Evidence-Based Summary
Afamelanotide (Scenesse) is an FDA-approved implant, inserted by a health professional, that increases pain-free light exposure in adults with erythropoietic protoporphyria (EPP), a rare inherited disease that makes light exposure painful. Two randomized trials support it, and its label requires skin checks. Melanotan II has never been FDA-approved; its published human data are three tiny 1990s studies. It is sold online as an unregulated "research" or tanning product, FDA lists it among bulk substances that may pose significant safety risks, and published case reports describe melanoma, new or changing moles, priapism, rhabdomyolysis, kidney infarction and brain swelling (PRES). The two are not interchangeable, and approval of afamelanotide says nothing about the safety of melanotan II.
Quick Comparison: Melanotan II vs Afamelanotide
A high-level comparison of molecule class, molecular receptor targets, FDA regulatory approvals, and verified clinical programs.
| Feature | Melanotan II | Afamelanotide |
|---|---|---|
| What it is | Synthetic cyclic 7-amino-acid alpha-MSH analogue, never developed into a medicine | Synthetic 13-amino-acid alpha-MSH analogue; approved medicine (Scenesse) |
| Target receptors | Several melanocortin receptors (pigment, sexual-function and appetite pathways) | Mainly the MC1 receptor on pigment cells |
| How it is given | Sold online as injectable powder; no approved form or quality control | Bioresorbable implant placed under the skin by a trained health professional |
| U.S. regulatory status | Not FDA-approved; on FDA's list of bulk substances that may present significant safety risks | FDA-approved (2019) for adults with phototoxic reactions from erythropoietic protoporphyria |
| Strongest human evidence | Three small 1990s studies (3 to 10 people each) | Two randomized, placebo-controlled Phase 3 trials (168 patients) plus long-term observational data |
| Main safety concerns | Case reports of melanoma, eruptive moles, priapism, rhabdomyolysis, kidney infarction, PRES; unknown purity | Implant-site reactions, nausea, skin darkening and darker moles; serious allergic reactions reported after approval |
| Approved use | None | Pain-free light exposure in adult EPP only; not for cosmetic tanning |
| WADA status (2026) | S0 Non-Approved Substances (no current approval for human therapeutic use) | Not named on the Prohibited List |
Broad vs Focused Melanocortin Activity
Alpha-MSH (alpha-melanocyte-stimulating hormone) signals through a family of melanocortin receptors. MC1 on pigment cells controls skin darkening; other subtypes in the brain affect sexual function and appetite. Which receptors a drug hits shapes its effects and risks.
Melanotan II
Primary Target: Multiple melanocortin receptors
Affinity Profile: Non-selective melanocortin agonist
Hitting several receptors at once explains why the same injection darkened skin, caused spontaneous erections, nausea and yawning in early volunteers, and why it has been linked to effects beyond the skin.
Afamelanotide
Primary Targets: MC1 receptor (main target)
Affinity Profile: Alpha-MSH analogue acting mainly at MC1
Increases eumelanin in skin without sun exposure. In EPP this is used to raise tolerance to light; patients still need sun and light protection.
One Approved Implant, One Unapproved Product
Checked 11 October 2026 against Drugs@FDA, DailyMed and FDA's compounding pages.
Melanotan II Status & Formulations
No FDA-approved medicine contains melanotan II. FDA lists it among bulk drug substances that may present significant safety risks in compounding, citing possible immunogenicity from aggregation or peptide-related impurities and published case reports of melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxidrome and priapism. Products sold as "research peptides" are unregulated and may not contain what the label says.
Afamelanotide Status & Formulations
Scenesse (NDA 210797, Clinuvel) is approved to increase pain-free light exposure in adult patients with a history of phototoxic reactions from erythropoietic protoporphyria. It is inserted under the skin by a trained health professional. Safety and effectiveness in children have not been established, and vitiligo and other uses remain investigational.
Critical Regulatory Distinction
PubChem lists "melanotan I" as a synonym for afamelanotide, but products sold online as "melanotan I" or "melanotan II" are unregulated and are not Scenesse. Approval applies to the specific Clinuvel implant, its indication and its population.
Controlled Trials vs Small Pilot Studies and Case Reports
The evidence gap is large. Afamelanotide was tested in randomized trials for a defined disease. Melanotan II was never taken through modern trials; most information on its harms comes from case reports in people who bought it online.
Melanotan II: Clinical Evidence Overview
In a 1996 pilot study, two of three healthy men had darker skin after injections over two weeks; spontaneous erections, stretching and yawning, nausea and, in one man, moderate sleepiness and fatigue were reported. Two small crossover studies in men with erectile dysfunction (10 each) found erections with melanotan II, with nausea common. No modern controlled trials exist. A 2017 review counts four case reports of melanoma arising from existing moles during or shortly after melanotan use, while stating that conclusive evidence of a causal link is lacking.
Afamelanotide: Clinical Evidence Overview
Two double-blind, placebo-controlled trials enrolled 168 adults with EPP. In the U.S. trial, median pain-free time in direct sunlight over 6 months was 69.4 hours with afamelanotide versus 40.8 with placebo (P=0.04); in the EU trial over 9 months it was 6.0 versus 0.8 hours (P=0.005), with fewer phototoxic reactions (77 vs 146). An observational study of 115 patients treated for up to 8 years reported sustained quality-of-life gains and mostly minor adverse events. Endpoints were self-reported and effect sizes modest.
Curated Clinical Evidence Table
A curated selection of the primary studies behind each compound’s evidence profile. Results from different studies are not directly comparable.
| Study & Citation | Population | Comparison & Dosing | Duration | Main Endpoint | Key Finding | Methodological Limitations |
|---|---|---|---|---|---|---|
| EPP Phase 3 trials (Langendonk et al., NEJM 2015) | 168 adults with erythropoietic protoporphyria (EU 74, U.S. 94) | Afamelanotide implant vs placebo implant | 180 and 270 days | Hours of pain-free direct sunlight exposure | U.S.: 69.4 vs 40.8 hours (P=0.04); EU: 6.0 vs 0.8 hours (P=0.005). | Self-reported diary endpoints; modest absolute effects; industry-funded. |
| Long-term EPP cohort (Biolcati et al., Br J Dermatol 2015) | 115 patients with EPP at two centres | Afamelanotide, no control group | Up to 8 years | Quality of life and adverse events | Quality-of-life scores rose and stayed higher; mostly minor adverse events such as nausea. | Observational; specialist centres. |
| Pilot Phase 1 (Dorr et al., Life Sci 1996) | 3 healthy men | Melanotan II vs saline, alternating days | 2 weeks | Tolerability and skin pigmentation | Two of three had darker skin; erections, yawning and nausea reported. | Three people; no long-term follow-up. |
| Melanoma case report (Hjuler et al., Dermatology 2014) | One 20-year-old woman using sunbeds | None (case report) | Not applicable | Clinical observation | Melanoma diagnosed three months after a course of self-injected melanotan II. | Single case; sunbed use also present; cannot prove cause. |
| Systemic toxicity case report (Nelson et al., Clin Toxicol 2012) | One 39-year-old man | None (case report) | Not applicable | Clinical observation | Sympathomimetic toxicity, rhabdomyolysis and kidney dysfunction after injecting internet-bought melanotan II; identity confirmed by mass spectrometry. | Single case of excessive self-dosing. |
Labelled Risks vs Case-Report Harms
Afamelanotide's risks are described in an FDA label based on trials and post-approval reports. Melanotan II has no label; what is known about its harms comes from case reports, which can raise alarms but cannot measure how often harms occur.
FDA safety concerns about melanotan II
FDA lists melanotan II among bulk substances that may present significant safety risks, citing immunogenicity concerns and published case reports of melanoma, posterior reversible encephalopathy syndrome (a form of brain swelling), sympathomimetic toxidrome and priapism. Further case reports describe eruptive moles, rhabdomyolysis and kidney infarction. Online products have no verified identity, purity or sterility.
| Safety Consideration | Melanotan II | Afamelanotide |
|---|---|---|
| Skin and moles | Case reports of eruptive moles, changing moles and melanoma; causality unproven | Label: skin darkening and darker moles and freckles; full-body skin examination twice yearly recommended |
| Serious reported events | Priapism needing surgery, rhabdomyolysis, kidney infarction, PRES (case reports) | Serious allergic reactions, including anaphylaxis, reported after approval |
| Common side effects | Nausea, stretching and yawning, spontaneous erections, sleepiness (small early studies) | Implant-site reaction, nausea, sore throat, cough, fatigue, dizziness, skin hyperpigmentation |
| Product quality | Unregulated; contents and sterility unverified | FDA-regulated manufacturing; implant placed by a professional |
What Melanotan II and Afamelanotide Have in Common
Where the two compounds overlap in biology, evidence or regulatory context.
Both mimic alpha-MSH
Each is a synthetic analogue of the hormone that darkens skin by stimulating melanocytes.
Both darken skin and moles
Pigment changes occur with both, which is why the afamelanotide label requires regular skin examinations.
Key Scientific & Clinical Differences
Meaningful distinctions in mechanism, strength of evidence, safety and regulatory status.
Approval and oversight
Afamelanotide is an FDA-approved implant used under specialist care; melanotan II is an unapproved product with no quality control.
Receptor selectivity
Afamelanotide acts mainly on MC1; melanotan II acts on several melanocortin receptors, affecting sexual function and other systems.
Purpose
Afamelanotide treats a painful rare disease; melanotan II is mainly used for cosmetic tanning, which no regulator has approved.
Quality of evidence
Randomized trials for afamelanotide versus three tiny studies and case reports for melanotan II.
Scientific Comparison vs Clinical Recommendations
Inside Peptides compares scientific evidence, receptor pharmacology, and official regulatory documents to advance public and professional understanding. We do not determine which compound is appropriate for an individual patient, rank medications with arbitrary scores, or recommend initiating or switching treatments.
Decisions about any medicine require a licensed healthcare professional who can weigh personal medical history, contraindications, interactions and monitoring needs. Unapproved peptides have no established safe use, and products sold as “research chemicals” are not the preparations studied in clinical research.
Approved Uses vs Online Claims
A critical scientific distinction between verified, FDA-approved clinical uses and unverified claims circulating on social media and vendor platforms.
Melanotan II is a safe way to tan without the sun
Not supportedNot FDA-approved for any use; no approved tanning drug exists.
There are no modern safety trials. Case reports describe melanoma, eruptive moles, priapism, rhabdomyolysis and other serious events, and FDA flags it as a significant safety risk.
Melanotan II is basically the same as the approved drug Scenesse
Not supportedScenesse's approval covers adults with EPP only.
They are different molecules with different receptor profiles. Scenesse is a regulated implant; melanotan II products are unregulated and may not contain what they claim.
A melanotan tan protects against skin cancer
Not supportedNo melanocortin drug is approved for sun or cancer protection.
No study shows that melanotan II lowers skin-cancer risk. Even with approved afamelanotide, the label tells patients to keep using sun and light protection.
Evidence Strength Across Clinical Domains
Inside Peptides evaluates scientific certainty at the claim level. Because clinical evidence varies significantly depending on the therapeutic endpoint evaluated, each domain is assessed independently.
Light tolerance in erythropoietic protoporphyria
Two randomized trials support afamelanotide; melanotan II has not been studied for EPP.
Skin darkening
Melanotan II darkened skin in a three-person pilot; afamelanotide's pigment effect is documented in trials and its label.
Long-term safety
Afamelanotide has observational follow-up and post-approval reporting; melanotan II has only case reports.
What Research Still Doesn’t Tell Us
Identifying open scientific questions, pending active-comparator trials, and areas where long-term clinical data remain incomplete.
How common melanotan II harms are
Case reports cannot show how often melanoma, priapism or other events occur, or whether contaminants play a role.
Melanoma risk with melanocortin drugs
Whether stimulating melanocytes changes melanoma risk over many years is not established for either drug; skin monitoring is the current safeguard.
Afamelanotide beyond EPP
Vitiligo and other uses are investigational and need completed Phase 3 results.
Related Compound Profiles
Individual profiles provide full molecular datasheets, CAS numbers, preclinical histories, and compound monographs.
Related Educational Resources
Scientific & Regulatory References
Every pharmacological mechanism, clinical trial result, and regulatory approval cited on this page is traceable to official FDA prescribing documentation, ClinicalTrials.gov registries, or peer-reviewed medical publications.
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Randomized controlled trials
Afamelanotide for Erythropoietic ProtoporphyriaTwo double-blind placebo-controlled trials (EU 74 and U.S. 94 patients); funded by Clinuvel and others.
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Observational study
Long-term observational study of afamelanotide in 115 patients with erythropoietic protoporphyria
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Official U.S. prescribing information
Scenesse (afamelanotide) implant, current U.S. labelChecked 11 October 2026.
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FDA approval record
Drugs@FDA: Scenesse, NDA 210797
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Trial registry record
Phase III Confirmatory Study in Erythropoietic ProtoporphyriaU.S. Phase 3 registry record; completed; sponsor Clinuvel.
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Pilot Phase 1 study
Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical studyThree healthy male volunteers.
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Crossover trial
Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover studyTen men.
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Review
Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review
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Case report
Melanoma associated with the use of melanotan-II
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Case report
Eruptive melanocytic naevi following melanotan injection
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Case report
Melanotan Tanning Injection: A Rare Cause of Priapism
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Case report
Melanotan II injection resulting in systemic toxicity and rhabdomyolysis
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Case report and review
Melanotan II: a possible cause of renal infarction: review of the literature and case report
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Case report (letter)
Melanotan and the posterior reversible encephalopathy syndrome
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FDA compounding list
Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety RisksMelanotan II entry checked 11 October 2026.
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Chemical database
Afamelanotide (CID 16197727) synonymsLists "Melanotan I" among synonyms. Checked 11 October 2026.