In the first instance, supplements are tested using the AOAC International's high-performance liquid chromatography (HPLC)-UV method, that determines the content of major alkaloids such as ephedrine and pseudoephedrine and minor alkaloids.
The method was published in the Jan-Feb 2004 issue of the JAOAC under the title "Determination of Ephedrine Alkaloids in Botanicals and Dietary Supplements by HPLC-UV: Collaborative Study".
Samples testing positive by this method are then subject to secondary testing - not necessarily carried out in the same laboratory but using samples from the same source - using a method published in an earlier issue of the JAOAC (Jul-Aug 2003) entitled "Determination of Ephedrine Alkaloids in Dietary Supplements and Botanicals by Liquid Chromatography/Tandem Mass Spectrometry: Collaborative Study."
Until they were judged to present an "unreasonable risk of illness or injury" and subject to a final rule banning their use which came into effect in April last year, ephedrine alkaloids contained in supplements were promoted for weight loss and to help enhance sports performance and increase energy.
The FDA's prohibition followed a report by the RAND Corporation, which showed that the stimulant can have potentially dangerous effects on the heart. The agency says that there is little evidence for its effectiveness other than for short-term weight loss.
Other studies have also indicated that ephedra use raises blood pressure and otherwise stresses the circulatory system, which could lead to heart disease and stroke.
The FDA has since pledged to root out companies still supplying products containing ephedra in the US. Last month it said it had seized $13,500 of supplements from a Pennsylvania company that were said to have been intended for shipment to Lithuania and Poland, where ephedra is legal.
The former chief executive of Metabolife, the company behind best-selling ephedra-based supplement Metablife 364, has been charged with making "fictitious and fraudulent representations" to the FDA about the safety of the product and "corruptly endeavoring to influence, obstruct and impede proceedings" in relation to the ban.
In a separate lawsuit earlier this month, however, an appeals court threw out a $4.1 million jury award against Metabolife, ruling that insufficient scientific evidence was presented at the 2002 trial to link its Metabolife 356 product to stroke or heart attacks.
Metabolife now sells a range of non-ephedra dietary supplements that it says are safe and effective when taken as directed.