GHK-Cu Copper Peptide: What the Published Literature Covers

GHK-Cu is the copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine. The peptide was first identified in human plasma in the early 1970s, and its affinity for copper ions is central to its literature. Published work covers skin and connective tissue models, wound models in animals, and analyses of gene expression data, much of it summarized in reviews by the peptide's original discoverer [1].

How does GHK bind copper?

GHK binds copper(II) through the nitrogen of the histidine imidazole ring, the N-terminal amine and a backbone amide nitrogen, forming a stable complex. That is why the compound is usually supplied and studied as the copper complex rather than as the free peptide, and why the powder is blue.

What has been studied?

Cell and animal studies have examined GHK-Cu in skin fibroblasts, collagen and extracellular matrix production, and wound models. A later line of work used public gene-expression databases to compare gene-activity patterns associated with GHK against patterns associated with tissue damage and aging, and reported that GHK was associated with changes in the expression of many genes [1]. Related tripeptide-copper complexes, such as AHK-Cu, have been studied in hair follicle cell models [2].

How should the literature be read?

Much of the review literature is written by researchers with a long involvement in GHK-Cu, and gene-expression connectivity analyses show associations rather than effects measured in tissue. Cosmetic formulations account for a large share of the applied literature, and those are distinct from lyophilized research material. None of this describes a use in humans for research material.

What matters for identification?

Mass spectrometry of copper complexes may show the free peptide at about 340.4 Da, the copper-bound species, or both. Because formulas for copper complexes are written with different proton counts, catalog molecular weights vary by a few daltons; the peptide sequence and the presence of copper are the stable facts.

Frequently asked questions

Is GHK-Cu the same as copper tripeptide-1?

Yes. Copper tripeptide-1 is a common name for GHK-Cu.

Why is GHK-Cu blue?

The copper(II) ion in the complex absorbs light in the red and yellow range, giving a blue to violet color.

Does FLASK list GHK-Cu?

Yes, as GHK-Cu 50 mg, and as a component of the GLOW and KLOW blends.