99% of all UFC fighters are roiding. The only few i would think aren't roiding are Diaz bros and maybe Bisping and ive said this since before the Diaz bros came out and started accusing everybody of roiding. You can't train for MMA and look like Reem, Lesnar, Lombard, etc. and have the gas to go more than a round. These are fighters not bodybuilders. Not only that but MMA fighters usually don't bodybuild when they do weight lift, its either strong man style or athletic style yet you got guys looking like bodybuilders.
Even the ones that aren't built like Woodley and Romero have been busted like Royce, Barnetto and Leben. If you're a top fighter and can survive wars you're roiding. MMA is just so hard to train for its impossible without roids.
Diaz bros are the only ones i think are clean because of their style. Very efficient. Maybe Mark Hunt. I used to think Bisping was clean but idk now. He's pretty efficient too. Its the guys putting out a lot of energy that are suspect. Bouncing around everywhere like Mighty Mouse, Cruz and Edgar. Throwing bombs and being light footed like DC and Rumble. Come on now...