GHK-Cu

What it is

GHK-Cu — glycyl-L-histidyl-L-lysine copper, also called "copper tripeptide" or, on cosmetic ingredient labels, "copper tripeptide-1" — is a naturally occurring tripeptide-copper(II) complex found in human blood plasma, saliva, and urine. It was first identified in 1973 as a plasma component that promoted survival of liver cells in culture, and it's since been studied extensively, primarily in cosmetic and dermatological contexts, for its ability to promote wound healing and stimulate collagen and glycosaminoglycan synthesis.¹

GHK-Cu is unusual among research peptides because it has a long, mainstream, legal history of commercial use — but strictly in topical, cosmetic form. Injectable GHK-Cu, marketed for purported systemic or "anti-aging" effects, is a separate, much less studied and unregulated product, and the two shouldn't be assumed to share a safety or efficacy profile.

GHK itself is naturally released from the alpha-2(I) chain of type I collagen and from the matricellular protein SPARC when tissue is damaged and proteolytic enzymes are activated — proposed as the biological basis for GHK-Cu's role as an early "damage signal" that helps trigger tissue repair. Unlike Semax or Selank, GHK-Cu wasn't developed abroad — it was discovered in the US by researcher Loren Pickart (UCSF, 1973) and developed primarily through the cosmetic and dermatology industries, with a wound-healing method patent issued in 1992. It's also known simply as copper peptide or Gly-His-Lys.

How it works

GHK-Cu's mechanism is unusually well-characterized at the molecular and genomic level compared with most research peptides — though that characterization comes overwhelmingly from in vitro, animal, and topical human studies, not from systemic or injectable human trials. Using the Broad Institute's Connectivity Map, GHK-Cu was found to up- or down-regulate a very large share of profiled human genes — roughly 31% changing by 50% or more — spanning tissue remodeling, antioxidant response, inflammation, blood vessel growth, nerve outgrowth, and anti-cancer pathways.¹

In fibroblast culture, the GHK-Cu complex stimulates synthesis of collagen, select glycosaminoglycans, and the small proteoglycan decorin, while modulating matrix metalloproteinase and anti-protease activity — effects first demonstrated in 1988 and further characterized through the late 1990s.² Early in tissue repair, GHK and related SPARC-derived peptides stimulate new blood vessel growth; later in the healing process they're reported to inhibit it, suggesting a regulatory, phase-dependent role rather than simple stimulation. GHK-Cu has also increased production of nerve growth factor and neurotrophins in study models, sped up nerve fiber regeneration in collagen-tube nerve regeneration models, and shown antioxidant activity by inactivating reactive lipid-peroxidation byproducts and reducing iron release from ferritin.

In a mouse model of acute lung injury, GHK-Cu reduced inflammatory cell infiltration, increased superoxide dismutase activity, decreased TNF-α and IL-6 production, and blocked NFκB p65 and p38 MAPK activation.³ Preclinical work has also found GHK down-regulates a panel of genes associated with metastasis and affects apoptosis- and DNA-repair-related genes in vitro — exploratory findings, not clinical evidence of anti-cancer efficacy in humans. Intraperitoneal GHK in rats has increased exploratory behavior and reduced pain-induced aggressive-defensive behavior in rodent models.⁴

Route matters a great deal here. GHK-Cu penetrates the stratum corneum, which supports its activity in topical cosmetic formulations, and penetration can be enhanced with liposomal or nano-lipid carrier delivery. But no detailed systemic pharmacokinetic profile — bioavailability, plasma half-life, clearance, or metabolism data — for injected GHK-Cu in humans was identified in the peer-reviewed literature.¹ Topical use is overwhelmingly the best-studied and most widely used route; injectable (subcutaneous) use is marketed in the research-chemical space for purported systemic effects, but this route has essentially no dedicated human clinical trial base.

What the research shows

Topical evidence (human)

These studies collectively support GHK-Cu's role as a legitimate, moderately well-evidenced topical cosmetic ingredient for signs of skin aging — though most are small, industry-sponsored, or presented at conferences rather than published as large independent peer-reviewed randomized trials, a limitation common across cosmetic dermatology research generally. Animal and preclinical wound-healing evidence — also topical, not injectable — includes veterinary studies of a topical tripeptide-copper complex on ischemic and open-wound healing in dogs and rabbits.

Human evidence — injectable/systemic

This is where the evidence base becomes markedly thinner, and it should not be confused with the topical data above. Systemic GHK-Cu effects have primarily been examined via intraperitoneal injection in rodents — for example, anti-anxiety and anti-aggression behavioral testing at approximately 0.5 micrograms/kg — and in some larger-animal topical wound models. No dedicated human clinical trial of injectable or subcutaneous GHK-Cu for systemic anti-aging, regenerative, or metabolic effects was identified in the literature reviewed for this brief. Claims about injectable GHK-Cu's systemic benefits in humans are extrapolations from topical human data and animal injection studies — a significant evidentiary gap that mirrors, though is somewhat less severe than, the human-data gap seen with TB-500.

Typical use and dosing

Topical and injectable use rest on entirely different evidence bases, and dosing information should be read with that route distinction in mind.

No standardized, validated dosing protocol exists for injectable GHK-Cu, because no human dose-finding trial for that route has been conducted.

Safety, side effects, and who should avoid it

Topical use: GHK-Cu has a long track record in over-the-counter cosmetic products without significant reported adverse events; the literature describes it as safe and inexpensive, with decades of cosmetic use and no notable safety signals. Occasional mild skin irritation is possible, as with most active cosmetic ingredients, particularly at higher concentrations or in sensitive skin.

Injectable/systemic use is a substantially different risk profile, and it is not adequately studied. Animal injection studies used low microgram-per-kilogram doses for short-term behavioral testing, not chronic, human-relevant dosing regimens. Long-term safety of repeated subcutaneous injection — including injection-site reactions, immune response to a copper-peptide complex, or effects of supraphysiological systemic copper exposure over time — hasn't been systematically studied. Because injectable GHK-Cu is sourced through unregulated research-chemical vendors rather than pharmaceutical manufacturers, purity, correct peptide-to-copper ratio, sterility, and endotoxin content can't be assured. There's essentially no long-term, multi-year human pharmacovigilance data for the injectable form.

Regulatory status

GHK-Cu is not FDA-approved as a drug for any indication, whether topical or injectable. Its topical cosmetic use is legal because FDA's cosmetic regulatory framework doesn't require premarket approval of cosmetic ingredients — it's regulated as a cosmetic active ingredient (INCI name "copper tripeptide-1"), not a drug.⁹

According to FDA's own bulk drug substances documentation (updated May 14, 2026), "GHK-Cu (except for injectable routes of administration)" is listed in Category 1 — "Bulk Drug Substances Under Evaluation" — of FDA's interim policy for the 503A bulks list.⁸ Category 1 substances aren't yet formally on the 503A list, but FDA has said it doesn't generally intend to pursue enforcement against compounders using Category 1 substances under specified conditions, pending final evaluation. This status has been in flux: non-injectable GHK-Cu was removed from Category 1 on April 22, 2026 after nominators withdrew their nomination, then added back on May 5, 2026 after a nominator clarified it intended to withdraw only the injectable-route nomination. FDA has stated it intends to consult the Pharmacy Compounding Advisory Committee regarding potential inclusion of GHK-Cu on the 503A bulks list before the end of February 2027.

Injectable GHK-Cu is explicitly excluded from the Category 1 listing. This means it doesn't currently benefit from FDA's non-enforcement policy for Category 1 substances and isn't eligible for 503A compounding at this time. In practical terms, a compounding pharmacy can pursue topical GHK-Cu preparations under the current interim policy, but cannot legally compound an injectable GHK-Cu product for a patient.⁸ Injectable GHK-Cu sold outside this framework is distributed through the same unregulated "research chemical" channels as TB-500, Semax, and Selank, carrying the same purity, sterility, and endotoxin-contamination risks associated with that supply chain.

GHK-Cu isn't explicitly named in any category of the WADA Prohibited List. Topical, cosmetic use is considered to carry negligible anti-doping regulatory exposure for athletes. Injectable use for systemic effect occupies more of a gray zone: WADA's S2.3 catch-all language prohibits growth factors or growth factor modulators affecting tissue protein synthesis, vascularization, or regenerative capacity, and GHK-Cu's mechanism could arguably fall within that language if WADA elected to invoke it — but no published WADA decision specifically addressing GHK-Cu was identified as of mid-2026.¹⁰ Athletes considering injectable GHK-Cu should treat its anti-doping status as unresolved.

Frequently asked questions