Guarana is a berry that grows in Venezuela and the northern parts of Brazil.
Its name comes from the Guarani tribe that lives in Brazil, and it plays a very important role in their culture, as this herb is believed to be magical, a cure for constipation and a way to regain strength.
Recent human studies show the effects of Guarana in reducing food intake.
Researchers once believed that the active ingredient of guarana was a chemical specific to the plant, guaranine. But they later discovered that it was just caffeine. Guarana has among the highest naturally occurring concentration of caffeine in any plant.