GHK-Cu

GHK-Cu (glycyl-L-histidyl-L-lysine copper(II)) is a naturally occurring tripeptide-copper complex found in human plasma, saliva, and urine. Plasma concentrations decline substantially with age, from roughly 200 ng/mL in young adults to approximately 80 ng/mL by the sixth decade, an observation that prompted early interest in its role in tissue maintenance.

The peptide binds Cu2+ with high affinity (stability constant approximately 10^-16 M), functioning as a copper chaperone that shuttles the metal into cells, where it is reduced to Cu+ and donated to cuproenzymes. Relevant enzymatic targets include lysyl oxidase, which catalyzes the cross-linking of collagen and elastin fibrils; Cu/Zn superoxide dismutase (SOD1), a key antioxidant enzyme; and cytochrome c oxidase in the mitochondrial electron transport chain.

Beyond copper transport, GHK-Cu activates the TGF-beta signaling pathway, stimulating fibroblast proliferation and extracellular matrix synthesis. It suppresses NF-kB p65 and p38 MAPK, reducing production of pro-inflammatory cytokines TNF-alpha and IL-6. In parallel, GHK-Cu stimulates expression of VEGF and FGF-2, supporting angiogenesis, and upregulates Nrf2 nuclear translocation, inducing the cytoprotective enzyme heme oxygenase-1 (HO-1).

A 2018 review by Pickart and Margolina (PMID 29986520) synthesized transcriptomic data and reported that GHK modulates roughly 31% of human genes with changes of 50% or more, with tissue-repair pathways (integrin signaling, ubiquitin-proteasome activation) upregulated and inflammatory cascades downregulated. The breadth of this gene-expression effect—documented in silico and in cell culture—distinguishes GHK-Cu from simple copper supplements and remains an area of active investigation.

Human clinical evidence for GHK-Cu is concentrated in topical dermatology and remains modest in scale. Several small, industry-associated placebo-controlled trials have examined photoaged skin endpoints.

In one 71-woman, 12-week placebo-controlled study of a GHK-Cu facial cream (described in the Pickart and Margolina 2015 review, PMC4508379), investigators reported improvements in skin density and thickness, reduced laxity, and reductions in fine lines and wrinkle depth. A parallel 41-woman, 12-week periorbital study found the GHK-Cu eye cream outperformed a vitamin K control on wrinkle and line measures. A separate double-blind trial using a nano-lipid-carrier formulation reported a 31.6% reduction in wrinkle volume relative to Matrixyl 3000 control and a 55.8% reduction versus an inert serum control, with a 32.8% reduction in wrinkle depth. A 21-subject randomized controlled trial led by Wayne Carey, MD (McGill University) tested a GHK-Cu gel formulation over three months and found a mean 28% increase in subdermal echogenic density (a proxy for collagen and elastin content by high-resolution ultrasound), with the highest-responding quartile approaching 51% improvement. Notably, none of these trials are large, all were of short duration, and several have overlapping authorship with commercial interests, warranting caution in interpretation.

In preclinical research, Campbell et al. (Genome Medicine 2012, PMID 22937864) performed gene-expression analysis on 64 lung tissue specimens from eight COPD patients with varying emphysema severity. Using the Connectivity Map, they identified GHK as a compound capable of reversing a 127-gene emphysema-destruction signature; treatment of cultured human lung fibroblasts with GHK recapitulated TGF-beta-induced actin organization and elevated integrin beta-1 expression.

Zhang et al. (Frontiers in Molecular Biosciences 2022, PMID 35936787) exposed male C57BL/6 mice (n=60) to cigarette smoke for 12 weeks; intraperitoneal GHK-Cu at 2 and 20 ug/g/day on alternate days significantly attenuated alveolar enlargement, restored MMP-9/TIMP-1 balance, reduced IL-1beta and TNF-alpha in bronchoalveolar lavage fluid, and upregulated Nrf2/HO-1. Dou et al. (Aging Pathobiology and Therapeutics 2020, PMID 35083444) reported that aged mice (28 months, n=10) receiving 10 mg/kg GHK-Cu five times weekly for three weeks showed improved spatial learning.

Injectable or systemic use in humans has not been tested in published controlled trials identified in this search. All evidence for that route remains anecdotal or derived from animal models.

Typical dosage: 1-3 mg (daily).

Topical (cosmeceutical and clinical): Clinical trials reviewed here used cream and gel formulations at approximately 1% active concentration, applied once or twice daily for 8 to 12 weeks. The 2015 Pickart and Margolina review references multiple trials in this range. Commercial skincare products typically list GHK-Cu at concentrations from 0.001% to 3%; EU cosmetic regulations permit topical use as a skin-conditioning agent, and one regulatory reference in the wound healing literature cites a maximum leave-on concentration of 0.002% for standard cosmetics, though clinician-compounded formulations and post-procedure serums often exceed this.

Injectable (subcutaneous; not FDA-approved for human use in the United States): Compounding pharmacies and clinical practitioners in the wellness-medicine space have circulated protocols suggesting subcutaneous injection of 1 to 2 mg per day, with some sources describing a starting dose of 200 to 500 mcg/day that is escalated over one to two weeks. Cycle lengths of 4 to 8 weeks on, followed by a rest period of comparable duration, are commonly reported. Reconstitution typically uses bacteriostatic water to yield a concentration of 0.5 mg/mL (500 mcg/mL), with dose delivery via insulin syringe. These injectable protocols originate from practitioner forums and compounding pharmacy guidance rather than published controlled trials, and no pharmacokinetic dose-ranging study in humans has been published to validate them.

Animal research used IP or IV doses of 0.5 ug/kg to 20 ug/g/day, which do not translate directly to human equivalents without further study.

This information is provided for educational and encyclopedic reference only and does not constitute medical advice. GHK-Cu is not approved by the FDA as a drug. Individuals considering use should consult a licensed healthcare provider.

Lyophilized (before reconstitution)

Multiple vendor sources cite 12–24 months at −20°C to 2–8°C for the lyophilized copper-complexed powder; only 2–4 months at room temperature. GHK-Cu is the standout exception to the usual "heat is the main enemy" rule for research peptides — light and oxidation, catalyzed by the bound copper ion, are flagged as equally or more important than temperature. Store in amber or opaque vials, dark, and away from any oxidizing environment.

Reconstituted

Commonly cited at ~28–30 days refrigerated (2–8°C) in bacteriostatic water. Never freeze. Protect rigorously from light throughout the in-use period. A visible shift toward greenish-blue discoloration is repeatedly cited across vendor sources as a sign that the copper complex has degraded — discard rather than use if this occurs. This is a vendor-derived convention rather than a peptide-specific stability study, and the discoloration cue is one of the few visible degradation markers available at this tier. See the Storage & handling primer for context.

For general storage chemistry (bacteriostatic vs sterile water, freeze-thaw, BUD framework), see Storage & handling.

Last reviewed: July 1, 2026

TriHex and TriHex 2.0 (GHK-Cu combined with hexapeptide-12, and in the extended version octapeptide as well) have been used in post-aesthetic-procedure wound care formulations. A small single-blinded clinical study referenced in a 2025 tripeptide wound-healing review (PMC12595317) found the combination produced less erythema, exudation, tenderness, and burning compared to control; the study lacked a large sample size, and evidence remains preliminary.

GHK-Cu combined with BPC-157 and TB-500 (thymosin beta-4 fragment): This three-peptide stack, sometimes marketed as the "GLOW" blend, is promoted in the compounding-medicine and wellness community for systemic tissue repair, injury recovery, and skin rejuvenation. The proposed rationale is complementary mechanism coverage—BPC-157 for angiogenesis and gastrointestinal/neural healing, TB-500 for actin polymerization and cell migration, and GHK-Cu for ECM remodeling and copper-dependent enzyme activation. No controlled human trial for this combination has been published. All evidence for the stack is anecdotal or derived from independent preclinical studies of each component.

GHK-Cu has also been incorporated into hydrogel and polysaccharide-based wound dressings for sustained topical delivery, with promising results in animal wound models, though human controlled data are lacking for these formulation combinations as well.

GHK-Cu is not currently FDA-approved for any indication. Effective April 22, 2026, the FDA removed GHK-Cu from Category 2 of its Section 503A bulk drug substances list after the original nominators withdrew their nominations. This removal lifts the prior “significant safety risk” designation but does not place GHK-Cu on the 503A Bulks List. Compounding pharmacies may prepare it with a valid physician prescription and pharmaceutical-grade API from an FDA-registered manufacturer. The FDA’s Pharmacy Compounding Advisory Committee (PCAC) is scheduled to review this substance at its July 23–24, 2026 public meeting. Removed from FDA Category 2 effective April 22, 2026. NOT selected for July 23-24, 2026 PCAC meeting. Deferred to second PCAC meeting before February 2027. NOT currently on 503A Bulks List — requires physician Rx and pharma-grade API. Source: FDA Advisory Committee Calendar / Lengea Law, May 2026.

PeptideSciences101 does not endorse vendors. For transparency metrics and third-party testing notes, see the vendor directory.

Reported side effects: Generally safe. Possible: mild skin irritation with topical use

Topical safety: GHK-Cu has appeared in cosmetic and skincare products for several decades. Standard preclinical safety testing including repeated-dose dermal toxicity, skin irritation, sensitization, and genotoxicity assays has been negative at cosmetic concentrations. The tripeptide-copper complex does not exhibit cytotoxicity to primary human cells in culture, which is attributed to the controlled copper-complexation chemistry. Occasional mild skin irritation or contact sensitization is possible, as with any topically applied bioactive ingredient, but serious cutaneous adverse events have not been documented in the published literature.

Injectable use: Injection site reactions—transient erythema, mild swelling, and local tenderness—are reported by practitioners and compounding pharmacy guidance documents. These are generally described as self-resolving within 24 to 48 hours. No formal incidence data from clinical trials is available.

Copper toxicity: At injectable doses of 1 to 3 mg/day, elemental copper delivery is substantially below the tolerable upper intake level for adults (10 mg/day, Institute of Medicine). Acute copper toxicity is therefore unlikely in metabolically healthy individuals. However, patients with Wilson's disease—a genetic disorder of copper excretion—face an elevated risk of copper accumulation and represent an absolute contraindication. Similarly, individuals undergoing chelation therapy for heavy metal removal should not use GHK-Cu, as the two interventions work at cross purposes.

Contraindications and special populations: Use during pregnancy or lactation is not supported by safety data and is generally avoided. Patients with active malignancy should not use GHK-Cu without oncology consultation, given the peptide's growth-promoting and gene-modulating properties. The compound has a short plasma half-life (estimated under 30 minutes after injection), limiting systemic exposure duration, but no formal pharmacokinetic human studies have been published. No clinically characterized drug-drug interactions have been described in the peer-reviewed literature.