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Product Review: Ginkgo (Ginkgo Biloba) Supplements Review

HOW PRODUCTS WERE EVALUATED:

How Products were Selected:
Products were selected to represent those commonly sold and/or available nationally in the U.S. ConsumerLab.com purchased products on the open market through retail stores, on-line retailers, and direct sales or multi-level marketing companies. Products were not accepted directly from manufacturers.

Testing Methods:
Products were tested for amount(s) of key marker compounds for Ginkgo biloba. Quantitative analysis of flavonol glycosides utilizing a HPLC method with UV detection and analysis of bilobalide and ginkgolides (Terpene Lactones) by HPLC using an Evaporative Light Scattering Detector (ELSD). Analyses included identification of potential contamination with lead in botanical products.

Analyses for lead were performed using Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) instrumentation.

Disintegration of non-chewable, non-capsule, non-enteric coated and non-time release formulations was analyzed by ConsumerLab.com utilizing USP (United States Pharmacopeia) <2040> methodology.

Products failing to meet any Passing Score were re-tested in a second independent laboratory using similar methods and instrumentation.

ConsumerLab.com may modify or use other appropriate test methods if necessary to test special product formulations.

Passing Score: *
To pass testing, a product had to:

Contain at least 100%, and not more than 150% of the expected amounts of total and individual flavonol glycosides and total terpene lactones based on the claimed amount of Ginkgo biloba leaf extract and the ratios defined below. (Ginkgo leaf products must contain a minimum of 0.8% flavonol glycosides.)

Flavonol Glycosides:
Total flavonol glycosides 22-27% (wt/wt)** (Sum of quercetin, kaempferol and isorhamnetin)

Quercetin minimum 9.5% (wt/wt)
Kaempferol minimum 10.5% (wt/wt)
Isorhamnetin minimum 2.0% (wt/wt)

Terpene Lactones:
Total terpene lactones 5-7% (wt/wt)** (Sum of ginkgolides A,B,C and bilobalide)

Ginkgolides A, B, C minimum 2.8%(wt/wt)**
Bilobalide minimum 2.6% (wt/wt)**

**Reference: German Commission E Monograph, American Herbal Pharmacopoeia Monograph
Not exceed California Prop 65 levels for lead contamination in a recommended daily serving of a dietary supplement, i.e., contain less than 0.5 mcg of lead per daily serving with an additional allowance of 1.0 mcg for supplements containing 1,000 mg/day or more of elemental calcium and 0.5 mcg for supplements containing specific other minerals.** For supplements not marketed for use by children, ConsumerLab.com provides an additional allowance of 0.5 mcg if containing 250 to 499 mg/day of elemental calcium, or 1.0 mcg if containing 500 to 999 mg/day of elemental calcium, and an allowance of 0.5 mcg if containing one whole herb (not extract) ingredient or 1.0 mcg for two or more whole herb ingredients. If a maximum recommended daily serving is not defined, a daily serving size will be determined and applied by CL.
Meet recommended USP parameters for disintegration for nutritional supplements (excluding capsule, chewable and time-release products).
Meet FDA labeling requirements.

* Passing scores allow for specific margins of technical error associated with each analysis. ConsumerLab.com reserves the right to disqualify a product at any time from passing its testing if it considers such product to present a safety risk or to provide misleading or inaccurate information in its labeling.

** Based on State of California's Prop 65 lead limit. California requires supplements exceeding this limit to bear a warning label regarding lead.

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