For years Floyd Mayweather has made his opponents submit to drug testing, making it seem as though he’s trying to help clean up boxing. But it looks like that might not be the case. In a long report about boxing and the U.S. Anti-Doping Agency, SB Nation’s Thomas Hauser found that Mayweather received an IV, which is prohibited no matter what it contains, a day before his May 2 bout with Manny Pacquiao. Mayweather’s two IVs contained multi-vitamins and Vitamin C, but IVs are disallowed because they can “dilute or mask the presence of another substance.” But the story only gets fishier. The USADA granted Mayweather a retroactive therapeutic use exemption for the IVs — 18 days after the fight, which Mayweather won by unanimous decision, happened on May 20. The undefeated boxer didn’t even apply for the TUE until May 19, and because of a loophole in their drug-testing contract, the USADA didn’t have to notify the Nevada State Athletic Commission and Pacquiao’s camp until after Mayweather received his exemption. UCLA Olympic Analytical Laboratory Don Catlin told Hauser that the USADA didn’t say why it granted the TUE to Mayweather. “It’s bizarre,” Catlin said. “It’s very troubling to me. USADA has yet to explain to my satisfaction why Mayweather needed an IV infusion. There might be a valid explanation, but I don’t know what it is.” The situation is even more interesting considering Pacquiao was denied a (legal) injection of Toradol before the fight for his torn rotator cuff because the request to the NSAC wasn’t made in a timely manner. Hauser’s report goes even deeper into the drug use in boxing and USADA’s relationship with the sport. It’s well worth a read if you’re a boxing fan.