What is the CAS number for GHK-Cu?

89030-95-5, corresponding to PubChem CID 71587328 at 402.92 Da. Free GHK is CAS 49557-75-7.

How can I check copper is actually present?

The complex is blue, and on a mass spectrum copper's two stable isotopes produce a characteristic doublet the free peptide cannot show.

Why do sources give different molecular weights?

PubChem indexes several copper-bound species at different charge states and stoichiometries. 402.92 corresponds to the CAS-registered 1:1 complex.

GHK-Cu CAS Number and Chemical Identity

The short answer

GHK-Cu carries CAS Registry Number 89030-95-5 and PubChem CID 71587328. Free GHK is a separate entity with CAS 49557-75-7 and CID 73587. Because both are described as GHK in practice, comparing identifiers rather than names is the only reliable check.

Key facts

GHK-Cu CAS: 89030-95-5
GHK-Cu PubChem CID: 71587328
Free GHK CAS: 49557-75-7
Free GHK PubChem CID: 73587
INCI name: Copper tripeptide-1
Other names: Prezatide; liver cell growth factor

Two compounds, two identifier sets

This is the category's central practical point. GHK and GHK-Cu have separate CAS numbers and separate PubChem records because they are separate chemical entities. Material described only as GHK could be either, and the difference is 62.54 Da, enough to shift any molarity calculation by roughly 15%.

Why more than one GHK-Cu record exists

PubChem indexes several copper-bound species at different charge states and stoichiometries. CAS 89030-95-5 corresponds to CID 71587328 at 402.92 Da, which is the 1:1 complex most material is described as. Others exist at 400.90 and 742.3. This is why published molecular weights disagree, and it is a database indexing artefact rather than a dispute about chemistry.

Research material referenced

GHK-Cu 100mg, third-party HPLC tested

Buy GHK-Cu · £24.99

Confirming identity

Mass spectrometry against the theoretical mass for whichever species is claimed. The peptide contains no methionine and no cysteine, so the +16 Da oxidation satellite common on many peptide spectra should not appear. For the complex, the copper isotope pattern is itself informative: copper has two stable isotopes in roughly a 69:31 ratio, producing a characteristic doublet that free GHK cannot show.

The colour check

Before any instrument, look at it. Copper(II) complexes are blue. Material sold as GHK-Cu that is white or colourless is either free peptide or something has gone wrong, and that is a check anyone can perform on arrival.

Confirming purity

Reverse-phase HPLC against truncated and deletion sequences. Three residues is about as short as a peptide synthesis gets, so purity is typically high and a low figure warrants explanation. Note that a metal complex can behave differently on reverse-phase columns from the free peptide, so a method validated for one is not automatically valid for the other.

Frequently asked questions

What is the CAS number for GHK-Cu?: 89030-95-5, corresponding to PubChem CID 71587328 at 402.92 Da. Free GHK is CAS 49557-75-7.
How can I check copper is actually present?: The complex is blue, and on a mass spectrum copper's two stable isotopes produce a characteristic doublet the free peptide cannot show.
Why do sources give different molecular weights?: PubChem indexes several copper-bound species at different charge states and stoichiometries. 402.92 corresponds to the CAS-registered 1:1 complex.

Extended research context

The GHK-Cu (Copper Peptide) deep dive

Deep dive: why the copper ion matters

The GHK tripeptide (Gly-His-Lys) coordinates a Cu²⁺ ion through the imidazole nitrogen of histidine, the terminal α-amino group of glycine, and a deprotonated peptide-bond nitrogen. This near-square-planar geometry is what gives the complex its characteristic deep-blue colour and its redox-modulating chemistry. Uncomplexed GHK is a different molecule pharmacologically. Nearly every peer-reviewed study attributes activity to the copper-bound form, which is why suppliers ship the pre-complexed GHK-Cu rather than plain GHK.

GHK-Cu in the transcriptomic literature

The most-cited modern papers on GHK-Cu come from the Pickart & Margolina group and independent transcriptomic re-analyses. GHK-Cu has been reported to modulate expression of >4,000 human genes at nanomolar concentrations in Broad Institute Connectivity Map re-analyses, including genes involved in DNA repair, antioxidant defence, and ECM remodelling. This gene-signature-level activity is the reason GHK-Cu appears in so many research reviews outside of dermatology.

Analytical fingerprinting of GHK-Cu

On reverse-phase HPLC, GHK-Cu elutes as a well-defined peak; free GHK and copper-free peptide impurities are distinguishable. UV-Vis at ~520 nm confirms the copper d-d transition band. Reputable suppliers publish both HPLC (≥98% area) and mass-spec identity (~340 Da complex, 340.4 free peptide) on the batch CoA.

Research applications

▸In vitro fibroblast and keratinocyte gene-expression studies
▸ECM turnover assays (collagen, elastin, decorin, MMP profiling)
▸Wound-healing scratch assays in cell culture models
▸Antioxidant-mechanism studies (copper redox modulation)
▸Formulation R&D: cosmetic and topical carrier compatibility research

Handling checklist

✓Store lyophilised vial at 2–8 °C, protected from light
✓Reconstitute with bacteriostatic or sterile water; expect a blue-tinted solution
✓Avoid contact with reducing agents (ascorbic acid destabilises Cu²⁺)
✓Aliquot reconstituted solution for freeze/thaw minimisation
✓Verify blue colour and CoA HPLC ≥98% before use

Common research-handling mistakes

Learnt from thousands of researcher orders across our UK labs.

✗ Buying GHK without copper

Fix: Confirm the CoA reads GHK-Cu (copper-bound); free GHK is a different pharmacology.

✗ Mixing with vitamin C in solution

Fix: Ascorbate reduces Cu²⁺ to Cu⁺ and destabilises the complex, keep them separate.

✗ Exposing to sunlight

Fix: Store in amber vial or foil-wrapped container at 2–8 °C.

Continue researching

Peer-reviewed guides, comparators and matched reference materials.

Primary sources & clinical trials

Peer-reviewed research and registered trials from PubMed, ClinicalTrials.gov, PubChem, FDA and NIH. All links open in a new tab and point to the primary source, so every claim can be verified at origin.

UKP

Written and reviewed by

The UK Peptides Editorial Team · Research library, UK Peptides

The editorial team is responsible for supplier selection, batch release decisions and the content published in this research library. Every article here is sourced to primary literature and every product page to a signed third-party certificate. Corrections are made in place and the review date updated.

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