Hi. Yes, I am well versed in understanding how t4 relates to t3. In my case the t4 levels are fine, but I am low in t3. My body does not seem to be doing well with converting t4 to t3. You have to have sufficient levels of the correct enzyme in your blood to do the conversion, which is one of the things an endocrinologist can investigate. 50 mcg of Levothyroxine is to low a dose for me, as even my t4 level crashes at that. At 62.5 mcg, my t4 levels are fine, but my t3 levels are not. At 75 mcg my t4 levels get too high and I get bad side effects, but my t3 levels are just barely reaching the minimum acceptable level.

I am in Canada and we do not have the same selection of thyroid medications that are available in the States or in England. There are only 3 available here, t4 replacement, t3 replacement and one natural sourced. Levothyroxine (t4 replacement) is the only thing gp’s will prescribe locally; therefore I have to wait to see an endocrinologist 😢
I’m hoping he investigates my enzyme levels and either prescribes an additional dose of t3 or switches me to trying the natural form.