Where to Buy GHK-Cu in 2026: Sizes, Purity Reports and Verification

GHK-Cu is the copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine. Listings for it routinely show two different molecular weights, so a buyer needs to know which species a CAS number, formula or mass-spectrometry report refers to. This guide covers the chemistry, the three vial sizes Pepta Labs lists, how to read the purity report, storage, and FDA status in 2026.

What Is GHK-Cu?

GHK-Cu is small by peptide standards: three residues and one metal ion. The copper is chelated by the glycine amino nitrogen, the deprotonated peptide amide nitrogen and the histidine imidazole nitrogen. That coordination gives the solid its blue to blue-violet colour and is why the complex has its own formula, CAS number and PubChem record.

Copper(II) complex or free tripeptide: why two molecular weights appear

Listings, catalogues and PubChem carry more than one number for "GHK-Cu"; the differences are not errors but different species.

The 1:1 complex weighs 61.5 g/mol more than the free tripeptide: one copper atom (63.55) is added and two hydrogens are lost when the amide and amine nitrogens deprotonate to bind the metal. PubChem also holds a record for the protonated cation (CID 71587328, 402.92). A listing quoting 340.38 g/mol or C14H24N6O4 describes copper-free GHK; one quoting 401.9 and C14H22CuN6O4 describes the copper complex, which is what Pepta Labs lists. See CAS numbers and molecular weights.

How Pepta Labs Lists GHK-Cu

Pepta Labs stocks GHK-Cu in three vial sizes, all lyophilized powder in a sealed glass vial with the reported reversed-phase HPLC purity on the product page and identity confirmed by mass spectrometry.

The label quantity is the nominal fill of the salt form of the complex; counter-ion and residual water are part of that mass, so net peptide content is a separate figure on the report, explained in our TFA vs acetate guide. The production-run report is sent by email on request, with no account or minimum order. Copper content, salt form and net peptide content appear on it.

How to Verify a GHK-Cu Listing

What an HPLC/MS report shows

A reversed-phase HPLC chromatogram shows how much of the UV-absorbing material elutes as one main peak; purity is that peak's area as a share of all peaks. Mass spectrometry shows whether the main peak has the mass expected for the stated formula. Together they answer two questions: is the material mostly one substance, and is that substance GHK-Cu?

What it does not show

• HPLC purity is relative peak area, not an absolute assay; a 99.3% figure says nothing about counter-ion or water content.
• Neither technique measures copper directly. Copper content comes from a separate method, and for GHK-Cu it is the line that confirms the complex, not the free tripeptide, was supplied.
• A report is not a sterility or endotoxin certificate, and it does not cover a vial's history after testing.

Production-run report vs lot-specific COA

Pepta Labs supplies the independent laboratory's report for the sourced production run, the synthesized batch from which the vials were filled. A lot-specific certificate of analysis is instead issued per fill lot after vialling. Both are legitimate; match the batch or lot identifier on your vial to the document and check the test date. Our COA verification guide walks through each line, and HPLC vs mass spec explains what each instrument measures.

Comparing observed mass to theoretical mass

For C14H22CuN6O4 the monoisotopic mass is 401.10 Da (copper-63), so an electrospray report should show [M+H]⁺ near m/z 402.1. Copper has two stable isotopes, 63Cu (about 69%) and 65Cu (about 31%), so a genuine GHK-Cu spectrum also shows a partner peak two mass units higher, near m/z 404.1, at close to half the height of the first. Copper-free GHK gives a single [M+H]⁺ at m/z 341.2 with no such partner. Some reports also list a 341.2 peak because the complex can partly dissociate in the ion source; check which ion the laboratory used to assign identity. An observed mass within about 0.5 Da of theory, with the isotope pair present, is consistent with the listing.

Storage and Shipping

GHK-Cu ships as a lyophilized powder at ambient temperature; the dry solid tolerates several days in transit without cold packs. On arrival, refrigerate sealed vials at 2-8 C, or place them at -20 C for long-term storage. Keep each vial sealed and dry and protect it from light. The powder should be blue to blue-violet; a white solid in a vial labelled GHK-Cu is a reason to request the report. Most orders ship the next business day with free US shipping.

US Regulatory Status in 2026

GHK-Cu is not a controlled substance; its FDA position concerns pharmacy compounding, not laboratory sale. FDA's list of bulk drug substances that may present significant safety risks (Category 2 under the section 503A and 503B interim policies), updated 22 April 2026, no longer shows GHK-Cu in the active Category 2 table. It sits under "bulk drug substances nominated but withdrawn", meaning the nomination that had placed it in Category 2 was withdrawn by the nominators. The FDA's 503A category list updated May 14, 2026 lists GHK-Cu (except for parenteral routes) under Category 1, the substances under evaluation. Neither list governs sale as a research chemical with research-use-only labelling. Status is summarised at peptide legal status 2026 and FDA Category 2 peptides 2026.

Frequently Asked Questions

Is the copper included in the quantity on the label?

Yes. The label quantity refers to the salt form of the complex, C14H22CuN6O4, in which copper is 63.55 of every 401.91 g/mol, about 15.8% by mass.

Which CAS number should a GHK-Cu listing show?

89030-95-5, the registry number for prezatide copper (copper tripeptide-1). A listing that pairs the name GHK-Cu with 340.38 g/mol is quoting the copper-free tripeptide, which has its own registry number and PubChem record (CID 73587).

Why is the powder blue?

The colour comes from copper(II) coordinated by the peptide's nitrogen donors. Free GHK is white. Colour is a quick visual check, not a substitute for the report.

Where to Buy GHK-Cu

All products are supplied for laboratory research use only and are not for human or animal use.