Nonapeptide-1 (Melanostatine-5)

Nonapeptide-1, also called Melanostatine-5, is a synthetic nine-amino-acid peptide with an amidated C-terminus. Its sequence — Met-Pro-D-Phe-Arg-D-Trp-Phe-Lys-Pro-Val-NH2 — includes two D-amino acids that stabilise its conformation and set it apart from an ordinary all-L peptide. The internal Phe-Arg-Trp stretch recalls part of the His-Phe-Arg-Trp message sequence shared by melanocortin ligands, although this analogue lacks that motif's histidine. It emerged from melanocortin peptide-library screening as a candidate antagonist of the melanocortin-1 receptor (MC1R).

We stock it only as a 200 mg vial — a large fill for a peptide in this price range — because of the work it is bought for: melanogenesis models and topical formulation studies use up material faster than milligram vials could supply. Assays are designed competitively, profiling the peptide against alpha-MSH at MC1R with readouts such as cAMP accumulation, tyrosinase activity and melanin content in melanocyte or melanoma cultures. Melanotan I, the 13-residue alpha-MSH analogue listed elsewhere in our catalogue, sits at the agonist end of the same receptor pharmacology and is the natural comparator. Keep the lyophilised powder at −20 °C and protect both powder and solutions from light.