Melanotan 2 (Melanotan II) is a synthetic peptide created at the University of Arizona to tan the skin. In early trials it also caused erections, which led to the development of PT-141.[4][5] It has never been approved anywhere, and regulators in the US, UK and Denmark have warned against it.[8][10][11] Dermatologists have reported melanoma and new or changing moles in users.[12]
What is Melanotan 2?
Melanotan II is a ring-shaped, 7-amino-acid version of alpha-MSH, the hormone that triggers skin pigment. It activates the MC1 receptor in skin, which darkens it, and MC3 and MC4 receptors in the brain, which affect sexual function and appetite.[4] Its sexual effects were discovered by accident during tanning studies.[5]
Melanotan 1 vs Melanotan 2
| Melanotan 1 (afamelanotide) | Melanotan 2 | |
|---|---|---|
| Structure | Linear 13-amino-acid peptide | Ring-shaped 7-amino-acid peptide |
| Approval | FDA-approved 2019 as Scenesse[6] | Not approved |
| Approved use | Light sensitivity in erythropoietic protoporphyria[7] | None |
| Originally studied for | Tanning[4] | Erectile dysfunction and tanning[4] |
What the research shows
All human trials were small University of Arizona studies published between 1996 and 2000:
- Tanning: 2 of 3 men tanned after 5 low doses; spontaneous erections and nausea also occurred.[1]
- Erectile dysfunction: erections in 8 of 10 men with psychological causes,[2] and after 12 of 19 injections in men with physical causes, versus 1 of 21 placebo.[3]
The 1996 pilot shows how small this evidence base is. Three healthy men received injections on alternating days, with salt-water placebo on the other days, starting at 0.01 mg per kg of body weight. Doses were raised to 0.025 or 0.03 mg per kg. At 0.03 mg per kg, one of two men had grade 2 (on the WHO scale) sleepiness and fatigue, and mild nausea occurred at most dose levels. Two of the three men had darker skin on the face, upper body and buttocks one week after dosing ended.[1]
Melanotan 2 side effects
Moles and melanoma
- New or darkening moles: reported within 24 hours of a single injection.[17][27][13]
- Melanoma: several cases in users, including one in the mouth after nasal spray use.[14][15][16]
A 2017 review counted four published case reports of melanoma arising from existing moles during or shortly after melanotan use.[12] A 2019 review of every published report of “eruptive” moles (many moles appearing suddenly) found 179 patients; drugs including immune-suppressing medicines, chemotherapy and melanotan were the suspected trigger in 41%. Sixteen percent had at least one abnormal (dysplastic) mole on biopsy, and five melanomas were reported.[13]
Even the approved relative, afamelanotide (Scenesse), carries this warning. Its label says it can darken existing moles and freckles and recommends a full-body skin exam twice a year.[6] Melanotan 2 users get no such monitoring.
See a doctor promptly if a mole appears suddenly, changes size, shape or color, bleeds, or looks different from your other moles, and tell them you have used melanotan.
Other reported effects
- Common in trials: nausea, yawning and stretching, and spontaneous erections.[1][3]
- Priapism (erections lasting hours).[18]
- Muscle breakdown (rhabdomyolysis) and stimulant-like toxicity.[19]
- Kidney infarction.[20]
- Posterior reversible encephalopathy syndrome, a brain swelling condition.[21]
Two of these reports show how serious problems can be. A 39-year-old man injected 6 mg bought online, which he said was six times the suggested starting dose. Within two hours he had body aches, sweating, anxiety, tremor and a heart rate up to 146 beats per minute. His muscle enzyme (CPK) later peaked above 17,000, his kidney function dropped, and he spent three days in intensive care.[19] In the priapism case, a man needed the blood drained from his penis and a medicine injected to end the erection; four weeks later he had not yet recovered erectile function.[18]
Melanotan 2 and sunbeds
Many users combine injections with sunbeds or sun exposure. Reported melanoma cases include a patient with five melanomas in situ who had used tanning beds, melanotan and anabolic hormones,[28] and a 20-year-old woman diagnosed with melanoma three months after a 3- to 4-week course of injections combined with sunbeds.[15] A 2017 dermatology review noted that conclusive evidence linking melanotan to melanoma is lacking, but advised caution.[12]
Melanotan 2 nasal spray
Nasal sprays are widely sold as an alternative to injections. In 2025, doctors reported melanoma inside the mouth of a nasal spray user and raised the spray as a possible risk factor.[16] In the UK, nasal sprays are classed as medicines only when sold with medical claims, while injectables always are.[10]
Melanotan 2 vs PT-141
| Melanotan 2 | PT-141 (bremelanotide) | |
|---|---|---|
| Status | Not approved anywhere[12] | FDA-approved as Vyleesi |
| Main use | Tanning | Low sexual desire in premenopausal women |
| Relationship | Original peptide[4] | Developed from Melanotan 2[4] |
Melanotan 2 dosage
The 1996 pilot study recommended 0.025 mg per kg for further research.[1] There is no approved dose. Products sold online are unregulated, and an analysis of internet products found impurities.[22] In that Danish lab analysis, vials from three online shops were each labeled as 10 mg but contained between 4.32 and 8.84 mg of melanotan II, and vials from two shops held 4.1% to 5.9% unknown impurities.[22] That means the real dose in any vial is uncertain.
Is Melanotan 2 legal?
- US: FDA treats it as an unapproved new drug, and one seller was convicted of a felony for selling it.[9] Its compounding nomination was withdrawn.[8]
- UK: injectable Melanotan is classed as a medicine and cannot legally be sold; MHRA says it has removed Melanotan products for more than 10 years.[10]
- Denmark: called an illegal product.[11]
- Sports: not named on WADA’s 2026 list, but as an unapproved substance it falls under the S0 category, which is prohibited at all times.[24]
This is general information, not legal advice.
Why Melanotan is popular
Social media has driven much of the interest: a 2025 dermatology study analyzed melanotan content trending on TikTok,[23] and a BBC investigation found dozens of influencers promoting it, one of whom said a company had offered her free nasal sprays to promote them.[25]
