GHK-Cu Drug-Drug Interactions: Complete Clinical Profile for Copper Tripeptide

Is there a GHK-Cu interaction list to check?

No. No FDA-approved medicine is known to contain GHK-Cu, so there is no manufacturer label with a drug interactions section for the peptide [1]. Compounded drugs are not FDA-approved, and FDA does not review their safety, effectiveness or quality before marketing [2]. Non-injectable GHK-Cu sits in category 1 of FDA's interim compounding policy, still under evaluation [1][3]. Injectable GHK-Cu is listed among substances nominated but withdrawn, with FDA citing potential immunogenicity from aggregation and peptide-related impurities and limited human safety data [4].

The copper medicine that does have a label

Cupric chloride injection, a different product from GHK-Cu, has FDA labeling as an intravenous supplement for patients on total parenteral nutrition. Its label says that copper given to patients with Wilson disease may increase hepatic copper accumulation and aggravate underlying hepatocellular degeneration, and that chelating agents such as D-penicillamine can be used to treat acute copper toxicity [8]. Copper histidinate (Zycubo) is FDA-approved for Menkes disease in children and is a different compound from GHK-Cu [9].

Zinc and copper absorption

Zinc acetate is FDA-approved for maintenance therapy of Wilson disease and works by inducing metallothionein in intestinal cells, which blocks copper absorption from the gut [10]. In a 10-week controlled trial, adult women given 50 mg of zinc a day as zinc gluconate had significantly lower erythrocyte copper-zinc superoxide dismutase, serum ferritin and hematocrit than before treatment, while serum ceruloplasmin and hemoglobin did not change [5]. That trial used oral zinc alone, with no GHK-Cu.

What the human GHK-Cu studies looked like

The human trials found are topical and small. A randomized trial in 13 patients with CO2-laser-resurfaced skin found no significant difference in redness resolution, wrinkles or overall skin quality on computer analysis and blinded assessment, though a patient questionnaire favoured GHK-Cu (P=.04) [6]. A randomized evaluator-blinded trial in 86 evaluable patients with venous stasis ulcers found a 0.4% tripeptide copper complex cream no different from an inert vehicle, while silver sulfadiazine 1% reduced ulcer size [7]. A 2026 systematic review of 64 retained records called the human literature thin and fragmented [12].

Topical copper peptide serums are sold as cosmetics, which do not need FDA approval before sale, while an injectable GHK-Cu product is not a cosmetic and is not FDA-approved [13].