The Food and Drug Administration is an agency of the US government which is responsible for assuring the safety of foods and cosmetics and the safety and effectiveness of pharmaceutical products (including drugs) and medical devices.

Before a drug can be marketed in the US, it is reviewed by the FDA. FDA approval is granted only if the drug has been subjected to a rigorous set of clinical studies which prove both that the drug is effective and that it does not have unacceptable side effects if used as specified on the label. FDA review also helps determine what dosages are recommended. Full details of this process are available at http://www.fda.gov/cder.

Dietary supplements, such as vitamins and herbal remedies, are considered to be food, rather than drugs, and so they are not subjected to the same rigorous testing as drugs. FDA approval is not required, which means that the FDA does not guarantee the safety, effectiveness, quality or composition of supplements sold in the US. The manufacturers are only obligated to demonstrate that the active ingredient is reasonably expected to be safe for use in a supplement, and to demonstrate that there is some evidence that the claims made on the label are not misleading. Supplement manufacturers are not legally required to disclose any negative information they may have about their product's safety or effectiveness, either to the public or to the FDA.

The manufacturers are also forbidden to claim on the label that the product treats, cures or prevents any specific disease -- unless such statements have been evaluated by the FDA using the same strict standards used to evaluate drugs. Thus, a supplement might legally claim that it "can relieve occasional sleeplessness" but not that it "helps relieve insomnia" -- unless the latter statement has been specifically approved by the FDA.

More information on the FDA regulation of dietary supplements is available on the website of the FDA's Center for Food Safety and Applied Nutrition; go to http://www.cfsan.fda.gov and click on "Dietary Supplements".