I've been on Doxepin for about 1.5 years now. This was my 3rd sleep aid I'd tried & the only thing that stabilized my sleep enough that I could work & function. I've felt symptoms of fatigue for years, but about 2.5 years ago I went over the cliff. I'd have frequent trouble going to sleep, but the worst thing would be waking up around 4:00am feeling major adrenaline & anxiety. If I could fall back asleep at all, it would usually be right before my 6:30am alarm would go off & I would feel like I had absolutely no sleep at all. I take Doxepin around 9:00pm each night & haven't noticed much difference trying at different times. When I find myself awake between 2:00am-4:30am in the morning, I supplement with Source Naturals Theanine Serene with Relora (helps lower cortisol), Magnesium & recently started adding 500MG of regular flush Niacin. Not full proof, but it usually helps me get back to sleep within an hour so I can function the next day.