Does MT2 cause melanoma?
Nobody has shown causation. There are published case reports of melanoma in users and a plausible mechanism, and no controlled study large enough to rule it out. That is the honest state of the evidence.
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Tier 2 — Small Human Trials
MT2
Multi-Receptor Melanocortin Agonism
Melanotan II — Cyclic Melanocortin Analog
Last reviewed: August 2026
Research Purposes Only. MT2 is supplied by Purgo Labs strictly for qualified laboratory research use only. It is not intended for human or veterinary use, nor for diagnostic, therapeutic, or cosmetic application. Statements on this page have not been evaluated by the FDA.
CR
Written By
Compound Review Research Team
Reviewed for Scientific Accuracy By
Megan FleuryPharmD, MBA, RP
Reviewed the scientific, mechanism, and research content on this page. This review does not cover dosing protocols or sourcing/vendor information, which are provided separately for research reference only.
Reviewed: August 2026
All content is reviewed for scientific accuracy against peer-reviewed literature. View our editorial methodology.
So What Does This Actually Mean?
Plain English summary — no PhD required
MT2 (Melanotan II) is a synthetic peptide related to MT1, but with a key structural difference: it's cyclic (ring-shaped) rather than linear. This structural change gives it a broader range of receptor targets, making it a more pharmacologically complex compound with a wider range of studied effects.
What It Does
While MT1 primarily targets one receptor (MC1R) for melanogenesis, MT2 activates four melanocortin receptors: MC1R (skin pigmentation), MC3R and MC4R (in the brain, affecting appetite and energy), and MC5R. The MC4R activation in the hypothalamus is of particular research interest because MC4R is a well-validated target in obesity and metabolic research — it's one of the most studied receptors in appetite regulation.
Why It Matters
MT2's broader receptor profile makes it a valuable research tool for studying the melanocortin system as a whole, rather than just skin biology. The fact that a single structural modification (cyclization) dramatically changes which receptors a peptide activates is exactly the kind of structure-activity relationship that makes MT2 scientifically interesting beyond its surface-level effects.
The Bottom Line
MT2 has a more complex and less clinically validated profile than MT1. Unlike MT1, it has not received regulatory approval for any indication. Its broader receptor activity means researchers need to account for a wider range of potential effects. It is supplied strictly for qualified laboratory research use only.
Overview
What is MT2?
Important: Melanotan II (MT2) has not received regulatory approval from the FDA, EMA, or any other major regulatory body for any indication. It is not approved for tanning, sexual function, weight loss, or any other use. It is a research compound only.
Melanotan II (MT2) is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (α-MSH), developed at the University of Arizona in the 1980s. Unlike MT1 (afamelanotide/Scenesse®, which is EU-approved for the rare condition erythropoietic protoporphyria), MT2 has no regulatory approval. Its broader receptor profile (MC1R, MC3R, MC4R, MC5R) produces multiple simultaneous effects that cannot be easily separated, and its safety profile in humans is not established through controlled clinical trials. Researchers should approach MT2 with awareness of its unapproved status and the significant difference between it and the approved drug afamelanotide (MT1).
Key Takeaways
- Melanotan II (MT2) is a cyclic heptapeptide analog of α-MSH with broad melanocortin receptor activity: MC1R (pigmentation), MC3R (energy homeostasis), MC4R (sexual function, appetite), and MC5R (exocrine glands).
- MC4R agonism is responsible for MT2's pro-erectile and aphrodisiac effects observed in research models — the same receptor targeted by the FDA-approved drug bremelanotide (Vyleesi®).
- The cyclic structure (disulfide bridge between Cys4 and Cys10) confers resistance to enzymatic degradation compared to linear α-MSH, extending the half-life from minutes to hours.
- MT2's broad receptor profile means it produces multiple simultaneous effects (tanning, appetite suppression, sexual arousal, nausea) that cannot be easily separated — a key limitation for targeted research.
- Bremelanotide (Vyleesi®), an FDA-approved MC4R agonist for hypoactive sexual desire disorder in women, shares MT2's core mechanism and provides clinical validation for the MC4R pathway.
Composition
Molecular Composition
Amino Acid Sequence
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2
MT2 is a cyclic 7-amino-acid peptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2. The cyclic structure is formed by a lactam bond between the side chains of aspartate (position 2) and lysine (position 7). This cyclization is a key structural feature that increases receptor binding affinity and metabolic stability compared to linear analogs.
Additional structural modifications include: norleucine (Nle) substitution at position 1 to prevent oxidative degradation, D-phenylalanine at position 4 to enhance receptor binding, and N-terminal acetylation with C-terminal amidation. The molecular weight is 1,024.18 Daltons.
Mechanism of Action
How Does It Work?
!
MT-2 drives tanning and sexual arousal by activating MC1R in melanocytes and MC3R/MC4R in the hypothalamus, producing effects through a single receptor family.
MT2 exerts its primary effects through agonism at multiple melanocortin receptor subtypes. At MC1R on melanocytes, it stimulates the cAMP/PKA/MITF pathway to increase eumelanin production, similar to MT1. At MC3R and MC4R in the central nervous system — particularly in the hypothalamus — MT2 modulates appetite, energy homeostasis, and sexual function through pathways involving the melanocortin system's interaction with neuropeptide Y (NPY) and agouti-related protein (AgRP) signaling.
The MC4R-mediated effects are of particular research interest: MC4R activation in the hypothalamus reduces food intake and increases energy expenditure, and has been extensively studied in the context of obesity research. MC4R is also expressed in the spinal cord and peripheral nervous system, where its activation has been linked to pro-erectile signaling through nitric oxide pathways.
"The multifaceted agonistic activity of Melanotan II across melanocortin receptor subtypes underscores its significant potential in modulating diverse physiological processes, from melanogenesis to central nervous system-mediated metabolic and sexual functions." — Melanocortin Pharmacology Review, 2022
Signaling Pathways
Key Research Pathways
MC1R / Melanogenesis
Activates MC1R on melanocytes, driving cAMP/PKA/MITF cascade and increasing eumelanin production.
MC4R / Hypothalamic Energy Regulation
MC4R agonism in the hypothalamus modulates NPY/AgRP signaling to reduce food intake and increase energy expenditure.
MC4R / Pro-erectile NO Signaling
Spinal and peripheral MC4R activation stimulates nitric oxide pathways associated with erectile function in preclinical models.
MC3R / Anti-inflammatory Modulation
MC3R activation contributes to anti-inflammatory and immune-modulatory effects observed in preclinical studies.
Research Highlights
Key Findings from the Literature
- Activates MC1R, MC3R, MC4R, and MC5R — broader receptor profile than MT1
- MC4R agonism in hypothalamus modulates appetite and energy homeostasis
- Stimulates melanogenesis via MC1R/cAMP/MITF pathway without UV requirement
- Pro-erectile signaling through MC4R/nitric oxide pathways studied in rodent models
- Cyclic structure confers enhanced metabolic stability vs. linear α-MSH analogs
- MC3R activation involved in anti-inflammatory and immune modulation research
Outcome Matrix
Evidence by Claimed Outcome
Each outcome rated by the highest level of evidence available. Tiers follow our 5-tier methodology.
StrongModeratePreliminaryPreclinicalTheoretical
Claimed Outcome
Evidence Tier
Studies
Key Evidence Note
Skin tanning (melanogenesis)
Moderate
5
Phase II data; consistent melanocyte stimulation
Erectile function
Moderate
4
Phase II data; MC4R agonism mechanism confirmed
Libido enhancement
Preliminary
2
Secondary endpoint in Phase II trials; not primary outcome
Appetite suppression
Preliminary
1
MC4R pathway; mechanistically plausible; limited human data
Study counts reflect peer-reviewed publications in the evidence database below. "Theoretical" outcomes have mechanistic rationale only. Learn about our evidence tiers →
Researcher Notes
Important Research Context
MT2 has a more complex safety and regulatory profile than MT1 due to its broader receptor activity. Unlike afamelanotide (MT1), MT2 has not received regulatory approval for any indication. The CNS effects mediated by MC3R and MC4R — including nausea, spontaneous erections, and appetite suppression — have been consistently reported in human self-experimentation literature, though formal clinical trials are limited. Researchers should approach MT2 with awareness of its broader pharmacological profile and the potential for off-target effects.
Research References
Peer-reviewed literature supporting the research profile of MT2
The following peer-reviewed studies form the primary evidence base for MT2's research profile. All references are sourced from PubMed, NCBI, and peer-reviewed scientific journals. Published research is available through PubMed, NCBI, and peer-reviewed biomedical journals.
- 1.
Wessells H, et al. Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction. Urology. 2000.PMID: 11018622
MT-II demonstrated pro-erectile effects via MC4R in men with organic erectile dysfunction.
- 2.
Dorr RT, et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sciences. 1996.PMID: 8637402
Phase I safety data for Melanotan II with characterization of pharmacological effects.
- 3.
King SH, et al. Melanocortin receptors, melanotropic peptides and penile erection. Current Topics in Medicinal Chemistry. 2007.PMID: 17584130
Review of MC3R/MC4R mechanisms underlying MT-II's pro-erectile and libido-modulating effects.
Research Databases
MT2
Skin & Anti-Aging Research
From $36.99
Purgo Labs list price, read 12 Sep 2026 · per-lot COA on the vendor page
1 vial (10mg)
List price · read 12 Sep 2026
$36.99
10mg $36.99 → $29.59 with code HEALTH (20% off; price read 1 Nov 2026)
Where to buy MT2
17 partners · prices read from product pages, latest 1 Nov · ranked by rubric, then price
- 1 certificate verified at the lab10mg$36.99→ $29.59
- 2 certificates verified at the lab10mg$30.00→ $24.00
- 1 certificate verified at the lab10mg$24.99$14.99→ $13.49
Every order also needs bacteriostatic water — add it to the same cart.All MT2 vendors, partners and not
Fast FedEx shipping · Discreet packaging
Sourced from Purgo Labs
✅≥99% Purity
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🏭cGMP Made
Technical Specifications
- Peptide Class
- Cyclic heptapeptide α-MSH analog
- Molecular Weight
- 1,024.18 Da
- Receptor Targets
- MC1R, MC3R, MC4R, MC5R
- Key Structural Feature
- Lactam bridge cyclization (Asp²–Lys⁷)
- Available Sizes
- 10mg vials
- Form
- Lyophilized powder
- Purity
- ≥99% (third-party tested)
Legal Status
Research Chemical
View full legal status guide →
Source MT2 at Purgo Labs
10mg $36.99 list · $29.59 with code HEALTH · lab-verifiable COA per lot
Vendor Scoreboard — top 3 by verified evidenceVerified 1 November 2026
Related Research
Other Compounds in This Guide
Safety
Melanotan II side effects
No human trial dataNo approval and no controlled human trial — what is known comes from early clinical studies and published case reports
Melanotan II is a non-selective melanocortin agonist that was abandoned in development and is sold only as a research chemical. The human literature is small early studies plus case reports: nausea, flushing, spontaneous erections, and pigmentary changes including darkening or new moles are consistently described, and there are published case reports of melanoma and of rhabdomyolysis in users. No frequency figures exist that we would print.
Research-use information only. Research-grade Melanotan II is not an approved medicine; where trial or label figures appear below they belong to the pharmaceutical product studied, not to any research vial. This section does not give dosing or medical advice.
What is reported
Every rate carries its source. Where no source exists, no rate is printed.
| Effect | Rate (sourced) | Detail | Source |
|---|---|---|---|
| Nausea, facial flushing, yawning, spontaneous erections | not quantified | Described in early human studies of MT-II (Dorr et al. 1996; Wessells et al. 1998). | Early clinical studies |
| Darkening of existing naevi, new naevi, generalised hyperpigmentation | not quantified | Repeatedly reported in dermatology case series. | Case reports / dermatology literature |
| Melanoma in users | not quantified | Published case reports; causation is not established but the concern is mechanistically plausible. | Case reports |
| Rhabdomyolysis, renal infarction, priapism | not quantified | Isolated case reports. | Case reports |
What is not known
- •Frequency of any of the above — there is no controlled trial.
- •Long-term consequences of repeated melanocortin stimulation.
- •Research-grade identity and dose.
Mechanism-based cautions
- •Non-selective MC3R/MC4R/MC1R activity: sexual and cardiovascular effects alongside pigmentation.
- •Anyone with atypical naevi or a melanoma history should treat the pigmentary signal as a red flag.
Regulatory status: Not approved anywhere; several national regulators have issued public warnings about melanotan II.
Side-effect references
- Dorr RT, et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a single-dose trial. Life Sciences, 1996.
- Wessells H, et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction. Journal of Urology, 1998.
What is actually in a research vial
Everything above describes Melanotan II the molecule. The risk specific to a research vial is different: it may not contain Melanotan II at the labelled amount, and it may contain what the synthesis left behind. Identity (mass spectrometry), purity (HPLC), measured net content and an endotoxin result are the four lines on a certificate that bear on adverse effects, and only a certificate you can check at the laboratory tells you any of them. This is what we have verified for Melanotan II so far.
Who sells Melanotan II, and what they document
26 of the 105 vendors on our scoreboard list Melanotan II with a price we read on the product page (23 Sep 2026–1 Nov 2026). Of those, 26 name their testing laboratory, 22 publish certificates that resolve on the lab's own site, and 25 publish measured milligrams against the label. The full ranking, with every dated price, is on Best Melanotan II Vendors.
| Vendor | Rubric | Lab named | Price read |
|---|---|---|---|
| MyPurePeptidepartner | 10/10 | Janoshik Analytical | $30.00 · 10mg · 1 Nov 2026 |
| Oneday Compoundspartner | 10/10 | ILS Laboratories (San Diego, CA) | $14.99 · 10mg · 29 Oct 2026 |
| Purgo Labspartner | 10/10 | SteriGenix · Freedom Diagnostics | $36.99 · 10mg · 1 Nov 2026 |
| ezPepspartner | 9/10 | ILS Laboratories (also Kovera Labs, Freedom Diagnostics, Horizon Analytical) | $33.99 · 10mg · 31 Oct 2026 |
| Oath Research | 9/10 | Freedom Diagnostics | $55.00 · 10mg · 1 Nov 2026 |
Top 5 by rubric score; 21 more on the ranking page.
Melanotan II certificates we have opened
None yet for Melanotan II specifically. The COA library holds the certificates we have read for each vendor on other compounds, which is the next best signal of how that vendor documents a lot.
Side-effect questions
Side-effect section last reviewed 2026-09-12. Moved from the standalone side-effects page on 10 October 2026; text unchanged.
Regulatory
Is Melanotan II (MT-2) legal?
Legal as a research chemical (restricted in some countries)Melanotan II is legal to purchase as a research chemical in the United States. However, it is banned for sale in the UK and Australia. It is not FDA-approved for human use and is not a controlled substance in the US.
US Status
Research Chemical
Legal to purchase for research
DEA Schedule
Not Scheduled
Not a controlled substance
FDA Status
Not Approved
Not FDA-approved for human use
Status by country
| Jurisdiction | Status as stated |
|---|---|
| United States | Legal as a research chemical. Not a scheduled substance. Not FDA-approved for human use. The FDA has issued warnings against products marketed for human use. |
| Canada | Not a scheduled substance. Available for research purposes. Not approved by Health Canada. |
| United Kingdom | Banned for sale as of 2015 under the Psychoactive Substances Act 2016 and prior MHRA enforcement actions. Not legal to sell in the UK. |
| Australia | Listed as a Schedule 4 (prescription-only) substance by the TGA. Illegal to sell without a prescription. |
| European Union | Regulatory status varies by member state. Generally restricted for human use. Not approved as a medicinal product by the EMA. |
Statements above are as our legal-status page for Melanotan II (MT-2) stated them in 2025; they were moved here on 10 October 2026 and were not re-verified in the move. Regulations change. This is general information, not legal advice; check the current position with your own jurisdiction's regulator before relying on it.
Legal questions
Is Melanotan II legal in the US?
Yes. Melanotan II is legal to purchase as a research chemical in the United States. It is not a controlled substance, though the FDA has issued warnings against its use in humans.
Is Melanotan II banned in the UK?
Yes. Melanotan II is effectively banned for sale in the UK. The MHRA has taken enforcement action against suppliers, and it falls under restrictions on unlicensed medicines.
Is Melanotan II legal in Australia?
No. Melanotan II is listed as a Schedule 4 (prescription-only) substance by the TGA in Australia. It is illegal to sell without a prescription.
Is Melanotan II a controlled substance?
In the United States, Melanotan II is not listed as a controlled substance under the DEA Controlled Substances Act. However, it is restricted in several other countries.
Is Melanotan II the same as Melanotan I?
No. Melanotan I (afamelanotide) is a linear peptide and is FDA-approved as Scenesse for erythropoietic protoporphyria. Melanotan II is a cyclic peptide with broader receptor activity and is not FDA-approved.
Research Guides
Related Research Guides
Everything we publish on MT2
More on MT2: comparisons, interactions, where to buy
Supporting Research
Limited Human DataLimited Human Data + Significant Safety Concerns
Evidence note: Melanotan II is not approved for human use; regulators have warned of safety risks including nausea, cardiovascular effects, and changes in moles/melanoma concern.
Small early human studies exist for erectile function and tanning, but Melanotan II is not approved anywhere. Regulators have issued safety warnings including nausea, cardiovascular effects, and reports of changing moles and melanoma concern. Safety must be foregrounded, not buried.
References
- Wessells H, et al.HUMAN — small crossover, n≈20Erectile response vs placebo in a small early double-blind crossover study; not a basis for broad efficacy claims.
Research Databases
PubMed
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