According to Steven Marrocco of MMAjunkie, the two substances that Jon Jones tested positive for and caused him to be pulled from the main event of UFC 200 against Daniel Cormier were revealed by the Nevada Athletic Commission in today's hearing.
So per the NSAC, Jones tested positive for Hydroxy-clomiphene, "an anti-estrogenic agent" & "Letrozole metabolite, an "aromatase inhibitor"
— Steven Marrocco (@MMAjunkieSteven) July 18, 2016