Researchers analyzing dietary supplements recalled by the US Food and Drug Administration discovered that around two thirds of these products still contained banned pharmaceutical ingredients at least 6 months after having been recalled.

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The FDA initiate class I drug recalls if they believe that the consumption of a product could have severe health consequences.

The study, published in JAMA, involved an examination of products that were recalled by the US Food and Drug Administration (FDA) from US markets for comprising of ingredients that could have serious adverse health consequences, including the possibility of death.

Since 2004, around half of all of the FDA's class I drug recalls have been for dietary supplements found to contain dangerous banned drugs. However, previous studies have found that some dietary supplements can be found available for purchase in retail stores even after FDA recall.

What experts do not know is whether these dietary supplements are free of the adulterants that led to their recall. Dr. Pieter A. Cohen, of Harvard Medical School in Boston, MA, and colleagues set out to analyze dietary supplements purchased at least 6 months after an FDA recall, in order to find out whether the banned drugs were still present.

"To our knowledge," write the authors, "this is the first study to determine if adulterants remain in supplements sold after FDA recalls."

Pharmaceutical adulterants

Dietary supplements included within the study had to meet the following inclusion criteria:

  1. The supplement had to be recalled due to "adulteration with pharmaceutical ingredients" between 2009 and 2012.
  2. The supplement had to be available for purchase directly from the manufacturers or specific supplement retailers in July or August 2013.
  3. The supplement name, manufacturer and distributor listed on the newly purchased supplement had to match the product details provided in the FDA recall.

Between 2009 and 2012, the FDA recalled 274 dietary supplements. Of these, 27 (9.9%) met the inclusion criteria for the study and were analyzed by the team. The researchers used the same methods as the FDA - gas chromatography, mass spectrometry - in order to test for banned substances.

The supplements were bought an average of 34.3 months after their initial FDA recall. American manufacturers were responsible for producing 74% of the assessed supplements.

One or more pharmaceutical adulterants were found in 66.7% of the dietary supplements that were available for purchase. The researchers broke this figure down for the different types of supplements:

  • Sports enhancement: 85% (11 out of 13)
  • Weight loss: 67% (6 out of 9)
  • Sexual enhancement: 20% (1 out of 5)
  • Produced by American manufacturers: 65% (13 out of 20).

A total of 63% of the dietary supplements were found to contain exactly the same adulterant identified originally by the FDA. One or more additional banned ingredients that were not identified by the FDA were found in 22.2% of the supplements. Some products were found to contain not only the previously identified adulterant, but also additional pharmaceutical adulterants.

FDA action 'has not been completely effective'

The authors acknowledge that they only tested for adulterants that they expected to find, based on what the supplements were marketed as. As such, they may have missed adulterants that would not have commonly been found in such products, along with newly introduced drug analogs.

They write that the FDA will need to alter their methods if they are to successfully stop potentially dangerous products being sold to the public:

"Action by the FDA has not been completely effective in eliminating all potentially dangerous adulterated supplements from the US marketplace. More aggressive enforcement of the law, changes to the law to increase the FDA's enforcement powers, or both will be required if sales of these products are to be prevented in the future."

This is not the first study to question the effectiveness of FDA regulation. Medical News Today recently reported on a study finding that several implanted medical devices had been cleared for market by the FDA without publicly available scientific data to prove their safety.