Be very careful when starting this. It is pure and powerful. You start with lowest dose and test.

A doctor gave me 100 mg of it. I had palpitations and was hyperthyroid. Later, I ended up with AFib.

Additives and preservatives make up part of dosage with some other drugs so 100 mg of one is not equivalent to Tirosint.

It is easier to get compounded T4... and probably safer.