I was on 900 mg for awhile. I recently came off of it because it just wasn't worth taking-- I have very atypical mood swings, and Lithium really isn't designed to handle those types of swings. Out of the 18 drugs I have tried, Lithium was the most tolerable, side-effect wise. I had some stomach problems with it (mostly when the dose was increased), a bad taste in my mouth, and some hair loss-- we're not talking clumps or bald spots here, lol... but definitely more hair than usual was coming out when I would be styling my hair.