Taking just Synthroid for 7 weeks, I know EXACTLY the BRAIN FOG you speak of. Many patients feel better when a T3 med, such as Cytomel, is added to Thyriod treatment. Synthroid is a time-released T4 that your body has to convert to T3. Some (many?)
patients have trouble with that conversion in itself. I felt like MYSELF again on a T3/t4 combo medication, quick acting Armour. (A is NOT the only T3/t4 med)
Right now I'm on 25 mcg's of Syn along with 3/4 grain of Armour. I'm only 3 months new to this thyroid RolLeRCoAsteR myself, so that could be different next month.
Synthroid isn't the only Thy med out there. (Synthroid & Zoloft didn't mix well for me - off Z now)
Have you done any research? We patients are our own BEST advocates
It's all about trying different things, to SEE what works BEST for YOU, in my opinion. They're OUR bodies afterall. Also, I'd recommend any of Mary Shomon's books. She is Hypo patient herself.
Good luck to you,