The TRT era was either one of the best or worst periods in MMA history, depending on who you ask. Fighters would apply for Testosterone Replacement Therapy and would essentially be granted a free license to have enhanced performance by the athletic commissions. Fighters in their 20s were granted exemptions to get TRT, and the practice quickly came under fire after multiple fighters began having career renaissances.
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No fighter stood out more from benefitting from the drug than Vitor Belfort, whose use led to arguably the best years of his career as he was approaching his 40s. However, Belfort was only one of many UFC fighters who used TRT, so let's take a look at a few others.
10 Dan Henderson
Dan Henderson was one of the earliest adopters of TRT. In 2007, Henderson applied for the exemption and was one of the first to actually get it, and he quickly began racking up knockouts. Despite Henderson approaching his 40s, he was putting on some of the greatest performances of his career including becoming Strikeforce champion.
Henderson's career was likely extended as a result of the drug. Despite it getting outlawed in 2014, Henderson continued fighting until 2016, finally retiring at the age of 46.
9 Todd Duffee
One of the most controversial fighters to use TRT was Todd Duffee. Duffee applied and got the TRT exemption from the Nevada athletic commission when he was only 24-years-old, with his massive physique coming under fire as a result.
Duffee unlike many entries on this list didn't have massive success with the drug. Despite initial success in the UFC, Duffee's career was considered a massive waste in the promotion. Despite having massive hype coming in, he's only compiled a 3-2 (1) in the promotion so far.
8 Chael Sonnen
'The American Gangster's history with TRT is a controversial one. Sonnen has claimed that he's used the drug as far back as 2008 and that he got an exemption to use it in Nevada, but there's no record of that ever happening.
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Sonnen eventually tested positive for it after his first loss to Anderson Silva. He officially got an exemption upon his return for suspension, but based on Sonnen's history it's unlikely that TRT wasn't the only thing in his system.
7 Nate Marquardt
Nate Marquardt is similar to Vitor Belfort in that his best years came under the use of TRT. Marquardt officially began using TRT after getting an exemption from New Jersey in 2011. Marquardt was under the Strikeforce banner at the time, and his physique quickly changed.
Marquardt put together the greatest win of his career in 2012 under TRT. Marquardt knocked out Tyron Woodley in a vicious fashion to become the Strikeforce welterweight champion, it was the last time he'd hold gold.
6 Frank Mir
Frank Mir's stint under TRT was arguably the worst that was ever recorded. Frank Mir officially got on the drug in 2012 and proceeded to have the worst run of his career while on it. A stark contrast to the rest of the fighters on this list.
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Mir went 0-4 from 2012 to 2014 while on TRT. All of the losses during that stretch were incredibly lopsided, as he lost to Junior dos Santos, Daniel Cormier, Josh Barnett, and Alistair Overeem all via knockout or unanimous decision.
5 Forrest Griffin
Forrest Griffin got on TRT in the final year of his career in 2012. While he didn't know it, he would only have one fight under the drug as he was eventually forced into retirement the following year due to a slew of injuries.
That fight was his trilogy bout against Tito Ortiz at UFC 148 in July 2012. Griffin secured the final win of his career under TRT, winning the bout via unanimous decision.
4 Rampage Jackson
Rampage Jackson was on the downslope by 2012, and as such he did what most aging fighters did at this time and he got on TRT. Officially getting approved for the drug by Japan for his fight against Ryan Bader in 2012, he would be on it until it got outlawed in 2014.
Rampage went 1-2 under the exemption period. He lost bouts to Ryan Bader and Glover Teixeira before picking up a knockout win over Joey Beltran when he departed to Bellator in 2013.
3 Ben Rothwell
Big Ben Rothwell was one of the last fighters to officially get on TRT on this list. He got his exemption for his fight against Brandon Vera in 2013, and he won the fight via knockout. However, the drama came post-fight when Rothwell tested higher than the allowed amount of TRT.
Rothwell was let off by the Wisconsin athletic commission with a warning, and he kept his win. However, the UFC eventually stepped in and suspended Rothwell for nine months due to his elevated levels.
2 Bigfoot Silva
Bigfoot Silva may be one of the few fighters during this time period that actually needed TRT. The Brazilian big man was granted a TRT exemption by Australia and the UFC due to him needing the drug due to his Acromegaly condition, which can result in a lack of testosterone.
Silva, however, got into hot water after his fight with Mark Hunt in 2013. He tested positive for higher levels than allowed of the drug, and as such, had his exemption taken away from him. Silva underwent a massive decline since that bout and has only won once since then.
1 Vitor Belfort
Vitor Belfort is rightfully the poster child for the TRT era in MMA, and for good reason. Belfort has claimed that his TRT use began in 2011 before his fight with Anderson Silva, however drug test results show that he had elevated testosterone as early as 2007 for his fight with Dan Henderson.
Funnily enough, after that Henderson fight, Belfort went on the greatest run of his career. Despite approaching his 40s, he went 10-2 over his next 12 bouts while on TRT. His sole losses during that stretch were to Anderson Silva and Jon Jones, and he nearly defeated the latter in 2012 in one of the closest submissions fans have seen.
