Multiple media outlets reported Tuesday that former UFC heavyweight champion Brock Lesnar tested positive for clomiphene in two failed drug tests performed in connection with his UFC 200 co-headliner against Mark Hunt.

LATimes.com and ESPN.com cited officials with knowledge of the substance. A UFC official declined comment to MMAjunkie on the drug’s identity, citing confidentiality during the results-management process.

According to UFC anti-doping partner USADA, Lesnar failed a June 28 out-of-competition test as well as a fight-night test in connection with the July 9 pay-per-view event at T-Mobile Arena in Las Vegas. Per the policies of the UFC and its anti-doping partner, USADA, the substance for which he tested positive was not disclosed, and won’t be until the fighter reveals it or the results-management process has concluded.

Following the first test failure, Lesnar (5-3 MMA, 4-3 UFC) told the Associated Press, “We will get to the bottom of this.”

Clomiphene is the same drug interim champ Jon Jones (22-1 MMA, 16-1 UFC) tested positive for prior to his title-unifier with champ Daniel Cormier at UFC 200, which was canceled when the results were confirmed to USADA three days prior to the fight. Clomiphene is classified as a performance enhancer and is banned year-round because it is often used in tandem with performance-enhancers and is also thought to restart natural testosterone production.

Jones’ out-of-competition test was on June 16 whereas Lesnar’s came on June 28. Because the results of Lesnar’s test were not confirmed until July 14 – five days after UFC 200 – the ex-champ fought and won a decision over Hunt (12-10-1 MMA, 7-4-1 UFC). Hunt subsequently demanded the UFC award him all of Lesnar’s purse or grant him a contractual release.

Lesnar has yet to comment on his second positive test. His fight with Hunt marked a return to the octagon after a five-year absence, as well as his first under the UFC’s anti-doping program. Prior to the fight, he was granted an exemption by USADA on a four-month period in which he would be subject to testing. USADA subsequently tested him eight times.

Responding to pre-event accusations from Hunt, who accused him of being “juiced to the gills,” Lesnar declared, “I’m a white boy, and I’m jacked. Deal with it.”

For complete coverage of UFC 200, check out the UFC Events section of the site.