Testosterone replacement therapy is probably one of the hottest topics in MMA and BJJ right now. Almost every major fight card has fighters that are either openly on TRT or who have tested positive for anabolic steroids at some point in their career. According to Larry Pepe the Nevada State Athletic Commission has given 6 UFC (current or former) fighters TRT exemptions.
If you think that the use of TRT is limited to MMA then you haven't been around the competitive BJJ scene for long. Prominent BJJ competitors, such as Caio Terra, have been very vocal on instituting testing of all black belt winners and addressing (in his opinion) the rampant use of PEDs in competition. To date there are no major tournaments that include PED testing for any of their athletes.
This article is meant to educate about TRT. It will not go into any detail on any aspect of using testosterone or other anabolic agents illegally. If you're not going to your physician to get a prescription and then filling it at your local pharmacy you should stop reading now. A level playing field is fundamental for all sports. Athletes should compete within the rules of the sport that they've chosen, whatever those rules happen to be.