Are we supposing that this is all in the absence of side effects and ruining my hormonal production altogether? Because I would go with T3 all the way. That said, T3 does fuck with your thyroid's ability to function on its own, and it is notably catabolic, so if I could have a COMBO, I'd go T3 and clen - because clen has been proven to be slightly anabolic. I don't know, my problem is never putting on muscle. My problem is putting on muscle without getting uncomfortably fat.