Consumers are taking dietary supplements with illegal—and potentially harmful—ingredients, a growing body of evidence shows.
A new study published online in JAMA Internal Medicine this week found experimental stimulants in dietary supplements both before and after the U.S. Food and Drug Administration issued public warnings about the stimulants.
The stimulants aren’t approved for human use and are believed to increase blood pressure and heart rates potentially, says Pieter Cohen, an associate professor at Harvard Medical School and general internist at Cambridge Health Alliance who conducted the study with researchers from the University of California, San Francisco. “They do things we are concerned 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One of the stimulants, DMAA, was used in nasal decongestants in the 1940s but withdrawn from the market several decades later. Another, oxilofrine, was approved for use in some European countries for patients with low blood pressure, but never approved in the U.S. Two others, BMPEA and DMBA, have never been approved for use in humans but are believed to function like stimulants based on animal studies.
The researchers looked at nine weight-loss supplements, two sports supplements and one cognitive-function one and tested them for the stimulants in 2014 and 2017. The supplements were bought online but can also be found in stores, Dr. Cohen says. The study doesn’t disclose the brands or companies that manufacture the supplements.
Once the FDA issues a public warning, the expectation is that supplements containing prohibited ingredients will be removed from the market and new products won’t be added, Dr. Cohen says. But he adds that in practice, that doesn’t always happen and there is a lack of clarity over what actions must be taken and what the consequences are.
Growing Body of Evidence
The JAMA Internal Medicine study comes on the heels of another JAMA study published earlier this month by the California Department of Public Health. It analyzed the FDA’s supplement warnings from 2007 to 2016 and found that prescription-drug ingredients were in 776 dietary supplements, many even after the FDA issued public warnings about the products. There were 157 products containing more than one unapproved ingredient.
The majority of products were marketed for sexual enhancement, weight loss or muscle building. Examples included sildenafil, sold as Viagra, in sexual-enhancement supplements, 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 U.S. adults take dietary supplements such as vitamins, botanicals and enzymes. Supplements are classified as a category of food and aren’t tightly regulated like prescription drugs. Supplement manufacturers don’t have to demonstrate safety or effectiveness to the FDA before their products go on the market.
“The drug ingredients have the potential to cause serious adverse health effects due to misuse, overuse or interaction with other medications, underlying health conditions, or other pharmaceuticals within the supplement,” Madhur Kumar, senior author of the earlier JAMA study and a research scientist at the California Department of Public Health, wrote in an email.
The FDA is in the process of reviewing the findings, says Jeremy Kahn, a spokesman for the agency.
“The FDA is committed to doing everything within its resources and authorities to identify and remove unsafe products from the market, and we continue to work collaboratively with all of our stakeholders to help ensure that products marketed as dietary supplements are safe, well-manufactured and accurately labeled,” he said in an emailed statement.
When the FDA issues a public warning, such as in the case of the stimulants, consumers are notified that the products in question may contain an undeclared ingredient and that they shouldn’t purchase or use the products, Mr. Kahn says.
Even when the FDA issues a recall or takes enforcement action against a distributor, other distributors often continue to sell the recalled product, or distributors relabel products to evade detection, Mr. Kahn says.
Dr. Cohen, who wrote an accompanying editorial to the California Department of Public Health analysis, says the FDA needs to do more.
His previous research looked at what happens after the FDA recalls supplements that contain prescription drugs illegally and found that years after recalls, two-thirds of the supplements available for sale still contain drugs.
Another study found that Boston consumers buying one brand of a weight-loss supplement weren’t aware of a recall and were still able to purchase the supplements.
The New Findings
In 2014, the FDA made an announcement about DMAA not being permitted in supplements. By 2017, it made separate announcements about all four stimulants not being permitted in supplements.
The researchers of the new study published Monday did a chemical analysis of the supplements. It found that in 2014, despite the FDA’s announcement about DMAA, it was present in half of the supplements tested. Two other stimulants, BMPEA and oxilofrine, were found in many of the supplements.
By 2017, researchers found DMAA in two supplements, oxilofrine in nine, BMPEA in one and DMBA, previously found in none, in four.
“Whatever the FDA is doing to try to eliminate these experimental stimulants from supplements is not working and consumers are going to continue to be exposed to this if the FDA doesn’t step up and become much more aggressive in its enforcement,” Dr. Cohen says.
A Washington, D.C.-based trade group of dietary supplements and functional food manufacturers sides 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 “menace.”
“We share disdain for this type of behavior,” Mr. MacKay says. “A responsible manufacturer with a big brand name, none of this ever happens.”
Sreek Cherukuri, an ear, nose and throat surgeon in Indiana, says in recent years more patients are asking about dietary supplements. Many aren’t properly informed.
He asks patients before surgery what supplements, vitamins and herbal products they take, because these can interfere with surgery and cause 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 don’t have any strong scientific data to validate their use,” Dr. Cherukuri says. “At best, they may not be doing what we think. At worst, they can be fraudulent or tainted and could put you in the hospital or emergency room.”
Expert Advice for Shopping for Supplements
Avoid supplements marketed for sexual health, weight loss and muscle building, which are most frequently tainted with illegal ingredients, Dr. Cherukuri says.
Do your due diligence on researching potential supplements. The majority of products are unproven. Even if they aren’t dangerous, they could be a waste of money, Dr. Cherukuri says. Be wary of bold claims or products that claim to treat a disease.
Talk to your health practitioner before starting any type of supplement.
Check products in the Council for Responsible Nutritions’ online voluntary product registry that includes about 12,000 labels.
Look for products that are certified by third parties and have seals certifying that what is on the label is what is inside the bottle, says Mr. MacKay of the Council for Responsible Nutrition. The United States Pharmacopeia certifies supplements with the USP seal. Other third-party seals include UL from Underwriter Labs and NSF from NSF International.
Write to Sumathi Reddy at firstname.lastname@example.org