How Products were Selected:Products were selected to represent those popular among readers of ConsumerLab.com and commonly 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.
Testing Method: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, cadmium, arsenic and mercury 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."
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:*To be "Approved" by Consumerlab.com, a product had to meet the following requirements:
- 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 (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 250-999 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 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 75lbs). 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 (based on EPA limit and state of New Jersey limit in 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, must meet recommended USP <2040> parameters for disintegration of dietary supplements (excluding capsule, chewable, sublingual and timed-release products).
- Be in compliance with FDA labeling requirements.