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| Rating | Health Concerns |
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Fatigue |
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary
studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but
minimal or no scientific evidence. For a supplement, little scientific support and/or minimal
health benefit. | |
The indigenous people of the Amazon rain forest have used crushed guaraná seed as a beverage and a medicine. Guaraná was used to treat diarrhoea, decrease fatigue, reduce hunger, and to help arthritis.1 It also has a history of use in treating hangovers from alcohol abuse and headaches related to menstruation.
Caffeine and the closely related alkaloids theobromine and theophylline make up the primary active constituents in guaraná. Caffeine’s effects are well known and include stimulating the central nervous system, increasing metabolic rate, and having a mild diuretic effect.2 One preliminary trial found no significant actions on thinking or mental function in humans taking guaraná.3 Guaraná also contains tannins, which act as astringents and may prevent diarrhoea. However, this action has not been studied in human clinical trials.
A cup of guaraná, prepared by adding 1/4–1/2 teaspoon (1–2 grams) of crushed seed or resin to 1 cup (250 ml) of water and boiling for ten minutes, can be consumed three times per day.4 Each cup may provide up to 50 mg of caffeine.
As with any caffeinated product, guaraná may cause insomnia, trembling, anxiety, palpitations, and urinary frequency.5 Guaraná should be avoided during pregnancy and breast-feeding.
Are there any drug
interactions?
Certain medicines may interact with guaraná. Refer to drug interactions for a list of those medicines.
1. Duke JA. CRC Handbook of Medicinal Herbs. Boca Raton, FL: CRC Press, 1985, 349.
2. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics, 2d ed. New York: John Wiley & Sons, 1996, 293–4.
3. Galduroz JC, Carlini EA. The effects of long-term administration of guarana on the cognition of normal, elderly volunteers. Rev Paul Med 1996;114:1073–8.
4. Duke JA. CRC Handbook of Medicinal Herbs. Boca Raton, FL: CRC Press, 1985, 349.
5. Gruenwald J, Brendler T, Jaenicke C, et al. (eds). PDR for Herbal Medicines. Montvale, NJ: Medical Economics, 1998, 1017–8.
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