Diet, sports supplements use banned ingredients, study finds

Researchers have found that several weight loss and sports supplements on the market contain prohibited stimulants, including an experimental drug from World War II era.

In 17 brands of supplements, researchers found nine prohibited stimulants that were mixed into eight different combinations, “none of which have been studied in humans,” according to a study published Tuesday in the journal Clinical Toxicology.

Among the stimulants detected were deterenol, which can cause serious health effects when consumed orally, and phenpromethamine, which was marketed as a pharmaceutical stimulant in the Vonedrine nasal inhaler in the 1940s and 1950s.

Neither of the stimulants has been approved for ingestion in the U.S. or elsewhere, but the Food and Drug Administration has not issued warnings to manufacturers or consumers about them, the study’s authors say.

Seven other stimulants — 1,3-DMAA, 1,4-DMAA, 1,3-DMBA, BMPEA, higenamine, oxilofrine and octodrine — also were detected in supplements. The FDA previously has taken regulatory action against these stimulants including seizing products and issuing warning letters and public notices, the researchers wrote.

“Overall, little is known about the health effects of any of these stimulants in humans. Some of the stimulants have never been studied or used in humans before — like DMBA,” said Dr. Pieter Cohen, one of the study’s authors and an associate professor of medicine at Harvard Medical School. “Other stimulants, such as higenamine and oxilofrine, have been used by clinicians and researchers in other countries to stimulate the heart. However, none of these are approved for use by the FDA.

“My concern would be that consumers could suffer similar effects to what was seen in Europe when supplements containing deterenol combined with other stimulants led to life-threatening adverse effects including cardiac arrest,” wrote Dr. Cohen.

The researchers hail from various organizations including NSF International, a product testing/inspection group based in Ann Arbor, Michigan.

As many as four different stimulants were found in a single supplement and the stimulants aren’t always listed on product labels, the researchers said.

One brand, Dexaprine (iForce Nutrition), reportedly contains a combination of stimulants that investigators linked to dozens of incidences of nausea, agitation, chest pain, cardiac arrest, palpitations, vomiting and sweating.

Deterenol was the most commonly found stimulant and detected in 13 of 17 supplements. Phenpromethamine came in second and was present in four brands of supplements.

The researchers wrote that the FDA does “not always act accordingly” in removing adulterated supplements from the marketplace. For example, the study notes that the agency prohibited deterenol in dietary supplements in 2004, but the stimulant has been found in several brands of supplements sold in the U.S. since 2018.

“The FDA should act swiftly to remove all experimental stimulants from the marketplace. The agency has a number of tools they can use including public alerts, warning letters and mandatory recalls,” Dr. Cohen said. “Until we can be certain that these stimulants are not found in over-the-counter supplements, clinicians should advise patients to avoid certain high-risk categories of supplements including those marketed as pre-workout supplements and weight loss supplements.”

In response to the new study, the FDA said it is “advancing its strategic priorities” for dietary supplements.

“We appreciate studies like this for raising awareness and bringing needed attention to these matters,” the agency said. “However, in general, the FDA does not comment on specific studies, but evaluates them as part of the body of evidence to further our understanding about a particular issue and assist in our mission to protect public health. The FDA is reviewing the findings of this paper.”

On its website, the FDA does warn that dietary supplements can contain hidden ingredients that could be harmful.