YES! As I always say, diet and exercise is the key. No matter what drugs a guy uses, its always the diet and cardio that matter. With T3, I would hold off until you are running gear to help preserve muscle, but as for clen, you are good running it without gear. 

start with 40mcg , then add 20 mcg every 2 wks and go no higher than 120mcg and run for a time no longer than 16 wks total on clen. Should be enough time to make a big difference with a good cardio and diet plan