GHK is a short peptide found in human blood that binds copper. The copper complex, GHK-Cu, is studied for how it influences the cells that build and remodel skin and connective tissue.
GHK-Cu · Copper-binding tripeptide
Skin and connective tissue are constantly being rebuilt. Cells lay down collagen, clear damaged material and respond to injury, and small signalling molecules help coordinate that work. GHK-Cu is studied because it appears to influence several of those processes at once. Most of the evidence comes from cell culture and from topical wound and skin studies, including one randomised human trial of a gel applied to diabetic foot ulcers.
GHK is a tripeptide: three amino acids joined in sequence, glycine, histidine and lysine. Pickart and Thaler first isolated it from human plasma in 1973, after noticing that a fraction of serum prolonged the survival of liver cells in culture. GHK binds copper(II) ions tightly, and the complex it forms is GHK-Cu. Most published work describes the copper complex, so the two names are not interchangeable when reading a result.
The proposed mechanisms are broad rather than single-target. In cell culture, GHK and GHK-Cu have been reported to attract repair cells such as macrophages, to change the synthesis of collagen and other matrix proteins, and to shift the expression of many genes at once. A 2012 study used the Connectivity Map, a database that matches gene-expression patterns to compounds, and identified GHK as a compound whose signature reversed the gene-expression pattern of emphysema-related lung destruction in cultured fibroblasts. That describes what the peptide does to cells in a dish, not what it does in a person.
The clearest human evidence is topical. A multicentre, randomised, evaluator-blinded, placebo-controlled trial by Mulder et al. (1994) applied a GHK-Cu gel to diabetic neuropathic foot ulcers alongside standardised wound care. Ulcers treated with the gel closed further than those treated with the vehicle and became infected less often. The result belongs to that gel, that wound and that route.
Cosmetic studies of GHK-Cu creams on aged skin, reporting changes in firmness, elasticity and fine lines, are summarised in reviews by Pickart (2008) and Pickart and Margolina (2018). Most are small, measure surface properties, and are reported by the author who discovered the peptide and holds commercial interests in it.
The often-quoted age observation, that plasma concentration falls from about 200 ng/mL at age 20 to about 80 ng/mL at 60, refers to measurements of GHK, the free peptide, not of GHK-Cu, and is cited in those reviews rather than reported in a large independent dataset. A lower level with age is an observation about the peptide. It is not evidence that supplying the copper complex corrects anything.
Systemic administration is a separate question. The gene-expression, lung and liver findings come from cell culture and animal models. This note did not identify a controlled human trial of injected or otherwise systemic GHK-Cu.
Whether any topical finding transfers to a systemic route is untested in people; a gel on a wound and a peptide in the bloodstream are different experiments. The age-related decline concerns free GHK, and the assays behind it are decades old. Much of the review literature comes from a single author with a commercial position, and independent replication of the cosmetic results is thin. Copper is essential but not inert, and how the complex distributes and hands over copper in tissue has not been characterised in human studies.
GHK-Cu is not an approved medicine in Australia; the TGA names it among unapproved peptide products in its advisory on importing, compounding and supplying such products. No regulator-approved GHK-Cu medicine was identified for this note; the peptide appears in cosmetic products, which are regulated differently from medicines.
Sources and status checked 2026-09-22
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