FDA is warning makers of "workout boosters" of dangers.

FDA is warning makers of "workout boosters" of dangers.

The New York Times (4/28, B2, Singer, Lattman) reported that the FDA is warning 10 companies that make or distribute some popular "workout boosters" that they "could increase people's blood pressure, potentially causing shortness of breath or heart attacks." The warning is based on the companies' failure "to demonstrate the safety of the crucial ingredient," DMAA or dimethylamylamine. The products are promoted as dietary supplements and have become "best sellers among fitness buffs at stores like GNC and the Vitamin Shoppe, as well as on Web sites like bodybuilding.com." The companies have 15 days to respond.