How Products were Selected:
Products were selected to represent those commonly sold and/or available in the U.S. ConsumerLab.com purchased products on the open market through retail stores, on-line retailers, direct sales or multi-level marketing companies. Products were not accepted directly from manufacturers.
Products were analyzed in one or more independent laboratories for the following:
- Quantification of hydrolyzed flavonoids as glycosides by High Performance Liquid Chromatography (HPLC) or other methodology deemed appropriate by CL.
- Quantification of bilobalide and ginkgolides (Terpene Lactones) by HPLC using an Evaporative Light Scattering Detector (ELSD) or Refractive Index (RI) detector.
- Quantification of unhydrolyzed rutin and quercetin by HPLC.
- Analyses of lead, arsenic, and cadmium performed using an Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) for products containing whole herbs and/or more than 250 mg of minerals per daily dose.
- Disintegration of non-chewable, non-capsule, and non-time release formulations was analyzed by ConsumerLab.com utilizing USP (United States Pharmacopeia) <2040> recommendations entitled "Disintegration and Dissolution of Nutritional Supplements."
Products failing to meet any Passing Score criteria were re-tested in a second independent laboratory using similar methods and instrumentation unless also failing to meet labeling requirements.
ConsumerLab.com may modify or use other appropriate test methods if necessary to test special product formulations.
Identities of the products were not disclosed to the laboratories performing the testing.
To achieve a "Pass" in the testing, a product had to meet the following criteria:
- Contain at least 100%, and not more than 150% of the labeled amounts of total flavonoids (sum of quercetin, kaempferol and isorhamnetin glycosides) and not more than 300% total terpene lactones (sum of ginkgolides A, B, C and bilobalide). If Product does not specify quantity of flavonoids or terpene lactones but doses specify the amount of extract, the product must meet the following minimum specifications; not less than 22% flavonoids and not less than 5.4% terpene lactones (DSC 2015). Ginkgo leaf products must contain a minimum of 0.5% flavonols and a minimum of 0.1% terpene lactones (DSC 2015). The minimums will be applied if the product does not state an amount of flavonoids or terpene lactones or if the claimed amount was lower than the expected minimum.
- A maximum of 4% unhydrolyzed rutin and 0.5% unhydrolyzed quercetin in ginkgo powdered extracts (DSC 2015).
Heavy Metals: Products containing whole herbs and/or more than 250 mg of minerals per daily dose must not exceed the following limits:
- Products marketed for use by children may not exceed California Prop 65 limits for lead in dietary supplements of 0.5 mcg per recommended daily serving with an additional allowance of 0.8 mcg if the product contains more than 1,000 mg/day of calcium.
- Products with a single serving weight of less than 5 grams which are not marketed for use by children, may not exceed the State of California's Prop 65 limits for lead in dietary supplements of 0.5 mcg per recommended daily serving with an additional allowance of 0.4 mcg if containing 250 to 999 mg/day of any combination of elemental calcium, magnesium and potassium or 0.8 mcg if containing more than 1,000 mg/day of any combination of these minerals. An additional allowance of 0.5 mcg is provided if containing 250-999 mg/day of whole herb (not extract) ingredient or 1.0 mcg if containing1000 mg/day or more of whole herb (not extract). However, total lead allowance will not exceed 2 mcg.
- Products with single serving weights of 5 grams or more which are not marketed for children may not exceed 2.5 mcg per serving nor 4.0 mcg per daily serving.
- If marketed for use by children, may not exceed 3.0 micrograms of cadmium per recommended daily serving (based on Canada's limit for a child weighing 75 lbs.). If not marketed for use by children, may not exceed 4.1 micrograms of cadmium per recommended daily serving (based on the State of California's Prop 65 limit).
- Contain less than 10 micrograms of total arsenic and no more than 5 micrograms of inorganic arsenic per daily serving (EPA and state of New Jersey limits - based on 1 liter of water.
- Meets recommended USP <2040> parameters for disintegration of dietary supplements (excluding capsule, chewable and time-release products).
- Meet FDA labeling requirements.
** Based on State of California's Prop 65 limit. California requires supplements exceeding this limit to bear a warning label regarding lead.
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.