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 II is studied as a tanning and libido-enhancing agent; increases melanin production and can reduce food intake and modulate sexual arousal in animal models and humans3545.
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 II is a cyclic heptapeptide melanocortin analog (Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2) that acts as a non-selective, high-potency agonist at MC1R, MC3R, MC4R, and MC5R, influencing pigmentation, appetite, and sexual behavior3545.
Length and Sequence
GHK-Cu is 3 amino acids long, whereas Melanotan II is longer as it has a length of 7 amino acids. GHK-Cu is made up of a sequence of Glycine, Histidine, Lysine. Melanotan II is made up of a sequence of Nle, Aspartic acid, Histidine, Phenylalanine, Arginine, Tryptophan, Lysine.