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 .  The infamous "duchess" cocktail allegedly administered to Russian athletes at the Sochi Winter Olympics consisted of oxandrolone , a metenolone ester, and a trenbolone ester. 
• Will Schanxer and Manfred Donike. Metabolism of anabolic steroids in man: synthesis and use of reference substances for identification of anabolic steroid metabolites. Aanaiytzca Chumca
Acta, 275 (1993) 23-48
• Detection and characterization of clostebol sulfate metabolites in Caucasian G, Pozo OJ, Garrostas L, Esquivel A1, Matabosch X, Kotronoulas A, Joglar J, Ventura R. J
Chromatogr B Analyt Technol Biomed Life Sci. 2016 Jun 1;1022:54-63. doi: /. Epub 2016 Mar 21.
• Clostebol-positive urine after consumption of contaminated meat.
• Debruyckere G1, de Sagher R, Van Peteghem C. Clin Chem. 1992 Sep;38(9):1869-73.