McGregor has been tested by the anti-doping agency ten times in comparison to five times for Mayweather. This is because McGregor’s UFC contract requires him to be available for random testing at all times, as well as new testing for the boxing match with Mayweather. So far, McGregor has been tested five times for MMA, and five times for boxing. USADA tests look for banned substances under the World Anti-Doping Agency guidelines, as well as EPO, HGH and other such illicit drugs. USADA:
[Testing] primarily focuses on out-of-competition testing, all samples are analyzed at WADA accredited labs and the rules are consistent with the WADA Code and UFC Anti-Doping Policy.