The Fine Print of Dietary Supplements

In 2020, when demand for immunity-boosting supplements surged against the backdrop of the coronavirus pandemic, market analyst Grand View Research valued global sales at $140.3 billion. In 2021, the market is expected to grow to $151.9 billion.

But federal law doesn’t require dietary supplements to be proven safe before they’re marketed.

Supplements include vitamins, minerals, amino acids, enzymes, organ tissues, glandulars, metabolites and botanicals such as herbs. They can be purchased as pills, powders or liquids—but they’re regulated as food, not drugs.

By law, supplements may only include approved dietary ingredients. But some have far more, or far less, of the ingredients than the labels promise, and some contain undisclosed drugs or unapproved substances.

“We’re talking about the extreme cases where the bad players are taking advantage and gaming the system to make as much money as they can as fast as they can and get out before they get caught,” said

David Trosin,

managing director of health-sciences certification at NSF International, a nonprofit organization that reviews dietary supplements.

According to the FDA, some products have had to be recalled for contamination by microbes, pesticides or heavy metals; having quantities of ingredients that didn’t match the label’s specifications; or not including ingredients that were claimed to be in the product.

Undeclared ingredients are most often a problem in products promoted for weight loss, bodybuilding, pain relief, sleep aid or sexual enhancement, which, according to the FDA, might contain approved drugs that have been falsely represented as dietary supplements.

Approved drugs cannot be marketed as dietary supplements, according to

Edward P. Wyszumiala,

director of customer engagement at United States Pharmacopeial Convention—USP for short—a nonprofit that sets standards for healthcare products in the U.S. “If it was used as a drug prior to dietary supplements, it can’t be used in that framework,” Mr. Wyszumiala said.

To aid consumers, NSF and USP, among other groups, will verify the quality of dietary supplements by auditing a company’s manufacturing facility to make sure it complies with industry standards and by testing the supplements to ensure that what’s on the labels is in the bottles. Certified products carry the verifying organization’s mark, in this case “NSF” or “USP Verified.”

The programs are voluntary, and only a fraction of all supplements are vetted. Around 5% to 7% of those found on the shelves of bricks-and-mortar stores have been verified by USP, Mr. Wyszumiala said.

About 10% of the products made by companies that request reviews by NSF fail to win certification, according to Mr. Trosin.

That can happen for a variety of reasons. “It could be because we found contaminants in the product or maybe it fails to have the stated level of ingredients,” Mr. Trosin said. “For the most part, companies that voluntarily choose to go through the certification process truly believe they’re doing the right thing. If a company is trying to get away with something, they don’t even try for certification because they know they won’t pass.”

Even without certification, manufacturers and distributors of dietary supplements are prohibited from marketing products that are adulterated or misbranded.

But it happens.

Scientists at NSF, Harvard Medical School, the Netherlands’ National Institute for Public Health and the Environment, and Belgium’s Sciensano tested 17 brands of supplements that listed deterenol, a banned synthetic stimulant that’s linked to nausea, palpitations and cardiac arrest, as an ingredient. The researchers found as many as four experimental stimulants in the tested products. Their results were published in the peer-reviewed journal Clinical Toxicology in March.

In December, the FDA warned that nearly 50 weight-loss and male sexual-enhancement products it purchased online, including some that were listed as bestsellers, contained undeclared pharmaceutical substances.

In 2017, researchers at the University of Guelph in Ontario examined 31 melatonin supplements commonly used for insomnia and found the melatonin content ranged from 83% less than what was promised to 478% more. The results were published in the peer-reviewed Journal of Clinical Sleep Medicine.

The health consequences of using mislabeled or adulterated supplements can be serious.

Last October, a federal court in Texas sentenced two dietary-supplement executives to prison and ordered two companies that had a role in developing, manufacturing or marketing their products to pay a combined $10.7 million for selling misbranded workout and weight-loss supplements, some of which had been linked to liver damage. The indictment alleged that the defendants, who pleaded guilty, sold the products without determining whether they were safe to use.

There are around 1,000 entries in the FDA’s database of tainted products marketed as dietary supplements, but the agency warns that the list includes only a fraction of the potentially hazardous supplements sold online and in stores.

And for consumers looking to boost their fitness or health, that might be a bitter pill to swallow.

Write to Jo Craven McGinty at [email protected]