how long does levothyroxine stay in system? I was on it for over 4 months and never felt any improvement in my chief complaints (extreme fatigue and joint pain). My initial TSH was 5.78, but 2 months after taking it, was down to .78, but then last week was down to .05, so I was given a new prescription for sythroid .1 mg (was on levo .125 mg). Since I had gone to the
T4 has a 7 day half-life. So you should be at an approx equivalent of 112 in a week then 106.25 in 2 weeks and near enough for government work to 100 mcgs in four weeks. Now it will take an added 2-4 weeks for your symptoms to settle out AFTER you hit the 100 mcgs mark.
If we learn by our mistakes, I am working on one hell of an education.