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 . 
Despite appearances, this theory has very little evidence to back itself up with no real scientific evidence to suggest that a bridge is even possible, although granted that the majority of our working knowledge comes through trial and error. However, even the proponents of a "d-bol bridge" admit that complete restoration of LH function will not be achieved until one is completely off of all compounds. With that said, it is unlikely that a "bridge" will help to maintain muscle mass while you are able to recover both HPTA and LH function. The only solution is to come completely off all substances and run a proper post-cycle therapy.
Not shortly after Roger Maris record was broken, another baseball player, Jason Giambi and various other athletes were either suspected of, or proven to have, taken anabolic steroids. Again, Congress convened a hearing, and just as they did the first time in 1990, they did not determine that steroids were a danger, but rather that the danger was more in protecting professional sports organizations. The updated statute has been updated to proscribe pro-hormones also The definition of an anabolic steroid as defined currently in the United States under (41)(A) is that "anabolic steroid" means any drug or hormonal substance, chemically and pharmacologically related to testosterone (other than estrogens , progestins, corticosteroids, and dehydroepiandrosterone (7).