Thyroid UK
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T4 and t3

My t4 is 15.6 and t3 5 tsh 6.2 on 25mg of Levi. How high can my t4 be before I'm over medicated? Also how high can my t3 be before I get hyper symptoms? I need to know because I've just asked the drs surgery for an increase in my Levo, as my Dr feels theres no need to take action with my results, I need some concrete reasons to debate an increase with him. Any help appreciated. P.s I m also due to attend a respiratory health clinic as I did a sleep study privately and I have sleep apnea and need to try c pap therapy.

2 Replies


You won't be over medicated and are unlikely to experience hyper symptoms until your FT4 and FT3 are over range. FT4 15.6 is low normal as most ranges top off at 22 or 24. I think you need to see a different GP if yours won't increase your Levothyroxine. I linked to Dr. Toft's article in your previous post and he comments that some patients need low TSH 0.5 which may cause elevated FT4 24-28 to feel well.

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TSH of 6.2 is much too high. For people who are on Thyroid medication the target is TSH at or below 1 to make them feel well.


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