# GHK-Cu: The Copper-Peptide Safety Record, Checked Claim by Claim > GHK-Cu is a copper-binding tripeptide with a long topical safety record and unproven systemic use. The skin, hair, and copper-handling research taped up and checked, every figure cited. The collagen dose-response, the hair-count trial, the copper-stability chemistry, and the places the human evidence still thins — every quantitative claim circled and cited to its source. ## GHK copper peptide: what the research describes GHK-Cu is the glycyl-L-histidyl-L-lysine copper(II) complex — a tripeptide present in human plasma, saliva, and urine that binds copper 1:1 and has been studied for skin remodeling, wound healing, and hair-follicle support. This page is a marked-up reading of that record: the figures the literature actually establishes are circled, the inflated ones are struck through, and the human-data gaps are flagged in the margin. The compound carries a long topical safety history and, separately, a set of genuine open questions about systemic use. The core finding is reproducible. In human fibroblast cultures, GHK-Cu raised collagen synthesis dose-dependently from 10^-12 M to a peak near 10^-9 M, with no change in cell number [1]. The copper coordination is not incidental: it is required for most of the documented tissue-repair activity, which is precisely why the form a study used — free GHK versus the copper chelate — matters when reading a claim [6]. The "GHK copper peptide" search term covers a broad umbrella, but the literature underneath it is specific. GHK-Cu stimulates synthesis of collagen, dermatan sulfate, chondroitin sulfate, and the proteoglycan decorin, and in one reviewed comparison topical GHK-Cu increased collagen production in 70% of treated subjects versus 50% for vitamin C and 40% for retinoic acid [3]. Those are study figures, summarized here for general readers — not a usage recommendation. ## What a copper peptide is A copper peptide is a short chain of amino acids bound to a copper(II) ion. GHK-Cu is the most-studied example: three amino acids — glycine, histidine, lysine — chelating one copper ion through the histidine imidazole nitrogen, the glycine amino nitrogen, and a deprotonated amide nitrogen, leaving the lysine side chain free [6]. The complex carries a molecular weight of 402.92 Da and CAS number 89030-95-5. The copper is the point. Bound this tightly, copper stops behaving as a loose pro-oxidant and starts acting as a controlled cofactor. The GHK-Cu chelate has a very high copper stability constant, log K of roughly 16.4, which limits release of free copper into tissue [7]. In oxidative-chemistry assays the bound complex completely blocked copper-dependent LDL oxidation — versus only about 20% protection from superoxide dismutase — and reduced iron release from ferritin by 87% [7]. The peptide also carries copper to lysyl oxidase, the copper-dependent enzyme that cross-links collagen and elastin [6]. This is the difference between a copper peptide and copper applied loose. The chelate is the safety architecture: high binding affinity, antioxidant behavior in the assays, and a measured dermal depot rather than a flood. The honest counterpart — that systemic copper handling over time has not been characterized in humans — is on the [copper peptide side effects](/side-effects) page. ## Copper Tripeptide-1 (the INCI name) Copper Tripeptide-1 is the INCI (cosmetic-ingredient) name for GHK-Cu — the label you find on a skincare ingredient list. It is a legal cosmetic ingredient in the US, EU, and UK. That regulatory status is narrow and worth reading precisely: it covers topical cosmetic use of the peptide as an ingredient. It does not make GHK-Cu an approved drug. There is no FDA- or EMA-approved GHK-Cu therapeutic product for any indication, and injectable, oral, or other systemic formulations are unapproved research chemicals with no established regulatory pathway. Whether [is GHK-Cu FDA approved](/side-effects) is a question with a clean answer: as a drug, no. Reading the INCI name correctly is itself a safety act. "Copper Tripeptide-1 is in my serum" is a cosmetic-ingredient statement, fully covered by the cosmetic safety record. "I am dosing GHK-Cu systemically" is a different claim entirely, sitting on top of a literature that has no validated human pharmacokinetics. ## What does a GHK-Cu peptide do? GHK-Cu is a copper-binding tripeptide (Gly-His-Lys) that, in research models, stimulates dermal fibroblast synthesis of collagen, elastin, and glycosaminoglycans and acts as a pleiotropic signaling molecule [1][6]. In human fibroblast cultures it increased collagen synthesis dose-dependently from 10^-12 to 10^-9 M without changing cell number, which marks the effect as a specific metabolic signal rather than a general growth push [1]. The same molecule chelates copper for cross-linking enzymes and shows antioxidant behavior in the test tube [6][7]. ## What is GHK-Cu and how does it work? GHK-Cu is the glycyl-L-histidyl-L-lysine copper(II) complex, a tripeptide present in human plasma that chelates copper 1:1 [6]. It works on two levels at once: as a copper chaperone, ferrying the ion to enzymes such as lysyl oxidase, and as a signaling molecule that directly stimulates fibroblast matrix synthesis and rebalances matrix metalloproteinases against their TIMP inhibitors toward controlled remodeling [3][6]. The copper-bound form is the active one — the free peptide does not reproduce MMP-2 stimulation in fibroblast cultures, so the chelate is what most repair findings rest on [6]. ## 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) [6]. The distinction is not pedantic. Copper coordination is required for most documented tissue-repair activity — the free peptide does not reproduce MMP-2 stimulation in fibroblast cultures — so the form a given study used changes how its result should be read [1][6]. Much of the genome-level work uses free GHK; much of the skin-remodeling work uses the copper chelate. [The difference between GHK and GHK-Cu](/) is the first thing to check before trusting a copper-peptide claim. --- The GHK-Cu copper-peptide literature cut out and taped to one wall — each verified figure circled by hand, each inflated one struck through, and every missing stretch of human data marked in the margin, with no clinic pinned to this board and nothing here for sale.