How long does caffeine stay in you system?

Answer 1

Caffeine, let's say in a can of coke. The caffeine has a 1/2 like of 3 - 4 hrs in a healthy adult. This means that 1/2 of the caffeine U drank will still be in Ur system 3-4 hours later. Hope this helps U

Answer 2

Probably not more than hours up to 6-8 How long does the lift last it gives you? Some people become dependent on it and get a headache that's relieved by another cup of coffee. How about that!