GHK-Cu is not a plain tripeptide — it is a copper complex, and that complexation is exactly what makes its handling and verification different from every other peptide on the shelf.
GHK-Cu is glycyl-L-histidyl-L-lysine bound to a copper(II) ion. The peptide backbone is only half the molecule; the coordinated copper is the other half, and any verification that ignores the metal is incomplete.
Why the colour is a first-pass check
Correctly complexed GHK-Cu is a distinct deep blue. Pale, patchy or off-white powder suggests incomplete complexation or copper loss. Colour is not a substitute for analytics, but it is the fastest disqualifying check available at the bench.
What a GHK-Cu certificate must include
- HPLC purity of the GHK tripeptide backbone
- LC-MS identity confirmation of the peptide sequence
- Copper content by mass, confirming the complexation ratio
- Water content, since the complex is hygroscopic
- Lot number and synthesis date tied to the production run
Stability and storage notes
- Store lyophilised, sealed and light-protected — the complex is photosensitive.
- Reconstituted solution has a shorter working window than plain peptides.
- Avoid chelating buffers, which strip copper from the complex.
GHK-Cu FAQ
Is GHK-Cu the same as GHK?
No. GHK is the uncomplexed tripeptide; GHK-Cu is the copper(II) complex, and the two behave differently in research settings.
Why is copper content reported separately?
Because peptide purity alone cannot confirm the complexation ratio. Both figures are needed to characterise the material.
