Hypothyroidism Support Group
Hypothyroidism is the disease state caused by insufficient production of thyrohormone by the thyroid gland. There are several distinct causes for chronic hypothyroidism, the most common being Hashimoto's thyroiditis and hypothyroidism following radioiodine therapy for hyperthyroidism. Advanced hypothyroidism may cause severe complications, the most serious one of which is...
Your thyroid meds dose would need to be adjusted accordingly if you plan on continuing with metformin.
Please know that your pre-diabetic condition just might resolve with proper treatment of your hypothyroidism.
TSH is not a reliable indicator of thyroid function - it's a pituitary hormone. Looking at TSH to judge thyroid status is like looking at the odometer to try and guess how much gas is in the tank.
To measure the "gas in your tank" (actual thyroid hormone levels), you need the FREE T4 and FREE T3 tests.
They often look like this on a lab requisition:
FreeT4: T4 or thyroxine, free, direct
FreeT3: tri-iodothyronine, free, serum
Just so you know, people optimally medicated will have TSH below 1 (and often below-range) and, more importantly, FreeT4 levels near the high end of the range (or slightly elevated) and FreeT3 levels in the upper quarter of the range.
If your doctor has never run these tests, I recommend that you insist on them - it's vital to your success with treatment.
I was told I was pre-diabetic by one endocrinologist and diabetic by another - I was neither. I was under-treated for hypothyroidism.
Once my hypothyroidism was corrected, my high cholesterol, blood sugar issues, and EXTREMELY high triglycerides (over 1030) came back down to normal.