How Guarana Benefits Your Body and Brain

Guarana (Paullinia cupana) is a plant extract commonly used to increase energy and improve alertness.. It contains caffeine, a well-known stimulant.

Guarana contains plant-based compounds with antioxidant properties, which may help protect cells from damage caused by free radicals (unstable molecules that damage cells). Early research also suggests it could potentially help with some side effects of cancer treatments, but more human studies are needed to confirm this.

While some studies suggest potential health benefits of guarana, many studies are small, preliminary, or conducted in animals. More high-quality human research on guarana is needed to confirm its benefits for any specific health conditions. The information presented in this article should not be interpreted as conclusive medical evidence.

Antioxidants

A review article analyzed a small clinical trial in which healthy participants took 3 grams (g) of guarana daily. The results of this short-term study suggested that guarana may help reduce oxidative stress (imbalance between free radicals and antioxidants), indicating possible antioxidant effects.

In general, antioxidants attack free radicals. Free radicals can damage components and systems within the body, including the hereditary material DNA.

Since this was a small and short-term study, further extensive research with more significant and longer-term clinical trials is necessary to assess guarana’s effects better.

Energy Boost

Guarana seeds contain more caffeine per gram than coffee beans. It is a a popular ingredient in energy drinks. The beverage industry in the United States uses approximately 70% of the guarana seeds produced annually.

The energy boost you get when you consume an energy drink containing guarana comes from its high caffeine content. Consuming large amounts of caffeine in any form can lead to adverse effects such as:

• Shaking
• Dizziness
• Heart palpitations
• Trouble sleeping

There is also some evidence that overconsumption of energy drinks can cause more serious problems such as:

• Electrolyte imbalance
• Heart problems, including abnormal heart rhythm and heart attack

Memory and Brain Function

A review article showed that guarana was associated with improvements in attention, alertness, and reaction time in some studies. However, most data are from small studies or may be confounded by other variables, such as guarana’s caffeine content.

The review article authors state that guarana has great potential for human health, but recognize that available evidence lacks human studies. They call for future studies to explore its mechanisms and applications to human health.

Another review article found that guarana might help improve response time during cognitive tasks without impacting accuracy, however, the improvement was small and researchers were unsure if the effect was related to the caffeine content of guarana or other plant compounds.

For these reasons, it might be challenging to quantify guarana’s effects. Future high-quality clinical trials should study more standardized guarana products and dosages.

Cancer Protection

Animal and laboratory studies have suggested that compounds in guarana, such as polyphenols and caffeine, may have anticarcinogenic (anticancer) effects. However, clinical evidence in humans is currently lacking to support this.

Because some of these effects may be related to the caffeine found in guarana, the anticancer benefits may not be specific to guarana itself but may also be present in caffeine obtained from other sources.

Some clinical trials have found that guarana may also help relieve some of the side effects of cancer-targeted treatment.

Although promising, more clinical trials are warranted, as guarana seemed to have positive results in people with only certain types of cancer.

Heart Health

One study in a review article observed the effects of drinking guarana at least twice weekly in older adults. Consuming guarana was associated with a lower severity of metabolic syndrome (a group of medical conditions that increases your risk of heart disease) in some observational studies of older adults.

While the results are promising, additional research with high-quality clinical trials is still needed to quantify further to what extent guarana lessens the effects of metabolic syndrome.

Weight Loss

Animal studies suggest that guarana seed powder may have a positive impact on weight regulation, but human studies are needed to confirm these effects.

The results of animal studies don’t always translate well to human beings, however, and more research is needed to confirm that guarana seed powder has the same effect on human beings.

Eye and Vision Health

Age-related macular degeneration is an eye condition that affects people as they get older. It affects the central part of the retina, the light-sensitive tissue located at the back of the eye. Age-related macular degeneration can lead to irreversible vision loss.

A preliminary study suggested an association between guarana use and reduced oxidative damage in retinal cells. However, more research is needed to assess the clinical relevance of these findings.

Side Effects and Precautions

As with many medications and natural products, guarana can have side effects.

Common Side Effects

Common side effects of guarana include:

Severe Side Effects

Severe side effects are possible, especially with large doses of guarana.

Examples of severe side effects include:

• Serious allergic reaction: A severe allergic reaction is a profound side effect possible with any medication or natural product. If you’re having a severe allergic reaction, your symptoms may include breathing difficulties, itchiness, and rash.
• Abnormal heart rhythm and rate: Large amounts of guarana may look similar to a caffeine overdose with symptoms of heart arrhythmia (abnormal heart rhythm and rate).

If you’re having a severe allergic reaction or if any of your symptoms feel life-threatening, call 911 and get medical help right away.

Precautions

A healthcare provider may advise against guarana use for certain people:

• People with health conditions that are adversely affected by caffeine consumption, such as a heart condition or a seizure disorder.
•  Guarana contains plant substances that may play a role in liver toxicity. While there are no documented cases of liver injury caused by guarana, caution is advised in people with liver conditions due to limited safety data. Long-term and high-dose guarana use isn’t recommended in people with liver problems.
• Children and people who are pregnant or breastfeeding should avoid guarana because of its high caffeine content.
• Avoid guarana if you have a known allergy to it or other ingredients or parts of the supplement. If you need clarification on whether it’s safe, ask a registered dietitian, pharmacist, or healthcare provider for more information.

Toxicity

More information about the safety, toxicity, and overdose of guarana in humans is needed. However, guarana toxicity likely resembles that of a caffeine overdose.

Signs of a potential overdose include:

• Heart arrhythmia
• Tachycardia

Per a systematic review, side effects might be less of an issue with maximum daily guarana doses of between 500 and 1,000 mg.

Interactions

Due to its caffeine content and potential enzyme interactions, guarana may alter the metabolism and effects of certain medications. Always consult a healthcare provider before combining guarana with any prescription or over-the-counter medications.

Some of guarana’s potential interactions include:

• People with high blood pressure should avoid guarana because its caffeine content can raise blood pressure.
• It’s also important to avoid taking guarana with certain supplements that increase heart rate or blood pressure. This can increase the risk of serious heart problems, including heart attack or sudden death.
• People taking medications for arrhythmia, such as amiodarone, should avoid taking guarana. Guarana may reduce amiodarone levels and interfere with how well amiodarone works.

Sources of Guarana

Guarana is naturally available as a native Amazonian Paullinia cupana (P. cupana) plant from the soapberry family called Sapindaceae. The U.S. Department of Agriculture (USDA) generally categorizes guarana or P. cupana as food.

In the United States, guarana is a common ingredient in energy drinks. This tends to be the most popular way to consume it.

Guarana is also available as a powder, which can be used to prepare tea. It’s sometimes also used as a flavoring agent. In fact, the FDA placed guarana on its approved list of substances added to food.

Guarana supplements are available in several different forms, with capsules being the most common.

Other supplement forms include:

• Food bars
• Gummies or chewables
• Liquid
• Lozenge
• Powder
• Tablets
• Wafers

Vegetarian and vegan options might also be available. You may also see guarana in combination with other ingredients.

While some studies on guarana in humans exist, more research with high-quality clinical trials is still necessary. For this reason, there are no guidelines on the appropriate dosage to use of guarana for any condition.

The specific dose may vary based on the dosage form and any medical conditions you may have. To safely take natural products like guarana, inform your healthcare providers and pharmacists about any medication changes. This includes over-the-counter (OTC), herbal, natural medicines, and supplements.

Summary

Guarana is naturally available as a native Amazonian plant from the soapberry family. It may have antioxidant effects, brain health support, heart health support, and relief from the side effects of cancer or its treatments. But like any medication or natural product, side effects and interactions are possible.

Because no conclusions have been made regarding the efficacy and safety of guarana, it should not be taken in place of getting an accurate diagnosis and treatment for any symptoms or conditions you may have. Before using guarana, involve a registered dietitian, pharmacist, or healthcare provider to help you safely achieve your health goals.

Although guarana shows promise in various areas, such as energy enhancement and antioxidant effects, most of the available evidence is preliminary and limited. Further well-designed clinical studies in humans are needed to confirm its benefits for any specific health conditions.