TweetBABY1 - Thank you for the information on T3 (andT4) and how it relates to thyroid function. I have a friend that isn't a body-builder and at 50 years old last year was desperately trying to lose weight. He was about 60 lbs overweight last spring when I met him and I got him on an exercise program that mainly consisted of high intensity circuit training and cardio (about 30 minutes of each) 4-5x's/week. I also got hi on a 6 week cycle of T3 and a stack of 300 mgs of cyp and 100 mgs of tren-a every 4 days. The results were almost hard to believe, he'd taken the T3 exactly as I told him to, starting w/25mcg/day for 4 days, then 50 for 4 days . . .leveling out at 100 mcgs then back down the same way to end his cycle at 6 weeks. He continued to lose weight for several more weeks and in a 10 week period had lost a total of 60 lbs! He kept it off for about a month then started to put it back on and wanted more T3. I told him he needed to be off for another couple weeks at least (6 weeks on/6 weeks off) and that if he didn't follow this he could screw up his thyroid and may need to take it for life. Then after about 10 weeks total had past I got him another cycle of T3. He'd put on about 30 lbs of the 60 he'd lost by then. Despite my instructions, I later came to find out that he didn't take 2nd T3 cycle as instructed claiming he couldn't take more than 25 mcg's without getting the shakes so he only took 25 mcgs/day but for longer than 6 weeks. I have no idea the duration since he recently tells me not only that he didn't lose any weight off the 2nd cycle but that he didn't take every day and when he did he only took one (25 mcgs/day) and he just recently ran out a few weeks ago and has no energy and is tired all the time and wants more. He no longer works out and again thinks he may have screwed up his thyroid, which I'm inclined to agree with. He was also sweating profusely over the last several months and no longer, since he's off the T3, is doing so. He won't see a doctor and I obviously will no longer be helping him in any way in this area. You'd mentioned a test to take in your above thread at end but I can't find it anywhere. Can you point me in right direction so I can get him to do so and offer any other advice to him that may help? Thanks.