How Products were Selected:
Products tested represent those commonly sold and/or available nationally in the U.S. and Canada. 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.
L-lysine products were tested in one or more independent laboratories for the following:
- Amounts of L-lysine by high performance liquid chromatography (HPLC) or other methodology deemed appropriate by CL.
- Analyses for lead, arsenic, and cadmium performed using an ICP-MS (Inductively Coupled Plasma-Mass Spectroscopy) 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 utilizing USP (United States Pharmacopeia) <2040> recommendations entitled "Disintegration and Dissolution of Nutritional Supplements."
Any product not passing any initial testing criterion was sent to a second independent laboratory for repeat analysis using a similar methodology. Identities of products were not disclosed to laboratories performing the tests.
To achieve a "Pass" in the testing, a product had to:
- Meet 100% of label claim and not more than 120% of label claim for free L-lysine (USP).
- 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 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 with an additional allowance of 0.4 mcg if containing 250-999 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) or 1.0 mcg if containing 1000 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.
Cadmium: 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 75lbs). 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).
Arsenic: Contain less than 10 micrograms of total arsenic and no more than 5 micrograms of inorganic arsenic per daily serving (EPA limit - based on 1 liter of water).
- Meet recommended USP <2040> parameters for disintegration for dietary supplements (excluding capsule, chewable and timed-release products).
- Be in compliance with FDA labeling requirements.
* Passing scores allow for specific margins of technical error associated with each analysis.
** If available for sale in California, a product that exceeds the State of California's Prop 65 lead limit requires a warning label. However, with or without this warning label, a product cannot pass ConsumerLab.com testing if it exceeds the levels described in this paragraph.
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.