Guarana is an extract made from the roasted and pulverized seeds of the plant Paullinia cupana, which is native to the Amazon Basin, especially common in Brazil. The seeds of guarana contain a high concentration of caffeine—about 2% to 8%, which is significantly higher than coffee beans. Besides caffeine, guarana seeds also have other stimulants such as theophylline and theobromine, along with antioxidants like tannins, saponins, catechins, and procyanidins. Traditionally, guarana has been used as a stimulant and tonic to combat fatigue, reduce hunger and thirst, and to treat headaches and menstrual pain. It is utilized in energy drinks, dietary supplements, and as a flavoring for teas. Most of guarana's effects—such as increasing alertness, vigilance, reaction time, and attention—are due to its caffeine content, though it also has antioxidant and anti-inflammatory properties. In high doses, it can cause side effects similar to caffeine, including jitteriness, agitation, increased heart rate, and dehydration. Guarana is available in many forms like capsules, tablets, and powders. Its rich historical and cultural roots among Amazonian indigenous peoples also include myths about the fruit, and it remains a popular natural energy enhancer used worldwide today. In summary, guarana is a caffeine-rich plant extract from the Amazon, prized for its stimulant effects and used traditionally and commercially to improve energy, focus, and reduce fatigue. It also has antioxidant and possibly other health benefits.