Based upon recent sales numbers, nutritional supplements play a key role in the lifestyle of a substantial proportion of the population. As well as products such as vitamins or minerals, several precursors of anabolic steroids are marketed as nutritional supplements. Another group of commercially available supplements are products for weight loss based upon herbal formulations originating from Ephedra species. Apart from supplements indicating the presence of these active compounds, numerous non-hormonal nutritional supplements were found that were contaminated with non-labelled anabolic steroids. Stimulating agents other than naturally occurring analogues of ephedrine were detected. A major group using dietary supplements are sportsmen, ranging from amateur level to elite athletes. Besides the possible health risks associated with the use of dietary supplements, athletes should take care not to violate the rules of the World Anti-Doping Agency because athletes remain responsible for substances detected in their biofluids, irrespective of their origin. Several analytical methods have been developed to determine the presence of doping agents as contaminants. The present review attempts to address the issues concerning the use of nutritional supplements and the detection of doping agents as contaminants in dietary supplements.

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ABSTRACT:The misuse of the anabolic steroid methyltestosterone is currently routinely monitored in doping control laboratories by gas chromatography-mass spectrometry (GC-MS) of two of its metabolites: 17␣-methyl-5␤-androstane-3␣,17␤-diol and 17␣-methyl-5␣-androstane-3␣,17␤-diol. Because of the absence of any easy ionizable moiety, these metabolites are poorly detectable using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). In this study, the metabolism of methyltestosterone has been reinvestigated by the use of a precursor ion scan method in LC-ESI-MS/MS. Two metabolites have been detected using this method. Both compounds have been confirmed in postadministration urine samples of an urokinase plasminogen activator-severe combined immunodeficiency (uPA-SCID) mouse with humanized liver and were characterized by LC-MS/MS and GC-MS using both quadrupole and time of flight analyzers. From the detailed study of the fragmentation, these metabolites were proposed to be epimethyltestosterone and a dehydrogenated compound. Epimethyltestosterone has previously been described as a minor metabolite, whereas the occurrence of the oxidized metabolite has not been reported. Comparison with the synthesized reference revealed that the structure of the dehydrogenated metabolite is 6-ene-epimethyltestosterone. A selected reaction monitoring method including three transitions for each metabolite has been developed and applied to samples from an excretion study and to samples declared positive after GC-MS analysis. 6-Ene-epimethyltestosterone was found in all samples, showing its applicability in the detection of methyltestosterone misuse.Anabolic androgenic steroids are among the most frequently misused compounds by athletes (WADA Laboratory Statistics, 2009, http://www.wada-ama.org/en/dynamic.ch2?pageCategory.idϭ335). 17␣-Methyltestosterone (17␤-hydroxy-17␣-methylandrost-4-en-3-one) has been one of the most detected compounds in doping analysis during the past few years (WADA Laboratory Statistics, 2009, http:// www.wada-ama.org/en/dynamic.ch2?pageCategory.idϭ335). 17␣-Methyltestosterone is rapidly metabolized in humans, and therefore the monitoring of the misuse of this steroid is normally performed by the detection of its metabolites. Two main metabolites were identified in the metabolism of 17␣-methyltestosterone in human: 17␣-methyl-5␣-androstane-3␣,17␤-diol (A2) and 17␣-methyl-5␤-androstane-3␣,17␤-diol (A3) (Schänzer and Donike, 1993). Hydroxylated metabolites have been described in several animals including the horse (Dumasia, 2003;McKinney et al., 2007;Yamada et al., 2007) and the heifer (Blokland et al., 2005).In doping control analysis, the detection of steroid metabolites is normally performed by gas chromatography-mass spectrometry (GC-MS) after trimethylsilylation (Schänzer and Donike, 1993;Ayotte et al., 1996;Saugy et al., 2000), achieving the required sensitivity of 2 ng/ml (WADA Technical Document TD2004MRPL version 1.0, 2007, http://www.wada-ama.org/rtecontent/document...