Function
While GHK-Cu acts as a tissue-remodeling and wound-healing signal, enhancing skin regeneration, angiogenesis, and repair while reducing inflammation and oxidative damage in experimental models31383, Melanotan I is approved in some regions for prevention of phototoxicity in erythropoietic protoporphyria and is studied as a skin-darkening, photoprotective peptide3444.
Mechanism
While GHK-Cu works as an endogenous tripeptide, Gly-His-Lys, that chelates Cu²⁺ and modulates gene expression, stimulating collagen, elastin, proteoglycan, and glycosaminoglycan synthesis while exerting antioxidant and anti-inflammatory effects31383, Melanotan I is a linear 13-amino-acid analog of α-MSH (afamelanotide) that selectively activates MC1R on melanocytes, increasing eumelanin synthesis and providing photoprotection3444.
Length and Sequence
GHK-Cu is 3 amino acids long, whereas Melanotan I is longer as it has a length of 13 amino acids. GHK-Cu is made up of a sequence of Glycine, Histidine, Lysine. Melanotan I is made up of a sequence of Serine, Tyrosine, Serine, Nle, Glutamic acid, Histidine, Phenylalanine, Arginine, Tryptophan, Glycine, Lysine, Proline, Valine.