Some of the analyzed dietary supplement products were found to contain FDA-prohibited substances.
A review of labels on dietary supplement products found that many do not accurately list the ingredients found in the supplement, and that some included FDA-prohibited performance-enhancing substances, according to a research letter published in the Journal of the American Medical Association.
In lieu of the FDA banning ephedra from dietary supplements in 2004, manufacturers have promoted complex alternatives for sports enhancement using botanical compounds. These include Rauwolfia vomitoria, methylliberine, halostachine, turkesterone, and octopamine, according to the study investigators.
Inspections by the FDA of their approved products have found that supplement manufacturers often don’t comply with basic standards in the manufacturing process, such as establishing the purity, identity, or composition of the final product, according to the study. This can be especially concerning given the products’ potentially complex physiological effects, as well as concerns regarding product quality, the researchers wrote.
As a result of these findings, the investigators sought to determine the accuracy of dietary supplement labels in declaring the presence of the 5 previously mentioned compounds. Supplements were included in the case series if they were labeled as including 1 of the compounds and excluded if the actual label did not list any of those ingredients.
Investigators reconstituted powder from the dietary supplement products in methanol and analyzed them for the presence and quantity of the 5 ingredients, as well as any FDA-prohibited ingredients, by way of liquid chromatography quadrupole time-of-flight mass spectrometry.
There were 63 dietary supplement products purchased; of these, 6 did not list 1 of the 5 ingredients on the label, which led to 57 products being analyzed (13 listing R vomitoria; 21, methylliberine; 8, turkesterone; 7, halostachine; and 8, octopamine). Twenty-three of the 57 products (40%) did not contain a detectable amount of the labeled ingredient, according to the results of the study.
In the products that contained detectable amounts of the listed ingredient, the actual quantity of the product ranged from 0.02% to 334% of the labeled quantity, whereas 6 of the 57 products (11%) contained a quantity of the ingredient within 10% of the labeled quantity, the investigators found.
Seven of the 57 products (12%) were found to contain at least 1 FDA-prohibited ingredient. A variety of FDA-prohibited compounds were found, including 4 synthetic simulants, 1,4-dimethyllamylamine, deterenol, octodrine, oxilofrine, and omberacetam. Of the products, 6 contained 1 of these prohibited ingredients and 1 product contained 4 different prohibited ingredients, the investigators found.
In total, 89% of the dietary supplement labels analyzed did not accurately declare the ingredients found in the products. This can be compared to prior studies of dietary supplements, one of which—prior to the FDA ban of ephedra—found that 50% of products contained ephedra within 10% of the labeled amount, according to the current study.
A more recent study of caffeine content in sports supplements found that 45% contained a quantity of caffeine within 10% of the labeled amount. The results of this current study, which is the first to quantify the 5 supplement ingredients, is in alignment with the reality that many dietary supplement products continue to be mislabeled, the authors noted.
Some of the limitations of the study include the small sample size, only analyzing 1 sample of each brand, and limiting the analysis to supplements that only contained 1 of the 5 targeted ingredients, the study authors discussed.
“Given these findings, clinicians should advise consumers that supplements listing botanical ingredients with purported stimulant or anabolic effects may not be accurately labeled and may contain FDA-prohibited drugs,” the study investigators concluded.
Cohen PA, Avula B, Katragunta K, et al. Presence and quantity of botanical ingredients with purported performance-enhancing properties in sports supplements. JAMA Netw Open. 2023;6(7):e2323879. doi:10.1001/jamanetworkopen.2023.23879