GHK and GHK-Cu are not two names for one substance. GHK is a free tripeptide;
GHK-Cu is that tripeptide coordinated to a copper(II) ion. They have different molecular formulas, different molecular
weights and different PubChem records, and research findings reported for one should not be attributed to the other
without checking which species the study actually used.
Product page: GHK-Cu.
The two species, side by side
| GHK (free tripeptide) | GHK-Cu (copper complex) | |
|---|---|---|
| Name | glycyl-L-histidyl-L-lysine | copper tripeptide / prezatide copper |
| Molecular formula | C14H24N6O4 | C14H23CuN6O4+ |
| Molecular weight | 340.38 g/mol | 402.92 g/mol |
| PubChem CID | 73587 | 71587328 |
The free tripeptide is the sequence Gly-His-Lys. In the copper complex, the Cu(II) ion is coordinated by the N-terminal amino nitrogen of glycine, the deprotonated amide nitrogen of the glycine–histidine peptide bond and an imidazole nitrogen of histidine, which is why the complex formula carries one copper atom and one hydrogen fewer than the free peptide.
Each identifier above was checked directly against its PubChem record. Note that PubChem also holds other
copper–GHK entries describing different charge states and salt forms; the figures quoted here are for the species
named in the column headings and should not be mixed between rows.
Why the distinction is not pedantic
The copper ion is not packaging. In the literature on this tripeptide, copper coordination is treated as central to
the chemistry being studied — the complex is what is characterised, and the free peptide and the complex are
handled as distinct entities. A molecular weight quoted for the free peptide alongside a formula that includes copper is
an internal contradiction, and it is a common one in vendor documentation.
The practical rule for research records: state which species was used, and carry the identifiers for that species
only. If a source does not make clear whether it studied GHK or GHK-Cu, that ambiguity should be recorded rather than
resolved by assumption.
What the literature describes
Maquart and colleagues reported stimulation of collagen synthesis in fibroblast cultures by the tripeptide–copper
complex. Pickart and colleagues have published reviews covering gene-expression profiling and fibroblast and extracellular-matrix research involving
this peptide. These are cell-culture and review sources; they describe experimental endpoints, not outcomes in people.
Which Medicina formulations contain GHK-Cu
GHK-Cu is supplied on its own and as one constituent of two multi-compound formulations,
GLOW and KLOW. As with any multi-constituent preparation, research on the
isolated compound does not establish findings for the finished formulation — see
GLOW vs KLOW for the composition comparison.
Research use only
Supplied strictly for in-vitro laboratory research. This page covers chemistry and identifier accuracy. It contains no
dosing, preparation, cosmetic or administration information.
References
Pickart L., Vasquez-Soltero J.M., Margolina A. (2015). Biomed Res Int, 2015:648108. PMID 26236730.
Pickart L., Margolina A. (2018). Int J Mol Sci, 19(7):1987. PMID 29986520.
PubChem. Glycyl-L-histidyl-L-lysine — Compound Summary, CID 73587. National Library of Medicine.
PubChem. Prezatide copper — Compound Summary, CID 71587328. National Library of Medicine.