It turns out Rashad Evans was correct.
In a hearing on Monday, the Nevada Athletic Commission announced that former UFC light heavyweight champion Jon Jones' failed June 16 out-of-competition anti-doping test -- the test that nixed his scheduled rematch at UFC 200 versus Daniel Cormier -- was for two estrogen-blocking substances. NAC attorney Caroline Bateman stated revealed that Jones tested positive for both the anti-estrogenic agent hydroxyclomiphene as well as letrozole metabolite, an aromatase inhibitor.
In male athletes, estrogen blockers and aromatase inhibitors are often used to both mask the use of exogenous steroids, help restart natural testosterone production, as well as potential physical symptoms stemming from steroid use such as gynecomastia. Jones' former training partner and title challenger, Rashad Evans, was the first to claim that Jones' June 16 failed test was for two estrogen blockers, citing a source in Jones' camp in a video report for CBSSports.com.
With the announcement of the two particular substances, the commission voted unanimously to extend the temporary suspension on Jones' license, pending a formal hearing anticipated in September or October.
Jones has been largely silent since his tearful July 7 press conference when he apologized for his failed test and scuttling the Cormier rematch, despite proclaiming his innocence. The 28-year-old Jones has since retained the services of attorney Howard Jacobs, who specializes not only in representing athletes, but specifically athletes in doping cases. Specific to MMA, Jacobs has represented former UFC lightweight champion Sean Sherk, former Bellator MMA middleweight champion Alexander Shlemenko and most recently and pertinently, Tim Means.
Means was pulled from a proposed bout against Donald Cerrone in February because he tested positive for ostarine, a selective androgen receptor modulator. Jacobs and Means were able to prove that Means had taken a contaminated supplement during training, negotiating a six-month suspension for Means as opposed to the two years potentially prescribed by USADA regulation.