Some bodybuilders and athletes use trenbolone for its muscle-building and otherwise performance-enhancing effects. [ citation needed ] Such use is illegal in the United States and many other countries. The DEA classifies trenbolone as a Schedule III controlled substance 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 administered to Russian athletes at the Sochi Winter Olympics consisted of oxandrolone , metenolone , and trenbolone. 
Results wise, users should expect extreme strength increases and weight gain in a relatively short 2-4 week period. Weight gain upwards of 20lbs in 4 weeks is not unheard of with this incredibly potent compound. Although subcutaneous water gain would be minimal, intramuscular water retention should be expected. This is due to inhibition of 11b-hydroxylase and build-up of mineralcorticoids which encourage salt and water retention within the muscles. The most obvious physical effects will be improved vascularity, aggressive muscular pumps, and oily skin.
While methyldrostanolone can stack well with most other steroids, it should never be stacked with another methylated (17aa) steroid.