From what I read T3 should only be used in the stack if you are using a lot of anabolic substances, since it is catabolic. People usually stack it with Tren Ace and Test. However, if this is not the case then T3 will cause you to loose muscle. If you read Unreal's Recomp thread, he mentions stacking it T3 with epistane and ephedrine is good for recomp results. If it were me, I would probably run the clen or ephedrine solo with a ph or AAS that is renowned for using whilst on a recomp diet. Personally, I have obtained better results with ephedrine compared to Clen, however the sides were greater aswell such as insomnia.