Pickart proposed that this activity in human plasma albumin was a tripeptide glycyl-L-histidyl-L-lysine and that it might function by chelating metal ions.

At picomolar to nanomolar concentrations, GHK-Cu stimulated the synthesis of collagen in skin fibroblasts, increased accumulation of total proteins, glycosaminoglycans (in a biphasic curve) and DNA in the dermal wounds in rats.

This GHK-Cu enriched material stimulated wound contraction and cell proliferation, as well as increased expression of antioxidant enzymes.

GHK-Cu treatment resulted in faster wound contraction and epithelization, higher level of glutathione and ascorbic acid, increased synthesis of collagen, and activation of fibroblasts and mast cells.

[21] Several controlled facial studies confirmed anti-aging, firming and anti-wrinkle activity of copper peptide GHK-Cu.

The small size of GHK permits speedy traveling in extracellular space and its easy access to cellular receptors.

Another carboxyl group of lysine from a neighboring complex provides the apical oxygen, resulting in the square-planar pyramid configuration.

[24] Many researchers proposed that at the physiological pH, GHK-Cu complexes can form binary and ternary structures which may involve amino acid histidine and/or the copper binding region of the albumin molecule.

A dozen enzymes (cuproenzymes) use changes in copper oxidation state to catalyze important biochemical reactions including cellular respiration (cytochrome c oxidase), antioxidant defense (ceruloplasmin, superoxide dismutase (SOD), detoxification (metallothioneins), blood clotting (blood clotting factors V and VIII), melanin production (tyrosinase) and the connective tissue formation (lysyl peroxidase).

Copper is required for iron metabolism, oxygenation, neurotransmission, embryonic development and many other essential biological processes.

Thus, GHK-Cu's ability to bind copper and to modulate its tissue level is a key factor determining its biological activity.