- ≥99% by HPLC, confirmed by mass spectrometry; lot-matched COA
- Lot-matched certificate of analysis
- Ships next business day, tracked
Melanotan I (Afamelanotide)
Afamelanotide — 13-amino-acid α-MSH analog for melanocortin receptor research
- FormWhite to off-white lyophilized powder in a sealed glass vial
- Mol. weight1646.87 g/mol
- Research areasMelanogenesis, eumelanin synthesis, MC1R signalling, UV-response models
Supplied for laboratory research use only. Not for human or veterinary use, and not intended to diagnose, treat, cure or prevent any disease.
Overview
Melanotan I, also catalogued as afamelanotide, is a synthetic 13-amino-acid analog of alpha-melanocyte-stimulating hormone (α-MSH). It carries two deliberate substitutions relative to the native hormone — norleucine at position 4 and D-phenylalanine at position 7 — which came out of structure–activity work on melanocortin ligands and which slow enzymatic breakdown while preserving receptor binding. The molecule is a linear, C-terminally amidated tridecapeptide that behaves in laboratory systems as a long-lived melanocortin receptor agonist.
Unlike the cyclic lactam Melanotan II, Melanotan I keeps the open-chain α-MSH backbone and is reported to have a comparatively narrower melanocortin profile, with its strongest described activity at the MC1R subtype expressed on melanocytes. That relative selectivity is why it turns up mainly in pigmentation, photobiology and receptor-signalling work rather than in the appetite or sexual-behaviour models where broader melanocortin coverage is wanted.
Specifications
Identity
- CAS number
- 75921-69-6
- Molecular formula
- C78H111N21O19
- Molecular weight
- 1646.87 g/mol
- Amino acid sequence
- Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2
- Peptide class
- Linear α-MSH (melanocortin) analog, tridecapeptide
Supply & purity
- Form
- White to off-white lyophilized powder in a sealed glass vial
- Purity
- ≥99% by HPLC, confirmed by mass spectrometry; lot-matched COA
- Available sizes
- 10 mg, 20 mg
- Solubility
- Bacteriostatic water or sterile water; aqueous stocks kept cold and dark
Handling & storage
- Storage (lyophilized)
- −20 °C, sealed, protected from light and moisture
- Storage (reconstituted)
- 2–8 °C, short study window; avoid repeated freeze–thaw
Additional detail
- Primary target
- Melanocortin receptors, with reported preference for MC1R
- Research areas
- Melanogenesis, eumelanin synthesis, MC1R signalling, UV-response models
Questions about Melanotan I (Afamelanotide)
What is Melanotan I and how does it differ from α-MSH?
It is a synthetic tridecapeptide analog of alpha-melanocyte-stimulating hormone with norleucine substituted at position 4 and D-phenylalanine at position 7. Those two changes were reported to slow enzymatic degradation and extend receptor interaction, so the analog behaves as a longer-lived melanocortin agonist than the native hormone in laboratory assays.
How is Melanotan I different from Melanotan II?
Melanotan I is the full-length linear peptide with activity weighted toward MC1R. Melanotan II is a shorter cyclic lactam analog with broader melanocortin receptor coverage, including MC3R and MC4R. Researchers often compare the two to distinguish pigment-pathway signalling from wider melanocortin system effects.
Is this lot third-party tested, and can I see the COA?
Yes. Every production lot is analysed by an independent laboratory for identity and purity — HPLC with mass-spectrometric confirmation — and the lot-matched certificate of analysis is available on request before purchase. The COA states the lot number, assay result and test date so it can be filed with your experimental records.
What sizes are available and what is in the vial?
Melanotan I is stocked in 10 mg and 20 mg lyophilized vials. Each vial contains only the peptide as a freeze-dried cake, with no diluent, preservative or excipient added, so the laboratory controls the reconstitution vehicle and final concentration.
How should the powder and any solution be stored?
Keep the sealed lyophilate at −20 °C away from light and moisture, where it is stable for extended periods. Once dissolved, hold the solution at 2–8 °C, protect it from light, and use it within a short defined study window rather than storing it long term.
What is it dissolved in for laboratory work?
Bacteriostatic water or sterile water is the usual choice; the peptide is readily water-soluble. Add diluent gently against the vial wall and swirl instead of shaking. Solvent choice should be documented alongside concentration because it affects stability in aqueous storage.
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