Overview

Guarana is a plant called Paullinia cupana that contains large amounts of caffeine. It is available in many products that are used to increase energy levels, including energy drinks and dietary supplements. It may also be used for other reasons, but its benefits for other uses are not well defined. Common side effects include a fast heartbeat, an increased need to pee, nervousness, irritability, an upset stomach, and trouble sleeping. Before taking guarana, make sure to tell your health care provider about any health conditions you have or medicines you are taking.

Uses

What is guarana used for?

Guarana (Paullinia cupana) is used to increase energy levels. It is also used to increase sexual performance and reduce appetite, but its benefits for these uses are not well defined.

Guarana is available as a dietary supplement in various strengths and dosage forms. It is also added to dietary supplements or products that contain other ingredients, such as vitamins, minerals, taurine, or caffeine.

Note: The FDA has not reviewed guarana for safety and effectiveness. Learn more about dietary supplements here.

How does guarana work (mechanism of action)?

Guarana refers to the roasted and crushed seeds of a plant called Paullinia cupana. The plant is native to Brazil and various parts of the Amazon rainforest, where guarana is used as a stimulant. Guarana seeds typically contain higher levels of caffeine than coffee beans.

Due to its caffeine content, guarana is added to many products that are used for their stimulant effects. Dietary supplements and energy drinks commonly contain guarana. Guarana is also available as a powder that can be added to drinks. These products are often marketed for increasing energy levels, improving weight loss, and enhancing sexual performance. Although caffeine is effective for increasing energy levels in most people, its benefits for sexual performance and weight loss are limited. Large amounts of caffeine can also increase your risk for side effects. See the Side Effects section for more information.

Herbal products, such as guarana, naturally contain many chemicals. The amounts of each chemical in a specific guarana product may vary. Some, none, or all of these chemicals may have effects on the body. These effects may change depending on how much of each chemical is found in the product you are taking.

How should I store guarana?

You should store guarana according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.

Side Effects

What are the most common side effects of guarana?

The most common side effects of guarana are listed below. These side effects may be more likely with higher doses and may vary depending on the specific product you are using. Tell your health care provider if you have any of these side effects that bother you.

• Fast heartbeat
• Increased need to pee
• Nervousness, restlessness, or irritability
• Nausea or an upset stomach
• Trouble sleeping (especially if you take guarana later in the day or close to bedtime)

There may be other side effects of guarana that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of guarana?

While less common, the most serious side effects of guarana are described below, along with what to do if they happen.

Severe Allergic Reactions. Guarana may cause allergic reactions, which can be serious. Stop taking guarana and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching or skin rash
• Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain

Heart Effects. Guarana contains caffeine, which may increase your risk for certain heart effects. It may raise your heart rate or blood pressure or cause an abnormal heart rhythm (arrhythmia). Higher doses of caffeine are more likely to cause heart effects. Many products that contain guarana also contain other sources of caffeine, and caffeine is found in many common foods and drinks. Keep track of all of your caffeine sources to make sure you are not getting too much.

If you measure your blood pressure and the top number (systolic) is 180 or higher or the bottom number (diastolic) is 120 or higher, get medical attention right away. Also call your health care provider or get medical attention right away if you have chest pain or a fast or irregular heartbeat or if you feel your heartbeat more than usual.

Seizures. Guarana contains large amounts of caffeine. Very high doses of caffeine can cause seizures. Many products that contain guarana also contain other sources of caffeine, and caffeine is found in many common foods and drinks. Keep track of all of your caffeine sources to make sure you are not getting too much. There are many types of seizures, and some of them are not easy to recognize. Get medical help if you have any of the following signs that a seizure is happening or could happen.

• Muscle twitching, jerking, spasms, tremors, or other uncontrolled movements
• Stiffening of your arms and legs
• Feeling anxious, nervous, confused, or a sense of dread
• Feeling dizzy or lightheaded
• Falling or losing consciousness

Precautions

Who should not use guarana?

Allergies to Ingredients. People who are allergic to any of the following should not take guarana.

• Guarana
• Paullinia cupana
• Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific guarana products they stock.

What should I know about guarana before using it?

Guarana is available as a dietary supplement and in many energy drinks. It cannot be marketed to treat or cure a disease.

Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.

Keep guarana out of the reach of children.

Herbal products, such as guarana, naturally contain many chemicals. The amount of each chemical in a specific guarana product can change for many reasons, including the area where the plant was grown, the weather during growth, the time of year when it was harvested, and the way that the plant was processed after it was harvested. If you switch to a new bottle or a different brand, you may not have the same effects or side effects because of this variability. Talk to your health care provider if you have questions or concerns.

Guarana naturally contains caffeine, and some dietary supplements and drinks that contain guarana also contain caffeine from other sources. But dietary supplements and non-soda beverages are not required to state their caffeine content. Use these products with caution, especially if you are sensitive to caffeine or you regularly drink caffeinated beverages. Too much caffeine can increase your risk for side effects.

Your body handles caffeine the same way whether you eat it, drink it, or take it as a medicine or supplement. Keep track of all sources of caffeine to make sure you are not getting too much.

Avoid taking caffeine late in the day. Taking it late in the day may make it harder for you to sleep.

The FDA has not tested guarana products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

What should I tell my health care provider before using guarana?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if guarana is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions.Tell your health care provider if you have any of the following.

• Anxiety
• Fibrocystic breasts
• Heart rhythm problems
• Heart disease
• Kidney or liver problems
• Seizures
• Stomach ulcers
• Tremors

Other Medicines and Supplements.Guarana may interact with other medicines and supplements. Before taking guarana, tell your health care provider about any prescription or OTC medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how guarana could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant. Also tell your health care provider how much caffeine you usually get from foods, drinks, and dietary supplements.

Breastfeeding. The caffeine in guarana passes into breast milk. Large amounts of caffeine can cause fussiness or sleeping problems in breastfed babies. Tell your health care provider if you are breastfeeding or plan to breastfeed. Also tell your health care provider how much caffeine you usually get from foods, drinks, and dietary supplements.

Interactions

Does guarana interact with foods or drinks?

There are no known interactions between guarana and foods or drinks. But guarana contains large amounts of caffeine, and caffeine is found in many common foods and drinks (such as coffee, tea, soda, chocolate, and some protein bars). Keep track of all of your caffeine sources to make sure you are not getting too much. Too much caffeine can increase your risk of having side effects.

Guarana contains large amounts of caffeine, which has the opposite effect of alcohol. When caffeine and alcohol are used together, you may feel like neither is affecting you the way it usually does. This may lead you to drink more alcohol or have more caffeine than you otherwise would, increasing your risk for side effects.

Does guarana interact with medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking guarana.

• Fluconazole (Diflucan), itraconazole (Sporanox, Tolsura), ketoconazole, posaconazole (Noxafil), or voriconazole (Vfend), which are medicines used for fungal infections
• Cimetidine (Tagamet HB), which is a medicine used for heartburn
• A barbiturate, such as butalbital, phenobarbital, or primidone, which is a medicine that may be used to treat insomnia, migraine, or seizures
• Phenytoin (Dilantin, Phenytek, and others), which is a medicine to control seizures
• Theophylline (Elixophyllin, Theo-24), which is a medicine for asthma or certain other breathing problems

Guarana contains large amounts of caffeine. Many medicines may alter the blood levels of caffeine, and vice versa. Tell your health care provider about all medicines that you take or have recently taken.

The interactions between guarana and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with guarana is incomplete. Always check with your health care provider before taking guarana with any medicines.

Dosing

What should I do if I accidentally use too much guarana?

If you or someone else has used too much guarana, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

Guarana comes in many forms and doses. It naturally contains caffeine, which may not be listed on the label. Read the product label closely, and speak with a health care provider about how to take guarana safely. Do not take double or extra doses, even if you miss a dose.