Have been on T3 only for nearly 15 yrs as didn't show any real conversion to T3 in tests but have just added a little T4 back in due to ongoing issues and worsening symptoms in the last couple of years since thyroid died and stopped producing it's own tiny amount of T4. Seems to have resolved the issue.
Anyway, I know there are problems with excess T4 inhibiting T4 to T3 conversion in those that still rely on T4 conversion to get their T3 etc but would any of these problems still apply to those not taking T4 for conversion use - just for it's possible other direct biological actions? Would it matter how much Rt3 is about if taking enough T3 for use elsewhere anyway?
I'm sure I read somewhere that excess Rt3 can actually physically block T3 receptors but I can't seem to remember where I read it or if it was just hypothetical or actually based on facts. Does anyone have any research paper or links to anything more solid regarding this? If this is the case, I'm assuming I should be really careful with what dose of T4 I take to ensure just the right amount - historically before these issues, my T4 levels were around 3-5 -normally 4 or under. If I still can't convert T4, any excess might just end up as Rt3???
Not hugely worried at this point just wondering if I need to monitor my T4 levels a bit more regularly to begin with? There is also the possibility that I can convert now as used to have chronic inflammation and other issues which I'm sure I also read somewhere that this can prevent conversion (again not sure where) in which case might not be so much of a problem anymore as resolved but I'll go initially with what has happened historically lol!
Ps - sorry just being lazy to see if anyone has anything to hand rather than spending hours searching lol