Caffeine is an alkaloid compound found particularly in tea and coffee, other performance supplements like pre-workouts or fat burners, and energy drinks. Often, we are familiar with the use of caffeine to prevent tiredness, caffeine helps keep us awake and alert by competing with a molecule that promotes tiredness called adenosine. Caffeine prevents adenosine from binding to its receptors as it has a very similar molecular shape! So how does caffeine provide a physical performance benefit?