Overview
Melanotan I (afamelanotide, CUV1647) is a synthetic linear tridecapeptide analog of alpha-melanocyte-stimulating hormone (α-MSH) and the first melanocortin peptide studied for clinical photoprotection applications. Key modifications include norleucine substitution for methionine at position 4 and D-phenylalanine for L-phenylalanine at position 7, conferring enzyme resistance and increased MC1R affinity. Unlike Melanotan II, it is linear (non-cyclic) with a sequence that more closely mirrors native α-MSH.
Unlike Melanotan II, afamelanotide has relatively selective MC1R over MC4R activity, so its primary research application relates to melanogenesis and photoprotection rather than sexual function. It has been studied extensively in photodermatology — particularly in erythropoietic protoporphyria (EPP) — and received regulatory approval in the EU and USA under the brand name Scenesse, making it one of the few melanocortin peptides with approved clinical data.
Mechanism of Action
- Selective MC1R agonism on melanocytes stimulating cAMP → PKA → MITF transcription factor activation
- MITF upregulation of tyrosinase, TRP-1, and TRP-2 accelerating eumelanin synthesis
- Eumelanin transfer to keratinocytes for UV absorption
- Upregulation of DNA repair enzymes (nucleotide excision repair) reducing UV-induced cyclobutane pyrimidine dimer formation
- Reduced UVA-induced ROS in melanocyte culture models
Specifications
| Full Name | Afamelanotide (Melanotan I) |
| Sequence | Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂ |
| Formula | C₇₈H₁₁₁N₂₁O₁₉ |
| MW | 1,646.9 Da |
| CAS | 75921-69-6 |
| Purity | ≥98% HPLC |
| Form | Lyophilized powder |
| Appearance | White to off-white powder |
| Storage (lyophilized) | −20°C protected from light |
| Storage (reconstituted) | 2–8°C, 4–6 weeks |
| Solubility | Sterile water or bacteriostatic water |
Reconstitution
Reconstitute with sterile or bacteriostatic water. Gently swirl. Store reconstituted at 2–8°C protected from light, use within 4–6 weeks. Do not freeze reconstituted solution.
Quality & Purity
Every batch undergoes third-party HPLC testing to verify ≥98% purity. COA included.
Research Use Only. Melanotan I is strictly for in vitro and laboratory research purposes. Not for human consumption, clinical use, or veterinary use. For use by qualified researchers only. These statements have not been evaluated by the FDA.