GHK-Cu is a copper complex of the tripeptide glycyl-L-histidyl-L-lysine. Loren Pickart isolated it from human plasma in the early 1970s, and by 1977 the active fragment had been identified as the GHK sequence. The peptide occurs naturally in blood, saliva, and urine, and it binds copper(II) with high affinity to form the complex sold today as copper tripeptide-1 (its INCI cosmetic name).
One often-cited detail: GHK is present in human plasma at roughly 200 ng/ml around age 20, and that level falls to about 80 ng/ml by age 60, per the figures compiled in the Wikipedia summary of the literature. That age-related decline is part of why it gets framed as a regenerative signal.
What the research actually shows
Most of the solid evidence is in skin and wound biology, and a lot of it is in vitro or animal work rather than large human trials.
- Collagen and the extracellular matrix. In cultured skin fibroblasts, GHK-Cu stimulates synthesis of collagen, glycosaminoglycans, and other matrix components, and it modulates matrix metalloproteinases involved in tissue remodeling. A foundational study on glycosaminoglycan and proteoglycan expression in wounds was published in the Journal of Investigative Dermatology.
- Wound healing. Animal work is the strongest part of the record. In a rat model, GHK-treated wounds closed faster than vehicle or untreated controls.
- Gene expression. Using the Broad Institute's Connectivity Map data, Pickart and colleagues estimated that GHK changes the expression of roughly 31.2% of assayed human genes by 50% or more in the cell lines tested. That figure, frequently quoted in marketing, comes from their analysis published in *Brain Sciences* (2017). It is a computational signature from cancer cell lines, not a clinical outcome.
- Skin penetration. A diffusion-cell study by Hostynek, Dreher, and Maibach in Inflammation Research (2010), available via PubMed Central, found the copper tripeptide penetrates and accumulates in skin in measurable amounts, which supports the case for topical use.
Claims that reach beyond skin (lung, liver, nerve, anti-cancer effects) appear mainly in review articles and preclinical or in silico data. They are interesting, but they are not the same as proven clinical benefit in people.
A note on the evidence
The Wikipedia entry itself flags that much of the GHK-Cu literature leans on primary sources and reviews by the same investigators, and that it needs more independent medical references. Treat the topical and wound-healing data as the well-supported core, and the systemic and disease claims as preliminary.
Regulatory and quality status
GHK-Cu is widely used as a cosmetic ingredient in anti-aging and hair products, where it is regulated as a topical cosmetic, not a drug. The injectable form is a different story. In the U.S. it is not an approved drug, and copper peptide GHK-Cu was placed on the FDA's Category 2 bulk drug substances list, which means compounding pharmacies cannot legally compound it. GHK-Cu is not explicitly named on the WADA Prohibited List, but athletes should not read that as a clearance, since WADA uses broad class-based catch-all categories.
Material sold as research powder or vials is sold for laboratory use only and is not approved for human consumption. None of this is medical or dosing advice.
What matters if you're comparing vendors
Because peptide vendors are not selling an approved drug, identity and purity are on the buyer to verify. For GHK-Cu specifically:
- Look for a recent, batch-specific Certificate of Analysis with identity (mass spec) and purity (HPLC), not a generic spec sheet.
- Copper content and the correct copper-to-peptide complex matter for this molecule; the copper is part of what does the work, so a COA that only reports peptide purity is incomplete.
- Cross-check the vendor against the independent third-party rating sources this site aggregates rather than relying on a seller's own marketing.
GHK-Cu has one of the deeper research trails among the peptides people ask about. Just keep the line clear between decades of skin-cell and animal data and the much thinner record for injection or systemic effects in humans.