GHK-Cu: Chemistry, Structure, and Stability Considerations for Laboratory Research
GHK-Cu is the copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine (Gly-His-Lys, or GHK). As supplied for laboratory research, it is typically provided as a lyophilized powder with the peptide sequence already coordinated to a copper ion, which distinguishes it analytically from the uncomplexed GHK tripeptide.
This article covers the chemistry, structure, and laboratory handling of GHK-Cu. It is written for laboratory, in-vitro, and analytical research audiences and is not a guide to product use, administration, or human or animal consumption.
Chemical Identity
GHK-Cu has the molecular formula C28H46CuN12O8 and a molecular weight of approximately 405.00 g/mol as the copper complex, with CAS number 49557-75-7 (PubChem CID 9831891). It is typically supplied as a solid, blue powder — the blue color is itself a visual indicator of copper(II) coordination, since copper(II) ions and many of their complexes absorb light in the visible range.
Copper Coordination Chemistry
The GHK sequence chelates copper(II) through a combination of donor atoms: the free alpha-amino group of the N-terminal glycine, the imidazole nitrogen of the histidine side chain, and a deprotonated backbone amide nitrogen. Together these form a stable, roughly square-planar coordination geometry around the copper ion. This coordination chemistry is why GHK-Cu behaves differently in analytical assays than the uncomplexed tripeptide — for example, in UV-Vis spectroscopy, where the copper complex shows characteristic absorbance bands that metal-free GHK does not.
Stability and Degradation Considerations
As with other lyophilized peptides, GHK-Cu is sensitive to moisture, heat, and light. Hygroscopic uptake of atmospheric moisture can promote hydrolysis of the peptide backbone over time, while the copper center introduces an additional degradation pathway: copper(II) can participate in redox chemistry, and prolonged light exposure or the presence of reducing agents can shift the copper between oxidation states, potentially altering the compound’s coordination structure and its analytical signature. For these reasons, GHK-Cu should be stored sealed, at or below 25°C, and protected from light and moisture until it is prepared for a specific laboratory workflow.
Analytical Characterization
Identity and purity verification for GHK-Cu follow the same general analytical approach described in our guide to reading a Certificate of Analysis: HPLC to assess purity by peak-area percentage, and mass spectrometry to confirm the observed molecular weight against the expected value for the copper complex. Because GHK-Cu contains a metal center, some laboratories supplement these methods with techniques such as inductively coupled plasma mass spectrometry (ICP-MS) or atomic absorption spectroscopy to independently verify copper content and confirm the stoichiometry of the complex.
Research Use Only
GHK-Cu is sold strictly for laboratory, in-vitro, and other non-clinical research applications. It is not a drug, dietary supplement, or cosmetic, and is not intended for human or animal use, consumption, or administration in any form. Nothing in this article should be interpreted as instructions for personal use.
