I take 900 mg and have gad mild problems with my thyroid and some cognitive issues.

My doctor checked my blood levels every two weeks to make sure my levels weren't toxic when I started. I get blood work done once a year now because im on the lower end of the dosage spectrum. If you are shaking I would recommend trying the extended release. If you are and are experiencing shaking I would quit. There is no guarantee the shakes will go away with extended use. Its better to look for alternatives.

I can't take 1200 for more than a week. It makes my acid reflex 1000000x worse.