I agree, dont be lazy and just do cardio. I would only do it if I had a high BF percentage and need something to help. Even though some say not to use it more then 6 weeks, I think 4 weeks should be the max. I work in the medical feild and I do my own labs and the thyroid is something you do not want to screw up with. I did a 6 weeks cycle and even when I stopped my levels continue to drop for 3 weeks after being off it. Scared me alittle and I was about to take some meds to reverse it, but it started to come back up. I think there is some sort of a rebound effect on the endocrine system. If I ever did it again I would limit it to 4 weeks. A low TSH means you are hyper not hypo.