The role of T4?

[AnneEvo]

This may seem a stupid question but.... if T4 is the inactive hormone, is it's sole purpose to hang around waiting to be converted into T3? Can it do anything else if it is inactive?

[shaws Administrator]

It is supposed to convert to T3. Many patients may find they don't do so effectively or actually need a T4/T3 combination which researchers have found that can resolve miserable symptoms.

Unfortunately if you're in the UK we used to get prescribed natural dessicated thyroid hormones (NDT - contains, T4, T3, T2, T1 and calcitonin) )- made from animals' thyroid glands - maybe more conducive to the human body.

We also got T4/T3 combination or T3 alone. NDT was withdrawn through False Statements made about it, depsite it being the only replacement hormone since 1892 onwards and it is also available today but prohibited in the UK.

Sometimes for us, the patient, we may need to trial more than levo because millions do fine on it but there's a section who don't.

[Hidden in reply to shaws]

I might even add that more and more people seem to do less than good on t4 only, with progressive Hashimotos. Even with perfect high range labs on Levo, people seem to suffer. Especially individuals with supressed tsh, who need a form of t3.

[shaws Administrator in reply to Hidden]

I agree with you.

I was far more unwell and more symptomatic on levo than before being diagnosed.

[Hidden in reply to shaws]

Totally same, especially on high doses of Levo, that do nothing. We will all get there!

[shaws Administrator in reply to Hidden]

I'm fortunate to have resolved that problem. Levo didn't suit me and I am aware when some patients get to an optimum dose of T4 that they feel well.

A number of Researchers have proven that a T4/T3 dose suits many and resolves symptoms.

The original - NDT - was given on a trial basis (no blood tests then only symptoms) This was based on their clinical symptoms alone and if they improved on NDT they were hypo and it was gradually increased.

[Hidden in reply to shaws]

Exactly, thankfully my Endo is not concerned about tsh and that nonsense. Just a dose that makes me feel well and thinks that would be anywhere 20-40 mcg t3 (I know, wide range!) Plus some Levo, most likely 50-75 mcg. Still have a good bit to go

[Angel_of_the_North]

There may be other things that it does, but no one really seems to have researched it

[Marz]

I believe some T4 is needed in the brain - but cannot remember where I read that ..

[Hidden]

I forgot where I have seen the research study, but t4 passes brain barrier more than t3 as they are specific mechanisms blocking pure t3 entering so people on t3 may need more t3 to restore brain function. Basically t4 changes to t3 in nucleus in the brain, but don't quote me on it Also t4 has a direct effect on hair nails and skin but not sure where I read it...

[AnneEvo]

Thank you Marz and ritatita.

[wellness1]

I had a vague idea that the Tired Thyroid website might have information on the role of T4. Found a couple of posts there.

tiredthyroid.com/rt3-7.html

tiredthyroid.com/rt3-6.html

Marz Hidden

[Hidden in reply to wellness1]

That's it! I have her book and she has listed research studies in there