The metal content of dietary supplements, including 13 ephedra-containing supplements, was studied.Methods
Samples of botanicals (black cohosh, echinacea, goldenseal, kava kava, milk thistle, saw palmetto, Synephrine, and valerian root), ephedra-containing dietary supplements (Amp II, EPH 833, Ephedra, Ephedra 1000, Hydroxycut, Metabolife 356, Metabolift, Ripped Fuel, Ripped Fuel Extreme, Ripped Fuel [ma huang-free], Stacker 2 [two lots], Super Stinger, Virgin Earth, Xenadrine RFA-1 [two lots], Yellow Jacket), and nonprescription reference agents (NoDoz and Primatene) were digested in acid, reacidified, and then spiked with internal standards. Metals were quantified using Environmental Protection Agency quality assurance and quality-control standards 6020 and 200.8. Forty-seven metals were analyzed by inductively coupled plasma–mass spectrometry, with subpart-per-trillion detection limits.Results
All metals detected were in concentrations below toxic levels or physiological limit levels for the daily doses specified by the products' labeling. Metals found in highest concentrations among all the supplements sampled were sodium, magnesium, calcium, potassium, aluminum, iron, titanium, mercury, strontium, lead, barium, and silver. Of the 27 supplements analyzed, those with the lowest metal concentrations were mostly single-ingredient botanical supplements, while multiple-component, ephedra-containing dietary supplements generally had higher metal concentrations. Significant lot-to-lot variations were found for two ephedra-containing dietary supplements.Conclusion
None of 47 metals was found in highly toxic amounts in 23 brands of dietary supplements and two nonprescription reference preparations.