How to prevent supplementary thyroid from reducing natural production?

[youngandold]

How to prevent extra thyroid hormones from reducing TSH and thus natural thyroid production?

It is said that even doing things to increase T4 to T3 conversion will reduce TSH and thyroid levels in the long run.

 

[MyUsernameHere]

That's literally the whole point of the pituitary to keep thyroid hormones at the same levels... It will always react to supplementary hormones by lowering, unless your pituitary is broken.
I don't think there's a way to bypass this, you just have to take more. Once the TSH is shut down your body will no longer circumvent your efforts.