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WHITE PLAINS, NY, May 17, 2000 - Testing of 26 brands of vitamin C dietary supplements indicated that fifteen percent either did not contain all of the claimed ingredient or failed to breakdown as needed for absorption in the body. Unexpectedly, results were no better for products claiming to meet USP (United States Pharmacopeia) standards compared to products not making such a claim. Neither the US FDA nor the United States Pharmacopeial Convention (which develops the USP standards) has programs to routinely test vitamin C products. These results were reported today by, which conducts the largest independent analysis of dietary supplements sold in the U.S.

Tod Cooperman, M.D., president of commented, "We did not expect to find these many problems with vitamin C supplements because there is a great deal of manufacturing experience with vitamin C and it is not an expensive raw material. There is clearly a need for better quality control for some manufacturers. The findings raise the question of a false general sense of security among consumers regarding vitamin C products and USP labeling."

The testing also revealed that many of the USP labeled products that passed testing produced values slightly less than their claimed amounts of vitamin C and only passed testing after allowing for an experimental margin of error. In contrast, non-USP labeled products that passed testing tended to have higher than labeled amounts of vitamin C. The USP permits products to contain 90% of their claimed amount of vitamin C, while the FDA requires at least 100%. It is possible that some manufacturers use USP labeling in order to produce product to the lower limit.

The list of products that passed's independent testing, as well as more information about the Product Review, are available at and as well as through's content partners such as eNutrition ( Results will also be published in's Buyer's Guide to Supplements to be available early next year. To further assist consumers, is licensing its flask-shaped Seal of Approved Quality to manufacturers and distributors to use on products that have passed testing. will periodically re-evaluate these products to ensure their compliance with its standards. purchased the tested products through retail stores, on-line retailers, and direct sales or multi-level marketing companies. This is the sixth major dietary supplement Product Review published by since its launch last November. The next Product Review, to be released within four weeks, is of ginseng products. By year-end, will have tested most of the popular categories of dietary supplements sold in the U.S. Complete results for all products tested are available in Technical Reports sold by publishes independent reviews and consumer information about health, wellness, and nutrition products and conducts the largest independent testing of dietary supplements sold in the U.S. The company is privately held and headquartered in White Plains, New York. It has no ownership or control from companies that manufacture, distribute, or sell consumer products. Parties interested in purchasing a Technical Report, licensing content or requesting testing of additional products may contact Lisa Sabin, Vice President for Business Development, at More information about is available at

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