Mixed Martial Arts (MMA) fighter Nate Diaz could find himself in trouble for using a vape pen shortly after his five-round loss against Conor McGregor at UFC 202 on 20 August. The United States Anti-Doping Agency (USADA) is currently investigating the use of a vape pen for potential anti-doping violations.

The incident occurred during the post fight press conference – with Diaz suffering a majority loss at the hands of McGregor –where the American was seen openly using a vape pen.

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"It's CBD. It helps with the healing process and inflammation, stuff like that. So you want to get these for before or after the fights, training. It will make your life a better place," Diaz said at the conference.

Cannabidiol which was present in the vape pen is one of 113 active cannabionids in cannabis. They are banned in-competition by the World Anti-Doping Agency (Wada) code over a certain usage, with in-competition considered to be six hours before and six hours after a fight. As it stands Diaz's post-fight press conference was within the six-hour time frame.

"I can confirm that USADA is aware of the situation and is currently gathering information in order to determine the next appropriate steps," a spokesperson for the anti-doping agency told MMAFighting.

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Nate Diaz is under investigation by the USADA over the use of a vape pen post Conor McGregor fight at UFC 202 Getty

If the agency rules that Diaz used the CBD oil within the time-frame he could face up to a one-year suspension. Although Diaz has never failed a drug test in his career, his older brother Nick, the welterweight fighter has three marijuana offences against him in the state of Nevada. He recently completed an 18-month suspension for a third marijuana-related offense. Nick is still under suspension as he still owes the Nevada Athletic Commission $75,000 (£56,798) in fines.

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