Anyone has experience with low TSH after taking Levothyroxine?
I have been on levothyroxine for about 17 years and in the last couple of years routine tests have shown that my TSH is dropping below normal even though I have been on the same or lower dose of T4. Free T4 remains normal so the pattern is consistent with subclinical hyperthyroidism but why it would emerge without a dose change is the question. I'm now 67 so maybe its a normal consequence of aging but I haven't found anything to substantiate that. Anyone else experience this?