GHK-Cu (Copper Tripeptide)

Also known as GHK, Copper tripeptide-1, Glycyl-L-histidyl-L-lysine copper(II), Tripeptide-1

GHK-Cu is a naturally-occurring tripeptide — glycyl-L-histidyl-L-lysine — that binds copper(II) ions with high affinity. It was first isolated by Loren Pickart in 1973 from human plasma fractions that promoted survival of older liver cells when exposed to plasma from younger subjects.^[1]

What GHK-Cu is

GHK is a tripeptide consisting of glycine, L-histidine, and L-lysine. Its biological activity depends on its ability to bind copper(II) ions; the GHK-Cu complex is the form found in human plasma, saliva, and urine, and the form most studied in biology.^[2]

Endogenous plasma GHK declines with age. Pickart's group has reported levels of approximately 200 ng/mL at age 20 falling to roughly 80 ng/mL by age 60 — a 60% age-related decline that frames much of the modern interest in GHK-Cu as an "aging" intervention.^[3]

GHK-Cu's most distinctive biological property is the breadth of its reported gene-expression effects. Genome-wide microarray analyses have associated GHK-Cu exposure with significant modulation of expression in over 4,000 human genes — roughly a third of the genome — affecting pathways involved in DNA repair, antioxidant defense, mitochondrial function, and tissue regeneration.^[4] This breadth is unusual for a small peptide and is both the basis of the molecule's scientific interest and a reason to interpret claims with care: broad gene modulation in cell culture does not predictably translate to clinical effect in vivo.

Mechanism of action

The proposed mechanisms are several, with varying degrees of evidence:

• Copper transport and delivery. GHK binds Cu²⁺ with high affinity and may act as a physiologic copper-delivery shuttle to cells. Local copper bioavailability is required for lysyl oxidase activity (collagen and elastin cross-linking) and for several wound-repair enzymes.^[2]
• Direct stimulation of collagen, glycosaminoglycan, and decorin synthesis in fibroblasts in vitro.^[2]
• Broad gene expression modulation with effects on antioxidant, anti-inflammatory, and tissue-remodeling pathways.^[4]

For most claimed applications — wound healing, skin remodeling, hair follicle support — the strongest evidence is in vitro and in animal models. The available human data is largely topical and cosmetic.

Human evidence

The clinical evidence for GHK-Cu is dominated by topical cosmetic applications. Systemic (injectable) human RCTs are essentially absent from the indexed literature, despite extensive marketing of injectable formulations.

The persistent gap in the GHK-Cu literature is the absence of properly designed randomized controlled trials of injectable GHK-Cu in humans for any of the systemic applications it is marketed for (anti-aging, wound healing, fibrosis, neuroprotection). The molecule has 50+ years of mechanistic study and a thin clinical record.

Marketed claims vs. published evidence

Note the asymmetry: the strongest human data supports a narrow cosmetic claim about topical use. The broad systemic claims marketed for injectable GHK-Cu rest on in vitro and animal data, with limited human trial support.

Regulatory status

GHK-Cu occupies an unusual regulatory position relative to the peptides that were swept into the 2023 Category 2 restriction:

• Not on the 2023 Category 2 list. Unlike BPC-157, TB-500, Thymosin Alpha-1, AOD-9604, MOTS-c, Selank, Semax, and KPV, GHK-Cu was not placed on the 2023 FDA Category 2 restriction list. It has been continuously compoundable under 503A throughout the 2023–2026 events.^[6]
• Cosmetic ingredient status. GHK-Cu is widely used as a cosmetic ingredient (Tripeptide-1, Copper Tripeptide-1) in over-the-counter skin care products. Cosmetic use is regulated separately from drug use and is generally permissible without FDA pre-market approval.
• No FDA-approved drug product. There is no FDA-approved GHK-Cu finished drug product.

Safety considerations

GHK-Cu has a long history of topical cosmetic use without major safety signals. Reported adverse events in cosmetic trials are minor (transient redness or irritation in a minority of subjects). The endogenous nature of the molecule and its low oral bioavailability further reduce systemic risk for topical exposure.

The safety picture for injectable GHK-Cu is less well characterized. There are no large modern RCTs of subcutaneous administration. Copper homeostasis is tightly regulated; concerns about supplemental copper delivery via injection are theoretical but not well-studied in this peptide's literature.

Dosing is not addressed on this page. Decisions about therapeutic use of GHK-Cu — particularly injectable use — belong with a licensed prescriber who can evaluate individual context.

Frequently asked questions

Related peptides

Citations

1. Pickart L, Thaler MM. Tripeptide in human serum which prolongs survival of normal liver cells and stimulates growth in neoplastic liver. Nature New Biology. 1973. PMID 4349963
2. Pickart L, Vasquez-Soltero JM, Margolina A. GHK peptide as a natural modulator of multiple cellular pathways in skin regeneration. BioMed Research International. 2015. ↗ Source DOI: 10.1155/2015/648108
3. Pickart L, Vasquez-Soltero JM, Margolina A. The human tripeptide GHK-Cu in prevention of oxidative stress and degenerative conditions of aging: implications for cognitive health. Oxidative Medicine and Cellular Longevity. 2012. PMID 22666519
4. Pickart L, Margolina A. Regenerative and protective actions of the GHK-Cu peptide in the light of the new gene data. International Journal of Molecular Sciences. 2018. PMID 29986520
5. Leyden J, Stephens T, Finkey MB, Appa Y, Barkovic S. Skin care benefits of copper peptide containing facial cream. American Academy of Dermatology Annual Meeting, abstract. 2002. ↗ Source Conference proceedings; not indexed in PubMed.
6. Amanecia Health editorial. FDA peptide reclassification 2026. amaneciahealth.com. 2026. ↗ Source industry-analysis