What is MELANOTAN-1?
Melanotan-1 (also referenced in the literature as afamelanotide) is a synthetic linear tridecapeptide belonging to the melanocortin class of peptides. It is a structural analog of endogenous alpha-melanocyte-stimulating hormone (α-MSH), engineered with targeted amino-acid substitutions that distinguish it from the native hormone. Its defined primary structure is Ac-Ser-Tyr-Ser-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2, comprising 13 amino acid residues with an N-terminal acetyl cap and a C-terminal amide.
The molecule carries the empirical formula C78H111N21O19 and a molecular weight of 1646.87 g/mol, and is catalogued under CAS registry number 75921-69-6. Two key modifications differentiate the sequence from wild-type α-MSH: the replacement of the native methionine at position 4 with norleucine (Nle), and the substitution of the L-phenylalanine at position 7 with its D-enantiomer (D-Phe). These substitutions are widely documented as increasing the analog's resistance to enzymatic degradation and its conformational stability relative to the parent hormone.
Within the scientific literature, Melanotan-1 is studied as a melanocortin receptor ligand and is used as a reference compound in in-vitro investigations of the melanocortin signaling system and pigmentation biology. American Peptides supplies this material strictly as a research chemical for in-vitro and laboratory investigation. It is not a drug, supplement, or article intended for human or veterinary use, and no physiological or therapeutic properties are represented here.
Reconstitution & handling
Melanotan-1 is shipped as a lyophilized (freeze-dried) powder and requires reconstitution in a compatible aqueous solvent before it can be handled in solution for laboratory work. Bacteriostatic water is the solvent most commonly cited for melanocortin peptides of this type; sterile water and dilute acetic acid solutions are also referenced in the literature for peptides bearing acidic and basic residues. To dissolve the solid, the chosen solvent is directed slowly down the inner wall of the vial rather than dispensed directly onto the peptide cake, then allowed to solubilize with gentle swirling. Vigorous agitation, vortexing, or shaking should be avoided, as mechanical shear and foaming can stress the peptide backbone.
As a 13-residue peptide containing polar and charged residues (Ser, Glu, Arg, Lys) alongside aromatic and hydrophobic residues (Tyr, Trp, Nle, Val), Melanotan-1 generally exhibits good solubility in aqueous buffers near neutral pH. Reconstituted material should be prepared fresh where feasible, kept cold during handling, and inspected visually to confirm a clear, particulate-free solution prior to use. All handling should follow standard laboratory practice for research chemicals of unknown biological activity.
Storage & stability
In its lyophilized form, Melanotan-1 is most stable and is best stored sealed and protected from light, moisture, and heat; long-term storage at -20°C is standard practice for research peptides, with brief periods at 2-8°C acceptable for short-term handling. Once reconstituted, the peptide is less stable in solution and should be held refrigerated at 2-8°C for near-term use or aliquoted and frozen for longer intervals to minimize degradation. Repeated freeze-thaw cycles should be avoided, as they can promote aggregation and loss of intact peptide; dividing solutions into single-use aliquots before freezing preserves integrity. Kept dry, cold, and dark, the lyophilized powder retains its characterized purity over extended storage.
How it's tested
Identity and purity of each Melanotan-1 lot are established by orthogonal analytical methods. Reversed-phase high-performance liquid chromatography (HPLC) quantifies chromatographic purity, with material released at ≥99% purity, and resolves process-related impurities and closely eluting peptide-related species. Mass spectrometry (MS) confirms molecular identity by measuring the observed mass against the theoretical mass derived from the C78H111N21O19 formula (1646.87 g/mol), verifying that the correct sequence and terminal modifications are present. A Certificate of Analysis (COA) documenting these results is available for the material, providing lot-specific traceability of purity and identity for laboratory records.