Quick answer: GHK-Cu is a naturally occurring tripeptide of glycine, histidine and lysine that binds copper(II). It was first isolated from human plasma in the 1970s, and its research literature concerns extracellular matrix signalling, wound-repair models and gene-expression profiling in cell culture. In the laboratory it is supplied as a blue lyophilized powder, and the points that matter when you buy it are confirming the copper complex, the measured purity and the vial size.
What GHK-Cu is
You will see the compound written as GHK-Cu, GHKCU, "GHK copper" and "copper peptide". They all refer to the same thing: the three-amino-acid sequence Gly-His-Lys complexed with a copper(II) ion. The peptide on its own is called GHK; adding copper gives GHK-Cu, and the two are different materials. The copper is not an additive. It is part of the molecule, held by the histidine and lysine residues, and it is what gives the powder and its solutions their blue colour.
The tripeptide was identified in the early 1970s by Loren Pickart, who found it in the albumin fraction of human plasma while studying how tissue responded to the plasma of older and younger donors. Since then it has become one of the most widely discussed research peptides in skin and extracellular-matrix biology. Our discovery and history article tells the story, and the structure and synthesis article explains how the copper is bound.
What the research literature describes
Published work on GHK-Cu spans several areas. In cell culture, researchers have examined its influence on the synthesis of collagen and glycosaminoglycans by fibroblasts, on the remodelling enzymes that break down matrix, and on the signalling of cell migration after a simulated wound. In animal models, it appears in studies of wound closure and tissue remodelling. A separate line of work used gene-expression databases to ask which genes change when cells are exposed to the peptide, and described a broad pattern of activity across many pathways.
These are findings from laboratory models and from analysis of existing data sets. They do not establish what the compound does in people, and this guide makes no such claim. Where the original papers are small or come from a limited number of groups, that is worth bearing in mind when you design an experiment. Our mechanism article, preclinical research article and the focused pieces on skin and collagen research and hair follicle research go through the models in detail.
Why the copper matters for quality
GHK-Cu is the one peptide in our catalogue where an ordinary purity test is not enough on its own. A standard HPLC analysis will show whether the peptide chain is intact and whether synthesis by-products are present. It will not necessarily show whether the copper is still attached, or in the right amount. A sample that has lost its copper is, chemically, just GHK; a sample with too much loosely bound copper is a different problem again.
This is why the colour and the metal content are worth asking about. A properly complexed GHK-Cu powder is blue. A white powder sold as GHK-Cu may be the copper-free tripeptide, and a powder with an unusual tint may be contaminated or degraded. Thoughtful suppliers confirm identity of the complex, not only of the peptide. When you read a certificate, look for how identity was established and whether the copper is mentioned at all. Our GHK-Cu purity testing article goes through the methods.
Reading a GHK-Cu certificate
- HPLC purity. A measured figure and the chromatogram. Understanding HPLC purity explains the trace.
- Identity of the complex. The report should say how the compound was confirmed and should not be silent about copper.
- Content per vial. A measured quantity, to be compared with the label. For this compound the mass includes the copper.
- Lot code and test date. Both should match the vial.
- Endotoxin and sterility. Important for cell-based work.
If the layout is new to you, how to read a COA walks through a certificate line by line. Our supplier checklist is in how to choose a research peptide supplier, and the sourcing notes for this compound are in where to buy GHK-Cu.
Vial sizes and the arithmetic
GHK-Cu is commonly supplied in larger vials than other research peptides, because the working concentrations in cell studies are higher. We supply it at 50 mg and 100 mg. The label gives the total mass, and for a metal complex it is worth confirming whether that number refers to the peptide alone or to the whole complex including the copper. When you prepare a stock solution, the difference is small but not zero, and it matters for a quantitative assay. The reconstitution calculator guide helps with the arithmetic.
Storage and handling
GHK-Cu is supplied as a lyophilized powder. General laboratory practice is to keep the sealed vial refrigerated and protected from light, heat and moisture. Copper complexes can be sensitive to the buffer they are dissolved in, because some buffer components bind copper themselves, so the choice of diluent is part of the assay design. Working solutions are best made fresh for each experiment. The reconstitution and storage article has the details.
Questions to ask a supplier
A short list of questions separates careful suppliers from careless ones. Ask how copper content is verified. Ask whether the stated vial mass is the peptide alone or the complete complex. Ask for the laboratory report for the lot you will receive, not a sample report from a different batch. And ask whether the report can be checked with the laboratory that issued it. A supplier that welcomes these questions is usually one that has done the work; one that deflects them has told you something too.
GHK-Cu inside blends
GHK-Cu is also the largest single component in several multi-peptide blends. It makes up 50 mg of the 70 mg Glow stack and of the 80 mg KLOW stack, and it is combined with KPV in a separate blend. For those products the copper question applies to the whole mixture, because the other peptides can interact with copper in solution. Our Glow overview and stack comparison explain the blends, and the KLOW explainer covers the four-peptide version.
What V8 Peptides publishes for GHK-Cu
A certificate for the GHK-Cu single-peptide vials is not yet published on our site. We have requested reports for every product that lacks one, and GHK-Cu is on that list. The Glow stack, which contains GHK-Cu, does have a published certificate with component-level results, and you can read it on the COA page and verify it with the laboratory directly. When the GHK-Cu report arrives we will add it there and update the product page.
Frequently asked questions
What is GHK-Cu?
A tripeptide of glycine, histidine and lysine bound to copper(II). It was first isolated from human plasma in the 1970s and is widely studied in cell and animal models of extracellular matrix and wound repair.
Are GHK-Cu, GHKCU and copper peptide the same?
Yes. They all refer to the copper-bound tripeptide. GHK without copper is a different material.
Why is the powder blue?
The colour comes from the copper(II) ion bound to the peptide. A white powder sold as GHK-Cu may be missing its copper.
Is an HPLC purity result enough for GHK-Cu?
It shows that the peptide chain is intact and clean, but not necessarily that the copper is attached in the right amount. Look for how the identity of the complex was confirmed.
What vial sizes does V8 Peptides supply?
GHK-Cu is supplied as 50 mg and 100 mg research vials.
Does V8 Peptides publish a certificate for GHK-Cu?
Not yet for the single-peptide vials. We have requested one. The Glow stack, which contains GHK-Cu, has a published certificate on the COA page.
How should the powder be stored?
General practice is refrigeration of the sealed vial, protected from light, heat and moisture. Buffer choice matters after reconstitution because some buffers bind copper.
Is this advice for use in people?
No. GHK-Cu is supplied for laboratory research only, and nothing here is guidance for use in people or animals.
Where to go next
For a fuller picture of the compound, start with the GHK-Cu copper peptide research guide and the research FAQ. To check the certificates we have published, visit the COA page.
References
- Pickart L, Margolina A. Regenerative and protective actions of the GHK-Cu peptide in the light of the new gene data. International Journal of Molecular Sciences. 2018;19(7):1987.
- Pickart L, Vasquez-Soltero JM, Margolina A. GHK peptide as a natural modulator of multiple cellular pathways in skin regeneration. BioMed Research International. 2015;2015:648108.
- Pickart L, Thaler MM. Tripeptide in human serum which prolongs survival of normal liver cells and stimulates growth in neoplastic liver cells. Nature New Biology. 1973;243(124):85-87.
- Maquart FX, et al. Stimulation of collagen synthesis in fibroblast cultures by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+. FEBS Letters. 1988;238(2):343-346.
For laboratory research use only. Not for human or animal consumption. Not a drug, food or cosmetic. This article is educational and describes published research; it makes no claims about outcomes in people or animals.