GHK-Cu

GHK-Cu is the copper(II) complex of GHK (glycyl-histidyl-lysine), a tripeptide found in human plasma. It is widely used as a cosmetic ingredient and studied in cell, animal and small human skin studies.

Last reviewed 2026-10-25 by the PeptideWiki editorial team. Editorial policy.

Overview

GHK is a tripeptide, glycyl-L-histidyl-L-lysine, first identified in human plasma in the 1970s during research on factors that affected liver cell behavior. It binds copper(II) ions with high affinity, and its copper complex is known as GHK-Cu. Plasma GHK levels have been reported to be lower in older individuals than in younger ones, which contributed to interest in the peptide in skin and aging research.

GHK-Cu is best known today as a cosmetic ingredient, listed under the INCI name copper tripeptide-1. The research literature includes cell studies on fibroblasts and keratinocytes, animal wound-healing studies, gene-expression analyses, and small human studies of topical cosmetic formulations. Much of the broad gene-expression literature comes from a limited number of authors, and controlled human data remain modest in size and mostly cosmetic in scope.

Compare: GHK vs GHK-Cu.

Structure

GHK is the tripeptide Gly-His-Lys with a free N-terminal amine and a free C-terminal carboxylic acid. It binds Cu(II) through the N-terminal amine, the glycine-histidine amide nitrogen and the histidine imidazole nitrogen, with additional coordination possible from the lysine or neighboring ligands. Depending on conditions, 1:1 and 2:1 peptide-to-copper species can form, which is why copper stoichiometry is an analytical concern. GHK-Cu is typically supplied as a blue to violet powder, often as an acetate or chloride salt, and the copper-free peptide GHK is also available as a distinct material.

Mechanism

Proposed mechanisms are based mainly on cell and animal studies. GHK-Cu has been reported to stimulate collagen and glycosaminoglycan synthesis in fibroblasts, influence matrix metalloproteinases and their inhibitors, and affect angiogenesis and inflammatory signaling in wound models. Copper delivery is considered central to some effects, since copper is a cofactor for enzymes such as lysyl oxidase, involved in collagen cross-linking. Gene-expression connectivity analyses have suggested that GHK alters expression of many genes, but these are associative and have not been translated into an established mechanism in people.

Research

Skin and cosmetic studies

GHK-Cu has been studied in topical cosmetic formulations, with small human studies reporting changes in measures such as skin thickness, firmness and the appearance of fine lines. These studies are usually short, small, and sponsored or designed in a cosmetic context, and they assess appearance-related endpoints rather than disease outcomes. They are consistent with in-vitro findings on fibroblast collagen production but do not establish medical effects.

Wound-healing models

Animal studies in rodents and other species have examined GHK-Cu in experimental wounds, reporting effects on contraction, granulation tissue, angiogenesis and collagen deposition. Some work has incorporated the complex into dressings, gels or biomaterials. These findings are preclinical, and controlled human trials in wound healing are limited, so clinical relevance remains uncertain. Study designs, copper ratios and formulations vary considerably, which makes it difficult to compare findings or to identify consistent effect sizes across the animal literature.

Hair follicle research

GHK-Cu and related copper peptides have been examined in hair follicle cell culture and animal models, with some reports of effects on follicle size or dermal papilla cell activity. The quality and quantity of evidence are limited, and human data are sparse. This area should be regarded as exploratory. Many reports involve small numbers of animals or samples, use different formulations, and lack independent replication, so no conclusions about effects in people can be drawn from them.

GHK versus GHK-Cu

Studies differ in whether they use copper-free GHK or the preformed copper complex, and in the peptide-to-copper ratio. Because free GHK can pick up copper from culture media or tissue, the distinction is not always clean experimentally. Readers comparing results should check which form was used, at what copper ratio, and whether copper alone was tested as a control. Copper-only controls matter.

Regulatory status

GHK-Cu is not approved by the FDA as a drug for any use. It is used as an ingredient in cosmetic products under the INCI name copper tripeptide-1, where it is regulated as a cosmetic ingredient rather than a drug; drug-like claims are not permitted for cosmetics. Its compounding status should be checked against current FDA lists. For sport, check the current WADA Prohibited List.

Status changes often. See the regulatory tracker for dated updates.

Quality and identity testing

A good certificate of analysis should distinguish GHK from GHK-Cu and quantify both components. Identity of the peptide should be confirmed by mass spectrometry, with the expected mass shown on this page; note that the copper complex may partly dissociate under electrospray conditions, so spectra can show free GHK alongside copper-bound species. HPLC purity of the peptide should be reported. Copper content should be measured independently, for example by ICP-MS, ICP-OES or atomic absorption, and expressed as a percentage or molar ratio, since an excess of free copper or a 2:1 complex changes the material's behavior. The counter-ion, water content and net peptide content should also be stated.

Open GHK-Cu in the sequence analyzer to see the expected [M+H]⁺ and multiply charged ions for an MS identity check.

For a walkthrough of each section of a certificate, see how to read a COA.

Storage and stability

Store lyophilized GHK-Cu sealed at -20 °C, protected from light and moisture; the powder can be hygroscopic. Equilibrate vials to room temperature before opening. In solution, the copper complex can be affected by pH, strong chelators such as EDTA, and reducing agents that can change the copper oxidation state, so choose buffers with care. Keep solutions refrigerated for short-term lab use, aliquot for frozen storage, and avoid repeated freeze-thaw cycles. A color change from blue may signal changes in copper coordination.

Download the GHK-Cu data sheet (PDF): sequence, masses, expected MS ions and handling on one printable page.

Latest research

Frequently asked questions

Related compounds

• Snap-8

  Snap-8, or acetyl octapeptide-3, is a synthetic eight-residue cosmetic peptide, Ac-EEMQRRAD-NH2, modeled on the N-terminal region of the SNARE protein SNAP-25. It is studied mainly in vitro and in cosmetic formulation research.

• BPC-157

  BPC-157 is a synthetic 15-amino-acid peptide whose sequence was derived from a protein fraction of gastric juice. It is studied mainly in rodent models of gastrointestinal, tendon and soft-tissue injury and is not approved for any use.

• Thymosin β4

  Thymosin β4 is a naturally occurring 43-amino-acid peptide that binds monomeric actin and is abundant in many cell types. It has been studied in animal models of tissue repair and in human trials of ophthalmic and topical formulations, and is not approved.

References

1. PubMed: all indexed literature on GHK-Cu
2. ClinicalTrials.gov: registered studies mentioning GHK-Cu