Medically reviewed on Jun 7, 2018
What is Guarana?
Guarana is the dried paste made from the crushed seeds of P. cupana or P. sorbilis, a woody perennial shrub native to Brazil and other regions of the Amazon. It bears orange-yellow fruits that contain up to 3 seeds each. The seeds are collected and dry-roasted over fire. The kernels are ground to a paste with cassava and molded into cylindrical sticks, which are then sun-dried. Today, the most common forms of guarana include syrups, extracts, and distillates used as flavorings and a source of caffeine by the soft drink industry. Guarana also is used as an ingredient in herbal weight loss preparations usually in combination with ephedra.
Paullinia cupana, sorbilis, P. sorbilis
Guarana also is known as guarana paste or gum, Brazilian cocoa, and Zoom.
What is it used for?
Guarana has played an important role in the Amazonian Indians' society. It often is taken during periods of fasting to improve tolerance of dietary restrictions. In certain regions, the extract is believed to be an aphrodisiac and to protect from malaria and dysentery. In 1840, caffeine was identified as guarana's principal constituent. In the 19th century, guarana became popular as a stimulating drink in France. In 1880 it was introduced as an official drug in the US Pharmacopeia, where it remained listed until 1910. Guarana is used by Brazilian Indians in a stimulating beverage used like tea or coffee. It sometimes is mixed with alcohol to prepare a more intoxicating beverage. The stems, leaves, and roots of guarana are used as a fish-killing drug in Central and South America.
Guarana contains caffeine, a stimulant. By comparison, coffee beans contain about 1-2% caffeine and the dried leaves of guarana contain from 1-4% caffeine.
Natural diet aids, which rely on daily doses of guarana, have been advertised in the lay press. Guarana occasionally is combined with glucomannan in natural weight loss tablets. The advertisements indicate that the ingredients in guarana have the same chemical makeup as caffeine and cocaine, but can be used for weight reduction without any of the side effects of these drugs. This is not entirely correct. Guarana does not contain cocaine, and may have serious side effects for some people.
The appetite suppressant effect is related to the caffeine content. The energy that guarana tablets are reported to give also is due to caffeine. This stimulating effect is so widely recognized that 1 guarana product was marketed as "Zoom." Numerous investigational studies have shown the ability of the sympathetic stimulant ephedrine, when coupled with caffeine, to have a synergistic effect on increasing metabolic rates with subsequent increased energy expenditure (thermogenesis), and to have fat reducing (lipolytic) effects. These effects have resulted in a statistically significant weight loss in animal and human trials when combined with diet.
Guarana has been used as a natural energizer, cognitive stimulant, flavoring for beverages, and as a component in natural weight loss products. However, it cannot be recommended as a natural energizer or weight loss aid because of its potential serious side effects.
What is the recommended dosage?
Guarana paste is used as a stimulant at a dose of 1 g, usually dissolved in water or juice. The caffeine content is between 3.6% and 5.8%.
Contraindicated in pregnancy and lactation. Use with caution in people with cardiovascular disease.
Documented low birth weight, birth defects, and premature birth. Avoid use.
Because of its caffeine content, guarana potentially may interact with lithium, theophylline, and clozapine.
Excessive nervousness, insomnia, and other health risks in patients sensitive to caffeine.
Research reveals little or no information regarding adverse reactions with the use of this product. Given its high tannin content, excessive use may lead to an increased risk of cancer of the oropharynx.