GHK-Cu in Canada: What the Copper Complex Changes on a Certificate

GHK-Cu is one of the few compounds in a peptide catalogue that arrives with two chemical identities attached to it, and almost every question we get about it comes from that fact. A certificate may report a mass near 340. Another may report a mass near 403. A supplier listing may call it GHK, copper peptide, copper tripeptide-1, or GHK-Cu, and all four are referring to material that started life as the same three amino acids. This article sets out what each of those names refers to, what a certificate of analysis for this compound actually establishes, and how to compare two documents for the same material without ending up comparing the wrong numbers.

Two identities for one tripeptide

Why there are two formulas and two CAS numbers

GHK is a tripeptide: glycine, histidine, lysine. On its own it is a small, unremarkable white peptide with a mass of about 340. The copper complex is that tripeptide coordinated to a copper(II) ion, and the coordination is the reason the material is blue rather than white. Adding copper adds roughly 62 g/mol to the mass, which is where 402.92 comes from. The two CAS numbers exist because the registry treats the free peptide and the copper complex as different substances, and because the cosmetic ingredient literature adopted the name copper tripeptide-1 for the complex while the biochemical literature mostly stayed with GHK-Cu.

None of that is a quality distinction. It is a labelling distinction, and it only causes trouble when two documents describing the same vial report against different conventions. If you are reconciling a certificate against a reference value, the first thing to establish is which of the two the document is reporting.

What a certificate for GHK-Cu establishes

A purity figure on an HPLC chromatogram is a statement about the peptide portion. It tells you what proportion of the peptide-containing material in the sample is the target sequence, and it is sensitive to truncated sequences, deletion sequences, and residual synthesis reagents. What it does not tell you, on its own, is anything about the copper. Copper content is established by a separate determination, and a certificate that reports peptide purity without addressing copper has characterized part of the material rather than all of it.

This matters more for GHK-Cu than for most compounds in a catalogue, because the copper is not an impurity to be minimized. It is part of what the material is supposed to be. A vial that assays well on peptide purity but is short on copper is not a pure sample of GHK-Cu; it is a good sample of GHK with a problem. Reading the two determinations as if they were one number is the most common error we see in comparisons.

Appearance is a useful secondary check here in a way it is not for white lyophilized peptides. The copper complex is blue. The depth and evenness of that colour is not a quantitative measurement and should not be treated as one, but a vial of GHK-Cu that reconstitutes colourless is telling you something worth investigating before you run anything on it.

Matching a vial to its certificate

Where a batch has been tested and the result published, it appears on the certificates of analysis page. Two things are worth knowing about how to use that page. A document belongs to a batch rather than to a product line, so the way to find the right one is by the cap colour and the crimp colour on the vial in front of you, not by the compound name. And coverage is deliberately not universal: not every product and not every batch has a published certificate. Where testing has been done it is by HPLC together with purity testing. The purity guarantee is the page that states the commitments and, just as usefully, the claims we decline to make.

Vial sizes and where GHK-Cu appears in the catalogue

GHK-Cu is stocked in two sizes in Canada, 50 mg and 100 mg. The two are the same compound; the difference is the quantity in the vial and the resulting cost per milligram, which is worth checking against the price index if quantity rather than compound is the variable in your planning. The 100 mg presentation is the larger of the two and is generally the one worth comparing when a protocol calls for repeated preparation from a single batch, since a single batch means a single certificate.

GHK-Cu also appears as a component of two multi-peptide blends we supply. GLOW 70mg contains BPC-157 10 mg, TB-500 10 mg and GHK-Cu 50 mg. KLOW 80mg contains the same three plus KPV 10 mg. If your comparison is between a single-compound vial and a blend, note that the blend is characterized as a blend, and the per-component documentation question is different from the single-vial case. The full range sits under copper peptides, and the blends under multi-peptide blends.

What to check first

GHK, copper peptide, copper tripeptide-1 and GHK-Cu are names that converge on the same three residues; the difference between 340 and 403 is a copper ion, and the difference between the two CAS numbers is which of those two things the registry is naming. A certificate tells you about peptide purity by HPLC. Copper content is a separate determination. Reconcile the convention before reconciling the numbers, and check the cap and crimp colours before assuming a document belongs to the vial in front of you.

All compounds referenced here are supplied by ExoLabz for laboratory research use only. They are not for human or veterinary use, are not authorised by Health Canada as a drug or natural health product, and nothing on this page is guidance on preparation, administration or use.