I have been taking thyroid hormones for over 25 years since I had RAI treatment. I used to take just Synthroid for a while, but then reduced that and added Armour which really help me a lot. My Free T3 levels were just to low. Recently I switched from Synthroid to Tirosint which doesn't have all of the fillers that Synthroid had and is better absorbed. If you are going to start with a T4 I would recommend Tirosint and see how you respond. You can then add T3 or a T3/T4 like Armour if your FreeT3 levels don't respond.

Most people do best when their Free T4 and Free T3 levels are in the upper end of the range around 60-70%. This has been true for me.

It is a long and slow process to get your levels balanced and you have to be patient. If on T4 it can take 6-8 weeks for your body to stabilize each time you make a dosage change and you want to take small steps.

Good luck.