The organization that certifies the purity of drugs and health care products will start putting its seal of approval on a small number of dietary supplements by year's end, giving consumers a chance to act on that information when they decide what to buy.

Before it has even begun, however, the program has been largely dismissed by supplement makers as redundant and decried by some consumer groups as irrelevant or even dangerous.

US Pharmacopeia's Dietary Supplement Verification Program determines whether the supplements contain the substances described on the label in the indicated quantities, are within acceptable limits on contaminants and are made in accordance with good manufacturing practices. Certified products display the USP seal.

"We're very well-positioned to have a verification program that is not a rubber stamp," said John T. Fowler, USP's chief operating officer. "What we're doing is going to be good for consumers, practitioners and the industry."

Dietary supplements, including vitamins, minerals and herbal, protein and sports supplements, are not subject to outside monitoring for quality control or to the extensive clinical trials required for new drugs. Several supplements, or contaminants they contained, have been blamed for serious side effects and deaths.

The USP, a nonprofit organization, began the Verification Program more than one year ago. Four supplement makers -- out of hundreds nationwide -- are participating in the voluntary effort. The companies pay for the testing.

USP has so far certified 59 products made by two companies, Nature Made and Kirkland Signature, and all but one of which are either vitamins or minerals. The other is a fish oil softgel made by Kirkland.

Michael McGuffin, president of the American Herbal Products Association, said the supplement industry did not need "a third party" referee between manufacturers and consumers, noting that much in the USP program is already required by law or in proposed laws.

Sidney Wolfe, director of the consumer organization Public Citizen's Health Research Group, called the USP program "unacceptable" because it didn't address supplements' safety and effectiveness and may even "afford legitimacy" to dangerous products.