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Product Review: Vitamin K Supplements (Including Combinations with Calcium and Vitamin D) |
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HOW PRODUCTS WERE EVALUATED:
How Product 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, catalogues, or multi-level marketing companies. Products were not accepted directly from manufacturers.
Testing Methods:
Calcium-containing products were tested for their amount of calcium as well as contamination with lead. Products with vitamin D and/or vitamin K were also tested for the form and amount of vitamin D and/or vitamin K. All tablets were tested for their ability to disintegrate (excluding chewable, time-release or extended-release forms).
Analyses for calcium and lead were performed using ICP-MS (Inductively Coupled Plasma-Mass Spectroscopy) method in an independent laboratory. Analysis for vitamin D and/or vitamin K utilized the USP extraction and HPLC methodology for finished products. Products not having passing levels of calcium, vitamin D, vitamin K or lead were then re-tested on the failing parameter in a second independent laboratory using similar methods.
Disintegration of non-chewable, non-capsule, non-enteric coated and non-time-release formulations were analyzed utilizing USP (United States Pharmacopeia) <2040> recommendations entitled "Disintegration and Dissolution of Nutritional Supplements."
The identities of the products were not disclosed to the laboratories performing the testing.
Passing Score:*
To pass testing, a product must meet the following criteria:
Calcium:
- Contain a minimum of 100% of its labeled amount of elemental calcium and not exceed 150% of this amount.
- Not exceed California Prop 65 levels for lead contamination in a recommended daily serving and, in no event, exceed 2 mcg of lead in a recommended daily serving. (The State of California has established its own strict standards for lead, including 0.5 micrograms of lead per day for foods and most supplements. Calcium products providing 1,000 mg or more of elemental calcium per day have a limit of 1.5 micrograms of lead. Products sold in California that exceed these levels are required to bear warning labels).
Vitamin D:
Contain a minimum of 100% of its labeled amount of total Vitamin D and specific claims for vitamin D2 or D3 and not exceed 150% of these amounts.
Vitamin K:
Contain a minimum of 100% of its labeled amount of total Vitamin K and specific claims for vitamin K1 or K2 (as menaquinone-4 and/or -7) and not exceed 150% of these amounts.
All Products:
- Meet recommended USP parameters for disintegration for vitamin supplements (excluding capsule, enteric coated, chewable and time-release products).
- Meet 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 present a safety risk or to provide misleading or inaccurate information in its labeling.
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