Do copper peptides (GHK-Cu) work in skincare?

GHK-Cu stimulates the production of several types of collagen in cell and laboratory studies. A combination with hyaluronic acid even showed a manifold increase in collagen production in cell cultures. That sounds impressive, but these are laboratory conditions, not the skin of real people.

Bold claims are made for GHK-Cu in cosmetic products: skin that becomes firmer, fewer wrinkles, less photo-damage and a more even complexion. However, those claims are largely traceable to lab and animal research. Large, independent clinical trials in humans are absent. Moreover, many of the sweeping claims, such as influencing thousands of genes and reducing inflammation, come from reviews by the same researchers who have a commercial involvement with GHK. That calls for caution when interpreting the evidence.

A fundamental problem is that GHK-Cu has difficulty penetrating the outermost skin layer, because it is a water-soluble molecule and that layer admits fat-soluble substances. As a result, the active ingredient may not reach deep enough into the skin to have an effect. Research into better delivery forms, such as a modified version of the peptide (GHK coupled to an arginine tail) that penetrates more effectively, is preliminary and limited to animal and cell models.

No concrete adverse-event data are available in the studies examined. Review articles mention a long history of use without problems, but formal clinical safety confirmation is lacking. There is no direct reason for concern, but that does not provide certainty either.