After long term synthroid (thyroxine) over dose of 200mcg for 5 years how long will it be till i feel better? lowered to 175 cancer suppression.

patience required: With history of cancer (? Thyroid you did not mention ) , TSH stimulates not only thyroid cell also cancer cell , (tsh levels 0.3 to 3) need to know your age and weight , status of tumor to calculate the dose, 200 mcg i don't think is over dose, always needs adjustment , you may have associated diseases , speak to your doctor will make you better with other medication good luck.