Illegal ingredients in your dietary supplements


Consumers are taking food supplements with illegal and potentially harmful ingredients, an increasing number of evidence shows.

A new study published online at JAMA Internal Medicine this week found experimental stimulants in food supplements both before and after the US Food and Drug Administration issued public warnings on stimulants.

Stimulants are not approved for human use and are believed to potentially increase blood pressure and heart rate, says Pieter Cohen, an associate professor at Harvard Medical School and general intern at the Cambridge Health Alliance who led the study with researchers from the University of California, San Francisco. "They do things we care about could lead to serious health effects like heart attacks and strokes," he says.

One of the stimulants, DMAA, was used in nasal decongestants in the 40s but was withdrawn from the market several decades later. Another, oxilofrine, has been approved for use in some European countries for patients with low blood pressure, but never approved in the United States. Two others, BMPEA and DMBA, have never been approved for use in humans, but are believed to function as animal-based stimulants.

The researchers examined nine weight loss supplements, two sports supplements and a cognitive-functional supplement and tested them for stimulants in 2014 and 2017. Supplements were purchased online but can also be found in stores, says Dr. Cohen. The study does not reveal the brands or the companies that produce the supplements.

Once the FDA issues a public warning, the expectation is that supplements containing prohibited ingredients will be removed from the market and no new products will be added, says Dr. Cohen. But he adds that, in practice, this does not always happen and there is a lack of clarity about what actions need to be taken and what the consequences are.

Growing body of evidence

The JAMA Internal Medicine study follows another JAMA study published at the start of the month by the California Department of Public Health. He analyzed the warnings on FDA supplements from 2007 to 2016 and found that the prescription drug ingredients were in 776 food supplements, many even after the FDA issued public product warnings. There were 157 products containing more than one unapproved ingredient.

Most products have been marketed for sexual enhancement, weight loss or muscle building. Examples included sildenafil, sold as Viagra, in supplements for sexual enhancement, steroids in muscle building supplements and sibutramine, withdrawn from the market due to potential risks, in weight loss supplements.

The analysis found that the FDA recalled the products less than half the time.

More than 50% of US adults take food supplements such as vitamins, plant substances and enzymes. Supplements are classified as a category of foods and are not strictly regulated as prescription drugs. Supplements manufacturers must not demonstrate safety or efficacy to the FDA before their products enter the market.

"The ingredients of the drug have the potential to cause serious adverse health effects due to abuse, overuse or interaction with other drugs, underlying health conditions or other pharmaceutical products within the supplement", Madhur Kumar, senior author of the previous JAMA study and researcher at the California Department of Public Health, he wrote in an e-mail.

The FDA is reviewing the results, says Jeremy Kahn, spokesperson for the agency.

"The FDA is committed to doing everything within its resources and authority to identify and remove unsafe products from the market, and we continue to work with all stakeholders to help ensure that products marketed as food supplements are safe, well fabricated and carefully labeled, "he said in a statement sent by email.

When the FDA issues a public warning, as in the case of stimulants, consumers are informed that the products in question may contain an undeclared ingredient and that they should not purchase or use the products, says Kahn.

Even when the FDA issues a call or takes legal action against a distributor, other distributors often continue to sell the withdrawn product, or distributors relabel products to escape detection, says Kahn.

Dr. Cohen, who wrote an accompanying editorial to the California Department of Public Health, says the FDA needs to do more.

His previous research examined what happens after the FDA recalled supplements that contain prescription drugs illegally and found that years after the recalls, two-thirds of the supplements available for sale still contain drugs.

Another study found that Boston consumers who buy a weight loss supplement brand were unaware of a recall and were still able to purchase supplements.

The new results

In 2014, the FDA announced that DMAA is not allowed in supplements. By 2017, he has made separate announcements on all four stimulants not allowed in supplements.

The researchers of the new study published on Monday have carried out a chemical analysis of the supplements. He found that in 2014, despite the FDA's announcement on DMAA, it was present in half of the tested supplements. Two other stimulants, BMPEA and oxilofrine, have been found in many of the supplements.

By 2017, researchers found DMAA in two supplements, nine-oxilofrine, BMPEA in one, and DMBA, previously not found in anyone, in four.

"Whatever the FDA is doing to try to eliminate these experimental stimulants from supplements does not work and consumers will continue to be exposed to this if the FDA does not increase and become much more aggressive in its application," Dr. Cohen says.

A commercial group of food supplements and functional food producers based in Washington, DC, sided with researchers. Duffy MacKay, senior vice president of scientific and regulatory affairs for the Council for Responsible Nutrition, says the examples in the studies are products that are a "threat".

"We share the contempt for this type of behavior," says MacKay. "A responsible manufacturer with a big brand, none of this ever happens."

Sreek Cherukuri, an ear, nose and throat surgeon in Indiana, says that in recent years, many patients are asking for food supplements. Many are not properly informed.

He asks patients before surgery what supplements, vitamins and herbal products they take, because they can interfere with surgery and cause a thinning of the blood, he says. To help educate consumers about supplements, he started a website about a year ago.

"The vast majority of supplements have no valid scientific data to validate their use," says Dr. Cherukuri. "At best, they might not do what we think – in the worst case, they can be fraudulent or contaminated and could put you in hospital or emergency room."

Expert tips for shopping for supplements

Avoiding supplements marketed for sexual health, weight loss and muscle building, which are more frequently contaminated with illegal ingredients, says Dr. Cherukuri.

Do your due diligence in the search for potential supplements. Most products are not proven. Even if they are not dangerous, they could be a waste of money, says Dr. Cherukuri. Beware of bold statements or products that claim to cure a disease.

Talk to your doctor before starting any type of supplement.

Check the products in the Council for Responsible Nutritions online volunteer product register which includes about 12,000 labels.

Look for certified products from third parties and seals that certify that what is on the label is what is contained in the bottle, says MacKay of the Council for Responsible Nutrition. The US Pharmacopeia certifies the supplements with the USP seal. Other third-party brands include UL from Underwriter Labs and NSF from NSF International.

Write to Sumathi Reddy at



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