Thyroid UK
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Metformin and Levothyroxine

Just read an article about Metformin and levothyroxine in the Thyroid UK newsletter. Apparently levothyroxine can interfere with blood glucose levels but does T3 or NDT do this too or is it just levothyroxine? I take Metformin but I am on T3 only. At some time in the future I hope to introduce some NDT so quite interested to know how this wd effect blood glucose levels if at all.

3 Replies

Hi Caze,

I can't tell you anything about Metformin and Thyroid Meds but I know it

can have an effect in Vitamin B12 levels.



Caze, T3 and NDT can too. I think it's advised that blood sugar levels are checked after increasing thyroid replacement dose as Metformin dose may also require increasing.


I take Metformin for insulin resistance and T3 only for hypothyroidism. I finally feel completely fine and my mucin and water retention are dropping off every day. I don't think that those two drugs interfere in any significant way and I am saying that from my own experience. I am finally really satisfied with my whole treatment.


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