What is 10mcg t3 equivalent too??I'm getting di... - Thyroid UK

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What is 10mcg t3 equivalent too??I'm getting different responses!

ThyroidObsessed profile image
8 Replies

So iv been told to reduce my Levo from 100mcg to 75 and add 10mcg of t3...

I'm very sensitive to any change and my mains symptoms are depression and anxiety I don't really suffer physically... will I need more than 75 of Levo and 10mcg t3? I feel like I will suffer if I go that low...

Latest results on just 100mcg of Levo are

- FT4 - 23 (11 - 23)

- FT3 - 4.55 (3.1- 6.8)

- TSH - 8 (0.27- 4.5)

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SeasideSusie profile image
SeasideSusieRemembering

What is 10mcg t3 equivalent too??I'm getting different responses!

What responses have you had? There are conflicting answers to this question even when researching as it's only a rough guide. It's said that T3 is roughly between 3 and 4 times the "strength" of T4. So 10mcg T3 could be the equivalent of 30-40mcg T4.

ThyroidObsessed profile image
ThyroidObsessed in reply to SeasideSusie

Iv had some people say 10mcg is equal to 50mcg of Levo and some say it's 30- 40 and some say 20 God knows...

Hi

What's your TSH please - is it 8 or .8 ?

I was hoping for some T3 as my FT3 was low in range (in lower half). Sadly, was refused. My FreeT3 wasn't retested after Levothyroxine increase so no way of knowing if it has improved - crazy.

Good to hear you succeeded in getting T3, your FreeT3 is not quite halfway in range but better than mine.

When will your next blood test be - I suppose the answer to your question will be in those results?

If your TSH is 8 (as it reads) and your FreeT4 at top of its range I think I would be querying high TSH.

Have you had any Pituitary Gland hormones tested?

ThyroidObsessed profile image
ThyroidObsessed in reply to Mary-intussuception

Hi yes my tsh is actually high at 8! Iv had all the tests under the sun including pituariaty testing, all come back normal, my NHS endo thinks that it's because the t4 is not converting and more t3 is needed...

30-40mcg of thyroxine, so that would be a slight dose increase. As your FT4 was high in range, I'd just start with 5mcg of T3 (and the 25mcg reduction in levo - that extra levo isn't doing much for you). But response is quite individual.

jimh111 profile image
jimh111

About 3x as potent ncbi.nlm.nih.gov/pmc/articl... . In the blood it is 4x to 5x as potent but doctors often forget that tablets have different absorption rates and half-lives.

helvella profile image
helvellaAdministratorThyroid UK in reply to jimh111

And everyone forgets that T3 is lighter than T4. Converting 100 micrograms of T4 perfectly into T3 would result in somewhat less than 100 micrograms of T3 - about 84 micrograms.

jimh111 profile image
jimh111 in reply to helvella

Yes a third factor in the equivalence calculation. Absorption, half-lives and molecular weights are all relevant and maybe something we haven't thought of. The Celi study is nice because it just compares tablets swallowed with equivalent TSH and no assumptions. Of course this study defines equivalence in terms of effect on TSH which is far from perfect but this is the best we can do.

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