How Products were Selected:Products selected by ConsumerLab.com for review 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, or direct sales companies. Products were not accepted directly from manufacturers.
- Products were analyzed for the R and S forms of alpha lipoic acid by High Performance Liquid Chromatography (HPLC) (USP-DSC 2023 modified).
- Quantitative analyses of lead, arsenic, mercury and cadmium were performed using 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 tablets (excluding chewable, sublingual and time release formulations) was performed using United States Pharmacopeia (USP) <2040> methodology for the disintegration of dietary supplements.
ConsumerLab.com may modify or use other appropriate test methods if necessary to test special product formulations.
Identities of products were not disclosed to laboratories performing the tests.
Passing Score:*Passing the ConsumerLab.com quality criteria included the following:
- Product must contain at least 100%, and not more than 115%, of its labeled amount of either R-alpha lipoic acid or R+S-alpha lipoic acid.
- Heavy Metals: Products containing whole herbs and/or more than 250 mg of minerals per daily dose must not exceed the following limits:
Lead: Not exceed the following limits for elemental 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 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 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 (based on the state of California's Prop 65 limit for lead in dietary supplements, above which a warning is required regarding reproductive harm, birth defects, or cancer risks) with an additional allowance of 0.4 mcg if containing 250 to 999 mg/day of elemental calcium, potassium and magnesium, 0.8 mcg if containing1000 mg/day of any combination of these minerals. An additional 0.5 mcg is provided if containing 250-999 mg/day of whole herb (not extract) ingredient or 1.0 mcg for products containing1000 mg/day or more of whole herb (not extract). However, total lead allowance will not exceed 2 mcg per 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 (above which California's Prop 65 law requires a "reproductive harm" warning due to developmental toxicity and male reproductive harm).
- Contain less than 10 micrograms of total arsenic per daily serving (EPA and state of New Jersey limits - based on 1 liter of water. Products found to exceed this amount were tested for inorganic arsenic and must not contain more than 2.1 micrograms of inorganic arsenic per daily serving (Canada's limit in natural health products).
- May not exceed 2 micrograms of mercury per daily serving (based on EPA limit for mercury in 1 liter of water).
- If applicable to the product, it must meet recommended USP <2040> parameters of disintegration for dietary supplements (excluding capsule, chewable 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 unacceptable variation in quality, present a safety risk, or provide misleading or inaccurate information in its labeling.