When I first took Lithium I didn't notice anything except some passing nausea that was eased when I took it with food. It took about 3 months before i noticed it was working well but I was going through a tough time so may not have noticed. I take 1000mg so 900mg is decent but not too much, unless of course your blood work says otherwise. The positives I felt was more mood stability and less suicidal ideation. Missing doses can hurt. I don't seem to react until I am off it for days. Off Lithium I am a mess so that is what keeps me taking it.