GHK-Cu Copper Peptide: A Research Reference

GHK-Cu is a naturally occurring copper–peptide complex. It consists of a short tripeptide — glycyl-L-histidyl-L-lysine, abbreviated GHK — bound to a single copper(II) ion. The complex is often referred to in the research literature as a copper peptide or copper tripeptide, and it appears under several spelling variants, including GHK-Cu, GHK copper peptide, and GHK copper tripeptide. The “Cu” (the chemical symbol for copper) denotes the metal ion that distinguishes the metallated complex from the metal-free GHK tripeptide.

This page is a non-promotional scientific reference for researchers. It summarises the chemical identity, molecular information, copper– peptide chemistry, and analytical identification of GHK-Cu, together with the terminology and documentation encountered when working with it in a laboratory. It does not discuss cosmetic, therapeutic, or human-use applications of any kind.

Chemical Identity and Amino Acid Sequence

The peptide component of GHK-Cu is the tripeptide glycyl-L-histidyl-L-lysine. In single-letter amino acid notation this sequence is written GHK, corresponding to glycine (G), histidine (H), and lysine (K). The sequence defines the molecule: the three residues are joined by two peptide bonds, and the order in which they appear is fixed.

In the copper complex, the histidine residue plays a central role in binding the metal ion. The imidazole side chain of histidine, together with the terminal amino group and backbone peptide nitrogen atoms, provides the coordination sites that hold the copper(II) ion in place. This is what makes GHK-Cu a copper peptide rather than a simple mixture of GHK and a copper salt.

Molecular Information

Several molecular properties are used to identify GHK-Cu in analytical documentation:

• Molecular formula: the copper complex has a well-defined stoichiometry of one copper ion per GHK molecule, so its formula is stated as a 1:1 complex of GHK and Cu(II).
• Molecular mass: the free tripeptide GHK has a nominal molecular weight of approximately 340 Da; the copper complex adds the atomic mass of one copper atom (approximately 63.5 Da). The exact value reported on a Certificate of Analysis should be checked against the analytical method used.
• Copper stoichiometry: the 1:1 peptide-to-copper ratio is a defining feature of the complex and is confirmed by elemental or mass-spectrometric analysis.

Because the presence of copper shifts the measured mass, mass spectrometry is a useful technique for distinguishing the copper complex from the metal-free tripeptide.

Copper–Peptide Chemistry

Copper–peptide complexes such as GHK-Cu are studied in chemistry for their coordination behaviour. A peptide that contains histidine can bind copper through its nitrogen donor atoms, forming a stable chelate. This chelation changes the spectroscopic and electrochemical properties of both the peptide and the metal.[1]

Relevant aspects of the chemistry include:

• Chelation: the metal ion is held by multiple donor atoms from the peptide, forming a ring structure rather than a single bond.
• Oxidation state: GHK-Cu normally contains copper in the +2 oxidation state, which is more stable in aqueous solution than uncomplexed copper(I).
• Solution behaviour: the complex is water-soluble and coloured (a pale blue solution), whereas the free tripeptide is colourless — a simple visual observation that can indicate complex formation.

This chemistry is a laboratory research topic; it is distinct from any claim about biological effect or therapeutic use, which is outside the scope of this reference.

Analytical Identification and Documentation

In a research supply context, GHK-Cu is characterised with the same analytical techniques used for other peptides:

• HPLC: high-performance liquid chromatography is used to estimate purity by separating the main component from impurities and reporting a percentage of total peak area.
• Mass spectrometry: confirms identity by measuring the molecular mass and comparing it with the theoretical mass of the copper complex.
• Copper confirmation: the metallated nature of the product may be confirmed by elemental analysis or by the mass shift observed relative to the free peptide.

For guidance on interpreting the resulting documents, see how to read a peptide Certificate of Analysis. Batch documentation, when available, links the analytical results to a specific production batch.

Common Research Terminology

Several terms recur in the research literature and vary in spelling or abbreviation. They all refer to the same copper–peptide complex:

• GHK-Cu (and the variant GHK-CU)
• GHK copper peptide
• Copper tripeptide
• Glycyl-histidyl-lysine copper

These are semantic variations of the same chemical entity, not distinct compounds. The research peptide glossary covers related terminology across the catalogue.

References

• [1] Pickart, L. (2008). The human tri-peptide GHK and tissue remodeling. Journal of Biomaterials Science, Polymer Edition, 19(8), 969–988. DOI 10.1163/156856208784909435.
• [2] Trapaidze, A., Hureau, C., Bal, W., Winterhalter, M., & Faller, P. (2012). Thermodynamic study of Cu²⁺ binding to the DAHK and GHK peptides by isothermal titration calorimetry (ITC) with the weaker competitor glycine. Journal of Biological Inorganic Chemistry, 17(1), 37–47. DOI 10.1007/s00775-011-0824-5.

Related Research Resources

• Peptide Mass Spectrometry Testing — how molecular identity is confirmed analytically.
• Reading a Peptide Certificate of Analysis — interpreting purity and identity data.

Related Analytical Documentation

The literature below describes the chemistry of GHK-Cu; it is distinct from the batch-specific testing performed on any supplied material. To review how documentation is organised and verified, see the Certificate of Analysis library, the batch verification tool, and the testing and quality process.