Guarana has a stimulating effect on intellectual activity and physical capacity, but this effect is soft, balanced and progressive.
When used in the frame of a weight-loss diet, it also diminishes the sensation of hunger while preserving the natural cycles of the body and sleep.
Additionally, however, guarana contains tiny amounts of theophylline and theobromine (the later is chemical that makes chocolate poisonous to dogs and cats), which are similar to caffeine, although they exert subtly different effects on the body.
Guarana also contains molecules called tannins, which some say causes the caffeine in guarana to release slowly, producing a long-lasting energy plateau.
Guarana has also been used to treat pain, overcome heat fatigue, combat premature aging and detoxify the blood. It has been found useful to control intestinal gas, obesity, dyspepsia, fatigue, and arteriosclerosis.