GHK-Cu

Research summary

GHK-Cu is the copper(II) complex of GHK (glycyl-L-histidyl-L-lysine), a three-amino-acid peptide first isolated from human plasma by Loren Pickart in the 1970s. It is one of the most-studied peptides in skin-matrix research: cell-culture and rodent studies have measured its effects on collagen and glycosaminoglycan synthesis, matrix metalloproteinases and gene expression, while controlled clinical evidence remains sparse. Peptides Only supplies GHK-Cu as a lyophilized compound for laboratory research only.

Also known as

GHK-Cu copper peptide · Glycyl-L-histidyl-L-lysine copper(II) · Copper tripeptide-1 · GHK copper complex

Sequence

Gly-His-Lys (copper(II) complex)

What is GHK-Cu?

GHK (Gly-His-Lys) was first reported in 1973 as a factor in human serum that prolonged the survival of normal liver cells and stimulated the growth of neoplastic liver cells¹. In 1980 Pickart's group found that the tripeptide co-isolates with roughly equimolar copper, readily forms a complex with copper(II) and increases copper uptake into cultured hepatoma cells. They noted its resemblance to the copper-transport site of albumin, where copper binds a histidine next to a basic residue². That copper complex, GHK-Cu, is the form most later studies used.

GHK is present in human plasma, saliva and urine, and Pickart's group reports that plasma levels decline with age³. A Gly-His-Lys triplet also occurs within the alpha-2 chain of type I collagen, which led researchers to propose that the tripeptide may be released by proteases at sites of tissue injury⁴.

Collagen and skin-matrix research

The work that made GHK-Cu a skin-matrix compound began in fibroblast cultures. Maquart and colleagues reported in 1988 that GHK-Cu stimulated collagen synthesis starting at picomolar concentrations and peaking near one nanomolar, without any change in cell number⁴.

The same group then moved to rats, using implanted wire-mesh wound chambers. Chambers that received GHK-Cu accumulated more dry weight, DNA, total protein, collagen and glycosaminoglycans than saline controls, in a concentration-dependent pattern. Type I and type III collagen mRNAs rose while TGF-beta mRNA did not, and a control tripeptide had no significant effect⁵.

Later work in the same model looked at matrix breakdown as well as synthesis. GHK-Cu raised pro- and active matrix metalloproteinase-2 (MMP-2) in the later stages of repair and prolonged MMP-9 expression in wound tissue, which the authors concluded might significantly alter wound remodeling⁶.

Gene-expression, lung and ligament studies

In 2012 a Boston University team profiled lung tissue from smokers with COPD and searched the Connectivity Map, a database of compound-induced gene-expression profiles, for molecules that oppose the emphysema-severity signature. GHK was one of them, and in cultured lung fibroblasts from COPD patients it restored collagen I gel contraction and remodeling⁷. This is a computational and cell-culture finding, not a clinical one.

Outside the skin, a randomized rat study of anterior cruciate ligament reconstruction found a smaller side-to-side difference in knee laxity and, in one group, higher graft stiffness with GHK-Cu at 6 weeks, but no differences at 12 weeks and none in ultimate load, gait or histology, so the effect was transient⁸.

Topical penetration has also been measured directly. In diffusion cells mounted with human skin, copper applied as GHK-Cu crossed dermatomed skin and part of it was retained in the tissue as a depot⁹. Studies like this show where the copper goes; they do not measure biological effects.

Limitations of the evidence

• Most data come from cell culture and rodents. Concentrations that act on fibroblasts in a dish do not translate directly to tissue or whole-animal exposure.
• Many of the most-cited reviews are written by Pickart and colleagues at Skin Biology's research and development department^3,10, so independent replication matters when weighing the broader claims made for GHK.
• A 2026 systematic evidence-mapping review found that preclinical data consistently support effects on matrix remodeling, epithelial repair, inflammatory and redox signaling and angiogenesis, but that clinical evidence is sparse: historical cosmetic reports were small or incompletely characterized, and a 13-participant study after CO2 laser resurfacing was negative on objective endpoints¹¹.
• The same review notes that papers often handle GHK-Cu as a single substance even though copper occupancy, free copper and stability vary with formulation, which makes results hard to compare¹¹.

Stability and handling in the lab

GHK-Cu is highly hydrophilic. In a preformulation study it was vulnerable to hydrolytic cleavage under basic and oxidative stress and, to a lesser extent, under acid; histidine was one of three degradation products identified. In water and in pH 4.5 to 7.4 buffers, however, it remained stable for at least two weeks at 60 °C¹². General guidance for lyophilized material is in our article on peptide storage and stability.

Sourcing GHK-Cu for research

Peptides Only supplies GHK-Cu as a lyophilized powder for laboratory research. Every lot ships from the USA with a lot-matched certificate of analysis from an independent laboratory, reporting HPLC purity and mass-spectrometry identity, and the certificates are published in our COA library. GHK-Cu is also a component of GLOW Blend and KLOW Blend; how those blends differ is set out in GLOW vs KLOW vs Wolverine.

Further reading

• GLOW vs KLOW vs Wolverine: What Is in Each Peptide Blend and What the Research Shows
• How to Choose a Research Peptide Supplier: A Vetting Checklist
• Peptide Sciences Closed: How to Vet a Replacement Research Peptide Supplier