Guarana is a natural source of caffeine which increases energy. Guarana is a plant native to the Amazon jungle. It is available as a commercial preparation - Josta by Pepsi Cola. It is also known as "zoom".
Guarana 800 mg tablets is about equivalent to 30 mg caffeine. About half a cup of coffee contains the same amount of caffeine. Besides coffee; tea, cola, and cocoa are other sources of caffeine.
Z Lebensm Unters Forsch 1996;203(1):95
The relevant product monographs must be regarded as the appropriate sources of prescribing information.