October 6, 2009
Subject: FDA Consumer Advisory Regarding Dietary Supplements that Contain Silver
Dear Health Care Professional Colleague:
The Food and Drug Administration (FDA) would like to bring to your attention a recently-issued FDA Consumer Advisory about the risk of argyria associated with the use of dietary supplements that contain silver compounds, such as colloidal silver (Dietary Supplements Containing Silver May Cause Permanent Discoloration of Skin and Mucous Membranes (Argyria)).
In the event that you are contacted about this advisory, FDA wants you to be aware of our advice to consumers. The advisory points out that some patients may experience significant negative psychological or social consequences as a result of argyria. FDA also advises that, based on current scientific research, it is not possible for FDA to define a "safe" level of silver in dietary supplements or an exposure that will not result in argyria. However, the advisory informs consumers that the Environmental Protection Agency (EPA) has established a chronic oral Reference Dose (RfD) of 5 micrograms (µg) of silver per kilogram (kg) of body weight per day (5 µg/kg/day) based on a review of 70 cases of argyria that were associated with oral, intranasal, or pharyngeal use of organic and colloidal silver compounds. As a matter of prudent public health policy, the advisory recommends keeping exposure below the RfD. FDA is advising consumers who use or are considering the use of dietary supplements that contain silver, to discuss any concerns they may have about the safety of those supplements in their particular circumstances, with their health care provider.
FDA urges you and your patients to report as soon as possible any cases of argyria or other adverse events that may be related to the use of silver-containing dietary supplements. These adverse events should be reported to FDA's MedWatch program by calling the toll-free number (1-800-332-1088) or through the Internet (http://www.fda.gov/medwatch).
Barbara O. Schneeman, Ph.D.
Office of Nutrition, Labeling, and Dietary Supplements
Center for Food Safety and Applied Nutrition