II that were 30% pure.15 The Belgian medicines agency found insulin in products sold as melanotan.39 Samples seized by Italian police included both melanotan II and bremelanotide.79

Peptides can clump together, and making them leaves near-copies of the chain as impurities. For these reasons the FDA says compounded melanotan II “may pose risk for immunogenicity”, an unwanted immune reaction, for some routes of use.43 Injecting anything also brings the risk of infection; see product risk and sterile technique.

If someone is going to do this anyway

This section exists to reduce harm. It gives no doses, schedules or sourcing advice, and it is not a recommendation to use this compound.

How can someone lower the risk?

Check the product, have your skin checked first, and know the emergency signs.

This section gives no amounts, schedules or sources. It is for people who already use melanotan II or have a product.

If your product did not come from a pharmacy: check before you use it

These checks can show that something is wrong. None of them can show that a product is good or free of germs.80,81,82

Tick each box when you have checked it.

  • The seal and the vial are whole

    A broken cap or seal, or a cracked vial, can let germs in. Then do not use it.83,84,85

  • The label shows the name, amount, batch number and expiry date

    In the EU, a medicine must show all four, even on a small vial. If one is missing, or the date has passed, that is a warning sign. Take a photo of the label.86,83

  • For Melanotan II

    Even a full label can be wrong. Tested vials held less than the label said. One sample was only 30% pure. Some products with this name held insulin.12,15,39

  • It looks right

    A liquid, or a powder after mixing, should be clear and colourless, with no bits. Is it cloudy, has it changed colour, or do you see bits? Then do not use it.87,88

  • A lab report proves little if:

    • its batch number is not the one on your vial;
    • it does not name the lab, or has no date or signature;
    • it shows only purity (HPLC), with no test of what it is, such as mass spectrometry;
    • it has no test for germs (sterility) or for toxins from germs (endotoxin).

    Even a full report covers only one sample. A report from the seller comes from someone who gains if it looks good. It cannot show that your vial is clean.89,90,91,92,93

    What a certificate of analysis shows, and what it does not

  • It was kept as the label says

    Heat, freezing and sunlight can damage a peptide. Did it arrive warm, or was it frozen? Then do not use it. Often nobody can tell you how it was kept on the way. If you cannot know, you cannot rule out damage. When in doubt, throw it out.88,94,95,85

    When to throw a vial away

  • Clean steps, and a new sterile needle and syringe every time

    Wash your hands and wipe the rubber top with alcohol. Never share a needle, a syringe or a vial.85,96,94

    Sterile technique, step by step

  • Keep the vial, its label and any papers

    Keep them, even when the vial is empty, until you know you feel well. If you need a doctor, bring them. A lab can test what was inside.97,98

    If something goes wrong

  • Tell a doctor, and agree which checks fit you

    A doctor can help you choose blood tests that fit what you use. In the Netherlands, your doctor must keep what you say private.99,100,101

    Which checks matter, and whyTalking to your doctor

  • Know the warning signs before you start

    Spreading redness, fever, a swollen face or hard breathing need help fast. If it is severe, call your local emergency number.102,103,104

    All warning signs, and how fast to act

A doctor can help you keep watch

A GP or a dermatologist can check your moles and compare them over time. Tell them you use melanotan. The changes it causes can look like melanoma. A doctor who knows about it can judge them better.67,105 A doctor can also check your blood pressure. See talking to your doctor.

Sources 77, 61, 63, 106, 64, 78, 107, 105, 16

Stop-now warning signs

Call your local emergency number now

  • Confusion or slurred speech, very fast breathing, or pale, blue or blotchy skin, often with fever or shivering These can be signs of sepsis: the body's reaction to an infection has started to damage its own organs.
  • Fainting and not waking up within a minute, or fainting with chest pain, a racing heart or a fit This can be a dangerous heart rhythm or a severe allergic reaction.
  • Pain at the injection spot that is much worse than it looks, or dark, purple or grey patches or blisters there This can be a rare, fast-spreading infection of the deep layers under the skin (necrotising fasciitis).
  • Swelling of the lips, tongue or throat, trouble breathing or swallowing, wheezing, a hoarse voice, or feeling faint, soon after an injection This can be a severe allergic reaction (anaphylaxis), which is life-threatening and gets worse very quickly.
  • Pain, pressure or tightness in the chest, or pain that spreads to the arm, neck, jaw or back This can be a heart attack, which needs treatment in hospital straight away.
  • Sudden, severe shortness of breath: gasping, or not able to finish a sentence This can be a serious problem with the heart, the lungs or an allergic reaction.
  • A racing, pounding or irregular heartbeat that does not settle, or that comes with chest pain, breathlessness or fainting This can be a dangerous heart rhythm.
  • A sudden, severe headache with blurred vision, chest pain, confusion or vomiting Blood pressure may be dangerously high, which can damage the brain, heart, kidneys and eyes.
  • An erection that lasts more than 3 hours, or a painful erection that will not go down Blood trapped in the penis can damage it for good if it is not treated quickly.
  • Shaking, sweating or sudden hunger that turns into confusion or drowsiness Very low blood sugar can cause a fit or loss of consciousness; take something sugary if you can still swallow safely.
  • Severe, constant pain in the upper belly that spreads to the back, often with vomiting This can be an inflamed pancreas (pancreatitis), a known risk of GLP-1 medicines such as semaglutide and tirzepatide.
  • Sudden weakness or numbness on one side, a drooping face, or slurred or confused speech These are signs of a stroke, which needs treatment in hospital straight away, even if the signs pass.
  • A headache that starts suddenly and is extremely painful, or a headache with a stiff neck, confusion or a fit This can be a stroke or another emergency in the brain.
  • Sudden loss of sight in one or both eyes This can be a stroke or damage to the nerve of the eye, and sight can be lost for good.
  • A fit (seizure): jerking movements, or suddenly not responding A fit can be caused by very low blood sugar or a problem in the brain, and needs checks straight away.

Get medical help today

  • Fever, shivering or feeling very ill in the days after an injection Germs from the needle, the skin or the product may have reached your blood. If you also have a fast heartbeat or fast breathing, call your local emergency number.
  • Redness, heat, swelling or pain around the injection spot that keeps growing or getting worse This can be a skin infection (cellulitis), which needs antibiotics before it spreads.
  • Red lines that run from the injection spot towards the armpit or groin The infection may be spreading along the lymph vessels, and from there into the blood. If you also have a fever with a fast heartbeat or fast breathing, call your local emergency number.
  • A painful, warm lump that fills with pus This is probably an abscess: it often needs draining by a doctor, so do not squeeze it.
  • You were pricked by a needle that someone else had used Blood on a used needle can pass on HIV and hepatitis B or C, and preventive treatment works best within hours.
  • Vomiting so often that you cannot keep fluids down, or passing very little urine Losing too much fluid can damage the kidneys.
  • Yellow skin, or yellow whites of the eyes This can be a sign of a liver problem, gallstones or an inflamed pancreas.
  • Dark, red or cola-coloured urine together with muscle pain, tenderness or weakness Damaged muscle can release a protein that harms the kidneys (rhabdomyolysis).

Stop and contact a doctor

  • You fainted, but woke up quickly and now feel well Fainting is often harmless, but a doctor should check the cause.
  • A new mole, or a mole that changes size, shape or colour, itches or bleeds A changing mole can be skin cancer, and tanning peptides such as melanotan II have been linked to new and changing moles in case reports.
  • A lump at an injection spot that does not go away, or keeps growing A doctor should check whether it is an abscess, a reaction to the product or something else.
  • An itchy, raised rash, or puffy eyes or lips, while breathing stays normal Your body may be reacting to the product, and using it again can bring the reaction back.
  • Palpitations that keep coming back, even if they pass and you then feel well A doctor can check whether your heart rhythm is normal.
In detail Skin checks that make sense, and why
  • A full skin check before you start, by a GP or dermatologist, with photos of your moles. New and darker moles can appear within days. Photos give you something to compare with.59,67
  • Regular checks while you use it and afterwards. If you have many moles, ask for dermoscopy (a lit magnifier). The changes can make a mole hard to tell from melanoma.67
  • Look in your mouth too. Brown patches on the gums and cheeks have been reported, and one melanoma inside the mouth.69,16
  • See a GP about any mole that changes size, shape or colour, itches, bleeds or crusts.105
  • Sunbeds add their own risk. They raise melanoma risk on their own, and a melanotan tan has not been shown to protect you.72,75
In detail Other checks, and why
  • Blood pressure, before and while using it. Related molecules that switch on MC4 receptors raised blood pressure in people. The US label for bremelanotide says not to use it with uncontrolled high blood pressure or known heart or blood vessel disease.27,11
  • Kidney tests and a muscle enzyme test (CK) if you had muscle pain, dark urine or a racing heart after an injection. Muscle breakdown releases a protein that can harm the kidneys.63,106
  • Report side effects. In the Netherlands, report to Lareb; in the UK, through the Yellow Card scheme.108,14
In detail Who should not use it at all
  • Anyone who has had melanoma, has many or atypical moles, or has melanoma in the family. Melanotan II stimulates the pigment cells that melanoma grows from. The people in the reported cases often had these risks.38,60,22
  • Anyone with high blood pressure or heart disease. Related molecules raise blood pressure. Bremelanotide must not be used with uncontrolled high blood pressure or known heart or blood vessel disease.11,27
  • Anyone pregnant, trying to conceive or breastfeeding. There are no data for melanotan II, and the US label advises stopping bremelanotide if pregnancy is suspected.11
  • Children and teenagers, for whom there are no data at all.
  • Athletes subject to anti-doping rules. By our reading of the List, it is prohibited at all times under S0.44,45
In detail Possible interactions (none has been studied)
  • Erection medicines (such as sildenafil or tadalafil) or penile injections: melanotan II starts erections by another route, so the effects may add up and raise the risk of priapism.25,61
  • Stimulants and other drugs that raise heart rate or blood pressure, because of the reported sympathomimetic reactions.63,49
  • Tablets taken by mouth, especially naltrexone: bremelanotide may slow stomach emptying and lowers the amount of oral naltrexone that is absorbed. Whether melanotan II does the same is unknown.11
  • Mixtures with other peptides or hormones, which make any reaction impossible to attribute; the 2026 melanoma case also involved melanotan I and testosterone.60
In detail Legal routes, if you want what it promises

There is no legal route to melanotan II itself. For the conditions its relatives treat, there are. In the EU, afamelanotide for EPP is prescribed only by specialist doctors in recognised centres.7 Bremelanotide is a US medicine for low sexual desire in some premenopausal women; it is not authorised in the EU.11,6 For erection problems or low desire, a doctor can look for causes and offer authorised treatment. See legal routes.

Sources

Every claim on this page links to one of these sources. Scholarly sources link to their DOI; regulatory sources to the regulator's own page.

In detail All 108 sources, numbered as in the text
  1. National Center for Biotechnology Information (2026). PubChem Compound Summary for CID 92432, Melanotan II. PubChem. Dataset pubchem.ncbi.nlm.nih.gov — accessed 22 October 2026 ↩
  2. Dorr RT, Lines R, Levine N, Brooks C, Xiang L, Hruby VJ, Hadley ME (1996). Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sciences 58:1777-1784. Clinical trial doi:10.1016/0024-3205(96)00160-9 ↩
  3. Haskell-Luevano C, Miwa H, Dickinson C, Hadley ME, Hruby VJ, Yamada T, Gantz I (1996). Characterizations of the unusual dissociation properties of melanotropin peptides from the melanocortin receptor, hMC1R. Journal of Medicinal Chemistry 39:432-435. Research article doi:10.1021/jm950407s ↩
  4. Hadley ME, Dorr RT (2006). Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization. Peptides 27:921-930. Review doi:10.1016/j.peptides.2005.01.029 ↩
  5. King SH, Mayorov AV, Balse-Srinivasan P, Hruby VJ, Vanderah TW, Wessells H (2007). Melanocortin receptors, melanotropic peptides and penile erection. Current Topics in Medicinal Chemistry 7:1098-1106. Review PMID 17584130 ↩
  6. European Medicines Agency (2026). Medicines data download (JSON report of all EPARs: authorised, refused, withdrawn and suspended medicines). Dataset ema.europa.eu — accessed 20 October 2026 ↩
  7. European Medicines Agency (2026). Scenesse (afamelanotide): EPAR — overview and product information. Official product information ema.europa.eu — accessed 22 October 2026 ↩
  8. U.S. Food and Drug Administration (2016). Debarment Order (FR Doc. 2016-27244), 14 November 2016. Federal Register. Regulator federalregister.gov — accessed 23 October 2026 ↩
  9. U.S. Food and Drug Administration (2026). Drugs@FDA: NDA 210797 (Scenesse, afamelanotide implant). Regulator accessdata.fda.gov — accessed 22 October 2026 ↩
  10. U.S. Food and Drug Administration (2026). Drugs@FDA: NDA 210557 (Vyleesi, bremelanotide acetate injection). Regulator accessdata.fda.gov — accessed 22 October 2026 ↩
  11. U.S. Food and Drug Administration / DailyMed (National Library of Medicine) (2025). VYLEESI (bremelanotide injection): prescribing information. Official product information dailymed.nlm.nih.gov — accessed 20 October 2026 ↩
  12. Breindahl T, Evans-Brown M, Hindersson P, McVeigh J, Bellis M, Stensballe A, Kimergård A (2015). Identification and characterization by LC-UV-MS/MS of melanotan II skin-tanning products sold illegally on the Internet. Drug Testing and Analysis 7:164-172. Research article doi:10.1002/dta.1655 ↩
  13. Al-Obeidi F, Castrucci AM, Hadley ME, Hruby VJ (1989). Potent and prolonged acting cyclic lactam analogues of alpha-melanotropin: design based on molecular dynamics. Journal of Medicinal Chemistry 32:2555-2561. Research article doi:10.1021/jm00132a010 ↩
  14. Medicines and Healthcare products Regulatory Agency (MHRA) (2024). FOI 24/274: Side effects reports of melanotan II products. Regulator assets.publishing.service.gov.uk — accessed 22 October 2026 ↩
  15. Deville M, Charlier C (2024). Barbie drug identification: Not a child's play. Journal of Forensic Sciences 69:2331-2338. Research article doi:10.1111/1556-4029.15633 ↩
  16. Yassin Alsabbagh A, Bhujel N, Singh RP (2025). Melanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma?. International Journal of Oral and Maxillofacial Surgery 54:806-808. Research article doi:10.1016/j.ijom.2025.03.014 ↩
  17. Gilhooley E, Daly S, McKenna D (2021). Melanotan II User Experience: A Qualitative Study of Online Discussion Forums. Dermatology 237:995-999. Research article doi:10.1159/000514492 ↩
  18. Hadley ME (2005). Discovery that a melanocortin regulates sexual functions in male and female humans. Peptides 26:1687-1689. Review doi:10.1016/j.peptides.2005.01.023 ↩
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