What's the ratio of T3:T4 in NDT?

[FancyPants54]

I know I've seen this talked about, but can't find it in the search so I must be searching for the wrong term.

Does anyone know what it is?

[london81]

in my NDT it’s measured in grains. one grain contains 38mcg t4 and 9 mcg t3

[FancyPants54 in reply to london81]

Yes, but it's written out like this (example only as I'm guessing the numbers!) 1:4

Do you know what yours is in that form?

[Lalatoot in reply to FancyPants54]

Almost top of the class. 9 X 4 = 36. So in the NDT mentioned above 9 parts of T3 goes with 38 parts T4. So divide by 9 to get 1 part T3........ goes with 38 ÷9 parts of T4. Answer 4.22. So 1 to 4 is about right

[Lalatoot]

However if you are going to use this as a basis for levo and lio combo dosing, you need to realise that this is not necessarily a working ratio for us all. You will find posts on here about folks that need to add T3 to their NDT dose because they need more T3. Equally some add levo to NDT to increase their T4 dose. We need what we need of each hormone.

[FancyPants54 in reply to Lalatoot]

Yes I understand that. But I wanted to know how my 125 Levo and 25 Lio compared. Not as a gospel to work towards, but out of curiosity.

[helvella Administrator Thyroid UK in reply to FancyPants54]

To make much of it, you need also to have an idea about how much is absorbed.

There are some typical figures available for T4 and T3 (50 to 80% of T4; 95% for T3) but I can't remember ever seeing equivalent percentages for desiccated thyroid.

[FancyPants54 in reply to helvella]

That's a big difference in absorption rates between the 2 hormones. Or at least it is potentially if you end up being the person only absorbing 55% of the Levo.

[helvella Administrator Thyroid UK in reply to FancyPants54]

Absolutely it is.

And makes a small difference in the amount in the tablets seem less important. Provided it works and is consistent.