I had taken Provigil for only 3 days. It gave me more energy, but It made me very gittery and anxious. It would feel like my heart was racing. Also, I couldn't go to sleep at night at all. The energy part for my fatique was great. But does it out way the problem of not being able to fall asleep at night. I found It isn't worth getting no rest. Because that may cause me bigger problems later on.