What is GHK-Cu (Copper Peptide)?
GHK-Cu is a metal-peptide coordination complex classified as a copper(II)-binding tripeptide. The organic ligand is the sequence glycyl-L-histidyl-L-lysine (Gly-His-Lys), a three-residue peptide comprising glycine, L-histidine, and L-lysine. In the complex, a divalent copper ion (Cu2+) is chelated by donor atoms contributed by the peptide backbone and side chains. The material carries CAS registry number 89030-95-5, the molecular formula C14H22CuN6O4, and a molecular weight of approximately 403.93 for the copper(II) complex.
Structurally, the tripeptide provides a well-defined coordination environment for the copper center. The N-terminal glycine amine, the deprotonated peptide amide nitrogen, and the imidazole nitrogen of the histidine residue are the principal donor atoms typically associated with copper binding in this class of Gly-His-Lys complexes, while the lysine side chain contributes a free primary amine that influences the overall charge and solubility profile of the molecule. This defined stoichiometry and geometry distinguish the copper complex from the free (apo) peptide and are reflected in its distinct spectroscopic signature.
In the scientific literature, GHK-Cu is studied as a model copper-transport and copper-binding peptide, and it appears in in-vitro investigations within skin-biology, extracellular-matrix, and tissue-culture research contexts. This reference page describes the identity and physicochemical characteristics of the material only. GHK-Cu (Copper Peptide) is offered strictly as a research chemical for laboratory use; it is not a drug, cosmetic, or dietary product, and no physiological or therapeutic properties are described or implied.
Reconstitution & handling
GHK-Cu is typically supplied as a lyophilized (freeze-dried) solid, characteristically blue owing to the copper(II) center, and is reconstituted immediately prior to laboratory use. Bacteriostatic or sterile water is the most common solvent for preparing aqueous stock solutions; the small, polar tripeptide framework and the ionic copper center generally confer good aqueous solubility. To dissolve the powder, the chosen diluent is directed slowly down the inner wall of the vial rather than injected forcefully onto the pellet, and the vial is left to stand and then swirled gently until a clear, faintly blue solution forms. Vortexing, sonication, or vigorous shaking is generally avoided because mechanical shear and foaming can stress peptide bonds and the metal-ligand coordination.
Handling should minimize exposure to strong acids, strong bases, and reducing agents, since extremes of pH and redox-active species can perturb the copper(II) coordination sphere or promote dissociation of the complex. Preparation on a clean bench with calibrated pipettes, and buffering near neutral pH where an experimental protocol requires it, help preserve the integrity of the complex. Any reconstitution volumes and concentrations are determined solely by the researcher's own validated experimental design.
Storage & stability
Lyophilized GHK-Cu is stable for extended periods when stored sealed, protected from light and moisture, at -20 C; brief excursions to standard freezer or refrigerator temperatures during handling are generally tolerated for a well-desiccated solid. Once reconstituted, the material is best kept refrigerated at 2-8 C for near-term use and aliquoted to limit repeated freeze-thaw cycles, which can degrade peptides and disturb metal-ligand equilibria. For longer-term storage of solutions, aliquots may be held frozen at -20 C or below. As a copper complex, the material benefits from protection from prolonged light exposure and from oxidizing or reducing conditions; a persistent, uniform blue color and the absence of visible precipitate are informal indicators consistent with an intact preparation.
How it's tested
Identity and purity of GHK-Cu are established analytically and documented on a Certificate of Analysis (COA) available for the material. Chromatographic purity is assessed by reversed-phase high-performance liquid chromatography (HPLC), which resolves the target complex from process-related impurities and reports a purity specification of >=99%. Mass spectrometry (MS), commonly electrospray-ionization MS, is used to confirm molecular identity by verifying the observed mass against the expected value for the C14H22CuN6O4 copper(II) complex, and the characteristic copper isotope pattern provides additional confirmation of metal incorporation. Complementary checks such as appearance, spectroscopic examination of the copper center, and moisture or counterion determination may accompany the COA to give a complete analytical profile for each lot.