Most Shocking Doping Scandals in UFC History
The UFC has produced some of the best fighters in sports, but its history also includes scandals that changed the course of several careers. Failed drug tests revealed the intense pressure that comes with competition and how easily success can turn into controversy. The substances may have differed, but the consequences were always serious.
T.J. Dillashaw’s Fall from the Top
T.J. Dillashaw, widely respected for his calculated fighting style and strategic preparation, saw his career take a sharp turn in 2019 when he returned a positive result for EPO. The failed test came after his attempt to drop down a weight class and challenge Henry Cejudo. EPO, a synthetic hormone that boosts red blood cell production, is injected directly, thereby removing any room for accidental use claims.
Dillashaw lost his bantamweight title and received a two-year suspension from USADA. He admitted to knowingly using the compound and cited the physical strain of cutting to 125 pounds as a major factor. When he returned to fighting, the reaction was divided. Various fans supported his comeback, but there were some who couldn’t look past the violation.
Nick Diaz’s Battle with Marijuana Policies
Nick Diaz and his repeated clashes with marijuana regulations were one of the most publicized disputes in combat sports. After his 2015 fight with Anderson Silva, a post-event test revealed marijuana metabolites, which triggered a five-year disciplinary sentence from the Nevada Athletic Commission.
Many argued the punishment was excessive, especially when compared to lesser punishments given to athletes who used performance-enhancing drugs. Diaz had already been highlighted in two prior tests for marijuana, which likely influenced the commission’s decision.
Eventually, the ban was reduced to 18 months, but the damage to his professional path had already taken hold. His time away from competition disrupted his momentum, even as his outspoken attitude kept him in the spotlight. The controversy added pressure on regulators to rethink their stance on cannabis, which offered no competitive edge.
Chael Sonnen’s Repeated Violations
Image via Wikimedia Commons/Sgt. Alex Kouns
Chael Sonnen quickly became one of the most controversial figures in UFC history for testing positive for banned enhancers multiple times. His outspoken personality and promotional skills made him a star, but his drug test failures told a different story. In 2010, after nearly defeating Anderson Silva for the middleweight title, Sonnen tested positive for elevated testosterone.
Four years later, a second failure revealed the use of human growth hormone, EPO, and anastrozole. The result was a two-year suspension and his retirement from the sport. Even after returning to fight under the Bellator banner, fans and media often focused more on his doping record than his matches.
Josh Barnett’s Stripped Title and Lasting Fallout
Image via Wikimedia Commons/Michael Dunn
It’s no small feat to become the youngest UFC heavyweight champion, but Josh Barnett’s historic win at 24 quickly lost its shine. After defeating Randy Couture in 2002, Barnett tested positive for banned substances and was stripped of his title.
His tenure, once filled with potential, began to unravel. In 2009, another failed result canceled a major fight with Fedor Emelianenko and played a role in the collapse of the Affliction promotion. Years later, in 2016, Barnett challenged USADA over their handling of yet another flagged test.
Though the case was eventually resolved, it further strained his connection with the UFC and prompted him to request a release.