Product Reviews
Magnesium Supplements Review (Including Calcium, Vitamins D & K, and Boron)
 


HOW PRODUCTS WERE EVALUATED:
How Products Were Selected:

Products selected 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 or direct sales. Products were not accepted directly from manufacturers.

Testing Methods:
Products were tested in one or more independent laboratories for the following:
  • Amount of vitamin D (D2, D3) by High Performance Liquid Chromatography (HPLC)or Capillary Electrophoresis (CE).
  • Amount of Vitamin K (K1, K2) by HPLC or CE.
  • Amount of Calcium, magnesium and boron by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS)
  • Lead, arsenic and cadmium by ICP-MS for products containing whole herbs and/or more than 250 mg of minerals per daily dose.
  • Disintegration of non-chewable, non-capsule and non-timed release formulations utilizing United States Pharmacopeial (USP) <2040> recommendations entitled "Disintegration and Dissolution of Nutritional Supplements."
Any product not passing initial testing criteria was sent to a second independent laboratory to repeat testing for the criterion on which it did not pass.

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 be "Approved" by Consumerlab.com, a product must meet the following requirements:

Vitamin D-containing products:
Contain a minimum of 100% (and not more than 165%) of its labeled amount(s) of vitamin D and meet any specific claims for vitamins D2 or D3. (USP 40 Dietary Supplements Official Monographs).

Vitamin K-containing products:
Contain a minimum of 100% (and not more than 165%) of its labeled amount(s) of vitamin K and meet any specific claims for vitamins K1 or K2 (as menaquinone-4 and/or -7) (USP 40 Dietary Supplements Official Monographs).

Calcium-containing products:
Contain a minimum of 100% of its labeled amount of elemental calcium and not exceed 150% of this amount.

Magnesium-containing products:
Contain a minimum of 100% of its labeled amount of elemental magnesium and a maximum of 135% if this amount does not exceed the daily upper limit (UL). A product may contain 125% of its labeled amount if the amount is over the UL.

Boron-containing products:
Contain a minimum of 100% of its labeled amount of elemental calcium and not exceed 160% of this amount.

Heavy Metals: Products containing whole herbs and/or more than 250 mg of minerals per daily dose must not exceed the following limits:
  1. 1. 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 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 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).
    Arsenic:
    • 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 limit - based on 1 liter of water).
All Products:
  1. If applicable to the product, it must meet recommended USP <2040> parameters of disintegration for dietary supplements "Disintegration and Dissolution of Nutritional Supplements." (excluding capsule, chewable and timed-release products).
  2. Be in compliance with FDA labeling requirements.
A "Pass" was based on meeting the above criteria in either the first or second rounds of testing.

*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, present a safety risk or to provide misleading or inaccurate information in its labeling.

** Based on State of California's Prop 65 lead limit. California requires supplements exceeding this limit to bear a warning label regarding lead.





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