GHK-Cu is one of the more thoroughly characterised peptides in the research catalogue, and one of the more frequently misdescribed. This is a plain guide to what it is, why the copper is part of the name, and what to look for on a certificate before you buy a vial of it.
What it is
GHK is a tripeptide — three amino acids, glycine, histidine and lysine, in that order. Hence the name. Written out it’s glycyl-L-histidyl-L-lysine.
The “-Cu” denotes that the peptide is complexed with copper(II). GHK binds copper ions with high affinity, and it’s this GHK–copper complex, rather than the bare tripeptide, that most of the published research concerns.
It was first described in human plasma in the 1970s by Loren Pickart, isolated during work on factors that differed between young and old serum. It occurs naturally in plasma, saliva and urine, and plasma levels have been reported to decline with age — an observation that drove much of the subsequent interest.
Why the copper matters
Copper is not an additive here. It’s structural.
The histidine imidazole nitrogen, the terminal amine and the backbone together form a coordination site that holds copper(II) tightly. The resulting complex has different physical and chemical behaviour from uncomplexed GHK — different stability, different colour, different interactions.
The visible consequence is straightforward: GHK-Cu in solution is blue. A properly complexed preparation produces a distinctly blue solution on reconstitution. This is a copper coordination effect, not a dye.
It also means “GHK” and “GHK-Cu” are not interchangeable terms, though they’re often used as though they were. Material sold as GHK-Cu should be the copper complex.
Where the research sits
The published literature on GHK and GHK-Cu is substantial and spans several decades. Work has largely centred on extracellular matrix biology and gene expression — studies in cell culture and animal models examining effects on collagen and other matrix components, and analyses of transcriptional changes across large numbers of genes.
Because copper is a cofactor for a range of enzymes, some of the interest concerns the complex as a copper delivery mechanism rather than the peptide sequence alone.
We’re deliberately not summarising outcomes here. The literature is accessible, much of it open, and a researcher choosing this compound should read the primary sources rather than a vendor’s paraphrase of them. Pickart’s review papers are a reasonable entry point into the citation network.
Handling in the lab
Storage. Lyophilized GHK-Cu is stable stored at −20°C, protected from light and moisture. Room-temperature transit does not meaningfully affect freeze-dried material, which is why it ships without cold chain.
Reconstitution. Add diluent slowly down the vial wall rather than directly onto the cake, and swirl rather than shake. Peptides are surface-active and vigorous agitation drives foaming and denaturation at the air–liquid interface.
After reconstitution. Refrigerate and treat as considerably less stable than the dry powder. Where a protocol allows, aliquot before freezing rather than repeatedly freeze-thawing a single vial.
Moisture. Lyophilized powder is hygroscopic. Let a vial reach room temperature before opening it, or condensation will form inside.
Our reconstitution calculator handles the concentration arithmetic.
What to check before buying
- A certificate for your lot number, not a representative one.
- Identity confirmed by mass spectrometry, not purity alone.
- A named testing laboratory.
- Net peptide content where it’s reported — the copper complex carries mass that isn’t peptide.
Our current lot, ML-003, was analysed by Freedom Diagnostics LLC at 99.54% purity with identity confirmed and net content of 53.65 mg against a 50 mg label. The report is downloadable by lot number.
All Molecula Labs products are supplied strictly for laboratory research use. Not for human or animal consumption. Not drugs, foods, cosmetics, supplements, or medical devices. Not evaluated by the FDA. Nothing on this page describes or recommends any use in humans or animals.