B.C.
Total nonsense and complete bullsh*t.
Your doctor is just trying to scare you off using Armor Thyroid - some doctors refuse to work with it (because it makes THEM feel comfortable having you on Synthroid regardless of how uncomfortable the patient is).
Plus Synthroid is WAY more expensive and I swear I think some doctors are getting a kickback on it, but that's just my personal theory.
I was on Synthroid for roughly 6 years. The tests said my TSH was at the high end of normal but I had symptoms that would not go away.
Finally I spoke with my doctor (who was a GREAT doctor) and said the low end of 'normal' was just as valid as the high end of the range and I wanted to see if Armour Thyroid made a difference (Synthroid is all T4 where Armout Thyroid has T4 AND T3).
We worked to find my optimal dosage and it turns out I feel best when I'm kept right on the cusp of being hyperthyroid.
I don't convert T4 to T3 well, so Armour Thyroid is perfect for me.
If your doctor will not work with you - fire him.
When we moved I had to interview 5 doctors before I found a good one, but it was well worth it.
I've been on Armour Thyroid for 11 years now and except for when there was a production problem and it was on back order, I've never felt better.