What in your sports supplement? Not what's on the label, study finds

Jun 19, 2023

Sports supplements may not contain what their bottle says they do ‒ and they might include unapproved drugs instead, according to a new study.

The study, published this week, examined 57 products claiming to include botanicals that improve sports performance.

Only six of the supplements ‒ just 11% ‒ included roughly what the label promised they would. Meanwhile, seven included drugs expressly prohibited by the Food and Drug Administration.

Forty percent had no detectable amount of the ingredient they were supposed to contain. Those that did have the advertised ingredient didn't always have the right amount of it – concentrations ranged from almost none to more than three times the amount listed on the label.

"Industry is reckless with consumer health," said Dr. Pieter Cohen, an internist at the Cambridge Health Alliance and Harvard Medical School, who helped lead the new research.

Steve Mister, president of the Council for Responsible Nutrition, which represents the supplement industry, said consumers can have confidence in mainstream products bought from reputable stores. But they should be careful with those purchased in "the dark corners of the internet."

Studies like the new one, Mister said "are unnecessarily concerning and worrying consumers and making consumers think that these products are the mainstream products they would find at their local pharmacy store or vitamin stores. They are atypical of the industry."

For his part, Cohen said he and his colleagues ordered the 57 products online after searching for five relatively new and commonly touted botanical ingredients. The products appeared to be from reputable outlets, he said, and they did not search the "dark web" or sketchy websites.

Cohen has spent years investigating and documenting problems with readily available supplements.

"In almost any corner of the supplement market, wherever you look you find results rather similar to these. It's unfortunate," said Dr. Peter Lurie, who was not involved in the new study, but wrote an accompanying editorial.

Supplements can cause side effects and contain contaminants like heavy metals. One study blamed more than 20,000 emergency room visits a year on supplement side effects.

The general public often doesn't realize that the supplement they see on their grocery store shelf hasn't been reviewed by the FDA for effectiveness. "People believe the FDA does more than it does," said Lurie, president and executive director of the Center for Science in the Public Interest, a nonprofit consumer advocacy group.

And supplements can cause "injury to the wallet," Lurie said.

Cohen said he's long been concerned about sports supplements. About 10 years ago, after the FDA banned the use of the stimulant ephedra, he found other potentially dangerous stimulants still present in supplements.

He alerted the FDA, which sent out warning letters to manufacturers, but never followed through, Cohen said.

"Industry has done nothing to clean up their act and FDA has done nothing to enforce the law," he said. "And the law is completely inadequate to prevent these products from coming on shelves in the first place."

At a minimum, Lurie said, the government should require companies to disclose what products they make.

Right now, it's impossible for the FDA to prioritize its limited inspection resources because it knows the names of the companies, but not whether they sell supplements that need extra vigilance. Some products are more likely to be sold to children, prone to heavy metal contamination, or commonly tainted with pharmaceuticals, so should be inspected more often, Lurie said.

Mister, of the supplement industry, agreed, saying the FDA should be doing more to enforce "around the corners of the marketplace."

An FDA spokesperson said via email products containing hidden or unlabeled ingredients present a serious concern, and the agency is reviewing the study's findings.

The new study found four unauthorized stimulants in botanical sports supplements, including three drugs that were formerly available in Europe ‒ octodrine, oxilofrine, and deterenol ‒ and one that has never been approved in any country, called 1,4-dimethylamylamine.

"These stimulants are generally suspected to increase pressure on the heart by either increasing blood pressure, increasing muscle contraction of the heart, or increasing heart rate," Cohen said.

A fifth unapproved drug found in the supplements, called omberacetam and available only in Russia, claims to improve brain function.

The study was limited by its small size. Only one sample of each brand was analyzed and only supplements containing one of the five targeted ingredients were analyzed.

Those ingredients are:

◾ Extracts of Rauwolfia vomitoriacontaining alpha-yohimbine.

◾ The caffeine-like compound methylliberine.

◾ The partial beta-agonist halostachine.

◾ The plant steroid turkesterone.

◾ Norepinephrine-like octopamine.

It is not clear whether other batches within a given brand would yield different results.

"Given these findings, clinicians should advise consumers that supplements listing botanical ingredients with purported stimulant or anabolic effects may not be accurately labeled and may contain FDA-prohibited drugs," the study concludes.

If you're buying supplements, Cohen recommends choosing those certified by either the U.S. Pharmacopeia, symbolized with the initial USP in an oval inside a circle, or the NSF, with the initials in a blue circle.

This certification "doesn't mean that ingredient's going to help your workout," Cohen said, but it provides some reassurance that you're getting what's on the label.

The Council for Responsible Nutrition offers similar tips and Mister advises people to buy products from mainstream retailers. "Buy them from brands you recognize," he said. "Don't visit the corners of the internet."

Only two ingredients have been shown to marginally improve workouts in the short term, Cohen said.

Creatine, an amino acid, can support muscles, and help with repetitive lifting, he said. And a small amount of caffeine ‒ about 100 mg or as much as a small cup of coffee ‒ can improve function if you're tired, he said, though the benefit is subtle.

"There are not many other legal supplement ingredients that will have an immediate effect on exercise," he said.

Contact Karen Weintraub at [email protected].

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