I tried a bunch of different 5HTP and this one works the best. First, any 5HTP can give you a headache starting or reducing amount suddenly. Second, I did use twice a day for appetite control - just not to feel hungry all day, but my doctor switched me to something else (berberine). But what I found is that this gives me incredibly restful sleep and I wake up energized, which never happens with chronic Epstein Barr. I researched a lot of different reasons and methods for taking it, but basically, take 30 min before meal for appetite and take before bed for sleep. You do tend to get used to it though. So sometimes I taper off, then start back.