Melanotan 1

Melanotan 1 (MT1, afamelanotide, [Nle4, D-Phe7]-alpha-MSH, NDP-alpha-MSH) is a synthetic 13-amino-acid peptide that is a structural analog (also spelled analog) of alpha-melanocyte-stimulating hormone (alpha-MSH). This naturally occurring pituitary hormone regulates skin pigmentation, inflammation, and immune function. ^(1,2) MT1 differs from native alpha-MSH at two amino acid positions: norleucine replaces methionine at position 4, and D-phenylalanine replaces L-phenylalanine at position 7. ^(1,2) These two substitutions dramatically increase the peptide’s potency (100-1,000 times more active than native alpha-MSH in bioassays) and resistance to enzymatic degradation, extending the half-life from seconds (for native alpha-MSH) to approximately 30 minutes. ^(2,4)

MT1 was originally synthesized (also spelled synthesized) at the University of Arizona in the 1980s as part of melanocortin research exploring sunless tanning agents. The compound was licensed to an Australian startup, Epitan, which later became Clinuvel Pharmaceuticals, the company that brought the drug to market as Scenesse. ⁽²⁾ Melanotan 2 (MT2), a cyclic heptapeptide with broader melanocortin receptor activity, was synthesized separately from the same research program but has followed a very different regulatory path. ^(1,3)

The key pharmacological distinction of Melanotan 1 is its selectivity. MT1 primarily activates the melanocortin-1 receptor (MC1R), the receptor specifically responsible for melanin synthesis in melanocytes (skin pigment cells). ^(1,2,3) This selectivity means MT1 produces robust skin darkening (tanning) with minimal activity at MC3R and MC4R receptors in the brain, which are responsible for the sexual arousal, appetite suppression, and other CNS effects associated with the less selective Melanotan 2. ^(1,3) This receptor selectivity is precisely what enabled afamelanotide to navigate the FDA approval process for Scenesse.

The FDA approved Afamelanotide (Scenesse) in October 2019 as a 16mg subcutaneous implant to increase pain-free light exposure in adults with erythropoietic protoporphyria (EPP). This rare genetic disorder causes extreme photosensitivity. ^(2,4) The EMA approved Scenesse in December 2014. ⁽²⁾ EPP is caused by the accumulation of photoactive protoporphyrin IX in tissue, which reacts with light to produce severe phototoxic pain. Afamelanotide increases eumelanin production independent of UV exposure, providing a protective pigment layer that allows EPP patients to tolerate light. ⁽⁴⁾ Phase III trials enrolled approximately 168 patients across the US and EU sites. ⁽⁴⁾

Unlike Melanotan 2, which was placed on the FDA Category 2 bulk drug substance list in September 2023, Melanotan 1/afamelanotide was not included in the Category 2 restrictions because it is an FDA-approved pharmaceutical product. ⁽⁵⁾ It is not classified as a controlled substance. It is not explicitly listed on the WADA Prohibited List, and because Scenesse is FDA-approved, the S0 (Non-Approved Substances) catch-all does not apply. ⁽⁶⁾ Healius supplies Melanotan 1 as a lyophilized (also referred to as lyophilized) powder in 10mg vials, intended strictly for laboratory and research applications.

Melanotan 1 exerts its primary effect by binding to the melanocortin-1 receptor (MC1R), a G-protein-coupled receptor expressed on melanocytes in the skin. ^(1,2,3)

MC1R activation stimulates adenylyl cyclase, increasing intracellular cyclic AMP (cAMP), which in turn activates the MITF transcription factor and upregulates tyrosinase, the rate-limiting enzyme in melanin synthesis. ^(1,2) This pathway drives the production of eumelanin, the brown/black pigment that provides genuine photoprotection by absorbing UV photons and converting the energy to harmless heat. ^(1,3) This is the same pathway triggered by natural UV exposure, but MT1 activates it without requiring UV-induced skin damage. ⁽³⁾

The distinction between eumelanin and pheomelanin is important for understanding MT1’s photoprotective value. Eumelanin (brown/black) acts as a natural sunscreen, absorbing and dissipating UV radiation. Pheomelanin (red/yellow), which predominates in fair-skinned and red-haired individuals due to MC1R gene variants, actually generates reactive oxygen species (free radicals) when exposed to UV light, potentially increasing DNA damage and skin cancer risk. ⁽³⁾ By driving melanin synthesis toward eumelanin regardless of the individual’s baseline MC1R genetic variants, MT1 can provide photoprotective tanning even in populations that naturally produce more pheomelanin. ⁽³⁾

Beyond pigmentation, MC1R activation by MT1 triggers additional protective mechanisms: increased antioxidant activity within melanocytes, enhanced DNA repair capacity (reduced thymine dimer formation and sunburn cells), and secretion of immunomodulatory proteins, including interleukin-10 (IL-10). ^(2,3) Anti-inflammatory and anti-fibrotic effects have been demonstrated in animal models, where alpha-MSH analogs reversed liver and skin fibrosis by modulating matrix metalloproteinases (MMPs) and suppressing fibrogenic signals like TGF-beta1. ⁽³⁾

The comparison between Melanotan 1 and Melanotan 2 (MT2) is the most frequently searched topic in melanocortin peptide research, and the differences are significant across structure, receptor selectivity, effects, regulatory status, and side effect profiles. ^(1,3)

Structurally, MT1 is a linear tridecapeptide (13 amino acids) while MT2 is a cyclic heptapeptide (7 amino acids with a lactam bridge). The cyclic structure of MT2 confers broader receptor activity but less selectivity, while the linear structure of MT1 provides focused MC1R activation. ^(1,3)

Receptor selectivity is the most important pharmacological difference. MT1 primarily activates MC1R (pigmentation) with minimal activity at MC3R/MC4R (sexual function, appetite, energy balance). ^(1,3) MT2 activates MC1R, MC3R, MC4R, and MC5R broadly. ^(1,3) This means MT2 produces tanning plus pronounced sexual arousal effects, appetite suppression, and other CNS effects that MT1 does not produce to a clinically significant degree.

Tanning characteristics differ. MT2 produces faster, more intense tanning that can appear darker and less even, particularly in fair-skinned individuals. ⁽³⁾ MT1 produces a more gradual, natural-looking tan over 2-3 weeks, with more even color (also spelled color) distribution. The melanin produced by MT1 is predominantly the protective eumelanin type. ⁽³⁾

Side effect profiles diverge substantially. MT2’s common side effects include nausea, facial flushing, sexual arousal (spontaneous erections in men), appetite suppression, and mole darkening. ^(1,3) MT1’s side effects are generally milder: nausea (especially initially), facial flushing, fatigue, headache, and mole/freckle darkening, but with minimal sexual function or appetite effects. ^(2,3) Both peptides warrant dermatological monitoring for mole changes.

Regulatory status is starkly different. MT1 (afamelanotide/Scenesse) is FDA-approved  ⁽²⁰¹⁹⁾ and EMA-approved ⁽²⁰¹⁴⁾ for EPP. ^(2,4) MT2 has no regulatory approval anywhere and was placed on the FDA Category 2 restricted list in 2023. ⁽⁵⁾ MT1 is the only melanocortin tanning peptide with regulatory approval in any jurisdiction, reflecting its cleaner selectivity profile and established safety data from clinical trials.

MT1’s clinical evidence base extends beyond EPP into several other dermatological and photoprotective research areas. ^(2,4,7)

The EPP Phase III trials demonstrated that afamelanotide significantly increased the time patients could spend in direct sunlight without phototoxic pain, allowing them to tolerate up to 7 times longer exposure to light. ^(4,7) The melanin produced provided genuine UV protection independent of UV exposure, meaning the protective pigment was synthesized before light exposure rather than in response to it. ^(2,4)

Vitiligo research has produced encouraging results. A 2015 randomized (also spelled randomized) multicentre trial found that subcutaneous afamelanotide combined with narrow-band UVB phototherapy produced faster and greater repigmentation (48.64%) than NB-UVB alone (33.26%) in patients with non-segmental vitiligo after four months of treatment. ⁽⁷⁾ Better responses were observed on the face and upper extremities. The combination therapy approach suggests that MC1R activation can promote melanoblast differentiation, proliferation, and eumelanogenesis in depigmented skin.

Acne vulgaris research (Phase II) demonstrated that MT1 reduced the number of inflammatory facial acne lesions, with concurrent improvements in quality of life as measured by the DLQI (Dermatology Life Quality Index). ⁽⁷⁾ The anti-inflammatory mechanism through MC1R activation and IL-10 secretion may contribute to these effects independently of the pigmentation response.

Active clinical trials as of 2025 include studies evaluating afamelanotide for xeroderma pigmentosum (a DNA repair disorder causing extreme UV sensitivity) and variegate porphyria, with most trials in the recruitment phase. ⁽²⁾ The expanding clinical trial program reflects growing interest in MC1R activation as a therapeutic strategy beyond simple pigmentation enhancement.

MT1/afamelanotide has the most well-characterized safety profile among melanocortin tanning peptides, owing to its FDA approval process and post-marketing surveillance. ^(2,4)

Common side effects from clinical trials include nausea (most common, especially with initial doses), facial flushing, headache, fatigue, drowsiness, decreased appetite, and injection site reactions. ^(2,4) These are generally mild and transient. Unlike Melanotan 2, MT1 does not typically produce significant sexual arousal effects or pronounced appetite changes because of its MC1R selectivity. ⁽³⁾

The primary safety concern specific to melanocortin peptides is the potential for mole changes. MT1 can darken existing freckles and moles, and new mole formation has been reported. ^(2,3) The Scenesse prescribing information recommends twice-yearly full body skin examination for patients receiving the implant, as there is a theoretical concern that increased melanocyte stimulation could affect mole biology in susceptible individuals. ^(2,4) No controlled human studies have definitively established an increased melanoma risk from MT1 use, but the theoretical concern exists, and dermatological monitoring is recommended for anyone using melanocortin peptides. ⁽³⁾

MT1 is FDA-approved (Scenesse) for EPP. It was NOT placed on the FDA Category 2 restricted list in 2023 because it is an approved pharmaceutical product. ⁽⁵⁾ It is not a controlled substance. It is not explicitly listed on the WADA Prohibited List, and because Scenesse is FDA-approved, the S0 catch-all provision does not apply. ⁽⁶⁾ Athletes should independently verify their current status with their anti-doping authority.

1. Wikipedia. Afamelanotide. Linear tridecapeptide, MC1R agonist, [Nle4, D-Phe7]-alpha-MSH, Scenesse, Clinuvel, EPP approval, melanocortin receptor selectivity, comparison with Melanotan II. Updated December 2025.

2. DrugBank. Afamelanotide. Comprehensive pharmacological profile: MC1R binding, eumelanin production, cAMP/MITF/tyrosinase pathway, FDA approval October 2019 (NDA 210797), EMA approval December 2014, orphan drug designation 2008, half-life 30 minutes.

3. PeptideDeck. Melanotan 1 vs Melanotan 2: Full Comparison Guide for 2026. Receptor selectivity comparison, tanning characteristics, side effect profiles, and regulatory status divergence.

4. FDA. NDA 210797. Scenesse (afamelanotide) implant 16mg. Approved October 2019 for EPP. Phase III trials: US (94 patients) and EU (74 patients). Clinuvel Pharmaceuticals. 100-1,000x more potent than native alpha-MSH.

5. FDA Category 2 Bulk Drug Substances. September 2023. Melanotan II is listed as Category 2. Melanotan 1/afamelanotide NOT listed (FDA-approved product).

6. WADA Prohibited List 2026. Afamelanotide is not explicitly listed. FDA/EMA-approved product; the S0 catch-all does not apply to approved pharmaceuticals.

7. Peptides.org. Melanotan 1: Reviews, Clinical Trials, and Safety. Phase II vitiligo trial (afamelanotide + NB-UVB: 48.64% repigmentation vs 33.26% NB-UVB alone). Phase II acne trial. EPP Phase III. Comprehensive clinical trial summaries.

8. PT-141 (bremelanotide): MC3R/MC4R-selective melanocortin agonist for sexual function. FDA-approved as Vyleesi (2019) for premenopausal HSDD. Derived from Melanotan II research.

9. PMC11664455. An overview of the benefits and risks of chronic melanocortin-1 receptor activation. JEADV. 2025. Comprehensive review of MC1R agonism: 201 patients treated in clinical settings, nevi monitoring, anti-inflammatory and antioxidant effects.

10. Peptide Catalog. Melanotan I: Research, Dosing, and Where to Buy. MC1R selectivity, eumelanin vs pheomelanin, dosing protocols, and reconstitution guidance. January 2026.

This product is sold strictly for laboratory and research use only. It is not intended for human or animal consumption. It is not a dietary supplement, food, drug, or cosmetic. It is not intended to diagnose, treat, cure, or prevent any disease or condition. The buyer assumes all responsibility for the lawful use of this product in accordance with all applicable local, state, national, and international laws and regulations. By purchasing this product, the buyer confirms that they are a qualified researcher or are purchasing on behalf of a research institution.