What Is Melanotan-1? Definition and What Research Reports

Definition

Melanotan-1 is the older research-era name for a synthetic, linear analogue of alpha-melanocyte-stimulating hormone (alpha-MSH) in which the amino acid at position 4 is replaced by norleucine and the residue at position 7 by D-phenylalanine. The same molecule appears in the chemistry literature as [Nle4, D-Phe7]-alpha-MSH (abbreviated NDP-alpha-MSH or NDP-MSH) and in the clinical and regulatory literature under the international non-proprietary name afamelanotide, which reviews described as an agonistic analogue of alpha-melanocyte-stimulating hormone developed for dermal phototoxicity in erythropoietic protoporphyria (PMID 21073357). Because alpha-MSH is a 13-residue peptide, Melanotan-1 is a short peptide rather than a small-molecule drug, and the two substitutions were made to resist enzymatic breakdown and increase receptor potency relative to the parent hormone (PMID 28063031). This page is for educational purposes only and is not medical advice; consult a licensed physician for any question about a medical condition or treatment.

What class of molecule it is

Melanotan-1 belongs to the melanocortin peptide class. Melanocortins are peptides derived from the proopiomelanocortin (POMC) precursor and act at a family of melanocortin receptors; a pharmacokinetic and pharmacodynamic review characterised afamelanotide as a melanocortin-1 receptor (MC1R) agonist that stimulates eumelanin synthesis in melanocytes (PMID 28063031). A review of melanocyte-stimulating hormone therapy placed afamelanotide within the broader history of MSH-based approaches in dermatology and described the rationale of using a stabilised analogue instead of native alpha-MSH (PMID 23884489).

In formulation terms, the clinical literature is dominated by a single delivery format: a review of the pharmacokinetics and clinical use of afamelanotide described it as administered from a subcutaneous controlled-release implant rather than as repeated bolus dosing (PMID 28063031). A review of afamelanotide in protoporphyria and other skin diseases likewise discussed the implant as the formulation used across the dermatologic studies it surveyed (PMID 38784937).

How the term is used in peptide research

Usage of the term depends on the audience. Older pharmacology papers and chemical catalogues tend to use Melanotan-1, MT-1, or the structural designation [Nle4, D-Phe7]-alpha-MSH; clinical papers almost always use afamelanotide, and one dermatology review also referenced the development code CUV1647 for the implant studied in erythropoietic protoporphyria (PMID 25470471). A study in Hailey-Hailey disease used the structural name directly, reporting on the melanocortin analogue Nle4-D-Phe7-alpha-melanocyte-stimulating hormone in affected patients (PMID 24256215). Readers searching one name will therefore find literature filed under several others.

What the published literature reports

Erythropoietic protoporphyria

The largest body of published work concerns erythropoietic protoporphyria (EPP), a rare porphyria in which sunlight exposure triggers painful phototoxic reactions. A review of afamelanotide for prevention of phototoxicity in EPP examined the implant as a strategy for reducing light-triggered phototoxic reactions in this population (PMID 33507118). An earlier review of afamelanotide (CUV1647) in dermal phototoxicity of EPP covered the trial programme that supported this indication (PMID 25470471), and a further review of the agonistic alpha-MSH analogue in dermal phototoxicity of EPP described the mechanistic rationale of increasing eumelanin as photoprotection (PMID 21073357). A dedicated drug review in American Journal of Clinical Dermatology summarised the clinical evidence for afamelanotide in erythropoietic protoporphyria and its place in management of the condition (PMID 26979527).

Other dermatologic settings

Beyond EPP, the literature is smaller and more exploratory. A review titled Afamelanotide: An Orphan Drug with Potential for Broad Dermatologic Applications discussed interest in the peptide across additional skin conditions while noting its orphan-drug origins (PMID 33683075). A 2024 review of afamelanotide in protoporphyria and other skin diseases surveyed reported uses outside the porphyrias (PMID 38784937). Researchers also reported on efficacy of the melanocortin analogue Nle4-D-Phe7-alpha-MSH in patients with Hailey-Hailey disease, a rare blistering genodermatosis (PMID 24256215), and a review of melanocyte-stimulating hormone therapy placed such reports within the wider MSH-therapy field (PMID 23884489).

Tolerability and Adverse Events: What Studies Report

Reported tolerability data come mainly from the EPP programme. The drug review in American Journal of Clinical Dermatology reported that afamelanotide was generally well tolerated in the studies it assessed, with adverse events that were mostly mild (PMID 26979527). A pharmacokinetic and pharmacodynamic review discussed increased skin pigmentation as an expected pharmacodynamic consequence of melanocortin-1 receptor agonism rather than an unexpected event (PMID 28063031), and the review of afamelanotide for prevention of phototoxicity in EPP addressed safety and monitoring considerations alongside efficacy (PMID 33507118). Because the published safety record is tied to a specific pharmaceutical implant used under medical supervision, it does not describe other formats, sources or settings.

Regulatory and research status

Afamelanotide is the form of this molecule that entered regulated clinical use: a dermatology review described it as an orphan drug, a designation granted for rare-disease indications (PMID 33683075), and reviews of its clinical use discussed it as a prescription product for erythropoietic protoporphyria rather than a general-purpose dermatologic agent (PMID 28063031). Material sold under the name "Melanotan-1" outside that regulated pathway is not the same as an approved pharmaceutical implant and is not covered by the trial data summarised above. Peptide reference material supplied for laboratory work is typically labelled research use only.

Terms it is often confused with

• Melanotan II (MT-2) — a separate, cyclic alpha-MSH analogue with a different structure and receptor profile; it is not the molecule described in the afamelanotide literature cited on this page, and none of the papers listed below studied it.
• Alpha-MSH — the endogenous 13-residue hormone from which Melanotan-1 was derived; a review of MSH therapy distinguished the native hormone from stabilised analogues used clinically (PMID 23884489).
• Melanocortin receptors (MC1R-MC5R) — the receptor family at which melanocortin peptides act; the pharmacology review focused on MC1R for pigmentation effects (PMID 28063031).

Limits of the evidence

Three limits are worth noting when reading this term. First, the strongest published evidence sits in one rare disease: multiple reviews framed the clinical case for afamelanotide around dermal phototoxicity in erythropoietic protoporphyria (PMID 25470471, PMID 26979527). Second, reports in other conditions are limited in size, as in the patient series describing the melanocortin analogue in Hailey-Hailey disease (PMID 24256215). Third, findings generated with a controlled-release implant studied in clinical settings (PMID 38784937) cannot be assumed to transfer to any other preparation. This entry describes what the literature contains; it does not describe use.

References

• Afamelanotide: An Orphan Drug with Potential for Broad Dermatologic Applications (Journal of Drugs in Dermatology, 2021)
• Pharmacokinetics and Pharmacodynamics of Afamelanotide and its Clinical Use in Treating Dermatologic Disorders (Clinical Pharmacokinetics, 2017)
• Afamelanotide for prevention of phototoxicity in erythropoietic protoporphyria (Expert Review of Clinical Pharmacology, 2021)
• Afamelanotide (CUV1647) in dermal phototoxicity of erythropoietic protoporphyria (Expert Review of Clinical Pharmacology, 2015)
• Afamelanotide in protoporphyria and other skin diseases: a review (Postepy Dermatologii i Alergologii, 2024)
• Afamelanotide, an agonistic analog of alpha-melanocyte-stimulating hormone, in dermal phototoxicity of erythropoietic protoporphyria (Expert Opinion on Investigational Drugs, 2010)
• Afamelanotide: A Review in Erythropoietic Protoporphyria (American Journal of Clinical Dermatology, 2016)
• Efficacy of the melanocortin analogue Nle4-D-Phe7-alpha-melanocyte-stimulating hormone in the treatment of patients with Hailey-Hailey disease (Clinical and Experimental Dermatology, 2014)
• A review and update on melanocyte stimulating hormone therapy: afamelanotide (Journal of Drugs in Dermatology, 2013)