Junior dos Santos has been a proponent of USADA ever since the agency began leading the UFC’s anti-doping program in 2015. He never envisioned a scenario where he’d be on the other side of things — trying to prove he was a clean athlete when he always knew he was.

Dos Santos received a reduced, six-month suspension last month after testing positive for a banned substance stemming from a sample collected in August. The Brazilian fighter was the victim, along with countrymen Antonio Rogerio Nogueira and Marcos Rogerio de Lima, of a Brazilian pharmacy that was producing contaminated supplements, a USADA investigation found.

Though dos Santos is now eligible to fight in the UFC again immediately, he still lost eight months of his career. And he was pulled from what would have been a big fight with Francis Ngannou at UFC 215 when the failed drug test came back in August. That isn’t the kind of justice dos Santos was hoping for when he beamed about USADA initially.

The former UFC heavyweight champion said last year was a “nightmare” and he feels like he was “going through hell” trying to prove to USADA he didn’t knowingly cheat.

“They stopped my whole career to investigate the thing,” dos Santos said. “I think that goes in the completely opposite direction of the law. I’m innocent until proven guilty. In this case, it’s different — you’re guilty until you’re proven innocent. So, yeah. This is not good, man. Especially in my case, that I knew I didn’t do anything wrong and I was going all through this situation. It was a very bad feeling.”

In most cases, when a fighter fails a USADA drug test, the UFC will announce that said fighter has been flagged for a potential anti-doping policy violation and provisionally suspended. After the adjudication process, which can vary in length depending on the case, USADA will then announce the sanction the fighter has received.

There has been criticism of that process, because the feeling among many is that once a “potential” violation is announced, that can be a stain on a fighter’s career. Even if it comes back that he or she used a tainted supplement and didn’t get a full one- or two-year suspension from USADA.

For dos Santos, though, he is more upset about the lost time. He believes fans understand that he did not knowingly take the prohibited substance hydrochlorothiazide, a diuretic.

“I feel the truth was found and everybody knows that was a tainted supplement,” dos Santos said. “It wasn’t my fault, it wasn’t my intention. There’s always negative people, that they keep saying bad things about you. They hold on the negative things. But I feel like I got my reputation back. It’s very, very important to me.”

Another issue JDS had with USADA is that, upon his own conversations, he was told that hydrochlorothiazide is not really an effective drug for doping. And because he had such low amounts in his system, dos Santos felt like USADA should have recognized right away that he wasn’t cheating.

“Based on those numbers, on those things, in my mind USADA would be the organization that know that I’m not a cheater,” dos Santos said. “But it wasn’t like that. I still went through this whole investigation, this whole scenario and they were putting me as a cheater. It was very bad, man. Now, I hope they can keep a clean sport however they can do that. But they have better rules, better ways to treat the athletes. Because it’s our lives.

“I hope the system gets better.”

Dos Santos, 34, said he still, for the most part, supports USADA and what it does, even if he does not agree with the full process. “Cigano” does not like that fighters had no say in the anti-doping program, but he is invested in having a clean sport.

“I know this sport, these drugs, these performance-enhancing drugs are a big problem for all the athletes,” dos Santos said. “Because everybody knows most of the athletes, in general, in other sports, too, sometimes they take PEDs. I want to see a clean sport, because we want to know who is the real champion. We don’t want to see a fake champion over there.”

Dos Santos (18-5) will now turn his attention to former World Series of Fighting champion Blagoy Ivanov, who he will meet in the main event of UFC Boise on July 14. In his last bout, “Cigano” fell to in a title fight against UFC heavyweight champion Stipe Miocic at UFC 211 and it’s his plan to get another crack at the belt he held in 2011 and 2012.

“This last year was a nightmare for me, because man, I never imagine I could go through something like that in my career,” dos Santos said. “I’ve been playing the fair game my entire career. I became the champion of the world like that and my goal is to become champion of the world again this way. This thing that happened with me and USADA, that was very sad for me.”