More than half of U.S. adults take dietary supplements, a category of products that include over-the-counter vitamins, minerals, botanicals, amino acids, and enzymes. But the supplement industry is only loosely regulated by the Food and Drug Administration (FDA), and a new study is shedding light on just how many of these products contain unapproved and potentially dangerous prescription-strength drugs.
Even though the FDA only inspects a small percentage of the supplements sold in the U.S. every year, the agency issued warnings about 776 different products that contained “undeclared, unapproved pharmaceutical ingredients” between 2007 and 2016, according to the study published this week in JAMA Network Open.
Experts have been warning about these problems in the pharmaceutical industry for years, but this is the first time FDA warnings have been quantified to show the extent of the problem.
More than 98% of the FDA’s warnings over this period pertained to supplements marketed for sexual enhancement, weight loss, or muscle building. Most commonly, the FDA found traces of the drugs sildenafil (the generic name for Viagra); sibutramine (a weight-loss drug that was taken off the market after it was linked to heart attacks and strokes); and synthetic steroids or steroid-like ingredients.
Other hidden drugs include antidepressants, laxatives, and stimulants. Some of those drugs have not been approved—or have been banned—by the FDA, and have been linked to serious side effects including suicidal thoughts, abnormal bleeding, and seizures.
In addition to those top three categories, the investigation also found unapproved ingredients in 14 supplements marketed for joint pain, muscle pain, osteoporosis, bone cancer, sleep issues, gout, or prostate health.