Clarification needed please.

[Tanyaking]

When we say that the t4 should ideally be in the top 3rd of the reference range and the T3 at the top,is that if you’re taking thyroxine only???

The results whilst on NDT won’t be like that will they?

So sorry it seams such a stupid question,but it’s something I need clarifying and my brain is so foggy,I need help too stop getting more anxious about it all.Thank you.

Tanya.xxx

[greygoose]

No, you're right. If you're taking NDT, the FT4 will be much lower, and it doesn't matter. The body only hangs on to what it needs, and it doesn't need as much T4 if you're taking T3 as well, because it doesn't have to do as much converting.

And, your FT3 should always be at a level that makes you well, whatever you're taking. If that means slightly over-range, then so be it.

[Jazzw]

On NDT, FT4 levels often fall to the lower part of the ref range and sometimes lower - presumably because there’s T3 around which means the body can dump excess T4.

So yes - when on either T3 alone or NDT, you’re looking for FT3 to be at the top of its range - TSH and FT4 are far less relevant.

I must admit, when people post results for comment I always look to the FT3 result first, no matter which thyroid hormone replacement they’re taking. If you’re a good converter, your FT4 might be only mid range with FT3 at the top of its range.

[SeasideSusie Remembering]

Not a stupid question at all, and your brain is working very well.

You are correct.

When taking Levo, if conversion is good the FT4 and FT3 should be in balance, and most of us feel best when it's in the upper part of the ranges.

When taking NDT or a Levo/T3 combo then the T3 tends to lower the FT4 and it's the FT3 result that is important. FT4 and FT3 wont be balanced like it is when taking Levo, because you're taking T3 and may have some natural conversion of the T4 to T3 as well.

[silverfox7]

The thing many doctorsdont like because they haven't a. Lie is that TSH will be suppressed and even the mention of that can send them into a melt down! The only accurate result is the FT3 which should be high if correct dose but I was told it should never go over!

[Angel_of_the_North]

If you are on NDT, ignore the free T4 recommendation.