From The July 2000 Issue of Nutrition Science News

Vitamin C Not Perfect

White Plains, N.Y.—Even vitamin C is a tricky purchase these days. According to the independent testing company consumerlab.com, based here, many vitamin C products—including those standardized to the United States Pharmacopoeia (USP)—do not contain the listed amount of ingredients or do not break down adequately for absorption. In fact, of 26 major brands tested, 15 percent (four brands) fell short, suggesting that standardization labels may not guarantee quality.

Interestingly, USP-labeled vitamin C tended to have slightly less than 100 percent of the claimed amount, while those not USP stamped tended to have slightly more than 100 percent vitamin C. For full test results, visit the consumerlab.com Web site.