You trick your brain into thinking your body has had enough restorative sleep when it hasn’t. Eventually, your body starts to break down. I’ve used 5-Hour Energy a few times over the last week and I’m kind of sorry I did. I don’t have side effects from the drink itself but haven’t actually gotten the sensible amount of sleep that would rid me of the need for it either. So, I haven’t fallen asleep at the office but I haven’t gotten the rest that my eyes and other body parts need either. My eyes are going a little crossed, I have a fatigue headache that won’t go away, and my brain just isn’t firing on all cylinders. I need some lengthy uninterrupted sleep this weekend, I think. And a regular sleep schedule. But, then, don’t I always?