GHK-Cu is a copper-binding tripeptide studied across skin, collagen and hair-growth research — read here as an audited ledger.

The compound, stated as a line item

GHK-Cu is the glycyl-L-histidyl-L-lysine copper(II) complex — a three-amino-acid peptide (glycine-histidine-lysine) carrying a single copper(II) ion, molecular weight 402.92 Da, cosmetic-ingredient name Copper Tripeptide-1 ^[3]. It was first isolated from human plasma by Loren Pickart in 1973 as a factor that caused aged human liver tissue to synthesize proteins like younger tissue ^[6]. This page reads the GHK-Cu literature the way a statement reads an account: each finding posted as a line, each number reconciled to its source, each regulatory status flagged with a badge.

The headline figures of that ledger are quantitative. In human fibroblast cultures GHK-Cu raised collagen synthesis dose-dependently, with onset between 10^-12 and 10^-11 M and a peak near 10^-9 M, and it did so without changing cell number — a specific metabolic effect, not a proliferation artifact ^[1]. Gene-expression analysis reports that GHK shifts roughly 31.2% of human genes at a 50%-or-greater change threshold toward repair, DNA-fidelity and antioxidant programs ^[2]. Topical formulations raised procollagen synthesis in 70% of treated subjects, against 50% for vitamin C and 40% for retinoic acid in the same comparison ^[3]. And in a six-month controlled hair trial of 45 men, a 5-aminolevulinic-acid plus GHK complex increased hair count by 71.5 at the 50 mg/mL dose versus 9.6 for placebo ^[4].

The boundaries are stated with the same precision as the findings. There is no FDA- or EMA-approved drug product for GHK-Cu by any route ^[3]. Topical Copper Tripeptide-1 is a legal cosmetic ingredient in the US, EU and UK. No validated human pharmacokinetic data — half-life, Cmax, bioavailability — exist for injectable or systemic use; the closest peer-reviewed pharmacokinetics is a rat study showing free GHK is rapidly metabolized in plasma to the dipeptide histidyl-lysine ^[10]. That separation — verified fact in one column, preclinical signal in another, no-human-data gap in a third — is the whole point of reading this compound as a ledger rather than a brochure.

What a copper peptide is

A copper peptide is a short chain of amino acids bound to a copper(II) ion, where the metal is not an impurity but a functional part of the molecule. In GHK-Cu the copper sits in a square-planar coordination held by the histidine imidazole nitrogen, the glycine alpha-amino nitrogen and a deprotonated amide nitrogen, leaving the lysine side chain free ^[6]. The complex forms at a 1:1 copper-to-peptide ratio with a very high stability constant (log K around 16.4), which keeps free, pro-oxidant copper from being released ^[3].

That distinction matters because copper coordination is required for most of the documented activity. The free tripeptide GHK (MW 340.38) and the copper chelate GHK-Cu (MW 402.92) are frequently conflated in the literature, but the free peptide does not reproduce the matrix-remodeling effects of the complex in fibroblast cultures ^[3]. When this site reports a finding, it tracks which form the underlying study used. The endogenous version of this molecule declines with age: plasma GHK falls from roughly 200 ng/mL at age 20 to about 80 ng/mL by age 60 ^[3], the observation that started the research program.

GHK copper peptide: what the research describes

The GHK copper peptide is best understood as two things at once: a copper chaperone and a pleiotropic signaling molecule. As a chaperone it enables copper-dependent reactions — lysyl-oxidase-mediated collagen and elastin cross-linking, and superoxide-dismutase-like antioxidant activity ^[6]. As a signal it directly stimulates dermal fibroblasts to synthesize collagen, elastin, glycosaminoglycans and the proteoglycan decorin, while rebalancing matrix metalloproteinases against their TIMP inhibitors toward controlled remodeling rather than tissue breakdown ^[3][6].

The research record across this molecule spans several tissue systems. In skin it is the most studied: collagen and matrix synthesis, photoaging repair, and small placebo-controlled facial trials ^[3]. In hair it has one controlled human signal — the ALAVAX hair-count trial — and preclinical anagen-induction work ^[4]. Beyond the surface, reviews document angiogenic (VEGF, FGF-2), anti-inflammatory (NF-kB suppression) and neurotrophic effects, largely in cell-culture and rodent models ^[6]. The reading list that follows sorts those domains and cites each one. Start with the GHK-Cu research summary, or jump to the copper peptide skin research and copper peptide serum research pages.

How to read this ledger

Three rules govern every page here. First, the headline is the number. Each section opens with what was measured — the dose, the percentage, the count, the species — and the attribution follows. Second, the form is tracked: where a study used free GHK rather than the copper complex, the entry says so, because the two are not interchangeable in the evidence ^[3]. Third, the evidence class is marked, not blurred. A human placebo-controlled result, an in-vitro dose-response, and a single rodent behavioral study are different grades of evidence, and a ledger that flattened them would be useless.

What that produces is an honest balance sheet rather than a sales page. The strongest entries — the Maquart 1988 collagen dose-response ^[1], the Pickart 2015 skin-regeneration review ^[3], the Lee 2016 hair-count trial ^[4], the Hostynek 2011 penetration study ^[5] — are real, dated and citable. The gaps — no validated human pharmacokinetics, a literature heavily weighted toward in-vitro and rodent work, a foundational body of mechanism papers from a single investigator group — are posted as line items too. The What a GHK-Cu peptide does question is answered in the next section; the copper peptide side effects and is copper peptide safe questions are answered on the FAQ.

What does a GHK-Cu peptide do?

What does a GHK-Cu peptide do?

In research models GHK-Cu acts as a copper-binding tripeptide that stimulates fibroblast synthesis of collagen, elastin and glycosaminoglycans and rebalances matrix-remodeling enzymes toward controlled repair ^[1][6]. It also carries broad tissue-repair gene effects, shifting expression of about 31.2% of human genes at a 50%-or-greater threshold toward repair and antioxidant programs ^[2]. Effects are documented across skin, hair-follicle, vascular and wound models.

What is GHK-Cu and how does it work?

GHK-Cu is the glycyl-histidyl-lysine copper(II) complex; it works as a copper chaperone and a pleiotropic signaling molecule, directly stimulating matrix synthesis at picomolar-to-nanomolar concentrations in study models ^[1]. Collagen synthesis in human fibroblasts began between 10^-12 and 10^-11 M and peaked near 10^-9 M, independent of cell number ^[1]. The copper coordination is what enables cross-linking and antioxidant chemistry ^[6].

What is the difference between GHK and GHK-Cu?

GHK is the free tripeptide (MW 340.38); GHK-Cu is its copper(II) chelate (MW 402.92) ^[3][6]. Copper coordination is required for most documented matrix-remodeling activity — the free peptide does not reproduce the complex's fibroblast effects ^[3]. Free GHK is also rapidly metabolized in plasma to the dipeptide histidyl-lysine, documented in a rat pharmacokinetic study ^[10].