GHK-Cu is a tripeptide-copper complex: glycyl-L-histidyl-L-lysine bound to a divalent copper ion. Molecular formula C14H24CuN6O4, molecular weight 403.93 g/mol. Supplied here as raw powder at 1g.
The copper is not an additive — it is the functional core of the molecule. GHK binds Cu2+ with high affinity through the histidine imidazole and the terminal amine, and it is the complex rather than the bare tripeptide that most published work concerns. This is why the powder is blue: that colour is the copper coordination itself, and it is the most immediate visual confirmation that the complex has formed correctly.
GHK was originally identified in human plasma, where its concentration declines markedly with age — an observation that prompted much of the subsequent research interest.
Research context
Published work centres on extracellular matrix biology: collagen and glycosaminoglycan synthesis, metalloproteinase and TIMP expression, and fibroblast behaviour in dermal preparations. A separate strand examines gene expression profiling, where GHK-Cu has been reported to shift transcription across a substantial number of genes in cultured cells.
Copper-dependent enzymology sits behind much of this — lysyl oxidase, which cross-links collagen and elastin, and superoxide dismutase both require copper — so the peptide is often studied as a delivery mechanism for bioavailable copper as much as a signalling molecule in its own right.
For a fuller treatment of the sequence, published models and technical data, see the GHK-Cu research guide.
Specification
CAS number 49557-75-7. Supplied as a blue powder, soluble in water. This batch assayed at 99.22% purity, verified by HPLC and LC-MS at ILS Lab.
Handling
Reconstitute with bacteriostatic or sterile water, introducing the diluent against the vial wall and swirling gently rather than shaking. A loss of blue colour indicates the copper complex has dissociated and the material should not be relied upon.
Avoid chelating agents such as EDTA in buffer preparations, which will strip the copper. Store lyophilized at −20°C protected from light; refrigerate at 2–8°C once reconstituted.
Ships with a batch-specific Certificate of Analysis. Cross-check the batch ID printed on your vial against the CoA before use — see the guide to reading a CoA if you are unfamiliar with the format.
Frequently asked questions about GHK-Cu
Why is GHK-Cu blue?
The colour is the copper coordination itself — a d-d electronic transition in the Cu2+ ion held by the peptide. It is not a dye or an additive. That makes it unusually useful as a quality check: blue means the complex has formed, and a loss of colour means the copper has dissociated and you are left with the bare tripeptide, which is a different molecule with different reported activity.
Why must EDTA and chelators be avoided?
Because they compete for the copper. EDTA binds Cu2+ with higher affinity than GHK does and will strip it out of the complex, leaving unbound GHK in solution. Since most published work concerns the copper complex rather than the free peptide, that changes what you are studying. Screen buffer components for chelating agents before preparing solutions.
Is GHK-Cu the same as GHK?
No, and the distinction matters. GHK is the bare tripeptide glycyl-histidyl-lysine; GHK-Cu is that peptide bound to copper. Much of the reported activity — particularly anything involving lysyl oxidase or superoxide dismutase, both copper-dependent enzymes — depends on the copper being present. Check which form a paper used before comparing results.
How does GHK-Cu compare with AHK-Cu?
Both are copper-binding tripeptides studied in similar dermal and matrix contexts. AHK-Cu substitutes alanine for glycine at the first position. GHK-Cu has substantially the larger literature and is the better-characterised of the two, so it is generally the appropriate reference compound.
Research use only. Not for human or veterinary use, not for use in diagnostic procedures, and not evaluated by the U.S. Food and Drug Administration.
