GHK-Cu 100mg

What is GHK-Cu ?

GHK-Cu is the copper(II) complex of GHK, a three-amino-acid peptide (glycyl-L-histidyl-L-lysine) that occurs naturally in human plasma, saliva and urine. As a research compound, the GHK-Cu peptide is studied for how it carries copper into cells and for its effects on the extracellular matrix. Each GHK-Cu 100mg vial holds a blue lyophilised powder. The colour comes from the bound copper.

Loren Pickart first isolated the tripeptide GHK from human plasma in 1973. In GHK-Cu, a single Cu(II) ion sits in a square-planar pocket formed by three nitrogen atoms: the N-terminal amine, the deprotonated glycyl amide nitrogen and the histidine imidazole. The binding strength (log K about 16.4) is close to that of the copper transport site on human serum albumin. For that reason GHK-Cu is usually modelled as a copper carrier that can swap copper with the body's own pools. Pickart and colleagues reported in Nature (1980) that the tripeptide helps cultured cells take up copper.

The GHK sequence also sits inside the alpha-2(I) chain of type I collagen. Fragments like this, released when the matrix is broken down, are called matrikines. Other names for the compound include GHK copper, ghkcu and copper peptide, though "copper peptide" is also used for different sequences such as AHK-Cu.

GHK-Cu Research Applications

• Copper transport : a binding strength close to albumin's copper site, and increased copper uptake by cultured cells (Pickart et al., Nature, 1980).
• Matrix turnover : fibroblast and rat wound-chamber studies from the Maquart and Simeon groups (1988 to 2000) reported more collagen, sulfated glycosaminoglycan and small proteoglycan synthesis. Matrix metalloproteinase-2 and its inhibitors rose too.
• Gene expression : Connectivity Map analyses suggest GHK changes the expression of around 4,000 human genes in cultured cell lines. This is a screening result, not an outcome study.
• Lung models : Campbell and colleagues (Genome Medicine, 2012) found GHK ran against a gene signature linked to emphysema-related lung damage, then studied collagen remodelling in lung fibroblasts.

Most published work falls into two groups. The first is extracellular matrix biology in fibroblast culture and rat wound-chamber models, where matrix building and matrix breakdown were both reported to increase together. Related cell work reported higher integrin expression and more p63-positive cells in keratinocyte culture. The second group is transcriptomic and lung research. Recent preclinical studies have looked at GHK-Cu in mouse models of pulmonary fibrosis and silicosis, measuring oxidative stress and inflammatory signalling.

GHK-Cu vs Copper-Free GHK

GHK and GHK-Cu are two different species. GHK is the free tripeptide (C₁₄H₂₄N₆O₄, 340.4 g/mol, CAS 49557-75-7). GHK-Cu carries one bound Cu(II) ion and is 63.5 g/mol heavier, at 403.9 g/mol. The difference matters at the bench. Molar calculations change. The copper complex is blue while the free peptide is colourless. The balance between the two forms shifts with free copper, competing chelators, phosphate and reducing agents in the medium. Both forms have their own literature, so a protocol should state which one it uses and control the copper content of the medium.

Research Overview

The free tripeptide binds Cu(II) through its N-terminal amine, the deprotonated glycyl amide nitrogen and the histidine imidazole. This square-planar complex is what makes a reconstituted solution deep blue. The stability constant is a log K of about 16.4, slightly above the copper transport site of human serum albumin at about 16.2. A ternary GHK-Cu-albumin complex has also been characterised directly.

In fibroblast culture and rat wound-chamber work, the Maquart and Simeon groups reported that GHK-Cu raised the synthesis of collagen, glycosaminoglycans and small proteoglycans. It also raised matrix metalloproteinase-2 and its tissue inhibitors (Life Sci, 2000). Matrix deposition and matrix turnover going up at the same time is the result most often cited from this work.

The gene expression work uses the Broad Institute Connectivity Map. Analyses reported by Pickart and colleagues indicate GHK alters the expression of around 4,000 human genes. These are profiles from cultured cell lines. Campbell et al. (Genome Medicine, 2012) used the same resource to identify GHK as inversely correlated with an emphysema-related lung destruction signature. They then tested its effect on collagen remodelling in cultured lung fibroblasts.

Circulating GHK is reported to fall from about 200 ng/mL at age 20 to about 80 ng/mL at age 60.

Storage and Reconstitution

Keep sealed vials at -20°C, away from light and moisture. Stored this way, the lyophilised powder is stable for up to 24 months. After reconstitution, keep the solution at 2-8°C in a light-proof container and use it within 4 weeks. Copper(II) peptide complexes are sensitive to light, so use amber or foil-wrapped vessels for aliquots. Freeze-thaw cycles can disturb the copper binding as well as damage the peptide, so freeze single-use aliquots at -20°C for longer storage.

Vials are sold on their own, without bacteriostatic water for mixing or other supplies.

How to reconstitute and handle

• Strong chelators, phosphate-rich buffers and reducing agents in an experimental medium compete for the copper and change the species actually present.

For the full method, see the peptide reconstitution guide and the reconstitution calculator.

Research References

• Growth-modulating plasma tripeptide may function by facilitating copper uptake into cells (Nature, 1980)
• GHK-Cu stimulates matrix metalloproteinase-2 expression by fibroblast cultures (Life Sci, 2000)
• A gene expression signature of emphysema-related lung destruction and its reversal by the tripeptide GHK (Genome Med, 2012)
• GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration (Biomed Res Int, 2015)

Published research on GHK-Cu is indexed on PubMed. See our full UK buyer's guide for Research Peptides, UK buyer's guide for GHK-Cu, UK buyer's guide for GHK-Cu 100mg and UK buyer's guide for GHK-Cu CoA.