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As cannabis laws around the country continue to change, so do those around combat sports. UFC announced on Thursday a formal change to its anti-doping policy, making marijuana OK for in-competition athletes. The only time where an athlete would be punished for using cannabis or cannabinoid is if "additional evidence exists that an athlete used it intentionally for performance-enhancing purposes."

"While we want to continue to prevent athletes from competing under the influence of marijuana, and we have learned that urinary levels of carboxy-THC are highly variable after out-of-competition use and have poor scientific correlation to in-competition impairment," UFC senior vice president Jeff Novitzky said in a statement. "THC is fat soluble, meaning that once ingested, it is stored in fatty tissues and organs in the body and can be released back into the circulation, and consequently carboxy-THC appears in the urine, sometimes long after ingestion. It is therefore not an ideal marker in athletes to indicate in-competition impairment."

Many fighters have faced suspension for having marijuana in their systems over the years. The most notable case being Nick Diaz, who tested positive on three separate occasions in Nevada with the final test resulting in an unprecedented five-year suspension from the state athletic commission. That was later reduced to 18 months.

"The bottom line is that in regard to marijuana, we care about what an athlete consumed the day of a fight, not days or weeks before a fight, which has often been the case in our historic positive THC cases. UFC athletes will still be subject to marijuana rules under various athletic commission regulations, but we hope this is a start to a broader discussion and changes on this issue with that group."