Melanotan II
PeptideThe medical evidence (score 22) is very low due to few small pilot studies [s3, s4, s5] and serious safety signals [s7, s8, s9]. The community rates MT-II considerably more favorably despite frequently reported adverse effects [c1, c2], as tanning and libido effects are subjectively perceived as reproducible, which explains the divergence of −33 points.
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TL;DR
Melanotan II works — tanning and libido enhancement are pharmacologically well-explained and widely confirmed by users. But the risk profile is serious: unpredictable nevus changes, priapism, hypertensive crises, and an unresolved melanoma risk make MT-II one of the most dangerous freely circulating peptides. Uncontrolled purity from grey-market sources compounds the problem significantly. The BfArM has issued explicit warnings and the UK has banned it outright — those warnings are justified.
Description
Synthetic melanocortin analogue for skin tanning and libido enhancement; not approved, significant safety concerns and unclear long-term risk profile [s1, s2, s11].
Melanotan II (MT-II) is a cyclic synthetic heptapeptide analogue of the natural alpha-melanocyte-stimulating hormone (α-MSH). It was originally developed at the University of Arizona to produce a safe tanning effect without intensive UV exposure [s1]. MT-II non-selectively activates melanocortin receptors MC1R, MC3R, MC4R, and MC5R [s2]. Via MC1R stimulation in cutaneous melanocytes, MT-II induces melanogenesis and thereby enhanced pigmentation [s1, s2]. Simultaneous activation of MC4R in the hypothalamus and spinal cord mediates central nervous system effects: spontaneous erections, increased libido, and appetite suppression have been described in clinical pilot studies and anecdotal reports [s3, s4, s5]. A structurally related, more selective MC4R agonist (bremelanotide/PT-141) received FDA approval in 2019 for female sexual arousal disorder — MT-II itself has never been approved [s6]. The safety profile of MT-II is substantially compromised: case reports describe rhabdomyolysis, renal failure, hypertensive crises, and priapism [s7, s8]. Dermatologically, eruptive dysplastic nevi and melanoma cases in young users have been documented [s9, s10]. The BfArM issued a public warning in 2010 [s11]. MT-II is distributed exclusively through the black market; product quality and sterility are uncontrolled [s13, s14].
Legal Status (DE)
In Germany, possession of Melanotan II is not explicitly a criminal offense; however, placing it on the market as an unapproved medicinal product is prohibited under the Medicinal Products Act (AMG). The BfArM explicitly warned against the use of melanotan-containing products in 2010 [s11]. In the EU, MT-II is classified as an unapproved medicinal product; the FDA (USA) classifies it as an unapproved new drug and has issued warning letters [s12]. In the United Kingdom, MT-II was completely banned in 2019 [s13]. In Switzerland and Austria, a comparable legal status applies: not approved as a medicinal product, placing on the market is illegal [s11].
Mechanism of Action
MT-II is a cyclic analogue of α-MSH that exhibits increased receptor affinity and prolonged half-life compared to the native hormone through truncation of the N- and C-termini, substitution of Glu5→Asp5 and Gly10→Lys10, and an intramolecular lactam bridge [s2]. MC1R activation (melanogenesis): Binding to MC1R on dermal melanocytes increases intracellular cAMP via Gs-protein coupling. This activates protein kinase A and induces the transcription factor cascade (MITF), which upregulates the enzymes tyrosinase, TRP-1, and TRP-2. The result is enhanced eumelanin synthesis and thus darker skin pigmentation [s1, s2]. MC4R activation (sexual and appetite function): MC4R is expressed in hypothalamic neurons and spinal erection centers. MT-II-mediated MC4R stimulation activates oxytocinergic-dopaminergic signaling pathways that trigger spontaneous erections and increased sexual arousal [s3, s4]. Simultaneously, MC4R activation in the arcuate nucleus inhibits anorexigenic signals, resulting in appetite suppression [s5]. MC3R activation (energy homeostasis): MC3R stimulation modulates energy homeostasis and is involved in the regulation of body weight [s5]. MC5R activation (exocrine glands): MC5R influences secretion of exocrine glands; clinical relevance in MT-II application is unclear [s2]. The biological plasma half-life of MT-II is short; however, the biological duration of action can persist for over 30 hours due to sustained receptor binding and downstream signaling cascades [s6].
Dosing
Hautbräunung (Ladephase, Forschungsprotokoll)
- Dose
- 250–500 mcg per injection
- Frequency
- 1× täglich subkutan
- Route
- injektion-subkutan
- Duration
- 6–8 Wochen
- Timing
- Evening, to reduce daytime nausea peaks
- With food
- optional
Hautbräunung (Erhaltungsphase)
- Dose
- 500–1000 mcg per injection
- Frequency
- 1–2× pro Woche
- Route
- injektion-subkutan
- Duration
- fortlaufend
- Timing
- Evening
- With food
- optional
Erektile Dysfunktion (Pilotstudie, Forschung)
- Dose
- 0.025 mg/kg body weight (approx. 1.75–2 mg for 70 kg)
- Frequency
- Einmalgabe nach Bedarf
- Route
- injektion-subkutan
- Duration
- Einmalgabe
- Timing
- 45–60 minutes before sexual activity
- With food
- optional
No officially validated upper limit exists. Pilot studies employed single doses of 0.025 mg/kg [s3]. Higher doses (>1 mg) are associated with a markedly increased adverse effect rate [s7, s8]. No safety upper limit for chronic use exists.
MT-II is not approved as a medicinal product. All dosage information derives from research protocols or user reports, not from validated clinical trials. Black market products exhibit uncontrolled purity; bacterial contamination and heavy metal adulteration have been documented [s14]. Use outside a controlled research context is explicitly discouraged by regulatory authorities [s11, s12].
Calculate reconstitution, plan dosing, look up injection technique
Side Effects
| Side Effect | Frequency | Severity |
|---|---|---|
| Priapismus Priapism as a serious adverse effect is documented in peer-reviewed case reports (s20, s21). The figure of '19%' could not be substantiated with a verified primary source; the value from commercial sources (s7, s8) should remain marked as unconfirmed until an original registry study is available. | selten | leicht |
| Hypertensive krise Hypertension and sympathomimetic symptoms following MT-II are documented in s20. The value '68% hypertensive crisis' could not be verified in a peer-reviewed primary source; use with reservation only. | selten | leicht |
Contraindications
MC1R stimulation may promote melanocytic proliferation; case reports of melanoma in MT-II users documented [s9, s10].
Eruptive dysplastic nevi have been reported following MT-II use; increased risk of transformation with pre-existing atypical lesions [s9, s10].
MT-II can trigger hypertensive crises; sympathomimetic effect documented. Hazardous in pre-existing cardiovascular disease [s8].
Priapism documented as a serious complication; contraindicated in patients with pre-existing predisposition to priapism [s7, s8].
No safety data available; contraindicated due to potent hormonal activity at melanocortin receptors and unestablished fetal safety profile [s11].
Rhabdomyolysis-associated renal failure documented; increased risk in pre-existing renal impairment [s17].
Interactions
Synergistic
Both substances activate MC4R; the combination would be expected to produce additive/synergistic central effects (libido, erection) and a markedly increased adverse effect rate. No clinical benefit of the combination has been established [s6].
Kisspeptin-10 stimulates the GnRH/LH axis, thereby increasing testosterone, while Melanotan II directly enhances sexual arousal in the CNS via MC4R. Both substances act through distinct mechanisms and may be complementary in sexual dysfunction.
Ashwagandha demonstrably increases testosterone and DHEA-S via HPA/HPG axis modulation, while MT-II enhances sexual arousal in the CNS via MC4R. Both substances may complement each other through complementary mechanisms in sexual dysfunction or libido enhancement.
Caution
MT-II can trigger hypertensive crises, thereby unpredictably antagonizing the efficacy of antihypertensives or producing circulatory instability through additive vascular effects [s8].
Additive pro-erectile effect via distinct mechanisms; increased risk of prolonged erection/priapism [s7].
MC4R activation interacts with dopaminergic signaling pathways; theoretically additive effect on cardiovascular stimulation and sexual function; clinical data lacking [s3].
Both substances can cause nausea and loss of appetite via distinct mechanisms — MT-II via MC4R activation, semaglutide via GLP-1 receptors. The additive effect may substantially potentiate gastrointestinal adverse effects.
MT-II activates MC4R in the hypothalamus, thereby causing loss of appetite and nausea. Tirzepatide acts as a dual GIP/GLP-1 receptor agonist and is likewise strongly anorectic and emetogenic. The combination may substantially potentiate gastrointestinal adverse effects and food refusal.
Studies
Tier A — High Evidence
Outcome: Penile tumescence in men with psychogenic or organic erectile dysfunction
Effect Size: 17/20 subjects showed erection after MT-II without sexual stimulation vs. placebo
Outcome: Penile tumescence in erectile dysfunction
Effect Size: Significant increase in rigidity vs. placebo (p<0.05)
Outcome: Skin pigmentation (tanning) via melanogenesis induction
Effect Size: Significantly greater tanning at low doses every other day vs. placebo
Tier B — Moderate Evidence
Outcome: Melanoma development in young MT-II users
Effect Size: 4 cases of malignant melanoma in individuals <40 years following MT-II use
Outcome: Systemic toxicity with rhabdomyolysis and renal failure following MT-II injection
Effect Size: CK markedly elevated, myoglobinuria, acute renal failure, full recovery after treatment
Tier C — Low Evidence
Outcome: Eruptive dysplastic nevi following melanotan use
Effect Size: Histopathologically confirmed dysplastic nevi following MT-I/II use
Outcome: Overview of mechanism of action, preclinical and clinical data on MT-II
Effect Size: No independent effect size; summary: MC1R/MC4R activation with melanogenesis and libido effects
Community Evidence
Top reported benefits
- Significant skin tanning without intensive UV exposure
- Increased sexual desire and libido
- Improved erectile quality
- Appetite suppression / weight reduction as a side effect
Top reported issues
- Severe nausea, particularly at doses above 0.5 mg
- Back pain and diffuse myalgias
- Unwanted spontaneous erections
- Quality issues with black market products (presumably ineffective product)
- Concerns regarding nevus changes and melanoma risk
Several users report significant safety concerns regarding melanoma risk and changes to moles [c1, c4]. The lack of product control in the grey market is rated as a serious problem [c1]. German forum posts describe detailed titration protocols while simultaneously warning against rhabdomyolysis and renal failure [c4]. The majority of experienced users advise regular dermatological monitoring.
Scientific Sources
- Melanotan II Research Guide: Melanocortin Peptide
Peptide Labs Inc. (2024). Peptide Labs Inc. (online resource)CLink - Melanoma associated with the use of melanotan-II
Cooke MS, Robinson JK, Bhatt DL, et al. (2014). PubMed (journal not specified in search results)CPMID:24355990 - BfArM warnt vor Anwendung melanotanhaltiger Produkte für kosmetische Zwecke
Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM) (2010). BfArM PressemitteilungenALink - Notice of Opportunity for Hearing (NOOH) Manookian, Edward 8/5/16
US Food and Drug Administration (2016). FDA Electronic Reading RoomALink - Is Melanotan Legal: Current Status
Oath Peptides (2025). Oath Peptides (online resource)DLink - Peptide Hype Check: Warnung vor BPC-157 & Melanotan Injektionen
Apo-Versand Redaktion (2024). apo-versand.de BlogCLink - Melanotan II Dosage Protocol
PeptideDosages.com (2025). PeptideDosages.com (online resource)CLink - Melanotan II Dosing Guide: Loading Dose, Maintenance & Side Effects (2026)
PeptideDosing Protocols (2026). peptidedosingprotocols.com (online resource)CLink - Melanotan II injection resulting in systemic toxicity and rhabdomyolysis
Grimmelpont M, Deray G, Abboud I (2012). Clinical ToxicologyCPMID:23121206DOI - Melanotan II – Wikipedia (Deutsch)
Wikipedia-Autoren (2023). Wikipedia DECLink - Die Risiken von Melanotan
Ultee J (2022). dr-jetskeultee.de BlogCLink - What is Melanotan II Peptide?
Creative Peptides (2023). Creative Peptides (online resource)CLink - Melanotan II overdose associated with priapism
Devlin J, Pomerleau A, Foote J (2013). Clinical Toxicology (Philadelphia)BPMID:23537392DOI - Beliefs, Attitudes, and Experiences of Individuals using Melanotan II
JAAD (Autorenangabe nicht vollständig aus Abstract extrahierbar) (2025). Journal of the American Academy of DermatologyBDOI - Melanocortin receptor agonists, penile erection, and sexual motivation in male rats
Wessells H, Fuciarelli K, Hansen J, et al. (1998). International Journal of Impotence ResearchAPMID:11035391DOI - Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study
Wessells H, Fuciarelli K, Hansen J, Hadley ME, Hruby VJ, Dorr R, Levine N (1998). Journal of UrologyAPMID:9679884DOI - Double-blind, placebo-controlled evaluation of the erectile response to transurethral alprostadil
Wessells H, Levine N, Hadley ME, et al. (2000). UrologyAPMID:10767453DOI - Preliminary double-blind, placebo-controlled studies on the efficacy of melanotan in inducing penile erection and skin tanning
Hadley ME, Dorr RT (2006). PeptidesAPMID:16837101DOI - PT-141 vs Melanotan II: Mechanism, Evidence & Pricing Compared (2026)
The Peptide Catalog (2026). The Peptide Catalog (online resource)CLink - Melanotan-2 Side Effects and Safety Profile
Peptide Protocol Wiki (2024). Peptide Protocol Wiki (online resource)CLink - Melanotan-2 Safety Profile — Research Risks Explained
Real Peptides (2024). Real Peptides (online resource)CLink - Eruptive Dysplastic Nevi Following Melanotan Use
Langan EA, Nie Z, Rhodes LE (2012). Actas Dermo-SifiliográficasCDOI
Community Sources
Storage
Unopened
Lyophilized powder: store at −20 °C to −80 °C, protected from light. Shelf life with correct storage according to manufacturer specifications (research suppliers) up to 24 months.
Opened
After reconstitution with bacteriostatic water: store at 2–8 °C (refrigerator); consumption within 4 weeks recommended. Do not freeze after reconstitution.
Notes
As MT-II is available exclusively through the black market, purity and sterility are not guaranteed. Contamination with bacteria or heavy metals has been documented [s14]. Storage information derives from research supplier protocols without regulatory validation.