How Products Were Selected:
Products tested 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 companies. Products were not accepted directly from manufacturers.Testing Methods:
- Quantification of total resveratrol content including trans/cis resveratrol and trans-resveratrol in the glucoside form (also known as polydatin) by High Performance Liquid Chromatography (HPLC).
- Quantification of lead, arsenic and cadmium by 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 pills (excluding capsule, chewable, sublingual, enteric-coated, and time-release formulations) using United States Pharmacopeia (USP) <2040> methodology.
Identities of products were not disclosed to laboratories performing the testing.
ConsumerLab.com may modify or use other appropriate test methods if necessary to test special product formulations.
Passing Score:*
To achieve a "Pass" in the testing a product had to:
- Contain 100%, and not more than 130%, of the claimed amount of total trans resveratrol.
Total trans resveratrol = sum of free trans resveratrol + trans-resveratrol in the glucoside form (polydatin) x 0.587 (note: polydatin glucoside is composed of 58.7% resveratrol). - Heavy Metals: Products containing whole herbs and/or more than 250 mg of minerals per daily dose must not exceed the following limits:
Lead**:- Products 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 of lead per daily serving with an additional allowance of 0.8 mcg if the product contains 1,000 mg/day of elemental calcium.
- Products with a single serving weights 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 1000mg/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). 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).If marketed for use by children, may not exceed 3.0 micrograms 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).
- Meet recommended USP <2040> parameters of disintegration of dietary supplements (excluding capsule, chewable, sublingual and time-release products).
- Be in compliance with 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 display an unacceptable variation in quality, present a safety risk or to provide misleading or inaccurate information in its labeling.
** The State of California's Prop 65 limit. California requires supplements exceeding this limit to bear a warning label.
