Dr. Pep

Peptides · Non-selective melanocortin agonist (tanning)

Melanotan II: what the studies show

Every line below comes from a study, label or regulator record, checked by two models, with the source linked. Information, not medical advice. For adults 18+.

What it is

  • Melanotan II (MT-II) is an unlicensed, lab-made cyclic peptide copy of alpha-MSH. It activates several melanocortin receptors, so it tans the skin and also affects appetite and sexual function. It is sold online for tanning and sexual effects.[1][2][3]
  • Name-alikes must be kept apart. Afamelanotide (also called melanotan I, [Nle4-D-Phe7]-alpha-MSH) is the only alpha-MSH analogue approved, for a limited number of medical uses, and is a different molecule from melanotan II. Bremelanotide (PT-141, Vyleesi) is also a separate approved molecule.[4][2][5]

Bottom line

  • Melanotan II has never been approved anywhere, human trials are a handful of small 1990s-2000s studies, and the human safety evidence is mostly case reports of dark moles, melanoma, toxicity and priapism.[6][7][1][3][8]

What the human studies found

  • Erections (MT-II): in a double-blind crossover study of 10 men with psychogenic erectile dysfunction, 0.025 mg/kg given under the skin produced clinically apparent erections in 8 of 10 men, with tip rigidity lasting 38.0 minutes versus 3.0 on placebo. Nausea, stretching and yawning, and reduced appetite were more frequent.[9]
  • In 10 men with erectile dysfunction from physical causes (double-blind crossover), MT-II 0.025 mg/kg initiated erections after 12 of 19 injections versus 1 of 21 on placebo, and raised reported sexual desire. 4 of 19 injections were linked to severe nausea, and yawning was also more common.[10]
  • A review of the same research group's work (20 men) reported erections in 17 of 20 and severe nausea in 12.9% at 0.025 mg/kg.[6]
  • The first pilot phase-I study (3 healthy men, single-blind, daily injections Monday to Friday for 2 weeks, 0.01 to 0.03 mg/kg) found spontaneous erections, mild nausea, increased pigmentation in two men, and somnolence and fatigue at 0.03 mg/kg in one.[11]
  • Tanning: the only controlled melanotan II data in our records are a 1996 pilot in 3 healthy men (alternating days of melanotan II or saline injections, 0.01 to 0.03 mg/kg); 2 of them had more pigmentation in the face, upper body and buttock. Most tanning trials here used melanotan I (afamelanotide), a different molecule: 10 daily injections at 0.16 mg/kg/day in 7 volunteers tanned 3 of 8 body sites, and a study of 77 people found it raised skin melanin more in those carrying MC1R variant genes. Those data are not for melanotan II.[11][5][12]

Known risks and side effects

  • Melanoma and moles (case reports): melanoma in situ; melanoma in a 20-year-old woman after a 3-4 week MT-II course combined with sunbeds; new atypical moles within a week of two injections; darkened and enlarging moles in a 16-year-old with a melanoma-prone syndrome who used MT-II and sunbeds; five melanomas in situ in a 49-year-old man who combined MT-II, tanning beds and anabolic hormones; and a mucosal melanoma of the upper jaw in a 22-year-old woman who used MT-II nasal spray. Causation is unproven in each; they are case reports with other exposures.[7][1][13][14][2][15]
  • Other mole and pigment changes: videodermoscopy in a 24-year-old man showed nevus changes that made them hard to tell from melanoma, and a man who injected more than 150 doses developed darker and new moles, including on the genitals; the two removed moles were not malignant. Another case report describes gum pigmentation after 64 days of injections.[16][17][18]
  • Toxicity: a man who injected 6 mg of MT-II had sympathetic overdrive (heart rate up to 146, anxiety, sweating, tremor) and rhabdomyolysis. A separate case report describes ischaemic priapism needing surgery after an MT-II injection. A further case describes pyoderma gangrenosum at injection sites after melanotan use.[3][19][20]
  • FDA notes published case reports of serious adverse events with compounded MT-II, including melanoma, posterior reversible encephalopathy syndrome, a sympathomimetic toxidrome and priapism. It also flags immunogenicity risk from aggregation or impurities.[8]
  • A qualitative study of online forums (205 users, 2016-2017) found misinformation, sunbed use and concerns about infection transmission and contaminated products. The MHRA recorded only 13 suspected-reaction reports for melanotan II from 2011 to 2021, which is not evidence of safety because reporting is voluntary.[21][22]

Legal status

  • Melanotan II is not an approved drug. FDA's category 2 bulk-substance list (page retrieved 2026-10-09) places MT-II among compounding substances that may present significant safety risks.[8]
  • UK: in a 2021-12-20 reply to a freedom-of-information request, the MHRA said it has repeatedly removed melanotan products from sale for over 10 years, but that injectable or nasal tanning products with MT-II are not automatically medicines. They count as medicines only if they meet the legal definition.[22]

Sources

  1. [1] Melanoma associated with the use of melanotan-II.
  2. [2] Five primary melanomas in situ in a patient with recent tanning bed use, melanotan exposure, and anabolic hormone use.
  3. [3] Melanotan II injection resulting in systemic toxicity and rhabdomyolysis.
  4. [4] Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review.
  5. [5] Increased eumelanin expression and tanning is induced by a superpotent melanotropin [Nle4-D-Phe7]-alpha-MSH in humans.
  6. [6] Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II.
  7. [7] Melanotan-associated melanoma in situ.
  8. [8] FDA: Certain bulk drug substances for use in compounding that may present significant safety risks (503A/503B category 2)
  9. [9] Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study.
  10. [10] Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction.
  11. [11] Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study.
  12. [12] Effect of MELANOTAN, [Nle(4), D-Phe(7)]-alpha-MSH, on melanin synthesis in humans with MC1R variant alleles.
  13. [13] Atypical melanocytic naevi following melanotan injection.
  14. [14] Changes of melanocytic lesions inducedby Melanotan injections and sun bed use ina teenage patient with FAMMM syndrome.
  15. [15] Melanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma?
  16. [16] [Dermoscopic changes in melanocytic nevi during use of melanotan II].
  17. [17] [Melanotan-induced lentigines and nevi].
  18. [18] Changes in Oral Mucosa Associated with Melanotan II Injections: A Case Report.
  19. [19] Melanotan Tanning Injection: A Rare Cause of Priapism.
  20. [20] Pyoderma Gangrenosum Secondary to Melanotan.
  21. [21] Melanotan II User Experience: A Qualitative Study of Online Discussion Forums.
  22. [22] MHRA: FOI 21/1237 response on Yellow Card reports for melanotan II products (2021)