GHK-Cu
A copper-carrying tripeptide that behaves more like a transcriptional signal than a nutrient.
Skin & dermal · 8 min read · updated 13 Aug 2026
Research use only. The ranges below are what published studies and community protocols report. They are reference material for laboratory research, not medical advice or a recommendation for human or veterinary use.
The compound
GHK-Cu
View- Type
- Copper Peptide Complex
- CAS
- 49557-75-7
- Formula
- C₁₄H₂₂CuN₆O₄
- Mass
- 401.9 g/mol
At a glance
- Class
- Copper(II) tripeptide complex
- Sequence
- Gly-His-Lys, complexed with Cu²⁺
- Molecular weight
- 401.9 g/mol
- CAS
- 89030-95-5
- Endogenous
- Yes — plasma levels fall roughly 60% between ages 20 and 60
- Vial sizes stocked
- 50 mg, 100 mg
GHK was identified in human plasma in the early 1970s as the factor that made old liver tissue behave like young liver tissue in culture. It is a three-residue peptide — glycine, histidine, lysine — with an exceptionally high affinity for copper(II). The physiological form is the copper complex, GHK-Cu, and the copper is not incidental: the peptide is a copper transporter, delivering the ion to enzymes that need it while keeping free copper, which is pro-oxidant, out of circulation.
The reason it attracts so much research interest is that its effects are far broader than copper delivery explains. Gene-expression profiling found GHK-Cu significantly altering the expression of a very large number of human genes — resetting expression patterns in fibroblasts toward a younger profile, upregulating the DNA repair and antioxidant programmes and downregulating a number of inflammatory ones. Whether the copper or the peptide is doing the signalling is still argued.
Plasma GHK falls with age, from roughly 200 ng/ml in young adults to around 80 ng/ml by age sixty. That decline is the observation that frames most of the research narrative around it.
Mechanism in detail
- Matrix synthesis: stimulates fibroblast production of collagen (types I and III), elastin, glycosaminoglycans and proteoglycans — the structural programme of dermal remodelling rather than a single fibre type.
- Matrix remodelling: modulates both matrix metalloproteinases and their tissue inhibitors, so it influences the breakdown side as well as the synthesis side. Repair requires both.
- Antioxidant: raises superoxide dismutase activity and, by chelating copper, prevents the Fenton chemistry that free copper would otherwise drive.
- Anti-inflammatory: reduces TNF-α and IL-6 signalling; part of why it appears in inflammation-resolution blends rather than only in cosmetic contexts.
- Angiogenesis and nerve outgrowth: promotes both in wound models, complementing the migration and vascular arms that TB-500 and BPC-157 supply.
- Hair follicle: extends the anagen phase and enlarges follicles in culture, the basis of the topical hair research literature.
Topical versus injected
GHK-Cu has the strongest topical evidence base of anything in this catalogue. Controlled cosmetic-dermatology studies of GHK-Cu creams and serums have reported measurable changes in skin density, wrinkle depth and photodamage markers over weeks to months. Topical is also the route where the concentration is well established: cosmetic formulations sit in the 0.1–2% range depending on the vehicle.
Injected GHK-Cu is a different proposition. It delivers the complex systemically, and the reported research protocols are correspondingly cautious about total copper load. It is the route used when the question is systemic — connective tissue, wound repair at depth, or the blend work described below — rather than skin surface.
The copper ceiling
This is the one compound in the catalogue where a hard upper limit comes from something other than peptide pharmacology. Each molecule of GHK-Cu carries one copper ion, and copper accumulates. The complex is roughly 16% copper by mass, so 50 mg of GHK-Cu carries in the region of 8 mg of copper — a meaningful amount against a typical daily dietary intake of 1–2 mg.
This is why reported injectable protocols run in short blocks — commonly 2–4 weeks on followed by 2–4 weeks off — rather than continuous use, and why total monthly exposure matters more here than daily dose. Copper accumulation is also the mechanism behind the bluish-grey discolouration occasionally reported at repeatedly used injection sites.
Storage
- Lyophilised: 2–8 °C, or −20 °C for extended storage, protected from light.
- Reconstituted: 2–8 °C, used within about 28 days.
- Light exposure matters more here than for most peptides — copper complexes are photo-reactive. Keep the vial in its box.
Cautions
- Copper accumulation is the real dose-limiting factor. Wilson's disease and any condition of impaired copper handling is an absolute exclusion.
- Injection-site discolouration is reported with repeated use at the same site; rotate.
- Do not co-formulate with ascorbic acid, retinoids at low pH, or strong chelators.
- Topical evidence is much stronger than injectable evidence. Systemic protocols are extrapolations from wound-healing work.
References & credit
- 1Pickart L, Margolina A — Int J Mol Sci 2018 — Regenerative and protective actions of GHK-Cu, including the gene-expression findings.
- 2Pickart L — J Biomater Sci Polym Ed 2008 — The GHK peptide in skin remodelling and wound repair.
- 3Maquart FX et al., FEBS Letters 1988 — Stimulation of collagen synthesis in fibroblast cultures by GHK-Cu.
This article was written in-house. Where a dose range reflects community practice rather than a published trial, the community references we consulted are credited above and the article says which is which.