I have been on various thyroid meds for over 30 years. The only time I have observed excessive perspiration is when the med dosage is too high. In reality the TSH is not a sufficient monitor for the amount needed for optimal health-or at least as much health as you can experience when you don't have a natural balance created by your own body. Synthroid is only T-4. You need that of course, and your TSH level will show that the pituitary gland is requesting it, but that does not mean your body is making it or using it correctly. There is a required conversion that takes place in order to get T-3. If you are not converting into free T 3 or if your conversion is into reverse T-3 you have to work on that. Reverse T-3 just sits around in the background and is not always required for a particular situation. Ask your dr. for the whole range of tests-not just TSH. You will discover the reason for sweating if you have a knowledgeable assessment of all the levels.