{"id":"melanotan-2","name":"Melanotan II","aliases":["MT-II","MT-2","melanotan 2","cyclic α-MSH analogue"],"url":"https://lyoresearch.com/compounds/melanotan-2","class":{"id":"melanocortins","name":"Melanocortin agonists","url":"https://lyoresearch.com/classes/melanocortins"},"summary":"Melanotan II is a synthetic cyclic peptide that mimics α-melanocyte-stimulating hormone. Small early trials in the 1990s showed it darkens skin and, separately, triggers erections in men — the two effects it is still sold for. It has never completed later-stage trials and is not approved anywhere. Reported harms include nausea, uncontrolled erections, darkening and change of moles, and case reports of serious events such as kidney infarction, which is why regulators warn against it.","overall_grade":"C","overall_grade_meaning":"weak human evidence","human_trials":"Small early-phase trials","regulatory_status":"Not approved","molecule":{"formula":"C50H69N15O9","molecular_weight":"1024.2","cas":"121062-08-6","pubchem_cid":92432,"note":null},"pharmacokinetics":{"basis":"none","route":"Subcutaneous in the 1996 pilot study, which reports no PK","half_life":"No human pharmacokinetic data","licensed_regimen":null,"product":null,"source":{"title":"Dorr RT, et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide, in a pilot phase-I clinical study. Life Sci 1996","url":"https://pubmed.ncbi.nlm.nih.gov/8637402/"}},"outcomes":[{"outcome":"Erectile function (psychogenic ED)","grade":"C","grade_meaning":"weak human evidence","effect_size":"moderate","adverse":false,"human_studies":"Small crossover RCTs","evidence":"In a 10-man double-blind crossover, Melanotan II produced clinically apparent erections in most treated men, far exceeding placebo — small, early, never taken to phase 3.","references":[{"citation":"Wessells H, et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: a double-blind, placebo-controlled crossover study.","where":"J Urol, 1998;160:389–393","url":"https://pubmed.ncbi.nlm.nih.gov/9679884/"}],"verbatim":{"text":"Mean duration of tip rigidity greater than 80% was 38.0 minutes with Melanotan-II and 3.0 with placebo (p=0.0045).","citation":"Wessells H, et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: a double-blind, placebo-controlled crossover study.","url":"https://pubmed.ncbi.nlm.nih.gov/9679884/"}},{"outcome":"Skin tanning","grade":"C","grade_meaning":"weak human evidence","effect_size":"moderate","adverse":false,"human_studies":"Pilot studies (n≈3–12)","evidence":"A pilot phase 1 study showed measurable tanning from a few low subcutaneous doses. The related peptide melanotan-1 (afamelanotide) went on to be developed properly and approved for a rare photosensitivity disorder; melanotan II did not.","references":[{"citation":"Dorr RT, et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide, in a pilot phase-1 clinical study.","where":"Life Sci, 1996;58:1777–1784","url":"https://pubmed.ncbi.nlm.nih.gov/8637402/"}],"verbatim":{"text":"These results demonstrate that MT-II has tanning activity in humans given only 5 low doses every other day by subcutaneous injection.","citation":"Dorr RT, et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide, in a pilot phase-1 clinical study.","url":"https://pubmed.ncbi.nlm.nih.gov/8637402/"}},{"outcome":"Safety in humans","grade":"C","grade_meaning":"weak human evidence","effect_size":"moderate","adverse":true,"human_studies":"Trials + case reports","evidence":"Nausea, flushing, spontaneous erections and darkening of moles are common; case reports describe rhabdomyolysis and kidney infarction, and dermatologists warn that new or changing moles can mask melanoma. No systematic long-term safety data exist.","references":[{"citation":"Wessells H, et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: a double-blind, placebo-controlled crossover study.","where":"J Urol, 1998;160:389–393","url":"https://pubmed.ncbi.nlm.nih.gov/9679884/"},{"citation":"Case reports of serious harm with melanotan II (e.g. renal infarction).","where":"CEN Case Rep and others, 2020","url":"https://pubmed.ncbi.nlm.nih.gov/31953620/"}]}],"regions":[{"region":"European Union","status":"Unauthorised medicinal product","note":"No marketing authorisation. National regulators (including in the UK and Nordic countries) have repeatedly warned against injectable melanotan sold online."},{"region":"United States","status":"Not approved","note":"Not approved by the FDA, which has warned consumers about melanotan products sold for tanning. The properly developed sibling, afamelanotide (Scenesse), is approved for a rare photosensitivity disorder — melanotan II is not."},{"region":"United Kingdom","status":"Unlicensed medicine","note":"Not licensed by the MHRA. Selling or supplying it for human use is an offence under the Human Medicines Regulations 2012."},{"region":"Australia","status":"Prescription-only / unapproved","note":"Not on the ARTG. Supply without a prescription is unlawful; imports are seized."},{"region":"Canada","status":"Not authorised","note":"No Drug Identification Number; selling it for human use is illegal."},{"region":"Sport (WADA)","status":"Not prohibited","note":"Not specifically named on the 2026 WADA Prohibited List, though as a non-approved substance it may fall under S0; athletes should verify."}],"faq":[{"q":"Does Melanotan II actually work for tanning?","a":"Small studies show it does darken skin. That is not the issue — the issue is that it is unapproved, non-selective, and the same activity changes moles and causes nausea and other effects, with no long-term safety data."},{"q":"Is it the same as the approved 'Scenesse'?","a":"No. Scenesse (afamelanotide) is a related but different, properly developed and approved peptide for a rare light-sensitivity disease. Melanotan II is the unapproved grey-market version."},{"q":"Why do regulators warn about it?","a":"Because it is injected without oversight, causes nausea, flushing and spontaneous erections, darkens and changes moles in a way that can hide melanoma, and has case reports of serious harm including kidney infarction."}],"references":[{"cite":"Wessells H, et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: a double-blind, placebo-controlled crossover study.","where":"J Urol, 1998;160:389–393","url":"https://pubmed.ncbi.nlm.nih.gov/9679884/","note":"10 men, crossover; the erection data."},{"cite":"Dorr RT, et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide, in a pilot phase-1 clinical study.","where":"Life Sci, 1996;58:1777–1784","url":"https://pubmed.ncbi.nlm.nih.gov/8637402/","note":"3 volunteers; the tanning data."},{"cite":"Case reports of serious harm with melanotan II (e.g. renal infarction).","where":"CEN Case Rep and others, 2020","url":"https://pubmed.ncbi.nlm.nih.gov/31953620/","note":"Illustrative of the unmonitored-use risk."}],"last_reviewed":"2026-09-03","literature_searched_to":"2026-09-03","changelog":[{"date":"2026-09-03","note":"Initial publication. Grade C — real small-trial efficacy, unquantified real-world harm."}],"license":"CC BY 4.0 — cite as “LYO Research” with a link.","methodology":"https://lyoresearch.com/methodology"}