LAS VEGAS -- Nevada state regulators on Thursday banned mixed martial arts fighters from using testosterone replacement therapy.
The Nevada Athletic Commission voted unanimously in Las Vegas to quit granting therapeutic use exemptions for fighters undergoing the so-called TRT.
"We just decided to say, 'Let's ban them as a whole,"' commission Chairman Francisco Aguilar told The Associated Press. "No one was grandfathered in and no new applications will be accepted."
The decision by the commission that regulates boxing and mixed martial arts in Nevada came several weeks after the Association of Ringside Physicians labeled so-called "unmerited testosterone" a health risk to combat sports athletes and their opponents.
The association had said testosterone replacement therapy for participants in combat sports might create "an unfair advantage contradictory to the integrity of sport."
UFC President Dana White said he also supported a ban.
Aguilar said the Nevada ban would directly affect two fighters -- veteran stars Chael Sonnen and Frank Mir.
Two other UFC fighters who in recent years have been given exemptions by other athletic commissions to use synthetic testosterone are Dan Henderson and Vitor Belfort.
The exemptions were granted for medical reasons including a deficiency in naturally occurring testosterone caused by hypogonadism -- a diminished function of the gonads.
Aguilar called the medical condition so rare that the four-member Nevada commission decided to vote for consistency.
"It gets us further along the line of knowing the fighters are clean," he said. "The challenge is going to be for organizations to determine what jurisdictions allow TRT and which ones don't."