Hello: T hank you for asking on HCM! I read carefully all your concerns and I can say as follows : Are you sure for Synthroid dose that you are taking? Your doctor increased may be at 200 mcg?I would like to know also the lab test for FT4 and FT3 . You are interesing to know what cases fluctattion in TSH level.? -Chainge the dose The most obvious cause of a TSH change is a change in dosage. IF TSH is high, your doctor will likely increase your dosage, so TSH drops. Please be sure fo the dose Synthroid. -Lab changes Different laboratories may return slightly different results. -Are you taking your pill at different times each day? -Are you taking thyroid hormone with food ? If you were taking your thyroid hormone on an empty stomach and start taking it with food, you may see an increase in TSH. And if you were taking it with food, and start taking it on an empty stomach, you may see a decrease in TSH. -Are you eating Too Many Soy Products ? For people with autoimmune thyroid disease, overconsumption of soy products ,may result in a higher TSH. - Are you taking? -Antidepressants ? Cholesterol-Lowering Drugs ?Corticosteroids/Adrenocorticosteroids ? Can suppress TSH, and can block conversion of T4 to T3 in some people. You did;d say if you are female/men? Menopause, with its fluctuating hormone levels, can also impact your TSH levels. Therapy with estrogen also impact your TSH level . Are you taking Irion or Calcium? Women at risk of osteoporosis or anemia, - take thyroid replacement along with supplemental calcium or iron. In many cases taking thyroid hormone at the same time as calcium supplements can make less thyroid hormone available, and cause TSH to rise. My advise is to chec again the thoid hormon, consult again with your endocrinologies and you can take your thyroid hormone first thing in the morning, on an empty stomach, waiting at least an hour to eat. This will ensure maximum absorption. Hope it was helpul for you. Kind Regards Dr Klodiana Poshi