Some bodybuilders and athletes use trenbolone esters for their muscle-building and otherwise performance-enhancing effects.  Such use is illegal in the United States and many other countries. The DEA classifies trenbolone and its esters as Schedule III controlled substances under the Controlled Substances Act .  Trenbolone is classified as a Schedule 4 drug in Canada  and a class C drug with no penalty for personal use or possession in the United Kingdom .  Use or possession of steroids without a prescription is a crime in Australia . 
AB - An ion with m/z 143 serves as a biomarker that is often continuously monitored in urine samples undergoing screening by electron ionization gas chromatography/mass spectrometry (EI GC/MS) for banned anabolic agents. The ion is known to arise from trimethylsilyl (TMS)-derivatized synthetic 17-hydroxy, 17-methyl steroids. The purpose of this work was to characterize, in detail, the origin(s), structure(s), and mechanism(s) of formation of such ions with m/z 143. High resolution mass spectrometry (HRMS) data revealed the elemental composition of the D-ring derived m/z 143 ion to be C7H 15OSi. Analysis of dihydrotestosterone (DHT) and its 2-methyl substituted analog dromostanolone by HRMS revealed that an elementally equivalent ion of m/z 143 could be derived from the A-ring of TMS-derivatized 3-keto-enol steroids demonstrating that an abnormally intense peak in the m/z 143 extracted ion chromatogram of urine samples undergoing screening for banned anabolic agents does not necessarily indicate the presence of a 17-hydroxy, 17-methyl steroid. To gain information on ion structure, breakdown curves for the most abundant product ions of the m/z 143 ion were generated using both native and perdeutero-TMS derivatives, providing structures for second, third, and fourth generation product ions. An EI-mass spectrum of [16,16,17- 2H3]-DHT (DHT-d3) demonstrated that one of the C-16 hydrogen atoms is removed prior to the formation of an ion that is highly analogous to the ion with m/z 143 strongly suggesting, in accord with all other evidence, one particular fragmentation pathway and resulting product: a resonance stabilized 3-(O-trimethylsilyl)but-1-ene ion.