I have idly wondered if I just don't absorb caffeine very well. Coffee and energy drinks neither pep me up nor keep me awake; I continue to drink them solely be

I have idly wondered if I just don't absorb caffeine very well. Coffee and energy drinks neither pep me up nor keep me awake; I continue to drink them solely because I enjoy them. The only consistent effect I've observed is that the first cup of the day jump starts things in the digestive department and brings on a trip to the bathroom with some haste, but I've suffered on and off with IBS-like symptoms over the years anyway—even before I started drinking coffee. In my early and mid-twenties I'd drink 5-6 cups of black coffee a day at work. I noticed no ill effects or really any effects at all—no crashes, no jitters, but also no increased alertness or focus. I now usually make myself one latte in the morning then an additional one or two black coffees through the day, but I can still drink a coffee right before bed with no noticeable effect on getting to sleep. I don't usually have any coffee at the weekend, because Saturday I take my machine apart for cleaning, and Sunday I'm typically out of the house at the times I would normally make one. If I go away on holiday somewhere I might go a full week without any coffee at all, again with no noticeable effect. Unfortunately I can't honestly say I have good sleep, because even now (I'm 31) my natural sleep schedule still wants to be something like 3am-11am, but society doesn't tolerate that. I really hoped that would be something I'd grow out of, but I haven't. So I'm pretty much tired all the time whether I drink coffee or I don't.