Guarana

Guarana, a common ingredient in many energy drinks, is a climbing plant native to the Amazon. It has traditionally been used in medicine to treat fatigue and depression. Notably, guarana contains about four times more caffeine than coffee beans, and it includes compounds that enhance caffeine's effects. This makes the actual caffeine content in energy drinks unclear, as the caffeine from guarana might be additive to what is listed on the label. The inclusion of guarana in energy drinks provides a significant, but not fully understood, boost in caffeine levels and affects human physiology in unique ways 1.