How to predict whether T4 or NDT would be better for you?

[vkg1]

Hello, could anyone advise on what if any predictors exist for determining whether or not it would be more appropriate to take Levothyroxine or NDT?

For example, if my blood tests show similarly low-side T4 and Free T3, might that be an indication that I am a good candidate for T4 only? I ask because I wonder if perhaps it suggests that I am converting to T3 just fine but only need more T4.

Conversely, when blood tests show low Free T3 and not as low T4, are those the people who typically do better on NDT?

Just hoping it might be possible to reduce some of the trial, error, and speculation frequently involved in thyroid treatment.

[greygoose]

Ahhhhh we all hope that!

I think you may be right in that if you are a good converter, you might do well on T4 only - but, even so, there's no guarantee.

But, if you're a bad converter, would NDT be the right choice? Perhaps not. There is only about 9 mcg T3 in 1 grain of NDT, and 38 mcg T4, which still needs converting. If you can't convert it, then it just mounts up and converts to rT3. With NDT, you cannot change the T4/T3 ratio. So, maybe you would be better off adding T3 to your levo, so that you can adjust the ration to one that suits you. Or, if you're a very bad converter, or cannot tolerate T4 in any shape of form, you might be better off with T3 only. But, you still need to try them to find out.