At 36-years-old, UFC light heavyweight Vitor Belfort is the best mixed martial artist he’s ever been. On May 18th, he knocked out Luke Rockhold, a 28-year-old rising star who had won nine straight, with a spinning heel kick that will go down as one of the greatest knockouts in UFC history. But this heel kick isn’t what’s firing up the MMA community. It’s Belfort’s body. And his past. And the Ultimate Fighting Championship’s current allowance of athletes diagnosed with low testosterone levels to undergo the controversial testosterone replacement therapy treatment.

Belfort burst onto the scene in 1996, a 19-year-old with blazing hand speed, incredible athleticism and one of the most jacked physiques in the fight game. Flash-forward to today, 17-years later, and he’s being described by Sport’s Illustrated as the possessor of a “...tantalizing combination of patience and explosiveness.” This would be great but for the fact that nearly every article that offers substantial coverage about his victory over Rockhold has more to do with his use of TRT than it does about his victory. Belfort, evolving and developing his martial arts techniques though he may be, is also more jacked than ever. Prior to the fight, Rockhold said the following to ESPN:

"It's pretty obvious to see. People don't transform like that naturally. I don't care how much weight you're lifting. Your veins and muscles don't just completely morph and change without some outside help. TRT ... is it really just TRT? I've seen guys on TRT working hard, and look nowhere near what Vitor looks like. I hate to make this the whole topic of this fight. It seems like it is.”

It’s clear that even Rockhold was confused on how to address this matter. How much of Belfort’s recent physical development is the result of his different and perhaps smarter training methods? After all, he’s been in the game a long time and likely has developed a sensitivity to what kind of training and dietary practices work best for him. How much is perhaps his body simply reacting more positively than others to TRT? Would TRT still take center stage if Belfort’s body hadn’t changed? How much of the talk here is about performance and how much is about sheer looks? And how much of Belfort’s brilliant performances and chiseled body might be due to some other substance he’s using – be it legal or illegal? It is this cloud of tough and perhaps unanswerable questions that has everybody talking.

Belfort’s less than squeaky clean past certainly doesn’t help lend credibility to his oft-mentioned “TRT doesn’t win fights” quote. Early in his career, when drug testing in MMA was essentially nonexistent, he was accused of heavily using steroids. Those longtime accusers certainly smiled when, in 2006, he tested positive for the anabolic steroid 4-Hydroxytestosterine following his bout with Dan Henderson.

Still, critics are split on a variety of issues. Many point out that Belfort’s past steroid use could be the reason for his naturally low testosterone levels and therefore his ability to qualify for TRT today. That is, his need for TRT is essentially self-inflicted. If indeed this is the case, should it matter? Others posit that Belfort is simply using every legal tool within his disposal to achieve peak performance – what elite athlete wouldn’t, they say. Others still could care less about Belfort’s use and instead put blame on the UFC for allowing athletes undergoing TRT to compete.

So what are the reported physical benefits of TRT? Every user I’ve talked to over the years expressed two main qualities: they feel younger and they recover from grueling workouts far faster than pre-TRT. When I pressed them on the former, most people insisted that their “feeling” likely came from their testosterone returning to what was defined as “normal” for their age. This is problem number one. There really isn’t a way to determine what is normal. Since the time he was nineteen, Belfort has been an incredibly muscular 200-lb. man. Unless he’s had doctors monitoring his (and perhaps even his parents’) testosterone levels all of these years, who is to say what’s normal for him? And what dangers might there be if we simply use a standard baseline for all males and grant doctors the power to recommend TRT not based on an individuals genetics or past but on an imperfect science, some questions about fatigue levels and a simple blood test? Regarding the quicker recovery times, many users told me that they felt like they were disrupting a sort of built-in balance: athletes who train for years come to know their body, what works for them and what doesn’t. While they possess such wisdom, it’s hard-earned and bought with time. In exchange for greater knowledge they’ve given up the vigor and energy of their youth. Users reported to me that they now feel as though they have the best of both worlds. They’ve got the wisdom and they’ve got the energy.

Had Rockhold dominated Belfort the TRT talk would have been hushed for a while, possibly forever or until a similar situation emerged. Now, with Belfort’s spectacular knockout and his knocking on the door of another title shot, look for the UFC and Dana White to make some announcements and perhaps even some changes to their current drug testing policy.

Where do you stand? Would Vitor Belfort – given his explosive fighting style and length of time participating in a sport renowned for the toll it can take on an athlete’s body – still be able to compete at such an elite level without the use of TRT?