Clinical research digest / Copper Tripeptide-1
GHK-Cu is a copper peptide studied for skin remodeling and matrix repair, read with its evidence clearly labelled.
What the picomolar collagen data, the 70-percent procollagen comparison, and the hair-count trial actually established, and where the human evidence stops. Every finding is tagged established, limited, context, or safety.
What GHK-Cu is, in one paragraph
GHK-Cu is the copper(II) chelate of the tripeptide glycyl-L-histidyl-L-lysine, a short three-amino-acid sequence (Gly-His-Lys) that binds a single copper ion and turns up naturally in human plasma, saliva, and urine. At picomolar-to-nanomolar concentrations it stimulates dermal fibroblast synthesis of collagen, elastin, glycosaminoglycans, and the proteoglycan decorin [2][6]. It carries the INCI label copper tripeptide-1 on skincare ingredient lists, the molecular formula C14H23CuN6O4+, a molecular weight of 402.92 Da, and the CAS number 89030-95-5 [2]. Plasma GHK is not fixed for life: it declines from roughly 200 ng/mL at age 20 to about 80 ng/mL by age 60, which is part of why the peptide is read as a repair signal that fades with age [2]. This site is a digest of the published GHK-Cu record. It is editorial, not a clinic, and it labels each finding by how strong the evidence behind it is.
What Is GHK Copper Peptide?
The phrase GHK copper peptide names the same molecule as GHK-Cu: the copper-bound form of the Gly-His-Lys tripeptide. The copper is not incidental. In fibroblast cultures, GHK-Cu stimulated matrix metalloproteinase-2 expression and concurrently raised the tissue inhibitors TIMP-1 and TIMP-2, and that effect was reproduced by the copper-bound complex but not by the free GHK peptide [3]. Copper coordination also enables lysyl-oxidase-mediated collagen and elastin cross-linking and a superoxide-dismutase-like antioxidant activity that the bare peptide does not provide [6]. Loren Pickart first isolated GHK in 1973 as a plasma factor that caused aged human liver tissue to synthesize proteins like younger tissue, and the copper complex is what most of the documented tissue-repair work has used since [6]. The single most important reading rule for this literature: check whether a study used free GHK or the copper chelate, because for matrix remodeling the two are not interchangeable [3].
Copper Peptides and the GHK Sequence
A copper peptide is, broadly, a short peptide that carries a copper ion; the GHK sequence is the best-studied endogenous example. The Gly-His-Lys tripeptide occurs naturally inside the alpha-2(I) chain of type I collagen and in the matrix protein SPARC/osteonectin, so the body already builds it into its own scaffolding [2]. When tissue is injured, GHK liberated from broken collagen is thought to act as a local repair signal, binding copper and switching fibroblasts toward synthesis. The foundational dose-response work showed collagen synthesis in human fibroblast cultures beginning between 10^-12 and 10^-11 M, peaking near 10^-9 M, and occurring without any change in cell number, which means the peptide changed what the cells did rather than simply making more of them [1]. That specificity, at vanishingly low concentrations, is the core of why the GHK sequence anchors the whole copper-peptide category. The deeper mechanism is set out under GHK-Cu mechanism of action.
Copper Tripeptide-1 (INCI name)
Copper Tripeptide-1 is the INCI (International Nomenclature of Cosmetic Ingredients) name for GHK-Cu, the label used to declare copper-peptide content on a skincare ingredient list [2]. The research compound and the cosmetic ingredient are the same molecule: the copper(II) chelate of glycyl-histidyl-lysine, MW 402.92 Da, CAS 89030-95-5 [2]. Topical Copper Tripeptide-1 is a legal, widely marketed cosmetic ingredient with a long safety record, which is a different regulatory status from injectable or systemic GHK-Cu, which is unapproved and research-only [2]. When this site uses "GHK-Cu" and a product label uses "Copper Tripeptide-1," they are naming the same thing for two different audiences.
What does a GHK-Cu peptide do?
GHK-Cu is a copper-binding tripeptide that, at picomolar-to-nanomolar levels, stimulates fibroblast synthesis of collagen, elastin, glycosaminoglycans, and decorin while rebalancing matrix metalloproteinases against their TIMP inhibitors [2][3]. Beyond skin, it behaves as a broad gene-modulating signaling molecule: gene-expression analyses report that GHK alters about 31% of human genes at a 50-percent-or-greater change threshold, favoring wound-repair, DNA-repair, and antioxidant programs [5]. It also chemoattracts repair cells and suppresses several inflammatory and oxidative signals in wound models [6]. The strongest direct human skin data is for copper peptide skin research, and the full slate of documented copper peptide benefits is weighted by evidence on its own page.
What is GHK-Cu and how does it work?
GHK-Cu is the copper(II) chelate of the glycyl-histidyl-lysine tripeptide. It works on two tracks at once. As a copper chaperone it delivers copper for lysyl-oxidase cross-linking of collagen and elastin and for SOD-like antioxidant chemistry [6]. As a signaling molecule it drives wound-repair, DNA-repair, and antioxidant gene programs while suppressing NF-kB-driven inflammation [5][6]. The copper form matters: MMP-2 stimulation in fibroblasts is produced by GHK-Cu but not by the free peptide, which is the clearest single demonstration that the metal is doing mechanistic work, not just riding along [3]. The full pathway map, with its established and limited claims separated, is on the GHK-Cu mechanism of action page.