FDA Scientists Find Amphetamine in Weight-Loss Supplements

WASHINGTONFollowing similar findings in sports supplements containing dendrobium extract, FDA scientists have found an amphetamine isomer in supplements containing Acacia rigidula extract. Published in the Journal of Pharmaceutical and Biomedical Analysis (88:457-466, 2014), the short communication report detailed testing results showing about half of the 21 weight-loss supplements contained beta-methylphenethylamine, a compound they were unable to find in any verified reference samples of the A. rigidula extract. FDA has issued no further comment on  what additional tests or actions it will take on these products.

The testing was completed using liquid chromatography-mass spectrometry (LC-MS) with validated methods  for both A. rigidula and the dietary supplements containing the extract. The report seemed to highlight the process as much as the test results. "Our study revealed significant differences in the amine profiles of authenticated plant materials and dietary supplements," they wrote. "b-methylphenethylamine is a positional isomer of amphetamine, and our results showed that it can be misidentified as amphetamine during LCMS analysis." In the end, the researchers noted the study exemplified why it is essential to confirm results with independent analytical methods especially in cases of unusual or unexpected compounds in dietary supplements.

FDA has not released the list of product or manufacturer names involved in the published study, but among the companies known to market a weight-loss supplement with A. rigidula extract is Hi-Tech Pharmaceuticals, which has had numerous encounters with FDA and FTC, including the recent federal seizure of $2 million in products that contained the banned substance DMAA.

Hi-Tech President Jared Wheat pointed to a prior Texas A&M study (Phytochemistry. 49(5):1377-1380, 1998) that found A. rigidula, a shrub called blackbrush and found in Texas and Mexico, naturally contained b-methylphenethylamine and other related compounds. However, FDA has said this Texas study did not provide sufficient information on the testing methods used to find these compounds.

The issue of natural occurrence in blackbrush is only one part of the issue. There are also questions on whether these amphetamine isomers pose safety risks. FDA said it has not found safety data on b-methylphenethylamine's use in humans. The Texas A&M study did note while none of the phenethylamines found in A.rigidula exhibited locomotor ataxia (inability to control body movements), "the presence of the amphetamines suggest the possibility for a reduction of monoamine oxidase activity." Monoamine oxidase activity inhibitors (MOAIs) can produce drug-level effects in the brain and interact dangerously with  dietary amines and psychoactive drugs. 

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