Can Guarana Boost Your Energy?

A popular beverage ingredient, guarana (Paullinia cupana) is a plant native to northern Brazil and other regions of the Amazon. The fruit contains caffeine-rich seeds which have up to three times the amount of caffeine as coffee beans. The seeds are also rich in tannins and the stimulants theophylline and theobromine.

Said to boost mental alertness, fight fatigue, and increase stamina and physical performance, guarana is often found in sodas and energy drinks. The seed paste, syrup or extract is used to flavor these drinks as well as provide a source of caffeine. In Brazil, guarana drinks and are considered health "tonics" and are almost as popular as traditional cola-based sodas.

Proponents also claim that guarana may help to suppress appetite and promote weight loss.

Guarana is used primarily as a stimulant due to its high caffeine content. 

An animal study examined the effect of 14 days of guarana supplementation on fat metabolism in sedentary and trained rats and found that the guarana's fat-burning effect is due to the caffeine content. Decaffeinated guarana extracts had no effect on lipid metabolism.

A Journal of Psychopharmacology study found that guarana improved memory, mood, and alertness at low (37.5 mg, 75 mg) vs. higher (150 mg, 300 mg) doses. However, another study examined the long-term use of guarana, caffeine, or placebo on the cognition of 45 older individuals. There were no significant effects of guarana on cognition.

Guarana contains a large amount of caffeine, which may not be indicated on a product's label. If you are sensitive to caffeine or xanthines or have heart problems, high blood pressure, kidney disease, an overactive thyroid, an anxiety disorder, insomnia, or epilepsy, you should talk with your healthcare provider before taking guarana.

High doses of caffeine (or combining guarana with other stimulants like yerba mate, diet aids, or performance-enhancing supplements) may lead to palpitations, arrhythmias, high blood pressure, seizures, and other adverse effects.

Since many doctors recommend limiting caffeine during pregnancy and breastfeeding, guarana should be avoided because the caffeine content differs from product to product and it isn't possible for consumers to accurately estimate how much caffeine they are consuming through guarana.

Guarana should not be taken with any products containing ephedra. Serious adverse effects have been reported with this combination. It may increase the risk of stroke, hemorrhage, myocardial infarction, and sudden death and has been associated with increases in heart rate, blood pressure, and potentially harmful changes in glucose and potassium levels. Guarana should not be combined with alcohol or MAO-inhibitors.

Guarana has been found to decrease platelet aggregation and thromboxane synthesis, so it may increase the risk of bleeding when taken with aspirin, anticoagulants such as warfarin (Coumadin®), and platelet inhibitors such as ticlopidine (Ticlid®), clopidogrel (Plavix®).

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A caffeine-based stimulant, guarana has a long history of use in Brazil as an ingredient in beverages and blended drinks. While it may seem like an appealing way to boost your energy, a problem with guarana is that products may not accurately indicate the caffeine content, leading some people to inadvertently consume high levels of caffeine. Also, some supplements may be mixed with other stimulants, increasing the likelihood of adverse effects.

If you're still considering trying guarana, speak with your healthcare provider about whether it's appropriate for you.