GHK-Cu drove collagen synthesis at picomolar doses and modulates roughly 31% of human genes.

The GHK-Cu balance, in plain figures

GHK-Cu is the copper(II) complex of glycyl-L-histidyl-L-lysine, a tripeptide first isolated from human plasma in 1973. Molecular weight: 402.92 Da. CAS: 89030-95-5. INCI name: Copper Tripeptide-1. It is a research peptide and a cosmetic ingredient, not an approved drug by any route.

The figures are the point of this page. In human fibroblast cultures, GHK-Cu raised collagen synthesis dose-dependently — onset between 10⁻¹² and 10⁻¹¹ M, peak near 10⁻⁹ M — with no change in cell number, which marks the effect as a specific metabolic shift rather than a growth artifact ^[1]. A Connectivity Map analysis reports that GHK alters expression of about 31.2% of human genes at a 50%-or-greater change threshold: 59% up, 41% down, with strong upregulation of ubiquitin-proteasome, DNA-repair and antioxidant gene sets ^[2]. The widely repeated "~4,000 genes" figure is an extrapolation; the verified threshold table reports on the order of 2,100 genes ^[2].

The sequence is not foreign to the body. GHK occurs within the alpha-2(I) chain of type I collagen and in SPARC/osteonectin, and circulates in plasma, saliva and urine. Plasma levels decline from about 200 ng/mL at age 20 to about 80 ng/mL by age 60, paralleling reduced tissue-repair capacity ^[3]. That decline is what frames GHK research as restorative — replacing a signal the body sheds with age — rather than introducing something new.

Every line on this statement carries a status. The confirmed entries are the topical-dermatologic and in-vitro figures — the collagen dose-response, the procollagen comparison, the 6-month hair-count delta. The flagged entries are the gaps: there is no validated human pharmacokinetic profile for GHK-Cu by any systemic route, and a large share of the foundational literature comes from one investigator group ^[2][6]. This digest posts both, and never hides the amber line behind the green one. The concentrations and routes behind these figures are itemized under GHK-Cu dosage in research models, and the tolerability record under copper peptide side effects and safety.

GHK-Cu, the GHK copper peptide

The GHK copper peptide is the most-studied member of the copper-peptide class, and its defining feature is the copper. The Cu(II) ion binds through the histidine imidazole nitrogen, the glycine alpha-amino nitrogen and the deprotonated glycine-histidine amide nitrogen, leaving the lysine side chain free. The complex carries a very high copper stability constant — log K approximately 16.4 — far higher than free GHK, which limits pro-oxidant free-copper release ^[6].

That chelation is functional, not incidental. Copper coordination enables lysyl-oxidase-mediated collagen and elastin cross-linking and superoxide-dismutase-like antioxidant chemistry, and it is required for most documented matrix-remodeling activity — the free peptide does not reproduce MMP-2 stimulation in fibroblast cultures ^[1][6]. Across study models the GHK copper peptide stimulates synthesis of collagen, dermatan sulfate, chondroitin sulfate and the proteoglycan decorin ^[3]. The full study-by-study breakdown sits in the GHK-Cu research summary.

What a copper peptide is

A copper peptide is a short amino-acid chain bound to a copper(II) ion. GHK-Cu — three amino acids, one copper atom — is the archetype of the class. The peptide does two jobs at once: it carries copper to the enzymes that depend on it, and it signals dermal fibroblasts to rebuild the extracellular matrix in study models ^[6].

The practical distinction a reader needs is GHK versus GHK-Cu. GHK is the free tripeptide (MW 340.38, CAS 49557-75-7); GHK-Cu is its copper(II) chelate (MW 402.92, CAS 89030-95-5). Several studies use free GHK and report systemic or gene-level effects, while copper coordination is required for most documented matrix activity — so the form a given study used governs how its claim should be read ^[1][2].

Copper Tripeptide-1 (the INCI name)

Copper Tripeptide-1 is the INCI cosmetic-ingredient name for GHK-Cu — the same molecule, labeled for skincare. On a product ingredient list, "Copper Tripeptide-1" denotes glycyl-histidyl-lysine copper(II) complex, CAS 89030-95-5. The label name and the research name describe one compound; this digest uses GHK-Cu throughout and notes the INCI synonym only for clarity.

The naming distinction matters because the regulatory status splits along it. Topical Copper Tripeptide-1 is a legal cosmetic ingredient with a long market history, whereas injectable or other systemic GHK-Cu is unapproved and research-only ^[6]. The literature this digest summarizes is overwhelmingly topical and in-vitro for exactly that reason.

What does a GHK-Cu peptide do?

What does a GHK-Cu peptide do?

A GHK-Cu peptide acts as a copper-binding signaling tripeptide. In research models it stimulates dermal fibroblast synthesis of collagen, elastin and glycosaminoglycans, supports angiogenesis and wound repair, and functions as a copper chaperone supplying the metal to copper-dependent enzymes ^[1][6]. It is, in short, a small molecule with a broad matrix-repair signature.

What is GHK-Cu and how does it work?

GHK-Cu is glycyl-L-histidyl-L-lysine chelated 1:1 to copper(II). At picomolar-to-nanomolar levels it directly stimulates matrix synthesis and broadly shifts gene expression toward repair, DNA-fidelity and antioxidant programs ^[1][2]. The dual mechanism — copper chaperone plus pleiotropic signal — is covered in full under how GHK-Cu works.

What is the difference between GHK and GHK-Cu?

GHK is the free tripeptide (MW 340.38, CAS 49557-75-7); GHK-Cu is its copper(II) chelate (MW 402.92, CAS 89030-95-5). Copper coordination is required for most documented tissue-repair activities, such as MMP-2 stimulation, which the free peptide does not reproduce in fibroblast cultures ^[1]. The form a study used is the first thing to check when reading its claim.