Compound reference
Melanotan I
Also known as Afamelanotide, NDP-MSH, Scenesse
Melanotan I is [Nle⁴,D-Phe⁷]-α-MSH — the molecule that, as afamelanotide (SCENESSE), became the only FDA-approved melanocortin-peptide therapy, licensed for the rare disease erythropoietic protoporphyria. The "Melanotan I" sold for cosmetic tanning is that same molecule used off-label, without the trials, implant delivery, or skin monitoring of the approved product.
- CAS
- 75921-69-6
- Sequence
- [Nle⁴, D-Phe⁷]-α-MSH — a 13-residue linear α-MSH analogue (afamelanotide)
Afamelanotide is FDA-approved for a specific erythropoietic protoporphyria indication; unapproved cosmetic tanning uses should not be conflated with the labeled product.
Mode of action
Melanotan I is [Nle⁴, D-Phe⁷]-α-MSH — a 13-residue linear analogue of α-melanocyte-stimulating hormone whose two substitutions make it far more resistant to breakdown, and more potent, than the natural hormone. Unlike the non-selective Melanotan II, it is comparatively selective for the melanocortin-1 receptor (MC1R) on melanocytes, where it stimulates synthesis of eumelanin — the darker, more photoprotective pigment — and enhances cellular DNA-repair capacity. That MC1R-focused profile means it largely lacks the central appetite and sexual effects that dominate Melanotan II's side-effect picture. It is the same molecule that, as afamelanotide, became the approved drug SCENESSE.
Main intended effect
Stimulation of eumelanin production — for photoprotection in a defined medical setting, and, in non-medical use, for cosmetic tanning.
Areas of interest
Its approved, evidence-backed use is photoprotection in erythropoietic protoporphyria (EPP), a rare disorder of painful phototoxicity; afamelanotide has also been studied in other photodermatoses. Quite separately, "Melanotan I" is sold on the gray market as a cosmetic sunless-tanning injectable — a use that is off-label and unstudied for safety.
Evidence for intended effects
Melanotan I has genuine, high-quality evidence — for its approved indication. Early human pharmacokinetic work (Ugwu, 1997) established that subcutaneous dosing is fully bioavailable (oral is not) and produces durable tanning lasting weeks. As afamelanotide it then went through pivotal phase 3 trials in EPP (NEJM 2015) demonstrating increased pain-free sunlight exposure, leading to FDA approval (SCENESSE, 2019). Melanocortin reviews treat it as the reference compound for chronic MC1R activation, noting that available evidence does not show increased melanoma incidence — but also does not show prevention — so dermatological surveillance remains necessary. What the evidence does not cover is cosmetic tanning in healthy people, for which there are no controlled safety outcomes.
| Strand | What exists | Tier |
|---|---|---|
| EPP photoprotection (afamelanotide) | Phase 3 RCTs; FDA approval (SCENESSE) | Established / approved |
| Pharmacokinetics & pigmentation | Human PK study (1997) | Established |
| Other photodermatoses | Exploratory studies | Investigational |
| Cosmetic tanning | No controlled safety data | Off-label / unproven |
Studied amounts (literature dosing context)
The approved product, SCENESSE, is a 16 mg afamelanotide bioresorbable implant inserted subcutaneously by a trained healthcare provider roughly every 60 days during periods of expected sun exposure. Historical human studies used intravenous and subcutaneous dosing. These are clinical and study figures; there is no established dose for cosmetic use, and this page does not provide dosing guidance.
Safety and regulatory status
As afamelanotide, Melanotan I is FDA-approved (SCENESSE, 2019; labeling updated 2024) to increase pain-free light exposure in adults with EPP — the sole approved therapeutic use of a melanocortin-peptide analogue in the United States. In that setting it is generally well tolerated (nausea, implant-site reactions, oropharyngeal pain), with mandatory skin surveillance for pigmented lesions because MC1R agonism neither causes nor prevents melanoma. The cosmetic-tanning use is entirely different: injectable "Melanotan I" bought online is unapproved, unregulated, and of unverified identity and purity (Melanotan-I has been named in regulatory seizures), and carries the melanotan-class concern of new or changing pigmented moles without the dermatological monitoring built into the approved pathway.
Sources
Skin pigmentation and pharmacokinetics of melanotan-I in humans
Ugwu and colleagues performed a comparative human pharmacokinetic and pharmacodynamic trial of Melanotan I — the [Nle4-D-Phe7]-α-MSH analog later branded afamelanotide — administered by intravenous, oral, and subcutaneous routes in volunteers. Subcutaneous dosing was completely bioavailable relative to intravenous, whereas oral dosing produced no detectable drug levels; significant tanning of the forehead, arms, and neck followed IV or SC dosing, peaking around one week and still present three weeks after a ten-dose regimen. The study established the subcutaneous route and the durable pigmentary response that underpin MT-I/afamelanotide's later clinical development. This is an early human study; afamelanotide is now approved only for erythropoietic protoporphyria, not for cosmetic tanning.
https://doi.org/10.1002/(sici)1099-081x(199704)18:3<259::aid-bdd20>3.0.co;2-x
Afamelanotide for Erythropoietic Protoporphyria
Pivotal phase 3 work (Langendonk, Balwani, Anderson and colleagues) comprising two randomized, double-blind, placebo-controlled trials (the European CUV029 and U.S. CUV039 studies, including NCT01605136) of 16 mg afamelanotide subcutaneous bioresorbable implants in adults with erythropoietic protoporphyria (EPP). The primary endpoint in each study was duration of pain-free time spent in direct sunlight, which was significantly greater with afamelanotide versus placebo in both trials. Quality of life and patient-reported photoprotection also improved. The treatment was generally well tolerated; afamelanotide subsequently received regulatory approval for EPP in Europe and the United States, making this the pivotal evidence base for its approved indication.
SCENESSE (afamelanotide) implant, for subcutaneous use — Prescribing Information
FDA prescribing information (updated March 2024) for SCENESSE (afamelanotide) 16 mg implant, a bioresorbable subcutaneous pellet and selective melanocortin-1 receptor (MC1R) agonist. Approved to increase pain-free light exposure in adults with a history of phototoxic reactions from erythropoietic protoporphyria (EPP); originally approved October 8, 2019. Each implant is administered subcutaneously every 60 days during periods of expected sun exposure, and must be inserted by a trained healthcare provider. Common adverse reactions include nausea, oropharyngeal pain, and implant-site reactions; long-term skin surveillance for pigmented lesions is required. Afamelanotide is the only FDA-approved pharmacotherapy for EPP and represents the sole approved therapeutic use of a melanocortin-peptide analog in the United States.
https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/210797s007lbl.pdf
Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization
Hadley and Dorr review the development of melanocortin peptide therapeutics, tracing milestones from α-MSH biology through clinical candidates and commercialization. Melanotan I, a linear superpotent α-MSH analog, was advanced for skin tanning and potential reduction of skin-cancer risk, while Melanotan II, a cyclic truncated analog, was originally tested for tanning but — owing to its erectogenic side effect — was redirected toward male erectile dysfunction; the MT-II-derived analog PT-141 (bremelanotide) was then developed and commercialized for sexual dysfunction in both sexes. Written by investigators central to the field, this is a historical and commercialization review rather than primary data.
An unhealthy glow? A review of melanotan use and associated clinical outcomes
Brennan, Wells, and Van Hout reviewed the literature on Melanotan I and Melanotan II, synthesizing eighteen clinical trials and twenty-one clinical case presentations to characterize the effects and harms of these synthetic melanotropic "synthetic-tanning" peptides. Reported adverse outcomes include nausea, darkening of existing naevi, yawning, a systemic sympathomimetic toxidrome, and melanoma. The authors emphasize that much of the harm stems from online sourcing of unregulated product — exposing users to bloodborne-virus and injection-site infection risk and to contaminated or mislabelled contents — set against socio-cultural pressure to be tanned and black-market diversion of MT-I/MT-II. This is a narrative clinical-outcomes review; both peptides are unlicensed and not approved for cosmetic tanning.
Use of melanotan I and II in the general population
Evans-Brown and colleagues describe the spread of the synthetic melanocortin analogues Melanotan I and Melanotan II into general, non-clinical use, driven by their skin-tanning effects and — for MT-II — induction of penile erections and increased sexual desire. The authors note the drugs are unlicensed yet easily obtained online and sold or administered in tanning salons, beauty parlours, and hairdressers, and they summarize development status: Melanotan I (afamelanotide) was in phase III trials as a photoprotective agent, while Melanotan II had earlier been developed for sexual dysfunction, yielding the analog/metabolite bremelanotide (PT-141). This is a short BMJ awareness piece on unregulated population use; both peptides were unlicensed for cosmetic use.
Melanotan
Mahiques-Santos's opinion article frames melanotan for dermatologists. It explains that melanotan is a synthetic α-MSH analog and distinguishes Melanotan I ([Nle4-D-Phe7]-α-MSH, a 13-amino-acid linear peptide, more melanin-selective, developed as the photoprotectant afamelanotide/SCENESSE) from Melanotan II (a shorter lactam-ring cyclic analog, less receptor-selective, which also suppresses appetite and increases libido and seeded the PT-141 program). The author reviews potential medical uses (photoprotection in erythropoietic protoporphyria and other photodermatoses; central erectogenic activity), then details black-market "Barbie drug" use and its harms — eruptive melanocytic naevi, changes in pre-existing nevi, a reported melanoma (without established causation), hypertension, and injection/needle-sharing infection risk — and advises clinicians to suspect, investigate, and report illicit use. An opinion/review article; unlicensed cosmetic use is discouraged pending completion of clinical trials.
Melanocortin 1 Receptor (MC1R): Pharmacological and Therapeutic Aspects
Peer-reviewed scientific review by Mun, Kim, and Shin (Int J Mol Sci, 2023) covering the structure, signalling, and therapeutic implications of melanocortin-1 receptor (MC1R). The authors describe the cAMP/PKA/CREB/MITF signalling cascade that drives melanin biosynthesis in melanocytes, and document MC1R expression across multiple cell types — including immune cells — that underpin its anti-inflammatory and neuroprotective roles beyond pigmentation. Therapeutic applications reviewed span skin pigmentation disorders, photoprotection, melanoma risk reduction, vitiligo, and inflammatory and neuroinflammatory conditions. Drug development strategies discussed include peptide-based agonists with stabilising amino-acid modifications (the basis for afamelanotide) and small-molecule scaffolds designed to address the bioavailability limitations inherent to peptide therapeutics. The authors note that achieving receptor subtype selectivity and acceptable pharmacokinetics remain key challenges in MC1R drug development.
An overview of benefits and risks of chronic melanocortin-1 receptor activation
Literature review by Böhm, Robert, Malhotra, Clément, and Farooqi (J Eur Acad Dermatol Venereol, 2024) examining the benefits and risks associated with chronic pharmacological MC1R activation, using afamelanotide as the primary reference compound. On the benefit side, the authors document UV-protective pigmentation, enhanced DNA repair capacity, and approved clinical indications including erythropoietic protoporphyria, sexual desire disorders, and monogenic obesity. Regarding cancer risk, the review concludes that chronic MC1R activation does not raise melanoma incidence in available evidence but equally does not prevent melanoma, particularly in individuals with established risk factors. The authors therefore emphasise that regular dermatological surveillance remains essential for patients receiving MC1R-agonist therapy, defining a practical monitoring framework rather than a contraindication.
The Melanocortin Receptor System: A Target for Multiple Degenerative Diseases
Peer-reviewed survey by Cai and Hruby (Curr Protein Pept Sci, 2016) of the five melanocortin G-protein-coupled receptors (MC1R–MC5R), their POMC-derived endogenous agonists (alpha-, beta-, and gamma-MSH and ACTH), and their tissue distribution and physiological functions relevant to multiple degenerative diseases. The authors characterise the conserved His-Phe-Arg-Trp pharmacophore shared by all endogenous ligands, explaining why achieving receptor-subtype selectivity in drug design is particularly challenging. Peptide, non-peptide, and peptidomimetic approaches to selective ligand design are reviewed, covering therapeutic targets including obesity (MC3R/MC4R), sexual dysfunction (MC4R), inflammation (MC1R/MC3R), and photoprotection (MC1R). The review underscores the broad translational potential of the melanocortin system while noting that the evolutionary conservation of the binding pharmacophore constitutes a fundamental obstacle to subtype selectivity.