GHK-Cu: what the research shows

What GHK-Cu is

GHK is the tripeptide glycyl-L-histidyl-L-lysine, three residues joined in that order. It was first isolated from human plasma in the 1970s, in work that started from the observation that plasma from young donors and plasma from older donors behaved differently in liver-cell culture, and traced the difference to a small copper-binding fraction. The tripeptide was the active component of that fraction.

GHK binds copper(II) tightly through the histidine imidazole, the N-terminal amine and a backbone nitrogen, and the resulting 1:1 complex is what GHK-Cu means. The copper is not decoration: the complex and the free peptide behave differently in most assays, and much of the literature treats GHK as a copper carrier as much as a signal in its own right. The material we sell is the pre-formed complex, which is why it is blue.

The plasma concentration of GHK is reported to fall substantially between early adulthood and later life, and the field has used that decline as one of its motivations. It is an observation about concentration in blood, not a finding about what restoring it does; the two should not be run together. In the literature the molecule appears as GHK, GHK-Cu, Gly-His-Lys copper and, in cosmetic ingredient lists, copper tripeptide-1. The catalogue product is the same molecule under all of them.

The mechanisms that have been studied

The most-cited line of work is gene-expression profiling. Human fibroblasts treated with GHK in culture were analysed on whole-genome arrays, and the reported result was a broad shift in which genes were up- and down-regulated, with the direction of change compared against expression patterns from tissue samples of various conditions. Reviews describe this as a resetting of expression toward a pattern seen in younger tissue. The strength of that claim is the strength of the array data and of the comparison method, and readers with a stake in it should go to the primary papers rather than the reviews.

The second line is extracellular-matrix synthesis. In fibroblast culture, GHK-Cu has been examined for its effect on the output of collagen, elastin and glycosaminoglycans, and on the expression of the enzymes that build and degrade them. Matrix metalloproteinases and their tissue inhibitors appear in this work as a paired readout: the interest is in whether the balance between matrix breakdown and deposition moves.

Alongside those two are studies of antioxidant and anti-inflammatory signalling in culture, including effects on reactive-oxygen-species handling, iron sequestration, and the expression of cytokines and growth factors such as TGF-beta and VEGF. Copper is a cofactor of superoxide dismutase and lysyl oxidase, and some of the results are difficult to separate from the effect of simply delivering copper to cells. That is a live question in the field rather than a settled one.

What the models actually were

Almost all GHK-Cu research uses one of four systems. Fibroblast culture is the largest: human dermal fibroblasts, sometimes keratinocytes or endothelial cells, treated in a dish and read out by gene arrays, protein assays or proliferation and migration counts. It is the basis for nearly every mechanistic claim.

Rodent wound models are the second group: full-thickness excisional or incisional wounds in rats and mice, with the complex applied to the wound bed, and closure rate, collagen deposition, angiogenesis and tensile strength as the endpoints. A smaller number of studies used rabbit or pig skin.

Ex-vivo skin sits between the two. Human skin explants, usually surgical discards, are kept alive for days in culture and treated topically, and the readout is histology or expression in the tissue. It preserves the tissue architecture that a monolayer lacks, while remaining a laboratory preparation rather than a person.

The fourth group is cosmetic formulation studies: small, short, mostly industry-funded assessments of finished creams that contain the peptide as one ingredient among many, read out by instrument measurements of skin surface. They are often cited as if they were trials of the molecule. They are not; they test a formulation, and most are not designed to isolate the peptide from the rest of it.

None of the above is controlled human evidence for the molecule, and there is no GHK-Cu product approved for any indication in Canada or elsewhere.

Cosmetic ingredient versus research reference standard

Copper tripeptide-1 has been in commercial skincare since the 1990s and appears in a long list of serums and creams. In those products it is typically present at low concentrations as one component of a formulated emulsion, alongside preservatives, humectants and other actives, at a level chosen for cost and stability rather than for any experimental purpose.

What we sell is not that. It is the lyophilised peptide-copper complex as a reference standard, with a certificate stating its HPLC purity and a mass on the label. It contains no base, no preservative and no other active, and it is not a cosmetic; it is not formulated, labelled or sold as one. A laboratory that needs a defined amount of the complex, of known purity, to make a working solution at a concentration of its own choosing is the customer this product exists for.

This matters when reading the literature too. A cosmetic study reports on a cream; a fibroblast study reports on the complex at a defined molar concentration. The two are answering different questions, and comparing our product to either one requires knowing which you are looking at.

Why it sits in the cosmetic and dermal area of this site

Our catalogue groups compounds by the research area their literature belongs to, and for GHK-Cu that area is dermal: fibroblast biology, matrix remodelling, wound models and skin explants. The product page is at /products/ghk-cu/.

It is also the anchor of the skin, hair and dermal remodelling stack at /protocols/stacks/skin-hair-dermal-remodeling/, which collects the compounds that appear together in dermal and hair-follicle research and summarises what the literature reports for each. As with every stack page, that is a summary of published protocols, not a recommendation, and it carries the same research-use framing as this page.

The grouping is about literature, not use. Placing the compound next to other dermal-research compounds says which papers it appears in, and nothing else.

Handling, storage and reconstitution

GHK-Cu is blue. The colour comes from the copper(II) centre coordinated by the peptide, the same electronic transition that makes copper sulphate solutions blue, and it is a quick sanity check on the material: lyophilised GHK-Cu should be blue to blue-violet, and its solution a clear blue that deepens with concentration. Colourless material is the free peptide without copper or something else, and a solution that turns green or brown, or throws a precipitate, has changed.

The complex is freely soluble in water and dissolves in bacteriostatic water without heating. It is light-sensitive in solution, so keep reconstituted solution in the dark in an amber or wrapped vial, and keep lyophilised vials out of light too. Store lyophilised material refrigerated at 2 to 8 C, dry, and let a cold vial reach room temperature before opening it so condensation stays off the powder. Reconstituted solution is kept refrigerated in the dark and used within weeks rather than months; do not freeze and thaw it repeatedly.

Reconstitution uses bacteriostatic water, sterile water with 0.9% benzyl alcohol as a preservative. Add the diluent slowly down the inside wall of the vial rather than onto the powder, then swirl or roll gently until the solution is a clear, uniform blue; do not shake. Diluent volume, the resulting concentration and everything downstream of that is protocol, and it is deliberately not on this page. The reported protocol for GHK-Cu, including a concentration table computed from the vial mass we actually ship, is at /protocols/ghk-cu/, and the general reconstitution guide is at /library/bacteriostatic-water-reconstitution/.

Reading the certificate for a GHK-Cu lot

Pure North commissioned Canada Peptide Testing, as a paying client. Published reports for this product: 50 mg vial, CPT-GHKCU-50-091226 (99.84% area purity; 40.80 mg measured content). Read the original documents at /lab-results/.

The published Canada Peptide Testing reports measure RP-HPLC-UV area purity and content. They do not include mass-spectrometry identity, endotoxin, water content or a related-substances breakdown. These results do not establish clinical safety or regulatory approval.

Match the compound, vial size and printed lot to the report before relying on it. An assigned reference is not automatically the batch code on a vial. If they differ, email purenorthpeptides@proton.me with the vial details and report number to confirm the connection. Do not extend a report to another size or lot.

Regulatory status in Canada

GHK-Cu is supplied in Canada as a research-use-only laboratory reference standard. It is not approved by Health Canada for any use in people, it carries no Drug Identification Number or Natural Product Number, and it is not sold or labelled as a cosmetic. That is the category the material sits in, and it constrains what we can say: no health claims and no outcomes. The schedules on the protocol pages are a summary of what the literature reports, not a recommendation, and they carry the same research-use framing as this page.

Every order requires a research-use declaration at checkout confirming that the material is for laboratory research. That is the buyer's side of the same category.

This page is general information, not legal advice. Classification is compound-specific and can change, Health Canada is the authority, and our overview of the research-use framework is at /library/are-research-peptides-legal-in-canada/.

Frequently asked

What is GHK-Cu?

GHK-Cu is the copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine, first isolated from human plasma in the 1970s. The peptide binds a single copper ion tightly, and the complex, not the free peptide, is what most of the literature studies. It is supplied as a lyophilised research-use-only reference standard.

Why is GHK-Cu blue?

The colour comes from the copper(II) ion held by the peptide, the same electronic transition that makes copper sulphate solutions blue. Lyophilised GHK-Cu is blue to blue-violet and dissolves to a clear blue solution. Colourless material is not the copper complex, and a solution that turns green or brown or precipitates has changed.

What has GHK-Cu been studied for?

In fibroblast culture it has been studied for effects on gene expression, collagen, elastin and glycosaminoglycan synthesis, metalloproteinase balance and antioxidant signalling. In rodent wound models and human skin explants it has been examined for closure rate, matrix deposition and angiogenesis. Cosmetic formulation studies test creams that contain it, not the molecule alone. None of this is human evidence for the compound, and no GHK-Cu product is approved for any indication.

Is research-grade GHK-Cu the same as the copper peptide in skincare?

Same molecule, different product. Skincare contains copper tripeptide-1 at low concentrations as one ingredient in a formulated cream or serum. Our product is the lyophilised peptide-copper complex as a reference standard, with a certificate and a stated mass, no base and no other actives. It is not a cosmetic and is not sold or labelled as one.

Is GHK-Cu legal in Canada?

It is sold as a research-use-only laboratory reference standard, a category distinct from products approved for human use and from cosmetics. It is not approved by Health Canada and carries no DIN or NPN, and buyers sign a research-use declaration at checkout. Classification can change; confirm your own position with Health Canada rather than with a supplier's website.

Referenced in our catalog