GHK-Cu (Copper Peptide) — Research Product Overview

**Disclaimer:** This product overview is provided strictly for in-vitro and preclinical research use. [GHK-Cu](/catalog/klow-blend) is not approved by the FDA as a drug, and nothing in this document constitutes medical advice or a recommendation for human administration. Materials are sold to qualified research professionals for laboratory investigation only.

Overview

GHK-Cu is the copper(II) complex of the human tripeptide glycyl-L-histidyl-L-lysine. The peptide moiety GHK was first isolated by Loren Pickart in 1973 as an activity in human albumin that restored protein synthesis to aged liver tissue at levels comparable to that of younger tissue. The tripeptide has an exceptionally strong affinity for divalent copper, and the resulting GHK-Cu complex is the form responsible for nearly all of the regenerative and protective activities documented in the literature. GHK is endogenously present in human plasma, saliva, and urine; circulating concentrations decline from approximately 200 ng/mL at age 20 to roughly 80 ng/mL by age 60, a decline that has been correlated with the age-related fall in regenerative capacity.

For broader context on copper-peptide research see our GHK-Cu copper peptide research overview, and for a head-to-head treatment of dermal repair pharmacology see GHK-Cu vs BPC-157 wound healing.

Sequence and Structural Notes

• Peptide sequence: Gly-L-His-L-Lys (GHK)
• Molecular formula (apo-peptide): C14H24N6O4
• Molecular weight (apo-peptide): 340.39 Da
• Molecular weight (Cu²⁺ complex): 401.94 Da (1:1 GHK:Cu)
• Length: 3 amino acids (tripeptide)
• Coordination: square-planar Cu²⁺ center; nitrogen donors from the histidine imidazole, the deprotonated peptide bond, and the N-terminal amine; the lysine ε-amine remains free
• Color: characteristic deep blue in solution due to d-d transitions of the bound Cu²⁺

The tight binding of copper(II) by GHK is the defining feature of this molecule. The complex acts as a physiologically buffered copper carrier, exchanging copper with serum albumin and intracellular metallochaperones rather than depositing copper indiscriminately.

Mechanism of Action (Summary)

1. Copper homeostasis — buffered delivery of Cu²⁺ to copper-dependent enzymes (lysyl oxidase, superoxide dismutase 1, cytochrome c oxidase).
2. Extracellular matrix remodeling — stimulates synthesis of collagen, dermatan sulfate, chondroitin sulfate, and decorin; modulates matrix metalloproteinases and their inhibitors (TIMPs).
3. Gene-expression modulation — microarray studies report GHK-induced changes in thousands of human genes, with enrichment for wound healing, antioxidant defense, DNA repair, anti-inflammatory signaling, and nerve outgrowth pathways.
4. Antioxidant activity — scavenges hydroxyl radicals and reduces iron-driven oxidative damage in lipid systems.
5. Anti-inflammatory action — reduces TNF-α and other inflammatory cytokines in injured tissue.

Preclinical Research Summary

Pickart and colleagues have published extensively on GHK-Cu's activity in dermal wound healing, accelerating contraction, re-epithelialization, and the take of skin grafts in animal models. The 2018 review by Pickart and Margolina in *International Journal of Molecular Sciences* synthesizes the bone, gastrointestinal, lung, and dermal repair literature. GHK-Cu has been studied in models of pulmonary fibrosis, COPD, peripheral nerve injury, and aged-skin restoration. Topical formulations have been the subject of multiple cosmetic-grade clinical investigations, although these are conducted under cosmetic rather than pharmaceutical regulatory frameworks.

Comparator Peptides and Molecules

GHK-Cu is the most extensively studied member of a small class of physiological copper-carrier peptides. Other copper-binding peptides in the literature include the histidine-rich amyloid-β fragments (Aβ1-16), the Cu-transport-mimetic peptides derived from prion protein octarepeats, and synthetic copper chelators based on 8-hydroxyquinoline scaffolds — none of which have approached the breadth of regenerative activity reported for GHK-Cu. The defining contrast is between GHK-Cu's *physiologically buffered* copper exchange (with serum albumin and intracellular metallochaperones) and the *deposit-and-release* behavior of less specific copper carriers, which often produce off-target oxidative damage. Within the regenerative-peptide field as a whole, GHK-Cu approaches tissue repair through ECM remodeling and antioxidant defense, while BPC-157 emphasizes migration and angiogenesis, and TB-500 emphasizes actin dynamics and progenitor reactivation. The detailed dermal-repair contrast is treated in GHK-Cu vs BPC-157 wound healing.

For research stacks combining copper-mediated repair with other longevity tool compounds, see Epitalon for a telomerase-focused alternative, FOXO4-DRI for a senolytic that complements rather than competes with GHK-Cu's regenerative profile, and NAD+ for a metabolic adjunct. GHK-Cu's copper-mediated nitric-oxide modulation also intersects the nitric-oxide-peptides axis and is occasionally considered alongside growth-hormone axis modulators in dermal aging research.

Deeper Preclinical Breakdown

Pickart and Margolina 2018 (*Int J Mol Sci* 19(7):1987, PMID 29986520) is the canonical synthesis of GHK-Cu biology. Its most-cited contribution is the systematic compilation of microarray data showing that GHK exposure modulates more than 4,000 human genes, with significant enrichment in DNA repair, antioxidant defense, anti-inflammatory signaling, and ECM remodeling categories. Cell systems studied included human dermal fibroblasts at 10 nM to 10 µM GHK or GHK-Cu for 24–72 hours. The broad gene-modulation profile is unusual among regenerative peptides and underpins many subsequent indication-specific studies.

Pickart, Vasquez-Soltero, and Margolina 2015 (*BioMed Res Int*, PMID 26236730) reviewed GHK skin-regenerative pharmacology, including copper-loading kinetics, square-planar coordination geometry, and mechanisms of fibroblast activation. The paper identifies the lysyl oxidase activation pathway as a central driver of collagen cross-linking enhancement in aged skin, and discusses interactions with TGF-β signaling. Limitations include a strong focus on dermal endpoints and limited treatment of systemic effects.

Hostynek, Dreher, and Maibach characterized GHK-Cu skin penetration kinetics from topical formulations using human skin in vitro, showing that the copper-peptide complex penetrates the stratum corneum largely intact and delivers physiologically relevant copper to viable epidermal layers. Topical formulations have typically been 0.01% to 1% w/w. Other groups have explored systemic effects of injected GHK-Cu in rabbit and rat models, showing accelerated wound contraction at 1–2 µg/kg subcutaneous administration. Limitations across this dataset include older methodology in some primary studies and a heavy concentration of work in a single research lineage (the Pickart group).

Formulation Considerations

GHK-Cu is supplied as a deep-blue lyophilized powder (the color comes from d-d transitions of the bound Cu²⁺), typically 50 mg or 100 mg per vial. Some grades are supplied as the apo-peptide (white powder) for in-house copper loading, which allows researchers to control the Cu:peptide stoichiometry exactly. Reconstitution is straightforward in sterile water or bacteriostatic water — the complex is highly water-soluble. The critical formulation constraint is pH: the GHK-Cu complex is most stable at pH 7.0–7.4. Below pH 5 the copper dissociates, producing the inactive apo-peptide and free Cu²⁺ (which can drive Fenton chemistry); above pH 9 the complex hydrolyzes and the peptide backbone degrades.

Common impurities visible on a quality COA include free copper (excess Cu²⁺ unbound to peptide), the apo-peptide (under-loaded material), and oxidized variants of the histidine residue. Researchers should verify Cu content by ICP-MS or atomic absorption (theoretical 15.4% for 1:1 complex) and the characteristic UV-Vis absorbance at 525 nm. EDTA and other strong chelators should never be added to GHK-Cu solutions, since they will strip the copper. See the peptide reconstitution guide, peptide storage stability, and how to read a peptide COA for protocol depth.

Research-Context Dosing Ranges

Published preclinical work has used a broad concentration range. Topical formulations: 0.01–1% w/w in cosmetic and dermal-research bases (Pickart group, Hostynek). Subcutaneous rodent injection: 1–2 µg/kg/day (rat wound studies, graft-take studies). In-vitro fibroblast collagen-synthesis assays: 1 nM to 10 µM. Hair-follicle research has used 100 nM to 1 µM in dermal papilla cell cultures. No human dosing is implied; topical cosmetic formulations are regulated separately and outside the scope of this research-use overview.

Common Research Applications

• In-vitro fibroblast collagen-synthesis assays (procollagen I C-terminal peptide, Sirius red)
• Dermal punch-biopsy and excisional wound models in rodents
• Antioxidant assays (DPPH, hydroxyl radical scavenging)
• Hair-follicle stem cell and dermal papilla cell viability assays
• Topical-formulation stability and skin-permeation studies

Handling, Reconstitution, and Storage

• Form supplied: blue lyophilized powder (color comes from the Cu²⁺ complex), typically 50 mg or 100 mg per vial; some grades supplied as the apo-peptide for in-house copper loading
• Reconstitution: sterile water or bacteriostatic water; the complex is highly water-soluble
• Working concentration: 0.1–1 mg/mL typical for in-vitro and topical-research applications
• pH sensitivity: the GHK-Cu complex is most stable at pH 7.0–7.4; below pH 5 the copper can dissociate, and above pH 9 the complex hydrolyzes
• Lyophilized stability: ≥24 months at -20 °C protected from light
• Reconstituted stability: up to 30 days at 2–8 °C if pH is buffered near 7.4; deep-freeze aliquots for longer-term storage
• Avoid: strong reducing agents (which can reduce Cu²⁺ to Cu⁺ and destabilize the complex) and EDTA-containing buffers (which strip copper)

See peptide reconstitution guide for further protocol detail.

Lab Specifications

• [HPLC](/research/glossary#hplc) purity target (apo-peptide): ≥98.0% by RP-HPLC at 220 nm
• Copper content: 14.5–16.5% w/w by ICP-MS or atomic absorption (theoretical 15.4% for 1:1 complex)
• Identity confirmation: ESI-MS for the peptide; UV-Vis absorbance at 525 nm for the Cu²⁺ complex
• Endotoxin: <1 EU/mg for cell-culture grade
• Residual solvents: within ICH Q3C limits
• Heavy metals other than Cu: <10 ppm

For COA interpretation see how to read a peptide COA.

Cross-References

Related Viking Labs research:

• GHK-Cu copper peptide research
• GHK-Cu vs BPC-157 wound healing
• Product overview: BPC-157
• Product overview: TB-500
• Peptides longevity research 2026
• Reading HPLC COA

Summary

GHK-Cu is unique among regenerative research peptides in that its activity is inseparable from its bound copper. The literature spans more than five decades and covers wound healing, antioxidant biology, gene-expression modulation, and ECM remodeling. Researchers should pay careful attention to copper content, complex stoichiometry, and buffer pH when designing experiments — small variations in any of these parameters can substantially affect bioactivity.

*This document is provided for research and educational purposes only. Viking Labs does not sell products intended for human consumption.*