A copper complex of the tripeptide glycine-histidine-lysine, which occurs naturally in human plasma and was identified there in 1973. It is studied both as a carrier that delivers copper to copper-dependent enzymes and as a signalling molecule in its own right.

What does research report about GHK-Cu and collagen?

In-vitro work on cultured human dermal fibroblasts reports effects on TGF-β secretion, and reviews collect findings on collagen, elastin and glycosaminoglycan synthesis. Copper is a cofactor for lysyl oxidase, which cross-links collagen, so a carrier role has a clear mechanistic basis. These are cell-culture findings.

Are there human trials of GHK-Cu?

No randomised controlled trial for any indication appears in the peer-reviewed literature. Human-facing work is largely cosmetic-science studies of varying design rather than controlled trials.

Dedicated toxicology has not been published, so the honest answer is that it has not been characterised. The open question a reader should hold onto is copper handling: copper is an essential element with a narrow tolerable range, and the literature does not address what repeated exposure to a copper-carrying complex does to it.

Does GHK-Cu absorb through skin?

Not readily. The intact complex permeates intact skin poorly, which is why delivery studies using microneedles exist. It means results from applying the peptide directly to cultured cells do not predict what crosses a skin barrier.

Research guides

GHK-Cu copper peptide: what the research says

The copper tripeptide GHK-Cu has the strongest published evidence of any repair peptide here, spanning wound models, gene expression and cosmetic dermatology.

Available in the catalogue

Supplied as research material. Sizes and pricing are on the product page. Availability is not a statement about what a compound does.

GHK-CU
Cosmetic & Dermal

GHK-Cu is among the older molecules in this catalogue, and its literature has a different shape from the others here: it starts with a clean 1973 identification in Nature New Biology and broadens over fifty years into skin biology, gene expression and cosmetic science.

What the molecule is

A three-amino-acid peptide — glycine, histidine, lysine — bound to a copper(II) ion. The peptide occurs naturally in human plasma, where Pickart and Thaler identified it in 1973 while investigating a factor in serum that affected cultured liver cells. Plasma concentrations decline with age, which is the observation that pointed the subsequent research towards repair and skin.

Copper carrier and signalling molecule

Two roles are described in the literature and they are not the same claim. The first is straightforward chemistry: the tripeptide has high affinity for copper(II) and moves it, and copper is a required cofactor for enzymes including lysyl oxidase, which cross-links collagen and elastin. The second is that the complex acts as a signalling molecule in its own right, with reported effects on the expression of a large number of genes.

The gene-expression claim is the more striking and the more dependent on how the underlying data is analysed. It rests substantially on surveys of transcriptional datasets rather than on targeted experiments, which is a legitimate method and a different kind of evidence from a controlled study of one outcome.

Reading the bibliography

As with BPC-157, a large share of the literature — particularly the reviews and the gene-expression work — is authored or co-authored by the researcher who identified the peptide. That is not unusual for a molecule with a fifty-year single-investigator history, and the 1973 primary identification is not in question. It does mean the reviews are best read as an argument advanced by an interested party rather than as independent synthesis, and that the in-vitro work from other groups carries proportionally more weight.

What studies reported

Each entry states what a study examined and the model it used. Nothing below describes an outcome for a person.

Everything below is drawn from published research, and each entry names the model the study used. Approval status varies by compound and by country, and nothing described here is supplied as a medicine or for use in a person.

Pickart & Thaler (1973)Nature New Biology · 243(124):85–7
The original identification of the tripeptide in human serum, and its effect on the survival of cultured liver cells.
in vitro, cultured liver cells Source
Gruchlik et al. (2014)Acta Poloniae Pharmaceutica · 71(6):954–8
Compared the free tripeptide against its copper complex for effect on TGF-β secretion in cultured human dermal fibroblasts.
in vitro, normal human dermal fibroblasts Source
Pickart et al. (2015)BioMed Research International · 2015:648108
A review of reported activity across skin regeneration pathways, collecting the collagen, elastin and glycosaminoglycan findings.
review of in vitro and gene-expression work Source
Pickart & Margolina (2018)International Journal of Molecular Sciences · 19(7):1987
A survey of transcriptional data reporting that the peptide modulates expression across a large number of human genes, many associated with tissue repair.
review of gene-expression data Source
Li et al. (2014)Pharmaceutical Research · 32(8):2678–89
Examined delivery of the copper peptide across skin using microneedles, characterising permeation of a molecule that does not readily cross intact skin.
in vitro and ex vivo skin, microneedle delivery Source

Adverse and null findings reported

No dedicated safety study has been published for this compound. That is not a finding that none exists — it means the question has not been asked in print, and the gaps below say so.

What the research does not establish

An absence cannot be cited, so these are stated plainly. They are the part of the picture that silence would otherwise hide.

No randomised controlled trial of GHK-Cu for any indication appears in the peer-reviewed literature. The human-facing evidence is largely cosmetic-science work of varying design.
The adverse list is empty because dedicated toxicology has not been published, not because studies looked and found nothing.
Copper is a required trace element with a narrow tolerable range, and the literature on the peptide does not characterise what repeated exposure to a copper-carrying complex does to copper handling. This is the most obvious open question about the molecule and it is not addressed.
The gene-expression findings derive from analyses of transcriptional datasets rather than from targeted experiments, and have not been independently replicated at the scale at which they are reported.
Skin permeation of the intact complex is poor, which the microneedle work above exists to address — so results obtained by direct application to cultured cells do not tell you what reaches anything through a skin barrier.

Common questions

What is GHK-Cu?: A copper complex of the tripeptide glycine-histidine-lysine, which occurs naturally in human plasma and was identified there in 1973. It is studied both as a carrier that delivers copper to copper-dependent enzymes and as a signalling molecule in its own right.
What does research report about GHK-Cu and collagen?: In-vitro work on cultured human dermal fibroblasts reports effects on TGF-β secretion, and reviews collect findings on collagen, elastin and glycosaminoglycan synthesis. Copper is a cofactor for lysyl oxidase, which cross-links collagen, so a carrier role has a clear mechanistic basis. These are cell-culture findings.
Are there human trials of GHK-Cu?: No randomised controlled trial for any indication appears in the peer-reviewed literature. Human-facing work is largely cosmetic-science studies of varying design rather than controlled trials.
Is GHK-Cu safe?: Dedicated toxicology has not been published, so the honest answer is that it has not been characterised. The open question a reader should hold onto is copper handling: copper is an essential element with a narrow tolerable range, and the literature does not address what repeated exposure to a copper-carrying complex does to it.
Does GHK-Cu absorb through skin?: Not readily. The intact complex permeates intact skin poorly, which is why delivery studies using microneedles exist. It means results from applying the peptide directly to cultured cells do not predict what crosses a skin barrier.

Compounds covered

The reference page for each compound this article discusses.

GHK-Cu

BPC-157: what the research says
Body Protection Compound 157 has a large rodent literature and almost no human data. What the studies measured, in which models, and the caveat behind them.
TB-500 and thymosin beta-4: what the research says
The fragment sold as TB-500 is not the molecule most of the literature studied. What the thymosin β4 research reported, including two human eye trials.
How to store research peptides
Lyophilised peptides at -20°C, reconstituted at 2–8°C, ambient in transit. Why the dry cake tolerates shipping, and what actually degrades a vial.

About this article

Everything reported here comes from published research, and each finding names the model the study used — cell culture, rat, or human. Findings in one model do not transfer to another, most of the work described is preclinical, and none of it is a claim that a compound is safe or effective for any purpose. Nothing on this page describes doses, routes of administration, or use in a person.

Approval status varies by compound and by country. A few of the substances described are the active ingredient of medicines authorised in the EU; most have no marketing authorisation anywhere and have never been assessed by a regulator. Neither is supplied as a medicine here. All material supplied by ASSAY is sold for in-vitro laboratory research only, and is not a drug, food, cosmetic or medical device, and not for human or veterinary use.

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