GHK-Cu copper peptide UK: chemistry, research uses, handling and COA
GHK-Cu for UK laboratories: the copper complex versus free GHK, molecular weight and CAS, the gene-expression literature, light-sensitive storage.
GHK-Cu is a naturally occurring copper-binding tripeptide with a research history stretching back to the 1970s and, unusually for a research peptide, a large published gene-expression literature. It is also one of the compounds where the form supplied matters most: the copper complex behaves differently from the free tripeptide, and the two are often confused in listings. This guide covers what GHK-Cu is, its chemistry, the research areas it appears in, how to store and reconstitute it, and how Alphex GHK-Cu is verified. All material is supplied for laboratory and in-vitro research only.
What GHK-Cu is
GHK is the tripeptide glycyl-L-histidyl-L-lysine (Gly-His-Lys). It was first isolated from human plasma, where it circulates at concentrations that decline markedly with age. It has a high affinity for copper(II), and the copper complex, GHK-Cu, is the form most research uses because the copper coordination changes the peptide's chemistry and much of its reported activity. In the complex the copper ion is coordinated by the histidine imidazole, the glycine amino group and backbone nitrogen atoms, giving a characteristic blue-violet colour in solution.
The free tripeptide has a molecular weight of 340.4 g/mol; the copper complex is 403.9 g/mol. When comparing suppliers, check which is being sold: "GHK-Cu" should be the complex, and the COA mass should reflect it.
Specification
- Structure: Gly-His-Lys : Cu(II) complex
- Molecular formula: C14H22CuN6O4
- Molecular weight: 403.9 g/mol (complex); 340.4 g/mol (free tripeptide)
- CAS number: 49557-75-7
- Synonyms: copper tripeptide-1, glycyl-L-histidyl-L-lysine copper
- Form supplied: lyophilised powder in a vacuum-sealed glass vial; blue to blue-violet colour is expected
- Purity specification: 99+% by RP-HPLC at 220 nm; identity by ESI-MS
- Sizes: 50 mg and 100 mg vials
GHK-Cu is supplied in larger vial sizes than most of the catalogue because typical in-vitro working concentrations and cosmetic-science formulation studies use considerably more material than assays of larger peptides.
Where GHK-Cu appears in the research literature
GHK-Cu has one of the broadest literatures of any short peptide, much of it in vitro or in animal models, with a distinctive strand of gene-expression profiling work. Themes include:
- Gene expression. Several studies have used connectivity-mapping and microarray approaches to profile how GHK-Cu changes gene expression in cultured cells, and this is the most-cited part of the literature.
- Extracellular matrix and dermal fibroblast models. Work on collagen, glycosaminoglycan and metalloproteinase expression in fibroblast cultures and skin models is where the compound first attracted attention.
- Wound and tissue models. Animal-model work on dermal and other tissue repair.
- Copper transport and antioxidant chemistry. Studies of the peptide as a copper carrier and of its behaviour in oxidative systems.
- Cosmetic science. A separate applied literature on formulation and stability in topical vehicles, which is where much of the demand for larger quantities comes from.
As with every compound in this catalogue, the literature does not establish any use outside research settings, and Alphex supplies GHK-Cu as a laboratory reagent only.
Handling, storage and reconstitution
Lyophilised: -20 C long term, 2-8 C short term. GHK-Cu is light sensitive: keep it in the original vial in the dark, or wrap the vial to exclude light. Allow it to reach room temperature before opening.
Reconstitution: the complex is highly water-soluble and gives a blue solution. Reconstitute in bacteriostatic water, sterile water or buffer, adding solvent gently. Because copper coordination is pH-dependent, note the pH of your vehicle: strongly acidic conditions can strip copper from the peptide, and strongly alkaline conditions can precipitate copper hydroxide. Most laboratories work between pH 6 and 7.5.
In solution: refrigerate at 2-8 C in the dark and use within a few weeks; aliquot and freeze at -20 C for longer storage. A colour change from blue toward green or a precipitate indicates copper loss or degradation and the stock should be discarded. Chelating buffers (EDTA, high citrate) will remove the copper and should be avoided unless that is the intent. Full handling guidance: storage, reconstitution and shelf life.
How Alphex verifies GHK-Cu
Every batch is run on reverse-phase HPLC at 220 nm against a reference standard with a 99+% area purity threshold. Results go onto a Certificate of Analysis carrying the batch number on the vial label, chromatogram included, laboratory named. Stock is UK-held and dispatched the same day for orders before 2pm Monday to Friday. Method: how Alphex tests every batch.
For GHK-Cu the visual check is also useful: a genuine copper complex is unmistakably blue. White or off-white powder sold as GHK-Cu is either the free tripeptide or something else, whatever the label says.
Buying GHK-Cu in the UK
Because GHK-Cu is used in both laboratory and cosmetic-science research, it is sold by a wide range of suppliers at wildly different quality levels, and the free tripeptide is sometimes sold as the copper complex at complex prices. Check the molecular weight on the COA (403.9, not 340.4), the colour, the HPLC threshold and the chromatogram, and run the rest of the 12-point supplier checklist before ordering from anyone.
Frequently asked questions
Why is the powder blue?
Because it is a copper(II) complex. The colour is the coordination of copper by the peptide and is a quick confirmation you have the complex rather than the free tripeptide.
Is GHK-Cu the same as "copper peptide"?
In most contexts "copper peptide" refers to GHK-Cu, but the term is imprecise and some products labelled that way contain other copper-complexed peptides or the free tripeptide with added copper salts. Check the sequence and mass.
Can I request the COA before ordering?
Yes: request the in-stock batch COA.
Is GHK-Cu legal to buy in the UK?
Yes, for laboratory research. It is not a controlled substance and is not licensed as a medicine. See UK research peptide compliance.
Alphex GHK-Cu is supplied for laboratory and in-vitro research by qualified researchers only. It is not authorised for human or veterinary use.
Research use only. Alphex products are supplied exclusively for laboratory and in-vitro research by qualified researchers. They are not authorised for human or veterinary use, and nothing in this note is advice on any such use.
Published 25 February 2026. Alphex reviews research notes when the testing method, the catalogue or UK guidance changes.