Many dietary supplements are tainted with hidden pharmaceuticals, study finds
C. Michael White, Professor of Pharmacy Practice, University of Connecticut: Many over-the-counter dietary supplement products — especially those used for sexual enhancement and weight loss — are tainted with unknown drug ingredients. This is the main finding of my recently published review Journal of Clinical Pharmacology.
My assessment of the Food and Drug Administration’s Health Fraud Product Database found 1,068 unique dietary supplement products marketed between 2007 and 2021 contained active ingredients found in prescription drugs or that were too large for people to use. was considered dangerous.
Of the tainted dietary supplements my study identified, 54 percent were for sexual dysfunction and 35 percent for weight loss.
While many such products are taken off the market once detected by the FDA, other tainted dietary supplements may make their way into the market in their place.
Why it matters
Dietary supplements are used by 58 percent of American adults. And according to recent surveys from the Council for Responsible Nutrition, American consumers have a moderate level of confidence in the quality and safety of dietary supplements.
However, my studies show that this belief is false, as many dietary supplement products contain unlabeled synthetic active ingredients.
So what are these hidden substances, and why do they matter?
The active ingredient in many tainted weight loss dietary supplements is sibutramine, which was recommended by the FDA to be removed from the U.S. market in 2010, when research showed it increased the risk of heart attack and stroke.
And phenolphthalein, which is commonly found in weight-loss dietary supplement products in the FDA database, was removed from over-the-counter laxative products in 1999 when the FDA recognized it as “generally recognized as safe and effective.” Reclassified as “No”.
FDA warning Studies have shown that the ingredient can damage people’s DNA and increase their risk of cancer.
My study also identified the presence of ingredients approved for use only in prescription drugs. These include sildenafil and tadalafil, which are used in FDA-approved erectile dysfunction drugs such as Viagra and Cialis.
Such inadvertent use can be dangerous, as the active ingredients in these drugs come with risks such as vision loss or priapism, or prolonged penile erection.
My studies also frequently documented cases in which more than one active ingredient found in erectile dysfunction drugs was linked in ways that had never been studied for safety.
Another reason hidden active ingredients are problematic is they pose the risk of serious drug interactions. When the active ingredients found in erectile dysfunction medicines are used with high blood pressure or prostate medications such as nitrates and alpha-1 blockers, a life-threatening drop in blood pressure can occur.
Similarly, two of the supplements identified in my study contained flibanserin, the active ingredient in the prescription drug Addyi, which is used to treat female sexual dysfunction. Flibanserin is generally safe but if used with alcohol it can seriously lower the blood pressure.
Pharmacists check for such drug interactions before giving prescription medicine. However, if undisclosed ingredients are hidden in dietary supplements, it is impossible to prevent unwanted drug interactions.
What is not yet known
Dietary supplement manufacturers do not provide the FDA with evidence of good manufacturing practices before selling them in the US, and these manufacturers may change their products without advance notice.
The FDA must prove that a dietary supplement product is unsafe before it can take action, but this is difficult to enforce when there are more than 29,000 dietary supplement products sold in the US.
FDA assessments are laborious and expensive because these evaluations also aim to rule out other dietary supplement problems such as the presence of heavy metals or bacterial or mold contamination.
The agency’s evaluation process of these supplements is also very short. The FDA alerts consumers to newly found tainted dietary supplements through its health fraud product database when attempting to remove these products from the market.
If a product you’re thinking of using is on that list, stay away from it. However, if your product is not included in the database, it may simply mean that it has not yet been evaluated.
This article is republished from The Conversation under a Creative Commons license.
April 28, 2022
