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.
- Identification and quantification of pyrroloquinoline quinone (PQQ) by High Performance Liquid Chromatography (HPLC).
- Quantitative analyses for lead, cadmium and arsenic by ICP/MS (Inductively Coupled Plasma-Mass Spectroscopy) for all products.
- Disintegration of tablets (excluding chewable, sublingual and time-release formulations) utilizing United States Pharmacopeia (USP) <2040> recommendations entitled "Disintegration and Dissolution of Nutritional Supplements".
ConsumerLab.com may modify or use other appropriate test methods if necessary to test special product formulations.
The identities of the products were not disclosed to the laboratories performing the testing.
Passing Score:*To achieve a "Pass" in the testing, a product had to:
- Contain at least 100% of its labeled amount of PQQ and no more than 150% of this amount.
- Heavy Metals: Products must not exceed the following limits:
- Products marketed for use by children may not exceed California's 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 single serving weights of less than 5 grams that 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 if containing 250 to 999 mg/day of any combination of elemental calcium, magnesium and potassium or 0.8 mcg if containing 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 one whole herb (not extract) or 1.0 mcg if containing 1000 mg/day or more whole herb (not extract). However, total lead allowance will not exceed 2 mcg per recommended daily serving.
- 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 limit and state of New Jersey limits - based on 1 liter of water).
- Meet recommended USP <2040> parameters of disintegration for dietary supplement tablets (excluding chewable, sublingual 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 it's testing if it considers such product to display unacceptable variation in quality, present a safety risk or to provide misleading or inaccurate label information.
** The state of California Prop 65 law requires products exceeding this limit to bear a warning label.