It is the responsibility of the US Food and Drug Administration (FDA) to identify and eliminate hazardous products from the market, including prohibiting specific additives. However, the current regulatory system relies on “post-market enforcement,” which researchers contend is insufficient to ensure user safety.

Researchers from the Department of Medicine at the Cambridge Health Alliance and Harvard Medical School in Boston, Massachusetts, conducted a study of public FDA notices regarding 4 prohibited symoathomimetic stimulants. Data were collected between 2013 and 2016. The researchers analyzed supplements with claims of weight loss, sports performance, or cognitive function on sale in 2014 that listed Acacia rigidula as an ingredient, revealing the presence of one of the prohibited stimulants. The samples from 2014 were consequently tested for the presence of the 3 other stimulants recently prohibited by the FDA. In 2017, the supplements were purchased again and re-analyzed for all 4 prohibited stimulants using liquid chromatography.

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In 2017, just over half of the brands purchased and analyzed in 2014 were still available, and all 12 of those available were analyzed for the presence of the prohibited substances. Of the 12 purchased in 2014 and again in 2017, 75% contained at least 1 of the stimulants previously prohibited by FDA notices and 50% contained 2 or more. In addition, 1 stimulant that was not detected in any of the 2014 samples and prohibited in 2015 was found to have been introduced in 33% of the supplements purchased in 2017.

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From these results, the researchers concluded that FDA recalls and public notices are only somewhat effective. Although they recognized that their study was limited by its small scope and the amount of samples used, the study provided evidence that the current methods for enforcing recalls are not efficient for determining the safety of dietary supplements. They concluded that future studies should be conducted to determine the impact of FDA public notices on the introduction of prohibited stimulants in supplements.


Cohen PA, Wen A, Gerona R. Prohibited stimulants in dietary supplements after enforcement actions by the US Food and Drug Administration. JAMA Intern Med. 2018 ;178(12) :1721-1723.