Thyroid UK
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Free T4 result. Doctor wants to lower thyroxine dose

Free T4 is 16 (9-21). Doc wants to lower meds but I can only function properly at 20 . we had a long conversation regarding this on my last visit. I thought she understood! The new reading is because I had already lowered dose and I am reluctant to do it again. Help!

TSH has consistently remained at 0.010 for years.

7 Replies

TSH is meaningless once you are supplementing. And to be honest, so is FT4. FT3, which measures the active hormone available, is the the critical measure. Most people only feel well when their FT3 is towards the top of the range.

Your doctor can do what she likes, of course, but you need to be persistent. And ask her to measure FT3 (she will need to be firm with the lab) - as long as that is not over range you are fine, and in no danger.


What is a good level of T3?

My B 12 was 267

Thank you


A good level of FT3 is the one that makes you feel well. And most people need their FT3 up near the top of the range to feel well.

Your B12 is rather low. Do you have symptoms of low B12?


I am not sure, I sometimes have to push myself to do things. I call myself a slothlike creature on many occasions. I have been told B12 is fine, by doc.

Are you able (?) To give me a guideline for acceptable levels of


Vit D

Free T3


My bilirubin level is 10.

I have looked for above "levels" but I get confused 😵 thank you


Having to push yourself is more than likely due to low thyroid. Your FT4 is rather low, not much more than mid-range. So, if you're not converting well, then you are still very hypo. Your doctor is rather ignorant about thyroid and is only looking at the TSH, and that is irrelevant - see here :

You don't want 'acceptable' levels of anything, you want optimal.

For B12, that's revealing itself to be complicated, but if you have symptoms, then it needs to be higher - over 500. But, you might be better off going on to the Pernicious Anemia forum and asking them.

Vit D needs to be around 100.

Free T3 needs to be where it makes you well, and that has nothing to do with blood tests.

T3 is an unacceptable test, because it doesn't give you any useful information.

Unfortunately, doctors know little about hormones/thyroid, and even less about nutrition. What gives them the idea that they are capable of treating us without knowing anything about it, I have no idea! But, that's why so many of us self-treat. It is essential to self-treat when it come to nutrients, because doctors always get it wrong!


Thank you, much appreciated.


You're welcome. :)

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