Guarana

A South American plant that produces berries with a high concentration (up to 7.5%) of caffeine.  Guarana extracts have been used in traditional folk medicine, as well as a base for soft drinks.  In North America, standardized guarana extracts are used as a “natural” source of caffeine in weight loss supplements and energy drinks.

See Paul’s review, “Guarana – Caffeine’s Fat-Burning Connection” for more information.