Still searching for answers as to why for 10yrs on 150mcg I had no obvious fluctuations or dose alterations, then everything went down hill last autumn when I found this group and started to learn about the disease I have and discovered I had been doing things wrong as regards taking my Levo.
Well for pretty much the last 10yrs I had been taking my 150mcg Levo every morning with water along with my antidepressant. On many occasions over those 10yrs I had also taken my Levo in the mornings with milk!! Obviously since coming here I learned that the above was wrong because both milk and antidepressants can affect the absorption of Levo, so maybe for the last 10yrs I wasn't actually getting the full 150mcg into my system. My annual bloods also came out within range.
Since doing things the correct way (morning with water and take my antidepressant about 2hrs later), my last 3 readings since October have come out over range in T4 when I lowered my Levo by 25mcg each time and I still feed overmedicated on 100mcg which I reduced to about 2wks ago.
It makes me think that my suited dose (doing it the correct way) is lower because I wasn't absorbing the full 150mcg for the last 10yrs, hence it seemingly being OK for me until last autumn when things changed (maybe menopause related).
Just a thought!