I've long been interested in how long caffeine stays in my body and what are the effects at different concentrations and times. For example, a popular site erowid has metabolism curves for most illegal drugs, along with side effects. However, it's caffeine entry is mostly anecdotal experiences.
Here's an example of what cannabis metabolic curve looks like: 
Is there a similar metabolic curve with onset, total duration, peak, plateau for caffeine? Does the kind of coffee consumed affect the curve?
