WHITE PLAINS, NEW YORK — MARCH 7, 2008 — reported test results today for a wide variety of vitamin C supplements. Vitamin C is the top-selling single vitamin in the U.S., with sales of $863 million in 2006 according to Nutrition Business Journal. One vitamin C supplement contained only 43.5% of its claimed amount of the nutrient. Twenty-two other products met their claims for vitamin C and all tablets disintegrated properly for absorption. However, found that two products suggested doses that could cause side effects in some individuals. This is's fourth review of vitamin C supplements. Results have generally been positive in recent years in contrast to the initial review in 2001 when several products contained less vitamin C than claimed and one product would not disintegrate properly.

Vitamin C helps build collagen, aids iron absorption, and, as an antioxidant, may protect the body and boost the immune system when under stress. Although vitamin C will probably not prevent the common cold, regular use of 1,000 mg during cold season may slightly reduce the symptoms and duration of a cold.

Consumers should be aware that diarrhea and other side effects may occur with consumption of too much of the vitamin. Specific supplements that exceed these levels are noted in the report. Vitamin C can also affect the absorption and/or metabolism of other nutrients or drugs and may interfere with diagnostic tests such as that for blood in stool.

The new report is available at Test results are shown for each product. Products include those made with vitamin C from Ester-C®, sodium ascorbate, and natural sources such as rose hips (the pear-shaped fruit of the rose) and/or acerola (a cherry-like fruit). Two of the products are marketed for children. selected sixteen of the products. Seven others are included for having passed the same testing through Voluntary Certification Program. Also listed are four products similar to ones that passed testing but are sold under different brand names.
Brands included in the report are Advocare, Child Life, Douglas Laboratories, Dynamic Health Laboratories, Emergen-C, Nature Smart, GNC, Halls, Longs, Member's Mark (Sam's Club), Nature Made, Nature's Bounty, New Chapter, NF Formulas, Nutrition Now, Origin (Target), Puritan's Pride, Rainbow Light, Schiff, Swanson, Trader Darwin (Trader Joe's), Vitamin Shoppe, and Vitamin World. Reviews of other popular types of supplements are also available at New reviews to be released soon include fish oils, iron, nutrition bars, and red yeast rice. is a leading provider of consumer information and independent evaluations of products that affect health and nutrition. The company is privately held and based in White Plains, New York. It has no ownership from, or interest in, companies that manufacture, distribute, or sell consumer products. is affiliated with (, an evaluator of online pharmacies. Subscription to is available online. For group subscriptions, Technical Reports, or product testing contact Lisa Sabin, Vice President for Business Development, at

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