GHK-Cu is one of the most widely studied small peptides in the published literature. It’s a three-amino-acid sequence that binds copper, and it has been examined in cell culture, animal models and analytical chemistry work for more than fifty years. This overview covers what GHK-Cu is, what its chemistry looks like, which preclinical studies are cited most often (and what models they used), and what laboratories should check before buying GHK-Cu for in vitro research.
Quick facts: GHK is glycyl-L-histidyl-L-lysine. GHK-Cu is that tripeptide bound to a copper(II) ion. The free peptide has the formula C14H24N6O4 and a molecular weight of about 340.4 g/mol. It is supplied for research use as a lyophilized (freeze-dried) powder, which is typically blue because of the bound copper.
What Is GHK-Cu?
GHK is a naturally occurring tripeptide made of glycine, histidine and lysine. It has a strong affinity for copper(II) ions, and the copper complex is called GHK-Cu (you will also see it called copper tripeptide-1 or copper peptide). In research catalogs GHK-Cu is listed as a synthetic peptide, made by solid-phase peptide synthesis and then complexed with copper.
Discovery
The peptide was first described by Loren Pickart and Thaler in a 1973 paper in Nature New Biology. They reported a factor from human serum that changed how liver cells behaved in culture (a cell-culture model). Later work by Pickart’s group identified the active factor as the tripeptide glycyl-histidyl-lysine and showed that it binds copper. Since then GHK-Cu has become a reference compound in studies of copper-binding peptides and extracellular matrix biology.
GHK-Cu Structure and Copper Binding
Most of the research interest in GHK comes from how it binds copper. Structural studies (X-ray crystallography, EPR and NMR) describe the Cu(II) ion as coordinated by three nitrogen atoms:
- the nitrogen of the histidine imidazole ring,
- the alpha-amino nitrogen of glycine,
- the deprotonated amide nitrogen of the glycine–histidine peptide bond.
In the solid state, carboxyl groups from neighboring molecules complete the coordination around the copper. The binding is tight: published stability-constant data put GHK’s affinity for copper in the same range as the high-affinity copper site of serum albumin. That’s why GHK-Cu is often used as a model compound in copper-transport chemistry.
Why the Copper Matters for Your Material
For a lab, the copper complex changes what you should verify. A vial labeled “GHK-Cu” should contain the copper complex, not free GHK. The two have different molecular weights and look different (GHK-Cu is blue; free GHK is white to off-white). Mass spectrometry data on a certificate of analysis should match the identity being sold.
What Preclinical Research Has Examined
The GHK-Cu literature is broad, but most of it is preclinical. The summaries below describe what each study measured and in which model. They are not evidence of any effect in people.
Extracellular Matrix and Fibroblast Studies (Cell Data)
- Collagen synthesis in fibroblast cultures. Maquart and colleagues (FEBS Letters, 1988) reported that GHK-Cu increased collagen synthesis in cultured fibroblasts. This is cell-culture data.
- MMP-2 expression. Siméon and colleagues (Life Sciences, 2000) reported that GHK-Cu increased matrix metalloproteinase-2 expression in fibroblast cultures. This is also cell-culture data.
Wound-Model Studies (Animal Data)
- Glycosaminoglycans and proteoglycans in experimental wounds. Siméon and colleagues (Journal of Investigative Dermatology, 2000) studied how GHK-Cu changed glycosaminoglycan and small proteoglycan (including decorin) expression in experimental wounds in rats. This is animal data.
Inflammation-Model Studies (Animal and Cell Data)
- Lipopolysaccharide (LPS) lung-injury model. Park and colleagues (Oncotarget, 2016) examined GHK-Cu in an LPS-induced acute lung injury model in mice. They also measured inflammatory markers in a macrophage cell line (RAW 264.7). This is animal and cell data.
Gene-Expression Analyses (Database Data)
- Review of gene-profiling data. Pickart and Margolina (International Journal of Molecular Sciences, 2018) reviewed published GHK research and gene-expression datasets. They proposed that GHK is associated with changes in many gene pathways. This is a review drawing on database and preclinical data, not a controlled experiment.
The literature is large, and the quality of studies varies. Many of the most-cited findings come from one research network, and cell or animal results often don’t translate. If you use GHK-Cu as a research tool, read the primary papers and note the model, the concentration range and the controls before designing your own experiments.
GHK-Cu vs GHK: What’s the Difference in the Lab?
| GHK (free peptide) | GHK-Cu (copper complex) | |
|---|---|---|
| Composition | Gly-His-Lys tripeptide | Gly-His-Lys bound to Cu(II) |
| Molecular weight | ~340.4 g/mol | Higher (adds copper; varies with salt form) |
| Appearance (lyophilized) | White to off-white | Blue |
| Common research use | Studying copper uptake and binding | Studying the pre-formed complex |
Because the salt form (for example, acetate) changes the reported molecular weight, check that the COA states which form the batch is.
How to Verify GHK-Cu Quality Before You Buy
Peptide quality varies a lot between suppliers. For GHK-Cu, a good certificate of analysis should show the following.
1. HPLC Purity
High-performance liquid chromatography separates the target peptide from synthesis by-products. Look for a chromatogram, not just a number, and check the purity percentage of the main peak. Our guide on what HPLC purity means for research peptides explains how to read the chart.
2. Mass Spectrometry Identity
Mass spec confirms that the molecule is what the label says. The observed mass should match the expected mass for GHK or the GHK-Cu complex, depending on what is being sold.
3. Batch Number and Testing Lab
The COA should name an independent testing lab and carry a batch or lot number that matches your vial. A generic, undated COA tells you very little. See how third-party peptide testing works for what to look for.
4. Appearance and Net Content
Lyophilized GHK-Cu should look like a uniform blue cake or powder. Some COAs also report net peptide content, which tells you how much of the vial’s mass is peptide versus salts and moisture.
For a step-by-step walkthrough, read How to Read a Peptide Certificate of Analysis (COA). You can view the batch reports for every OxygenLab product on our COA page.
Storage and Handling in the Lab
Like most research peptides, GHK-Cu is shipped lyophilized because freeze-dried peptides are more stable than solutions. General lab practice for lyophilized peptides:
- Store sealed vials cold, dry and away from light.
- Let a vial reach room temperature before opening it, so moisture doesn’t condense inside.
- Avoid repeated freeze–thaw cycles of solutions. Prepare aliquots if your experimental design allows.
- Label every vial with the batch number so results can be traced back to the COA.
Our article on how to store lyophilized peptides in the lab covers this in more detail. For background on freeze-drying itself, see What Is Lyophilization?
Sourcing GHK-Cu for Research
OxygenLab supplies GHK-Cu for laboratory research in 50 mg and 100 mg vials. GHK-Cu is third-party tested; the published certificate is on our COA page. Orders ship from the US in 2–3 business days.
Free: The Research Peptide Buyer’s Guide. Learn how to verify purity, spot a weak COA and compare suppliers before you order. Join the OxygenLab email list on our homepage to get the guide, plus 20% off your first order.
Frequently Asked Questions
What does GHK-Cu stand for?
GHK is the one-letter amino acid code for glycine (G), histidine (H) and lysine (K). “Cu” is the chemical symbol for copper, so GHK-Cu is the tripeptide bound to a copper(II) ion.
Who discovered GHK?
Loren Pickart and Thaler first described it in 1973 in Nature New Biology. They reported it as a factor in human serum and studied it in liver-cell cultures.
Why is GHK-Cu powder blue?
The blue color comes from the copper(II) ion bound to the peptide. Free GHK without copper is white to off-white, so color is a quick (but not sufficient) first check of what’s in the vial.
Is GHK-Cu research mostly done in humans?
No. Most of the published mechanistic literature uses cell cultures (such as fibroblasts) and animal models (such as rats and mice), plus reviews of gene-expression data. Results from these models can’t be assumed to apply to people.
What should a GHK-Cu certificate of analysis include?
At minimum: HPLC purity with a chromatogram, mass spectrometry identity, a batch or lot number matching the vial, the testing lab’s name and a test date. Our COA reading guide explains each part.
How should lyophilized GHK-Cu be stored?
Store sealed vials cold, dry and protected from light. Let a vial reach room temperature before opening it, and keep solutions in single-use aliquots to avoid freeze–thaw cycles.
Research Use Only. All OxygenLab products are sold strictly for laboratory research use. They are not for human or veterinary use and are not intended to diagnose, treat, cure or prevent any disease. Nothing in this article is medical advice. The studies summarized here are preclinical (cell-culture, animal or review data) and are described for scientific context only. Products must be handled by qualified professionals in accordance with applicable laws and regulations.
