May 18, 2013; Jaragua do Sul, BRAZIL; Luke Rockhold (blue shorts) fights against Vitor Belfort (red shorts) during UFC on FX 8 at ARena Jaragua. Mandatory Credit: Jason da Silva-USA TODAY Sports

Lucas Ketelle is a writer for FanSided partner BroJackson.com. For more great content, head on over to Bro Jackson and check out Lucas’ work.

Doctors prescribe TRT, which stands for Testosterone Replacement Therapy, to some men who are experiencing low levels of testosterone in their 40s and 50s. In MMA, the inconvenient truth is that fighters in their 30s and, in rare cases, 20s are getting the same treatment. What are the advantages to this? The debate has been a hot-button issue in the MMA realm, and threatens to unravel the sports’ credibility as we learn more about its benefits. The pundits that threw fits over Fallon Fox don’t have an opinion on TRT. But what’s for sure is that synthetic testosterone is showing an ugly side of the sport, even though we’re not sure what it does yet.

But there’s smoke: casual biker Andrew Tilin wrote in Outdoor Magazine about his clear competitive progression after a year of TRT. No other major sports allow for TRT and there are consequences for its use—in the Bay Area alone last year Melky Cabrera of the San Francisco Giants and Bartolo Colon of the Oakland Athletics were both busted. Cabrera used a cream similar to what Tilin described in his piece. Gone are the days of seedy syringes behind strip mall gyms. TRT is rampantly available, and with a doctor’s signature secures a personal, discrete treatment and an MMA exemption.

My first familiarity with TRT was in 2010 when I was constantly sick, sought advice, and a friend recommended this route. It wasn’t for me because of the Rogaine angle—once you start using, you have to keep at it since your body will no longer naturally produce the chemicals in your body needed to make testosterone naturally.

In MMA, if you are not allowed a TRT exemption you should come in with below average levels of testosterone on tests. In January, Nevada State Athletic Commissioner Keith Kizer issued a nine-month suspension to Allistair Overeem when he was found with heightened levels of testosterone in a random drug test. He lost out on a title fight against then-UFC heavyweight champ Junior Dos Santos.

Yet there is one big problem: if a fighter has abused steroids in the past NSAC takes the stance that it will be very difficult for you to get approved for TRT. It’s an illogical line to draw because it inherently cedes that TRT is a competitive advantage: You can take TRT and fight but you can’t take TRT and fight . . . if you’ve used steroids before.

Since the majority of those caught have been wrestlers, it could simply be that years of cutting weight have drained the body and now it is not producing nearly as much testosterone. In present day MMA we have one odd example who stands out like a sore thumb–Vitor Belfort.

Belfort is a strange case as Belfort has been in the sport since he was 18, originally competing at heavyweight with a much larger frame than he has now. Belfort is unwilling to talk about TRT and during the build-up of his fight with Michael Bisping danced around the subject matter altogether in interviews. It’s also worth mentioning that Belfort was caught using steroids by Pride Fighting Championship in 2006 and Pride was known for having a bad drug testing system. Belfort claimed that the substance he tested positive for was an over-the-counter supplement.

Belfort treats the media with disdain when this is brought up—pathetically joking that someone should beat up MMAJunkie.com’s John Morgan for asking about the validity of his last two knockout wins in light of Belfort’s TRT use.

Belfort went from being a fighter who needed to catch you with a flurry of punches within the first three minutes of the first round (and getting viciously knocked out by Anderson Silva), to now looking both in better shape than he has ever been as well as performing moves he has never done. The variable of TRT seems to be the one factor that is most at play here.

The fighter widely considered the godfather of TRT, Dan Henderson, talks openly. “Yeah, I’d still be competing, but I’d probably be getting sick more and be lying on the couch more. But, in the same token, If I wasn’t fighting, I’d still be having to take it,” he told MMA Weekly in February.

For those unaware, Henderson is 42 years old, Belfort is 36–both seemingly fit the WebMD diagnosis for needing to use the treatment. But the gray area we’re still working through in MMA is whether TRT is an inside the lines way to help stick around a few more years, or as Dana White maintains, a Pandora’s box that will lead to a new age of cheating if left unchecked.

In Henderson’s case, his points seem valid. But he’s a nice guy and those get more media flexibility. Just look at Nate Marquardt (a “gentleman” of the sport who once tested positive for anabolic steroids). Marquardt went on Ariel Helwani’s The MMA Hour to talk about his low testosterone and how TRT had not just saved his fighting career, but marriage and relationship with his children.

Shane Carwin keeps it curt and minimalist with steroid questions (“[I] will just wait”), and is skewered over coals. Henderson and Marquardt are open, friendly, and have gotten a pass in the eyes of media and fans for their use of TRT.

For now the good news is that there are clear ways to test. The answer is very simple and that’s to use a test that shows whether or not the testosterone in one’s body is being produced naturally or not. The test has proven effective and catches folks with easy. Such was the case with pro boxer LaMont Peterson, who was caught with a testosterone pellet that had been placed on his bicep. Peterson did not have a TRT exemption and he never brought up the use of TRT to the commission prior to going that route. His transgressions were easy to map, he was punished accordingly.

The sad fact is that a lot of guys are using testosterone because it is readily available, gets great results, does not carry the social stigma of cheating. That makes it a growingly essential experiment for aging fighters. After nearly beating Anderson Silva, Chael Sonnen tested positive for a very high ratio of testosterone–about three times over the legal limit of 4/1 in California–and has found himself using TRT after every fight since. Then we have the aforementioned Belfort who basically can’t fight in Las Vegas anymore, because he can’t use TRT. So now UFC sends him to Brazil where the regulations are looser. And this lack of competitive consistency is why MMA in particular is a sounding board for TRT debate.

Even if 10 percent of its fighters are using TRT, it’s still significant. TRT should be banned in MMA outright, before the gray area continues to expand and darken the sport.