How Caffeine Works
A good place to start is by looking at precisely what caffeine does to the body.
Essentially, caffeine’s effects occur because it is able to replace a substance called adenosine. Caffeine and adenosine are molecularly very similar and this means that when you have more caffeine in the blood, your body will mistake it for adenosine.
This then allows the caffeine to bind to adenosine receptors, preventing it from being effective. It’s like putting a fake key in the lock so that the real key can’t fit in.