GHK-Cu: A Research Primer

GHK-Cu is a copper-binding tripeptide that occurs naturally in human blood plasma. Chemically it is the amino acid sequence glycine-histidine-lysine bound to a copper(II) ion, and it appears in the research literature under the name copper tripeptide-1. This primer covers what the molecule is, its chemistry, the research topics it shows up in, and how it is handled as a reagent. It does not cover use, because there is no use to cover here. It ships as a laboratory material.

What GHK-Cu is

GHK-Cu is a short peptide, three amino acids long, complexed with copper.

The peptide portion, GHK, is glycyl-L-histidyl-L-lysine, a tripeptide first identified in human plasma. On its own, GHK is just the three-residue chain. The "Cu" is a copper(II) ion held by the peptide. GHK binds copper with high affinity, and that bound form is what people mean when they write GHK-Cu. You will also see it called copper tripeptide-1, or simply copper peptide. Same molecule.

Because it occurs endogenously in humans, it is one of a small number of research peptides that are not purely synthetic inventions. The sequence exists in the body. What a supplier ships is the isolated, manufactured compound at reagent grade, not an extract of anything.

The chemistry

The identity data is the part that does not change between suppliers, so it is the first thing to check.

• CAS number: 89030-95-5
• Molecular formula: C14H24N6O4Cu
• Molecular weight: 401.94 g/mol
• Sequence: Gly-His-Lys (glycine, histidine, lysine)
• Also known as: copper tripeptide-1, GHK-copper

The formula includes the copper atom. That is why a molecular-weight lookup for the bare GHK peptide, with no copper, returns a lower number. If you are cross-checking a certificate, make sure you are comparing against the copper complex and not the free tripeptide. Mixing the two up is a common reason a mass-spec figure looks wrong when it is actually fine.

Copper is coordinated by the peptide through its nitrogen and oxygen atoms, largely via the histidine side chain and the peptide backbone. That copper-binding behaviour is the defining structural feature of the molecule, and the reason it gets grouped with the copper peptides rather than with plain tripeptides.

Where it appears in the research literature

GHK-Cu shows up mainly in two areas of published research: skin science and cell signalling. Both are named here as research topics, nothing more.

Both are named as fields of study, nothing more. This primer does not summarize what any of that research reported. The line between naming a research area and describing an outcome is exactly the line a primer stays behind, so if you want the actual findings, the sequence and CAS number above are what you search on.

If you are surveying the primary sources, "GHK-Cu", "copper tripeptide", and the CAS number will find the underlying papers faster than any of the trade names.

How it is supplied and handled

It is supplied as a lyophilized (freeze-dried) solid, stored cold and kept out of light.

GHK-Cu ships lyophilized. Store it at -20C and protect it from light. The copper complex has a characteristic blue colour, and light and heat are the handling variables worth controlling for a copper peptide. Kept sealed, cold, and dark, a lyophilized peptide holds up well over long periods. As with any freeze-dried peptide, there is usually a bulking agent in the vial so there is something visible to work with, and a proper certificate accounts for that filler in the mass.

That is the whole handling story: storage temperature, light protection, and an intact seal. None of this is reconstitution guidance.

How the lots are tested

Every lot is third-party tested and gets its own certificate of analysis. Purity is measured by HPLC read at 220 nm, the standard wavelength for peptide bonds, and identity is confirmed by mass spectrometry, the test that verifies the molecule matches the label instead of only measuring how clean the sample is. Lots go to independent labs like BT Labs in West Palm Beach, Florida and Krause Analytical in Austin, Texas, and the full PDF is published on each batch page.

If you have not read a peptide COA before, there is a walkthrough on [how to read one](/research/how-to-read-a-peptide-coa) using two real reports, plus a broader [checklist for sourcing research peptides in Canada](/research/buying-research-peptides-canada). Kits Peptides ships tracked from Vancouver, BC across Canada.

*All products are supplied as laboratory reagents for research use only. Not for human or veterinary use.*