According to a Journal of the American Medical Association (JAMA) research letter, 66.7 percent of dietary supplements, recalled due to adulteration with pharmaceutical ingredients between January 2009 and December 2012, that were still available for purchase at least six months after the recalls remained adulterated with banned ingredients. Pieter A. Cohen, et al., “Presence of Banned Drugs in Dietary Supplements Following FDA Recalls,” JAMA, October 22/29, 2014. The researchers purchased the supplements in July or August 2013 directly from the Websites of supplement manufacturers or retailers rather than through e-commerce sites such as They were subjected to the same type of testing used by the U.S. Food and Drug Administration (FDA), but just as to the common adulterants anticipated based on the marketing claims. The supplements remained adulterated in 85 percent of those sold for sports enhancement, 67 percent for weight loss and 20 percent for sexual enhancement.