"i started off on the wellbutrin 150 mg xl twice a day and i was exhausted everyday, not to mention the nausea was so bad i had to stop taking it. just started on wellbutrin immediate release at 100 mg once a day and it is a complete difference. i have so much more energy and focus, so far i love it. i do get a little headache by the end of the day but its not a big deal."