300 mg. Supposed to be 1-2 hours before bedtime (so once a day). I took it with my pm meds. As the day went on, the feeling wore off. I suspect it'll be a bit wonky for awhile till I adjust. It was actually prescribed for RLS (restless legs), chosen because it can play nice with my other meds (that's not *quite* how the doctor put it, lol, but that was the gist of it ).