UFC champion Israel Adesanya shot down suggestions that his swollen pectoral muscle during his fight with Paulo Costa was due to the use of performance-enhancing drugs, and said he was told it could be due to his use of marijuana.

Adesanya, who demolished Costa to extend his perfect record to 20-0 as he defended his UFC middleweight title at UFC 253, was questioned about a strangely swollen right pectoral muscle, with some observers suggesting that it could be the sign of PED usage.

Adesanya immediately denied those claims, and has since undergone a series of medical tests to determine the cause.

“Pec-gate. No, (I don’t have an update),” Adesanya said to ESPN.

“My pituitary gland was checked, hormone levels are fine, estrogen and testosterone. Yesterday we had an ultrasound and a mammogram. I had one for the first time.

“To be honest it might have just been unhealthy living a little bit. Like smoking weed, that’s what the doctor from the UFC said. He said I need to stop, but I’m not stopping, I’m just going to slow down on the smoking weed.”

The condition of swelling in male breast tissue is called gynecomastia, and is believed to be triggered by a host of factors, including usage of drugs and alcohol, as well as medications and herbal remedies. Some suggested that Adesanya’s case was caused specifically by use of banned substances, but the UFC champion strenuously denied those claims.

“It’s calmed down,” Adesanya explained.

“It’s just a fat deposit. I mean, but after a performance like that, I’d think I was on steroids too because it was just mind-blowing.

“What the f*ck did I just do to that guy? The guy that, ‘He walked down Romero! No one walks down Romero! Why didn’t he use his boxing?! Costa should’ve stuck to his game plan, he would have won!’ Nah, bruh. There’s the common denominator.

“Some people are so stupid sometimes and it really baffles me. Do you understand y’all look stupid? There’s a reason he couldn’t use his boxing. There’s a reason he couldn’t just walk me down. If you know fighting, if you know, you know.”

Adesanya is set to return to action when he challenges newly-crowned UFC light heavyweight champion Jan Blachowicz. No date has currently been set for the fight.