With T4 you need to get up into the range of about 150-200mcg depending on your size. 100mcg would work with T3 but T4 needs to be dosed higher. I use T3 on cycle to help me stay somewhat lean and increase my appetite. Make sure that when you come down you do it slowly or you run the risk of shutting down your thyroid and screwing up your metabolism. I wouldn't run it for more than 3 weeks either. Be careful, thyroid hormones can mess you up when run too high or for too long without coming down slowly enough. Good luck.