If a person is taking too much T3, could reverse T3 kick in, slow them down and make them feel hypothyroid?
If yes, then how would it affect a blood test--would the test reflect the slowing down and make it look like they could use even more T3, or would it be out of range-showing that they are taking too much?
ReverseT3 is made from T4 , not T3 ,
T4 can either be made into T3 , or into ReverseT3 ~ depending on what the deiodinase's think is needed .
eg if there is too much T4 they will make more T4 into ReverseT3 (to inactivate it)
T3 is inactivated into T2 (by the same deiodinase that inactivates T4 into ReverseT3)
Are we talking about someone who is just taking T3 ?
or someone taking T4 and T3 ?
edit >>> there are a lot of outdated ideas about "ReverseT3 'blocking' T3 receptors" still out there on the internet , but that is not what Reverse T3 does , so make sure what you are reading is up to date : healthunlocked.com/thyroidu.... pooling-an-outdated-concept-list-of-useful-posts-which-explain-why-reverse-t3-blocking-t3-receptors-is-not-a-thing-.
ps . i note from your first post a year ago that you were testing 18hours after the last dose of T3.. no one seems to have picked up on that at the time , but 18hrs is too long .
To see the mid levels of T3 you need to be testing 8-12 hours after the last dose of T3. (24 hrs after last dose of levo )
Testing after 18hrs will show a lower T3 level than you have for most of the day .
What timings are you using for the blood tests now ?
what T3 dose are you taking now /split how /what times ?
Hi Tattybogle, Long story ahead...
Thank you for the info! I didn't understand a lot of the t3 stuff--seems more complicated than i thought. I am so brain fogged i can't really concentrate. I was taking .100 levo and also T3.My practitioner said it was ok to slowly increase the t3 until i felt better. After a few days of increase i would get tired again. In Nov. I ended up on 23 mcg of T3 but was still getting sleepy in afternoon. At this point my ft3 was: 3.7 (range 2.3-4.2), but i was still feeling hypo. Am beginning to think it's not all thyroid related.
I started having chest pain while exercising-had bunches of tests and everything is fine.Then in March I was in a hurry and accidentally took 36 extra mcg in the afternoon instead of the 3 I should have taken! I couldn't take any for quite a while. Now I am on .100 levo and 13mcg lio. Blood test on 5/6--FT3 was 3.6. I am extremely exhausted by early afternoon. I am afraid that the higher lio was causing chest pain bec it has now stopped. My latest test is about the same as in Nov but i am taking way less. I am trying to figure whether labs will show when i'm taking too much liothyronine or if RT3 would slow me down and keep my labs in range.
Sorry this is so rambling...
Hi marlyn ....will have a look in the morning .. my brain isn't much use after dark 
Hi if you give us your blood results from each dose we will be able to help you understand more:
for each set of results we need to know:
Date.
Dose of T4 / Dose of T3.
how long were you on that dose before test .
how many hours before test was last dose Levo taken.
how many hours before test was last dose T3 taken .
TSH result [range]
fT4 result [range]
fT3 result [range]
Whether dose was changed after the blood test.
Thanks for your response. I see that i need to document what i'm doing if I'm ever going to get this right. I haven't been, so i guess I start where i am right now and take it from there.
Banning T3 - what do you do next ? 
A little too much T3?
