Adulterated Diet Supplements: Should FDA Do More?
Written by Editor   
Tuesday, October 16, 2018 01:29 PM

Even after FDA warnings are issued, many adulterated dietary supplements remain available for purchase, according to a quality-improvement study.  Of dietary supplements available for sale in the U.S. from 2007 to 2016, the FDA identified 776 that were adulterated with active pharmaceuticals.

Calling this an “important public health concern," these researchers said that nearly 68% of these supplements had new unapproved ingredients that were reported in the second or third warning by the FDA, "consistent with the assumption that the FDA found the product to be adulterated more than once."

The products identified in the study appeared in the agency's Tainted Supplements database, and most often were marketed for sexual enhancement (46%), weight loss (41%), or muscle building (12%).

The most common adulterants, the researchers found, were sildenafil for sexual enhancement supplements, sibutramine for weight loss supplements, and synthetic steroids or steroid-like ingredients for muscle building supplements, with 157 products (20%) containing more than one unapproved ingredient.

In the adulterated supplements marketed as sexual enhancement products, over 20% contained some amount of tadalafil, the active ingredient in Cialis (Eli Lilly), while several contained vardenafil, the active ingredient in Levitra (Bayer); in addition, several of these supplements also contained dapoxetine, an antidepressant not currently approved by the FDA.

In the adulterated products marketed as weight loss supplements, other common ingredients were phenolphthalein, sibutramine, or sibutramine analogues, which the FDA removed from the market several years ago due to cardiovascular risks.

In the adulterated supplements marketed as muscle-building products, 10 had aromatase inhibitors, which block estrogen receptors and are used in the treatment of breast cancer in postmenopausal women

Among the adulterated supplements, nearly 80% contained at least one hidden, unapproved ingredient, while 16% contained at least two ingredients. 

Clinicians should take away from these findings to keep in mind that not all ingredients in these supplements may be listed on the label, and that these ingredients have the potential to be “as potent as prescription drugs.”