I worked my way up to 40 mg. I started at 10 mg and initially experienced some dizziness, but that quickly passed. I've been on 40 mg for about 2 years. If I'm having a hard time falling asleep I will sometimes take an additional 10mg. Other than the initial dizziness, I haven't really experienced any side effects. If your are experiencing AM fatigue, you might want to try taking it earlier in the evening.