Switching from NDT to T4/T3 combo: Could someone... - Thyroid UK

Thyroid UK

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Switching from NDT to T4/T3 combo


Could someone tell me how I would switch from 2 grains of NDT to the equivalent T3/T4? Any idea would be appreciated. Not doing well on NDT. I was on T3 only 55mcg.

I think I may have an allergy to it or it has raised my anti bodies.

Thank you.

6 Replies

It is stated that NDT at 1gr is equivalent to around 100mcg of levo. 25mcg of T3 is around 100mcg in it's 'effect' .

So 100mcg of T4 plus 25mcg of T3 is about 2 grains of NDT. Take pulse and temp before you begin so you have a starting point should you feel hot, have palps etc but I doubt you will as you've been on thyroid hormones I should think for sometime. This link may be helpful:


You can do a straight switchover from one to another.

mischa in reply to shaws

Thank you Shaws. I feel as though I've been round the Mulberry Bush and back to square one. This is where I began.

shawsAdministrator in reply to mischa

I hope it works well for you this time around :)

Or, you took one hell of a decrease in dose when changing from 55 mcg T3, to two grains of NDT.

Presumably you were on T3 only because you don't convert well. So, why change to a dose of 75 mcg T4 and only 18 mcg of T3?

If you want to go back to T4+T3, just start with 75 mcg T4 and 20/25 mcg T3 - that will be giving you a tiny increase in dose.

mischa in reply to greygoose

Hi GG I thought I was on the same equivalent. Anyhow NDT is just not for me sadly. Has really made me ill. Glands up under my neck. Going back to the combo.

Thank you for replying.

greygoose in reply to mischa

It's not for everyone. Didn't suit me, either.

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