Guarana has been used for centuries by South American Indians, and is presently taken daily as a health tonic by millions of Brazilians, who believe that it helps overcome fatigue, combats premature aging, detoxifies the blood, and is useful for overcoming obesity and arteriosclerosis. Worldwide it is well-known for its stimulant, aphrodisiac, and thermogenic action. Guarana contains the alkaloid guaranine, which is similar to caffeine, but unlike caffeine, is released into the bloodstream slowly, producing a long-lasting energy boost and revitalizing effect. Guarana also contains theobromine, which is the stimulant/euphoriant in chocolate.