I have hashimotos and have been on thyroid replacement for many years. I could not lose weight until I found the correct dosage, and for me I needed combo therapy, I take both T4 and T3. But with a knowledgable endocrinologist monitoring you its not that hard. For me, I would only gain weight if I were being under-treated, which for me meant not getting enough T3. When my endo replaced some of my T4 with T3 everything fell into place.

I cannot imagine living without my medication so I don't think you need to be afraid. You will only feel better.

To clarify the previous post, I agree that many of us need combo therapy, and that while armour is one way to get both T4 and T3, you should know that you can also take synthetic versions of both T4 and T3 (the T4 I take is called synthroid and the T3 is called cytomel). What is nice about the synthetics, is that you can titrate the dosages of each hormone separately, and end up with very consistent dosing.