Health Benefits of Guarana

Jillian Kubala, RD
·7 min read

Medically reviewed by Kierra Brown, RD

Guarana (Paullinia cupana) is a plant native to the Amazon basin in South America. Guarana seeds have been consumed by indigenous communities in the Amazon region for centuries, both as an energy source and as a natural medicine for conditions such as headaches, period pain, and digestive disorders.

Best known for its stimulating properties, guarana has one of the highest caffeine contents of all plants. It contains approximately four times more caffeine than coffee beans.

Because of its energizing effects, guarana is a common ingredient in stimulant supplements and products, such as energy drinks and pre-workouts. While consuming guarana may benefit certain aspects of health, such as cognitive function and athletic performance, guarana is associated with several side effects and health concerns.

<p>Design by Health / Getty Images</p>

Design by Health / Getty Images

May Improve Energy and Alertness

Guarana has powerful stimulating effects, and products have been used for centuries to boost energy and alertness. Guarana contains several compounds that affect the central nervous system (brain and spinal cord) to help you feel more awake and energized.

Guarana seeds contain up to 8% caffeine by weight. Caffeine crosses the blood-brain barrier—a barrier between the blood vessels of the brain and the brain tissue that prevents harmful substances from reaching the brain. It blocks receptors for adenosine, a neurotransmitter that plays a critical role in the sleep cycle.

Adenosine increases the need for sleep by making you feel drowsy. Caffeine blocks adenosine’s ability to bind with adenosine receptors, which makes you feel less sleepy and more alert.

In addition to caffeine, guarana contains other stimulating compounds, such as catechins and tannins, which may have energy-boosting effects on the body. Studies show that guarana is more effective for increasing energy levels than caffeine alone.

Consuming guarana products like energy drinks and supplements could help you feel more awake. For example, one small 2023 study that included 25 participants found that those who ingested 125 milligrams per kilogram (mg/kg) of guarana experienced significant improvements in alertness scores compared to people who received a placebo treatment (e.g., a sugar pill).

Has Cognitive-Enhancing Properties

Some study findings suggest that guarana supplements can improve cognitive performance. This may benefit those who need a boost before a mentally taxing task, such as a marathon study session or an important presentation.

For example, a 2023 review of eight studies found guarana ingestion effective for improving response time during various cognitive tasks. It also didn't have any negative effects on accuracy. Though the improvement seen in this study was small, it suggests that consuming guarana may help boost your performance on time-related tasks.

Additionally, the 2023 study of 25 people mentioned above found that those who took guarana supplements experienced significant improvements in reaction times on cognitive tests before and after intense exercise.

Some research findings suggest that guarana supplements may also increase information processing, which may help you perform better at work or school.

May Boost Athletic Performance

Guarana may be a useful supplement for athletes and those looking to improve their exercise performance. Study findings suggest that taking guarana before exercising may make your workout feel easier and increase your workout efficiency.

One small 2019 study of 10 high-level athletes found that consuming 300 mg of guarana before and during exercises reduced levels of perceived exertion and improved cognitive performance compared to a placebo.

Additionally, the researchers of the 2023 study of 25 participants suggested that guarana may be helpful for athletes involved in sports and activities that require quick responses, like soccer and hockey, as it helps improve reaction times.

How To Take Guarana

Guarana is available in several forms, such as capsules, liquids, and powders. It’s often combined with other natural stimulants like caffeine and ginseng in products designed to boost energy and concentration.

Guarana is a popular ingredient in energy drinks, protein bars, and other food and beverage products designed to fight fatigue. It can be taken when you need a boost of energy or want to improve focus and concentration, such as when studying for an exam.

Pre-workouts containing guarana are commonly consumed by gym-goers before a workout to enhance their exercise performance and improve their reaction time and focus. Avoid taking it before bed because it can disrupt sleep and cause insomnia.

Dosage

Guarana doses typically range from 37.5-222 mg, though higher doses have been used. Research studies have also used doses of guarana ranging from 75-100 mg per day for up to four weeks.

Always read product labels for dosing recommendations, as guarana is commonly combined with different ingredients.

Is Guarana Safe?

Guarana is generally considered safe when taken in recommended doses, but its use has been associated with several health concerns. For example, overuse of guarana-containing supplements and products containing guarana, like energy drinks, might negatively affect heart health and lead to irregular heartbeat, high blood pressure, and several other heart-related side effects. This is especially true for people with pre-existing cardiovascular conditions.

There have also been reports of seizures in healthy young adults who consumed energy drinks containing guarana and other ingredients.

Guarana contains caffeine, so avoid it if you're pregnant, breastfeeding, or sensitive to caffeine. Caffeine may worsen symptoms of some health conditions, such as anxiety and cardiac conditions like arrhythmia (irregular heartbeat).

Caffeine Toxicity

Guarana, which is already high in caffeine, is often combined with other stimulants. Therefore, caffeine toxicity is another risk. Caffeine toxicity can cause dangerous symptoms like seizures, vomiting, and hallucinations. It’s recommended that adults keep their caffeine intake to less than 400 milligrams per day.Although rare, you can consume a fatal dose of caffeine, which is estimated to be between 10-14 grams (g).

This is why it’s important to know how much caffeine is in guarana products, like supplements and energy drinks, and to avoid products that contain very high doses of this stimulant.

Potential Drug Interactions

Guarana has the potential to interact with several commonly prescribed medications, including:

  • Blood-thinners: Guarana may increase the effects of blood-thinning medications, such as warfarin, as it might decrease the body’s ability to clot blood. Though this potential effect hasn't been confirmed in humans, always check with your healthcare provider before supplementing with guarana if you take blood thinners.

  • Adenosine: Adenosine is a drug used to treat heart rhythm disorders. It's also sometimes used during a cardiovascular stress test. Guarana seems to block the absorption of adenosine, so it may interfere with how this drug works. Avoid all caffeine-containing products, including guarana, for at least 24 hours before undergoing a stress test.  

  • Clozapine: Clozapine is an antipsychotic medication. Caffeine may increase its effects and worsen psychotic symptoms.

Guarana may interact with other drugs, so always talk to your healthcare provider before trying it.

What To Look For

If you’re interested in taking a guarana supplement, it’s important to choose a safe supplement from a reputable company. Many supplement companies are certified by third-party organizations like UL, USP, and NSF International, which set strict standards for supplement safety and quality.

Read product labels carefully for other ingredients that might interact with medications or might not be safe for you.

Can You Take Too Much Guarana?


Guarana contains caffeine, which can lead to dangerous side effects if over-consumed. As mentioned above, it’s recommended to keep your caffeine intake to less than 400 mg per day to avoid side effects such as sleep disturbances, irregular heart rate, irritability, and insomnia.

Some guarana-containing products, like energy drinks, contain multiple servings per container, which can easily lead you to over-consume caffeine. Read ingredient labels and note how much caffeine the product contains so you can stay within a safe limit.

Side Effects of Guarana

Guarana can lead to many side effects, especially when consumed in high doses. Here are some of the most common:

The potential for adverse side effects may increase if you’re taking a supplement or ingesting a product that contains multiple stimulants.

If you experience any side effects, stop taking the product and consult your healthcare provider if the symptoms don’t resolve.

A Quick Review

Known for its stimulating properties, guarana is a popular ingredient in products like pre-workouts and energy drinks. Some research suggests that supplementing with guarana may improve energy levels, alertness, athletic performance, and cognitive function. However, guarana is high in caffeine and can lead to adverse side effects when taken in large doses.

Guarana isn’t safe for everyone and has the potential to interact with common medications. It can also worsen symptoms of several health conditions. Always consult your healthcare provider before trying it.

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