Guarana, which is pronounced gwa-ra-NAH, is a creeping shrub native to Venezuela and northern Brazil in the Amazon rain forest. The plant produces small, bright red fruits with black seeds.

Guarana seeds are extremely rich in caffeine containing up to 4-8 percent caffeine. The seeds are also rich in tannins and xanthine alkaloids, theophylline and theobromine. Guarana is known to stimulate and increase mental alertness, fend off fatigue, and increase stamina and physical endurance.

In addition to its properties as a stimulant, Guarana is commonly used in weight loss pills. There has been evidence to show that that herb may help with appetite suppression and work to increase fat-burning.