These compounds include extracts of Rauwolfia vomitoria containing α-yohimbine, methylliberine, halostachine, turkesterone, and octopamine, all of which are marketed for their stimulant or anabolic effects.
However, the FDA does not preapprove these ingredients for efficacy or safety before their introduction, and inspections have revealed manufacturing quality concerns among supplement manufacturers, such as failures to establish the identity, purity, or composition of the final product.
Dietary supplement products were selected for this case series if they were labeled as containing any of the five specified ingredients. The researchers purchased all products online, and those that did not list one of the five ingredients were excluded. The powder from these dietary supplement products was reconstituted in methanol and analyzed using liquid chromatography quadrupole time-of-flight mass spectrometry to identify and quantify the five ingredients and any FDA-prohibited ingredients.
Out of the 63 purchased products, six did not list any of the five targeted ingredients, leaving 57 products for analysis. Among these, 13 were labeled to contain R. vomitoria, 21 methylliberine, 8 turkesterone, 7 halostachine, and 8 octopamine.
Surprisingly, 23 out of 57 products (40%) did not contain any detectable amount of the labeled ingredient. For products that did contain the listed ingredient, the actual quantity varied significantly, ranging from as low as 0.02% to as high as 334% of the labeled amount.
The study identified five different FDA-prohibited compounds, including 1,4-dimethylamylamine, deterenol, octodrine, oxilofrine, and omberacetam. Of the analyzed products, six contained one of these prohibited ingredients, while one product contained an alarming mix of four different prohibited ingredients.
The findings of this study are concerning, as 89% of dietary supplement labels inaccurately declared the ingredients present in the products.
This significantly deviates from prior studies conducted before the FDA’s ephedra ban, which showed that 50% of products contained ephedra within 10% of the labeled amount. A more recent study on caffeine content in sports supplements found that 45% of products contained caffeine quantities within 10% of the labeled amount. In contrast, this study highlights that only 11% of products accurately listed the actual ingredients, with the remaining products either lacking the claimed ingredient or containing inaccurate quantities.
Moreover, the study’s limitations should be acknowledged, including the small sample size, the analysis of only one sample per brand, and the focus on supplements containing the five targeted ingredients. These limitations may raise questions about the generalizability of the results to other botanical ingredients in sports supplements and whether ingredient quantities might also vary among batches within the same brand.
In light of the findings, clinicians should advise consumers to exercise caution when considering supplements that claim to contain botanical ingredients with stimulant or anabolic effects. The study demonstrates that the majority of dietary supplement labels do not accurately declare their ingredients, and some products even contain FDA-prohibited drugs. This calls for heightened scrutiny and regulation in the dietary supplement industry to ensure consumer safety and product efficacy.
Abbreviations: 1,4-DMAA, 1,4-dimethylamylamine; NA, not applicable; ND, not detected;
NP, not possible (estimate not possible given lack of declared quantity of ingredient on label).
a R vomitoria extract was considered not detected if analyses did not detect at least 5 common R vomitoria alkaloids (ie, rauwolsine, ajmaline, serpentinine, yohimbine, and reserpine), with a limit of detection of 10 ng/mL for each alkaloid.
b The mechanism of action of omberacetam is unknown; it is marketed in Russia as Noopept. The drug has never been approved for use in the US.
c Ingredient is declared on label.
d Octodrine was marketed as part of a multicomponent oral medication in Germany. The drug has never been approved for oral use in the US.
e 1,4-DMAA is an analogue of 1,3-dimethylamylamine, a sympathomimetic amine introduced in nasal inhalers in the 1940s in the US. 1,4-DMAA has never been approved as a medication for use in the US or elsewhere.
f The ingredient was not declared on the label.
g For turkesterone products, ND means not detected, with a limit of detection of 25 ng/mL.
h For halostachine and octopamine products, ND means not detected, with a limit of detection of 50 ng/mL.
i Deterenol is a β-agonist that was formerly available in Europe as an ophthalmologic preparation for the treatment of glaucoma. It has never been approved for use by the US Food and Drug Administration.
j Oxilofrine is a pharmaceutical drug developed in Europe in the 1930s with cardiac stimulatory effects similar to ephedrine. The drug has never been approved for use by the US Food and Drug Administration.
reference link : https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2807343