Consumerlab has highlighted quality problems with ginkgo since it began testing the herb in 1999.
Of the ginkgo products tested, two contained less ginkgo than claimed on their labels, two others contained contaminants, one of which was lead. Another product didn’t identify the part of the ginkgo plant used, a Food and Drug Administration (FDA) labeling requirement.
The results formed part of a wider Consumerlab market scan of memory products that included huperzine A and acetyl-L-carnitine. Two of three huperzine and five of five acetyl-L-carnitine supplements were deemed fit for purpose.
The relatively high cost of ginkgo may have contributed to the large percentage of failed products, Consumerlab suggested.
“Some companies put less of it in their products than they claim or use ingredient that has been adulterated with inexpensive material that can fool non-specific tests,” said Dr William Obermeyer, ConsumerLab’s vice president for research and a former FDA natural products chemist, has been monitoring problems with ginkgo for several years.
“Highly specific test methods, such as HPLC (high performance liquid chromatography), reveal these shortcomings, allowing us to direct consumers toward products of better quality.”
But companies continued to make products with little to no ginkgo in them, leading Consumerlab to suggest “ginkgo is among the most adulterated herbs.”
ConsumerLab's 1999 review of ginkgo products found nearly one quarter of thirty brands tested did not have the expected levels of chemical marker compounds, despite claims to have been "standardized."
2003 testing found seven of nine ginkgo products lacked adequate levels of certain marker compounds, with six products failed testing for the same reason in 2005.
In the current assessment, of the ginkgo products tested, only Freeda Ginkgo Biloba and Ginkgo-Go! Ginkgo Biloba Extract passed while Vitamin Shoppe Standardized Herbs Ginkgo Biloba Extract passed voluntary testing.