A total of 746 over-the-counter supplements from 146 different companies contained potentially harmful and undeclared ingredients not approved by the U.S. Food and Drug Administration. Photo by stevepb/pixabay

Oct. 12 (UPI) -- Researchers found 746 over-the-counter supplements contained potentially harmful and undeclared ingredients not approved by the U.S. Food and Drug Administration.

The study analyzed data from a tainted supplements database maintained by the FDA for trends in adulterated dietary supplements associated with a warning by the FDA. The findings, which covered data from 2007 through 2016, were published Friday in JAMA Network Open.


Although two-thirds of adults in the United States report using dietary supplements, according to the Council for Responsible Nutrition, the FDA treats dietary supplements more like special foods and does not hold them up to the same safety and effectiveness requirements of medications. Supplements aren't intended as a substitute for food.

Researchers found products from 146 different companies included 353 marketed for sexual enhancement, 317 for weight loss and 92 for muscle building. Some of the products are marketed for more than one thing.

RELATED Vitamin D supplements not effective against osteoporosis in older adults

"Active pharmaceuticals continue to be identified in dietary supplements, especially those marketed for sexual enhancement or weight loss, even after FDA warnings," study authors wrote. "The drug ingredients in these dietary supplements have the potential to cause serious adverse health effects owing to accidental misuse, overuse or interaction with other medications, underlying health conditions or other pharmaceuticals within the supplement."

A total of 157 adulterated products contained more than one unapproved ingredient. Twenty-eight products were named in two or three warnings more than 6 months apart. Nineteen were reported to contain new unapproved ingredients in the second or third warning.

For weight loss products, sibutramine, sibutramine analogues and the laxative phenolphthalein were the most common drug ingredients detected. Sibutramine was removed from the U.S. market in 2019 because of cardiovascular risk, and phenolphthalein in 1999 for potential carcinogenic risk, as well as carrying the risk for gastrointestinal disturbances or irregular heartbeat.

Fluoxetine, a prescription antidepressant from the same class of drugs as dapoxetine, which has been been associated with suicidal thinking, abnormal bleeding and seizures, was found in 17 of 317 weight-loss products.

Dietary ingredients include vitamins, minerals, amino acids, and herbs or botanicals, as well as other substances, that can be used to supplement the diet.

Federal law does not require dietary supplements to be proven safe to FDA's satisfaction before they are marketed. Dietary supplements are regulated under the Dietary Supplement Health and Education Act of 1994.

The agency requires dietary supplements not contain anything that may have "a significant or unreasonable risk of illness or injury" when used as directed on the label, or with normal use if there are no directions on the label.

Dr. Pieter A. Cohen, writing in an accompanying editorial, called it a "dereliction of duty" by the FDA in the treatment of adulterated supplements.

"The agency's failure to aggressively use all available tools to remove pharmaceutically adulterated supplements from commerce leaves consumers' health at risk," wrote Cohen, an associate professor of medicine at the Cambridge Health Alliance.

He questioned the effectiveness of voluntary recalls -- the most common approach by the FDA.

"More than FDA action will be required to ensure that all adulterated supplements are effectively and swiftly removed from the market," Cohen wrote. "Congress would need to reform the Dietary Supplement Health and Education Act of 1994."

He said firms should be required to register supplements with the FDA before sale and "Congress could provide the FDA with more effective enforcement tools such as immediately revoking a product's registration if a supplement is found to be adulterated with pharmaceutical drugs."