Copper peptide promotes and supports the synthesis of collagen. The copper ion (Cu++) has an affinity for proteins, a property that is the basis for a traditional method to measure protein concentration. The N-terminal sequence of human albumin (Asp-Ala-His-Lys) is the site for the transport of copper ion in the bloodstream. Tight binding also occurs when histidine is in position 2, like in the naturally occurring copper (II) complex of Gly-His-Lys. The peptide Gly-His-Lys, bound or unbound to copper, has been used in skin care as an anti-aging active.
It is interesting that the studies on cell cultures (1988, 1992) dealt with experiments on the effect of copper peptide at concentrations in the order of picomolar (-10 M), finding that higher concentrations (still minute, like 10-8 M) were not beneficial. Moreover, at higher concentrations copper peptide seems to promote protein breakdown (Allen 2001). For unknown reasons, clinical studies used much higher concentrations, e.g. 0.4%. Not surprisingly, copper peptide at those high concentrations did not help with healing (Bishop et al. 1992). Looking back at these studies, it is clear that copper peptide should not be used at high concentrations.