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RUO · Research Use Only⚠ Cancer Concern+2 more

Melanotan II

A synthetic melanocortin agonist that darkens skin by stimulating melanin. We read all 60 studies. The protocol is below.

Updated 03 May 2026Read 12 minEvidence ●○○○○Citations 60
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The Melanotan II Report · $19

Everything you need to start: dose, sourcing, safety, our verdict.

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Built from 60 cited studies.

Status
Research-only
Class
Cancer Concern
Evidence
1/ 5●○○○○
FDA-approved?
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Approved anywhere?
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Case reports of mole changes
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⚠ Cancer Concern
Read this if
  • you're a pale Northern-European-descent gym-bro doing pre-vacation tanning cycles
  • you're a man running it for the MC4-driven libido side effects, with the tan as a bonus
  • you've heard about the new-mole and dark-mole stories and want to know how serious they are
  • **you assumed forum dose protocols were trial-derived** — they're not. The community MT-II dose is extrapolated from rodent work and tiny human experimental cohorts in the 1990s. There is no validated human dose, anywhere
  • **you came here for the libido side-effect** — read the [PT-141 report](/peptides/pt-141) instead. Same melanocortin family, FDA-approved for HSDD, cleaner risk profile, no tanning side-effect
Skip this if
  • you have a personal or family history of melanoma or atypical mole syndrome
  • you have hypertension or cardiovascular disease — the MC4 effects are real
  • you can't be talked into regular full-body skin checks for the rest of your life
  • **you can't get a mass-spec identity test** — RUO 'Melanotan II' vials commonly vary 30–50% in actual peptide content. The only checks are mass-spec identity on the COA plus a visual look at the lyo-cake density. If the COA shows IR-only identity, treat that as no identity test at all
The 4 ways you can buy Melanotan II
Brand
✗
Not available
No legal branded MT-II; PT-141 / Vyleesi is the only approved melanocortin agonist.
Compounded 503A
✗
Not available
Not meaningfully available
Documented melanoma case reports + the existence of Vyleesi as the legal alternative mean almost n…
RUO (research-only)
✓
Sold 'for research only'
$25–$60/mo
The dominant channel. Cardiovascular and melanoma case reports apply regardless of source quality.
Gray market
✓
Unregulated overseas import
$4–$8/mo
Crypto/Wise pay; one 10mg×10 box covers years at typical cyclical dosing. Same melanoma + cardiova…
Click any lane for the full Sourcing breakdown.
First 90 days · Melanotan II
Weeks 1–2
Tolerability check. Mild contact irritation or transient redness is normal for the first 1–2 weeks. Stop and patch-test if you get persistent dermatitis.
Weeks 4–8
Texture changes if it's going to work. Take a baseline photo at week 0 — week 8 vs baseline is the honest comparator. Your memory of how your skin looked is unreliable.
Week 12 — decide
Side-by-side photo decision. Cosmetic peptide effects are slow and modest. Anyone promising fast dramatic results is selling marketing, not skin biology.
Quit if
  • Persistent contact dermatitis or worsening irritation.
  • No perceived change in week 8 and week 12 photo comparisons (cosmetic peptides usually take longer than 12 weeks, but at 16 weeks if nothing has changed, the formulation isn't reaching the target).
  • Any pigmentation changes that persist after stopping.
Identity

What it is.

Melanotan II is a synthetic analog of alpha-MSH (alpha-melanocyte-stimulating hormone), the hormone that tells skin to produce melanin. It binds the melanocortin-1 receptor (the tanning one) and also the melanocortin-3 and -4 receptors (the libido and appetite ones), which is why people who use it report tanning *and* a side-helping of nausea, flushing, and erections.

It was developed in the 1980s at the University of Arizona, originally as a way to reduce skin cancer risk by encouraging tanning without UV exposure. The program was sold to a biotech, which licensed it to Clinuvel — who took the single-receptor cousin afamelanotide (Scenesse) through the FDA and got it approved in 2019 for a rare light-sensitivity disorder.

Melanotan II itself was never approved anywhere. It's sold strictly as a research chemical (RUO). The injectable tanning market runs on grey-market vials.

TL;DR

TL;DR. 30-second version.

The compressed verdict — what Melanotan II actually is, what the human evidence shows, and the watch-for in three bullets. Locked.

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Mechanism

Mechanism.

Mechanism · in the Melanotan II report

How the molecule actually works — receptor profile, downstream signaling, what to expect mechanistically.

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Evidence

Evidence. What we actually know in humans.

Evidence · in the Melanotan II report

The trial breakdown — phase, n, primary endpoint, who funded, what hit, what didn't.

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Human-Evidence Factbox
FDA-approved?
$19 ↓
Approved anywhere?
$19 ↓
Case reports of mole changes
$19 ↓
Case reports of melanoma after use
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Phase 2/3 trials in humans
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Years sold underground
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RUO vial-to-vial content variance
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IR-only identity on the COA
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Community dose protocol — provenance
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Dose

Dose. The actual protocol.

Dose · in the Melanotan II report

The specific protocol — dose, titration schedule, cycle pattern, frequency, route.

We read 60 studies to write this report.
Get the report · $19 ↓
Sourcing

Sourcing. Where the cohort actually buys.

Sourcing · in the Melanotan II report

Sourcing breakdown — vendor methodology, red flags, our published test results, COA checklist.

We read 60 studies to write this report.
Get the report · $19 ↓
Safety

Safety. Side effects.

Safety · in the Melanotan II report

The watch-for list — contraindications, drug interactions, monitoring labs, when to stop.

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Editorial Position

Editorial position.

Editorial Position · in the Melanotan II report

Our editorial position — explicit yes / no / depends, with the reasoning behind it.

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Citations

Citations.

  1. 01Todorovic M, et al. 5-Hydroxypyrroloindoline Affords Tryptathionine and 2,2'-bis-Indole Peptide Staples: Application to Melanotan-II. Chemistry (Weinheim an der Bergstrasse, Germany). 2024;30(19):e202304270. PMID: 38285527.
  2. 02Wekwejt P, et al. Melanotan-II reverses memory impairment induced by a short-term HF diet. Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie. 2023;165:115129. PMID: 37478579.
  3. 03Peters B, et al. Melanotan II: a possible cause of renal infarction: review of the literature and case report. CEN case reports. 2020;9(2):159-161. PMID: 31953620.
  4. 04Gilhooley E, et al. Melanotan II User Experience: A Qualitative Study of Online Discussion Forums. Dermatology (Basel, Switzerland). 2021;237(6):995-999. PMID: 34464955.
  5. 05Evans-Brown M, et al. Use of melanotan I and II in the general population. BMJ (Clinical research ed.). 2009;338:b566. PMID: 19224885.
+Show all 60 citations
  1. 06Minakova E, et al. Melanotan-II reverses autistic features in a maternal immune activation mouse model of autism. PloS one. 2019;14(1):e0210389. PMID: 30629642.
  2. 07Tomassi S, et al. CLIPSing Melanotan-II to Discover Multiple Functionally Selective hMCR Agonists. Journal of medicinal chemistry. 2022;65(5):4007-4017. PMID: 35188390.
  3. 08Eliason NL, et al. Melanocortin receptor agonist melanotan-II microinjected in the nucleus accumbens decreases appetitive and consumptive responding for food. Neuropeptides. 2022;96:102289. PMID: 36155088.
  4. 09Hjuler KF, et al. Melanoma associated with the use of melanotan-II. Dermatology (Basel, Switzerland). 2014;228(1):34-6. PMID: 24355990.
  5. 10Dorr RT, et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life sciences. 1996;58(20):1777-84. PMID: 8637402.
  6. 11Cui J, et al. Disruption of Gpr45 causes reduced hypothalamic POMC expression and obesity. The Journal of clinical investigation. 2016;126(9):3192-206. PMID: 27500489.
  7. 12Giuliano F, et al. Melanotan-II: Investigation of the inducer and facilitator effects on penile erection in anaesthetized rat. Neuroscience. 2006;138(1):293-301. PMID: 16360286.
  8. 13Burian EA, et al. Eruptive Melanocytic Nevi: A Review. American journal of clinical dermatology. 2019;20(5):669-682. PMID: 31119650.
  9. 14Nelson ME, et al. Melanotan II injection resulting in systemic toxicity and rhabdomyolysis. Clinical toxicology (Philadelphia, Pa.). 2012;50(10):1169-73. PMID: 23121206.
  10. 15Wolters FL, et al. Co-treatment with melanotan-II, a potent melanocortin, does not protect against cisplatin ototoxicity. Hearing research. 2002;172(1-2):110-7. PMID: 12361873.
  11. 16Dreyer BA, et al. Melanotan-induced priapism: a hard-earned tan. BMJ case reports. 2019;12(2). PMID: 30796078.
  12. 17Hadley ME, et al. Discovery and development of novel melanogenic drugs. Melanotan-I and -II. Pharmaceutical biotechnology. 1998;11:575-95. PMID: 9760697.
  13. 18Paurobally D, et al. Melanotan-associated melanoma. The British journal of dermatology. 2011;164(6):1403-5. PMID: 21564053.
  14. 19Devlin J, et al. Melanotan II overdose associated with priapism. Clinical toxicology (Philadelphia, Pa.). 2013;51(4):383. PMID: 23537392.
  15. 20Callaghan Iii DJ. A glimpse into the underground market of melanotan. Dermatology online journal. 2018;24(5). PMID: 30142729.
  16. 21Raposinho PD, et al. The melanocortin agonist Melanotan-II reduces the orexigenic and adipogenic effects of neuropeptide Y (NPY) but does not affect the NPY-driven suppressive effects on the gonadotropic and somatotropic axes in the male rat. Journal of neuroendocrinology. 2003;15(2):173-81. PMID: 12535159.
  17. 22Paiva L, et al. Effect of Melanotan-II on Brain Fos Immunoreactivity and Oxytocin Neuronal Activity and Secretion in Rats. Journal of neuroendocrinology. 2017;29(2). PMID: 28009464.
  18. 23Ter Laak MP, et al. The potent melanocortin receptor agonist melanotan-II promotes peripheral nerve regeneration and has neuroprotective properties in the rat. European journal of pharmacology. 2003;462(1-3):179-83. PMID: 12591111.
  19. 24Giuliano F, et al. The use of telemetry technology to test the proerectile effect of melanotan-II (MT-II) in conscious rats. European urology. 2005;48(1):145-51; discussion 151-2. PMID: 15967265.
  20. 25Mahiques-Santos L. [Melanotan]. Actas dermo-sifiliograficas. 2012;103(4):257-9. PMID: 22051769.
  21. 26Breindahl T, et al. Identification and characterization by LC-UV-MS/MS of melanotan II skin-tanning products sold illegally on the Internet. Drug testing and analysis. 2015;7(2):164-72. PMID: 24771717.
  22. 27Jain S, et al. Melanotan II causes hypothermia in mice by activation of mast cells and stimulation of histamine 1 receptors. American journal of physiology. Endocrinology and metabolism. 2018;315(3):E357-E366. PMID: 29812984.
  23. 28Deville M, et al. Barbie drug identification: Not a child's play. Journal of forensic sciences. 2024;69(6):2331-2338. PMID: 39302005.
  24. 29McMillan TR, et al. Melanotan II, a melanocortin agonist, partially rescues the impaired thermogenic capacity of pituitary adenylate cyclase-activating polypeptide deficient mice. Experimental physiology. 2021;106(2):427-437. PMID: 33332767.
  25. 30Rössler AS, et al. The melanocortin agonist, melanotan II, enhances proceptive sexual behaviors in the female rat. Pharmacology, biochemistry, and behavior. 2006;85(3):514-21. PMID: 17113634.
  26. 31Wessells H, et al. Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II. International journal of impotence research. 2000;12 Suppl 4:S74-9. PMID: 11035391.
  27. 32Ryakhovsky VV, et al. The first preparative solution phase synthesis of melanotan II. Beilstein journal of organic chemistry. 2008;4:39. PMID: 19043625.
  28. 33Banno R, et al. The melanocortin agonist melanotan II increases insulin sensitivity in OLETF rats. Peptides. 2004;25(8):1279-86. PMID: 15350695.
  29. 34Yassin Alsabbagh A, et al. Melanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma?. International journal of oral and maxillofacial surgery. 2025;54(9):806-808. PMID: 40210573.
  30. 35Gao L, et al. Analogue of Melanotan II (MTII): A Novel Melanotropin with Superpotent Action on Frog Skin. Protein and peptide letters. 2015;22(8):762-6. PMID: 26095376.
  31. 36Janvier S, et al. Falsification of biotechnology drugs: current dangers and/or future disasters?. Journal of pharmaceutical and biomedical analysis. 2018;161:175-191. PMID: 30165334.
  32. 37Ugwu SO, et al. A comparison of HPLC and bioassay methods for plasma melanotan-II (MT-II) determination: application to a pharmacokinetic study in rats. Biopharmaceutics & drug disposition. 1994;15(5):383-90. PMID: 7981427.
  33. 38Chen B, et al. Combining MALDI mass spectrometry imaging and droplet-base surface sampling analysis for tissue distribution, metabolite profiling, and relative quantification of cyclic peptide melanotan II. Analytica chimica acta. 2020;1125:279-287. PMID: 32674774.
  34. 39Habbema L, et al. Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review. International journal of dermatology. 2017;56(10):975-980. PMID: 28266027.
  35. 40Inozemtseva LS, et al. Antidepressant-like and antistress effects of the ACTH(4-10) synthetic analogs Semax and Melanotan II on male rats in a model of chronic unpredictable stress. European journal of pharmacology. 2024;984:177068. PMID: 39442746.
  36. 41Mallory CW, et al. Melanotan Tanning Injection: A Rare Cause of Priapism. Sexual medicine. 2021;9(1):100298. PMID: 33460908.
  37. 42Lan EL, et al. Preformulation studies with melanotan-II: a potential skin cancer chemopreventive peptide. Journal of pharmaceutical sciences. 1994;83(8):1081-4. PMID: 7983590.
  38. 43Mestria S, et al. LC-HRMS characterization of the skin pigmentation and sexual enhancers melanotan II and bremelanotide sold on the black market of performance and image enhancing drugs. Drug testing and analysis. 2021;13(4):876-882. PMID: 33245851.
  39. 44Hadley ME, et al. Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization. Peptides. 2006;27(4):921-30. PMID: 16412534.
  40. 45Hatziieremia S, et al. A liquid chromatographic/tandem mass spectroscopic method for quantification of the cyclic peptide melanotan-II. Plasma and brain tissue concentrations following administration in mice. Rapid communications in mass spectrometry : RCM. 2007;21(15):2431-8. PMID: 17610239.
  41. 46Kimura Y, et al. 5-HT(2C) receptor activation is a common mechanism on proerectile effects of apomorphine, oxytocin and melanotan-II in rats. European journal of pharmacology. 2008;589(1-3):157-62. PMID: 18582863.
  42. 47Glavas MM, et al. Melanocortinergic activation by melanotan II inhibits feeding and increases uncoupling protein 1 messenger ribonucleic acid in the developing rat. Endocrinology. 2007;148(7):3279-87. PMID: 17412803.
  43. 48Wang J, et al. Effects of ghrelin, corticotrophin-releasing hormone, and melanotan-II on food intake in rats with paraventricular nucleus lesions. Experimental and clinical endocrinology & diabetes : official journal, German Society of Endocrinology [and] German Diabetes Association. 2007;115(10):669-73. PMID: 18058602.
  44. 49Kilpeläinen M, et al. Nanostructured porous silicon microparticles enable sustained peptide (Melanotan II) delivery. European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V. 2011;77(1):20-5. PMID: 20965250.
  45. 50Mock S, et al. Determination of melanotan-II in rat plasma by liquid chromatography/tandem mass spectrometry: determination of pharmacokinetic parameters in rat following intravenous administration. Rapid communications in mass spectrometry : RCM. 2002;16(22):2142-7. PMID: 12415547.
  46. 51Heijboer AC, et al. Intracerebroventricular administration of melanotan II increases insulin sensitivity of glucose disposal in mice. Diabetologia. 2005;48(8):1621-6. PMID: 15971058.
  47. 52Klenerová V, et al. Effects of melanotan II, a melanocortin agonist, on grooming and exploration in rats after repeated restraint/immobilization. Neuroscience letters. 2008;432(3):202-5. PMID: 18191328.
  48. 53Allard J, et al. Central nervous system agents in the treatment of erectile dysfunction: how do they work?. Current urology reports. 2001;2(6):488-94. PMID: 12084236.
  49. 54René P, et al. Pharmacological chaperone action in humanized mouse models of MC4R-linked obesity. JCI insight. 2021;6(4). PMID: 33434184.
  50. 55Bonchev A. Changes in Oral Mucosa Associated with Melanotan II Injections: A Case Report. Life (Basel, Switzerland). 2026;16(2). PMID: 41752902.
  51. 56Bartness TJ, et al. Sympathetic and sensory innervation of brown adipose tissue. International journal of obesity (2005). 2010;34 Suppl 1(0 1):S36-42. PMID: 20935665.
  52. 57Ford CL, et al. Melanocortin agonism in a social context selectively activates nucleus accumbens in an oxytocin-dependent manner. Neuropharmacology. 2024;247:109848. PMID: 38253222.
  53. 58Monge-Roffarello B, et al. The medial preoptic nucleus as a site of the thermogenic and metabolic actions of melanotan II in male rats. American journal of physiology. Regulatory, integrative and comparative physiology. 2014;307(2):R158-66. PMID: 24808495.
  54. 59van den Heuvel JK, et al. Inhibitory Effect of the Melanocortin Receptor Agonist Melanotan-II (MTII) on Feeding Depends on Dietary Fat Content and not Obesity in Rats on Free-Choice Diets. Frontiers in behavioral neuroscience. 2015;9:358. PMID: 26733840.
  55. 60Yu H, et al. Hypothalamic POMC deficiency increases circulating adiponectin despite obesity. Molecular metabolism. 2020;35:100957. PMID: 32244188.
The Melanotan II Report · $19

Everything you need to start.

Dose, sourcing, safety, our verdict. One purchase. Yours forever.

Built from 60 cited studies.

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