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 administered to Russian athletes at the Sochi Winter Olympics consisted of oxandrolone , a metenolone ester, and a trenbolone ester. 
Then there are the cardiovascular problems. Because of the way they affect heart cells, anabolic steroids can cause chronic high blood pressure, as well as enlargement of the heart. Your cholesterol levels also get thrown out of balance, since your steroid-saturated body is producing more LDL cholesterol and less HDL cholesterol , which is the opposite of what the American Heart Association recommends. The hormonal effects of steroid use also increase your risk of prostate cancer (if you’re male) and can cause kidney and liver damage.
“Several studies have indicated that the maintenance of training intensity during periods of reduced training and taper (...) is of paramount importance in order to keep training-induced physiological and performance adaptations. [59,64,68-74] On the other hand, training volume can be reduced to a great extent without falling into detraining. This reduction can reach 60 to 90% of previous weekly volume, depending on the duration of the reduced training period, both in highly trained athletes and recently trained individuals. [28,29,57-60,63,69-8]”