Does Guarana Work?
No studies have been published concerning the effectiveness of guarana. However, since caffeine is the active ingredient in guarana, it is assumed that guarana is just as effective as caffeine for any use. For some people, caffeine (and, therefore, guarana) can increase energy. Although caffeine (and guarana) may help some people lose a little extra weight, the dangerous effects of high doses of these products limits their usefulness for weight loss.