More fatigue than I've ever felt in my life. I'd take it at night and fall asleep within 45 minutes, which was great because I have mild/moderate insomnia from time-to-time. Also, I'd wake up early - like 8:30-9AM early, regardless of when I went to bed. This was actually a great thing. The downfall was the fact that I was tired constantly. I'd get a full night's sleep, be awake for an hour, then feel exhausted all day. Even naps didn't help. I was half asleep every day and had to be taken off of it.