Last reviewed: October 2026 · Cleared Peptides research team
GHK-Cu is the copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine (GHK). First isolated from human plasma by Loren Pickart in 1973, it is one of the most extensively studied copper-binding peptides and a reference compound in extracellular-matrix and cosmetic-science research.
In this guide:
GHK-Cu Structure and Identifiers
| Name | GHK-Cu |
|---|---|
| Synonyms | Copper tripeptide-1; glycyl-L-histidyl-L-lysine copper(II) |
| CAS number | 89030-95-5 |
| PubChem CID | 71587328 |
| Molecular formula | C14H22CuN6O4 |
| Molecular weight | ≈401.9 g/mol |
| Sequence | Gly-His-Lys · Cu(II) |
| Appearance | Blue to violet powder |
How GHK Binds Copper
GHK binds Cu(II) with high affinity through the α-amino group of glycine, the deprotonated amide nitrogen of the Gly–His bond and the imidazole nitrogen of histidine, forming a stable square-planar-type complex. The blue colour of GHK-Cu powder and solutions comes from this copper complex. Because the free tripeptide (GHK) is also available, researchers can separate peptide effects from copper effects.
Published In-Vitro Research Areas
- Collagen and glycosaminoglycan synthesis in fibroblast cultures
- Matrix metalloproteinase and TIMP expression studies
- Gene-expression profiling (GHK appears in Connectivity Map analyses)
- Copper transport and antioxidant-enzyme research
- Cosmetic-science formulation and stability work
This summary describes laboratory research only and makes no claim about effects in humans or animals.
GHK-Cu Research Formats
Cleared Peptides supplies GHK-Cu vials, GHK-Cu raw powder (1 g), a pre-mixed GHK-Cu research pouch, the analog AHK-Cu, and the GLOW and KLOW blends. Lot COAs are on our COA page.
Research materials referenced in this guide
Frequently Asked Questions
What is GHK-Cu?
GHK-Cu is the copper(II) complex of the tripeptide Gly-His-Lys (CAS 89030-95-5), used as a reference compound in copper-peptide research.
What is the difference between GHK and GHK-Cu?
GHK is the free tripeptide; GHK-Cu is the same peptide bound to a copper(II) ion.
What is the difference between GHK-Cu and AHK-Cu?
AHK-Cu replaces glycine with alanine (Ala-His-Lys · Cu). Both are studied as copper tripeptides.
Is GHK-Cu for human use?
No. Cleared Peptides supplies GHK-Cu for laboratory research use only.
Selected References
Peer-reviewed literature on the compounds discussed in this guide, listed as scientific background for laboratory researchers. Citation does not imply endorsement by the authors or any use other than in-vitro research.
- Mehr A, et al. The copper(II)-binding tripeptide GHK, a valuable crystallization and phasing tag for macromolecular crystallography. Acta Crystallogr D Struct Biol. 2020;76(Pt 12):1222-1232. PubMed 33263328 · DOI
- Hureau C, et al. X-ray and solution structures of Cu(II) GHK and Cu(II) DAHK complexes: influence on their redox properties. Chemistry. 2011;17(36):10151-60. PubMed 21780203 · DOI
Laboratory note: solubility depends on salt form and solvent. This guide does not state a single solubility figure. Handling of lyophilized material is described in the peptide storage guide.
Research Use Only Notice
This guide is provided for educational and laboratory reference purposes. It summarizes published, primarily in-vitro and structural research literature and does not describe, recommend or imply any use in humans or animals. Products sold by Cleared Peptides are for laboratory research use only; they are not drugs, foods, cosmetics or dietary supplements, are not FDA-approved, and are not intended to diagnose, treat, cure, mitigate or prevent any disease. No dosing, administration or therapeutic information is provided.
