Cris Cyborg did not test positive for a performance-enhancing drug.

The top UFC female fighter said in a statement Thursday on Facebook that her failed USADA drug test was due to a diuretic called spironolactone. USADA spokesperson Ryan Madden confirmed that Cyborg did indeed test positive for that drug, which is banned in- and out-of-competition under the UFC’s anti-doping policy and the WADA Code.

I have been notified today by USADA of a potential violation stemming from an Out of Competition Sample collected Dec. 5... Posted by Cristiane "Cyborg" Santos on Thursday, December 22, 2016

A diuretic is considered a specified substance in the UFC’s anti-doping policy, which means Cyborg is facing at least a one-year suspension from USADA. Diuretics can also be used to mask the presence of performance-enhancing drugs.

In her statement, Cyborg said she was prescribed the drug by her doctor back in September to help her recover from a bad weight cut and was supposed to be on it for at least 90 days. It does not appear that Cyborg applied for a therapeutic use exemption (TUE) with USADA, which could have allowed her to use the substance.

Spironolactone can be used to treat heart, liver and kidney issues, as well as high-blood pressure and low potassium.

Cyborg, 31, added that she also turned down a potential inaugural 145-pound women’s title fight because her doctor did not want her to go into a training camp or another weight cut. Cyborg said she has been tested 14 times by USADA previously (11 times this year) and never tested positive for anything before now.

“You can feel confident that the substance they are inquiring about is not for performance enhancing use, and is needed for my specific treatments,” Cyborg said in her statement.

Cyborg (17-1, 1 NC), whose real name is Cristiane Justino, did test positive for a steroid in 2011, but it’s unlikely that will be taken into account by USADA in factoring in her suspension length.

Cyborg said it was the severe weight cutting that caused her to seek medical attention and ultimately led to this drug-test failure. Cyborg had to cut from more than 170 pounds to 140 for her last two UFC bouts. She beat Lina Lansberg by second-round TKO on Sept. 24 in Brazil.

“It is my hope that my experiences will continue to bring awareness to the dangers of extreme weight cutting,” Cyborg said. “I cut weight 3 times in 8 months during 2016 competing twice at 140lbs. It is because of the measures needed to make the required 140lbs weight limit Sept 24 that my body is needing the on-going medical treatment.”

The UFC announced that Cyborg was flagged by USADA for a potential anti-doping policy violation earlier Thursday. The collection sample that tested positive was taken Dec. 5.

Cyborg has not lost a fight since 2005, is the most dominant female fighter in the world, and a popular figure the UFC would have likely given pay-per-view headlining fights in 2017.