Fresh guarana fruits (Paullinia cupana), whole guarana seeds, broken guarana seeds and guarana powder on a white background. Cut-out. Guarana is a plant with high concentration of caffeine, native of the Amazon bassin. It is used as a dietary supplement (effective energy booster). Guarana is used in Brazil in sweetened or carbonated soft drinks and energy shots, or as an ingredient of herbal tea or contained in capsules.