The National Toxicology Program (NTP) recently released its peer-reviewed report on the toxicology and carcinogenesis of Ginkgo biloba, “an herbal remedy and dietary supplement purported to improve memory and brain function.” Based on long-term studies in which researchers “deposited solutions of Ginkgo biloba extract in corn oil directly into the stomachs of male and female mice and rats five times a week for two years,” the report concluded that animals exposed to Ginkgo biloba extract “experienced increased rates of a variety of lesions in the liver, thyroid, and nose” as well as “increased incidences of cancers of the thyroid gland… in male and female rats and male mice and liver cancers in male and female mice.”

Citing these studies, the Center for Science in the Public Interest (CSPI) has since issued a warning to consumers, advising them to avoid a number of products, including energy drinks, that list ginkgo as an ingredient. According to CSPI, the Food and Drug Administration has already sent “warning labels [sic] to several drink companies…, stating that ginkgo is not generally recognized as safe, or GRAS, for use in food, though it is legal as an herbal supplement.”

“Ginkgo has been used in recent years to let companies pretend that supplements or energy drinks with it confer some sort of benefit for memory or concentration,” said CSPI Executive Director Michael Jacobson. “The evidence for those claims has been dubious, at best. The pretend benefits are now outweighed by the real risk of harm.” Meanwhile, the American Herbal Products Association (AHPA) strongly criticized the report for failing to distinguish between the extract used in the study and products sold commercially, which, the organization contends, are not chemically similar. American Botanical Council founder and executive director Mark Blumenthal observed that the dosage levels administered in the lab were significantly higher than levels ordinarily used by consumers. See CSPI and AHPA News Releases, April 18, 2013.