I'm a bit puzzled by this as well as a few Dr's who have seen my blood work. But my Thyroid hormone levels randomly became elevated. I got my thyroid done on an arbitrary panel 2-3 months before I got it retested again. In the first test TSH and Free t3 etc were all normal, but on the higher end of the range, which is fine and didn't raise any flags. From what seems randomly, 3 months or so later my TSH my bloodwork was this: (As taken at 6am on an empty stomach) TSH: 4.5 (.5-4.3mIU/L) Free T3: 1.5 (.9-1.4ng/dl) I hadn't been on any new medications or anything. I don't have too many symptoms of hyperthyroidism, but I do have a very fast resting HR (at least for me) at ~80-95 bpm, a bit of trouble sleeping, cardio is difficult, body just feels stimulated even when I'm really tired, the most noticeable is absolutely profuse sweating during exercise. It just pours off it's gross. Otherwise, I haven't really lost any weight maybe 2-4lb's (haven't gained any either) but as soon as I noticed the loss I just added some cheat foods to my diet and everything went back to normal. I've also noticed that i've been pretty shredded despite not trying to lose fat. I haven't really been losing strength either. Blood pressure is fine at around ~125/85. I'm not sure if it's risen since I last got it tested, but I'm getting results on a full panel on Thursday. High TSH usually indicates hypothyroidism, but my Free T4 is not low. Granted I didn't get all the other tests, such as Total T3, T4 and free T3 but that is on Thursday. High T4 and low TSH would indicate Hyperthyroidism, but I don't have low TSH either. I did a little bit of googling on the subject but didn't find much out, but I didn't go in depth. I'm not terribly worried about it, but it would be nice to at least figure it out. The endo I saw on Wednesday said he had never seen it before and he's been practicing for 55 years. Discuss.