An evidence wall, marked up by hand · Copper Tripeptide-1
GHK-Cu is a copper tripeptide with a long topical safety record, real human-data gaps, and a literature taped up and checked claim by claim.
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 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 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.