Brazilian Cocoa, Cacao Brésilien, Guarana Seed Extract, Guaranine, Paullinia cupana, Paullinia sorbilis, Zoom.<br/><br/>


Overview Information

Guarana is a plant. It is named for the Guarani tribe in the Amazon, who used its seeds to brew a drink. Today, guarana seeds are still used as medicine.

People take guarana by mouth for obesity, athletic performance, mental performance, to increase energy, as an aphrodisiac, and for many other conditions, but there is no good scientific evidence to support these uses. Guarana can also be unsafe when taken long-term in large amounts.

How does it work?

Guarana contains caffeine. Caffeine works by stimulating the central nervous system (CNS), heart, and muscles. Guarana also contains theophylline and theobromine, which are chemicals similar to caffeine.


Uses & Effectiveness?

Insufficient Evidence for

  • Anxiety. Early research shows that taking a product containing hawthorn, black horehound, passionflower, valerian, cola nut, and guarana can reduce anxiety in some people. It is not clear if guarana alone is beneficial.
  • Lack of appetite in people with cancer. Early research shows that taking guarana extract slightly improves appetite and prevents weight loss in people with cancer who have lost their appetite and are losing weight. But the benefit is very small.
  • Tiredness in people treated with cancer drugs. Some research shows that taking guarana can reduce feelings of tiredness in some people undergoing chemotherapy. But conflicting results exist.
  • Improving memory and thinking skills (cognitive function). Early research in healthy people shows that taking a single dose of guarana extract can improve thinking speed and some aspects of memory. However, other research shows that taking guarana does not improve mental function in adults or older people.
  • Athletic performance. Research shows that taking a single dose of a product containing guarana, B vitamins, vitamin C, and minerals improves exercise tolerance in trained athletes by a very small amount. It is not clear if guarana alone is beneficial.
  • Obesity. Taking guarana along with mate and damiana seems to increase weight loss. There is also developing evidence that taking a specific combination product containing guarana, ephedra, and 17 other vitamins, minerals, and supplements helps reduce weight by approximately 2.7 kg over 8 weeks when used with a low-fat diet and exercise. It is not clear if guarana alone is beneficial.
  • Feelings of well-being. Early research shows that taking guarana does not improve feelings of well-being in healthy individuals.
  • Serious illness caused by radiation exposure. Research shows that taking guarana does not improve symptoms of depression or tiredness in people undergoing radiation treatment.
  • Athletic performance.
  • Chronic fatigue syndrome (CFS).
  • Diarrhea.
  • Fatigue.
  • Fever.
  • Fluid retention.
  • Headache.
  • Heart disease.
  • Increasing sexual desire in healthy people.
  • Low blood pressure.
  • Malaria.
  • Menstrual cramps (dysmenorrhea).
  • Rheumatoid arthritis (RA).
  • Other conditions.
More evidence is needed to rate the effectiveness of guarana for these uses.

Side Effects

Side Effects & Safety

When taken by mouth: Guarana is LIKELY SAFE for most adults when taken in amounts commonly found in foods. When taken by mouth in medicinal amounts for a short time, guarana is POSSIBLY SAFE.

When taken by mouth in high doses for a long time, guarana is POSSIBLY UNSAFE. Guarana contains caffeine. Doses containing more than 400 mg of caffeine daily have been linked to side effects. Side effects depend on the dose. At typical doses, the caffeine in guarana can cause insomnia, nervousness and restlessness, stomach irritation, nausea, vomiting, increased heart rate and blood pressure, rapid breathing, tremors, delirium, diuresis, and other side effects. Large guarana doses might cause headache, anxiety, agitation, ringing in the ears, pain when urinating, stomach cramps, and irregular heartbeats. People who take guarana regularly may experience caffeine withdrawal symptoms if they reduce their usual dose.

When taken by mouth or injected in very high doses, guarana is LIKELY UNSAFE and even deadly, due to its caffeine content. The fatal dose of caffeine is estimated to be 10-14 grams. Serious poisoning can also occur at lower doses, depending on an individual's caffeine sensitivity or smoking behavior, age, and prior caffeine use.

Special Precautions & Warnings:

Pregnancy and breast-feeding: Guarana is POSSIBLY SAFE for pregnant and breast feeding women when taken in amounts commonly found in foods. If you are pregnant or breast-feeding, guarana should be taken with caution due to the caffeine content. Small amounts are probably not harmful. However, taking guarana in high doses by mouth is POSSIBLY UNSAFE. Consuming more than 300 mg of caffeine daily has been linked to an increased risk of miscarriage and other negative effects.

In women who are nursing, caffeine passes into breast milk and can affect a nursing infant. Nursing mothers should closely monitor caffeine intake to make sure it is on the low side. High intake of caffeine by nursing mothers can cause sleep problems, irritability, and increased bowel activity in breast-fed infants.

Anxiety: The caffeine in guarana might make feelings of anxiety worse.

Bleeding disorders: There is some evidence suggesting that the caffeine in guarana might make bleeding disorders worse, although this has not been reported in people. If you have a bleeding disorder, check with your healthcare provider before starting guarana.

Diabetes: Some research suggests that the caffeine in guarana may affect the way people with diabetes process sugar (glucose) and may complicate blood sugar control. There is also some interesting research that suggests caffeine may enhance the warning symptoms of low blood sugar in patients with type 1 diabetes. Some studies show that the symptoms of low blood sugar are more intense when they start in the absence of caffeine, but as low blood sugar continues, symptoms are greater with caffeine. This might increase the ability of diabetic patients to detect and treat low blood sugar. However, the downside is that caffeine might actually increase the number of low-sugar episodes. If you have diabetes, talk with your healthcare provider before starting guarana.

Diarrhea. Guarana contains caffeine. The caffeine in guarana, especially when taken in large amounts, can worsen diarrhea.

Seizures. Guarana contains caffeine. The caffeine in guarana might increase the risk of seizures and reduce the benefits of many medications used to control seizures. If you have seizures, talk to your healthcare provider before using guarana.

Irritable bowel syndrome (IBS): Guarana contains caffeine. The caffeine in guarana, especially when taken in large amounts, can worsen diarrhea and might worsen the diarrhea some people have with IBS.

Heart disease: The caffeine in guarana might cause irregular heartbeat in certain people. Use with caution.

High blood pressure: Taking guarana might raise blood pressure, in people with high blood pressure due to its caffeine content. However, this effect might be less in people who are regular coffee-drinkers or otherwise use caffeine on a regular basis.

Glaucoma: The caffeine in guarana increases the pressure inside the eye. The increase occurs within 30 minutes and lasts for at least 90 minutes after drinking caffeinated beverages.

Bladder control problems (Incontinence): Guarana contains caffeine. The caffeine in guarana might reduce bladder control, especially in older women. If you need to urinate often with high urgency, use guarana cautiously.

Osteoporosis: The caffeine in guarana can flush calcium out of the body through the kidneys. This calcium loss might weaken bones. If you have osteoporosis, don't consume more than 300 mg of caffeine per day. Taking calcium supplements may also help to replace any lost calcium. If you are generally healthy and getting enough calcium from your food or supplements, taking up to 400 mg of caffeine per day doesn't seem to increase the risk of getting osteoporosis.

Schizophrenia: Guarana contains caffeine. The caffeine in guarana might make some symptoms of schizophrenia worse. If you have schizophrenia, use guarana cautiously.



Major Interaction

Do not take this combination

  • Amphetamines interacts with GUARANA

    Stimulant drugs such as amphetamines speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and increase your heart rate. The caffeine in guarana might also speed up the nervous system. Taking guarana along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with caffeine.

  • Cocaine interacts with GUARANA

    Stimulant drugs such as cocaine speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and increase your heart rate. The caffeine in guarana might also speed up the nervous system. Taking guarana along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with caffeine.

  • Ephedrine interacts with GUARANA

    Stimulant drugs speed up the nervous system. Caffeine (contained in guarana) and ephedrine are both stimulant drugs. Taking guarana along with ephedrine might cause too much stimulation and sometimes serious side effects and heart problems. Do not take caffeine-containing products and ephedrine at the same time.

Moderate Interaction

Be cautious with this combination

  • Adenosine (Adenocard) interacts with GUARANA

    Guarana contains caffeine. The caffeine in guarana might block the affects of adenosine (Adenocard). Adenosine (Adenocard) is often used by doctors to do a test on the heart. This test is called a cardiac stress test. Stop consuming guarana or other caffeine-containing products at least 24 hours before a cardiac stress test.

  • Antibiotics (Quinolone antibiotics) interacts with GUARANA

    The body breaks down caffeine to get rid of it. Some antibiotics might decrease how quickly the body breaks down caffeine. Taking these antibiotics along with guarana can increase the risk of side effects including jitteriness, headache, increased heart rate, and other side effects.<br/><br/> Some antibiotics that decrease how quickly the body breaks down caffeine include ciprofloxacin (Cipro), enoxacin (Penetrex), norfloxacin (Chibroxin, Noroxin), sparfloxacin (Zagam), trovafloxacin (Trovan), and grepafloxacin (Raxar).

  • Cimetidine (Tagamet) interacts with GUARANA

    Guarana contains caffeine. The body breaks down caffeine to get rid of it. Cimetidine (Tagamet) can decrease how quickly your body breaks down caffeine. Taking cimetidine (Tagamet) along with guarana might increase the chance of caffeine side effects including jitteriness, headache, fast heartbeat, and others.

  • Clozapine (Clozaril) interacts with GUARANA

    The body breaks down clozapine (Clozaril) to get rid of it. The caffeine in guarana seems to decrease how quickly the body breaks down clozapine (Clozaril). Taking guarana along with clozapine (Clozaril) can increase the effects and side effects of clozapine (Clozaril).

  • Dipyridamole (Persantine) interacts with GUARANA

    Guarana contains caffeine. The caffeine in guarana might block the affects of dipyridamole (Persantine). Dipyridamole (Persantine) is often used by doctors to do a test on the heart. This test is called a cardiac stress test. Stop consuming guarana or other caffeine-containing products at least 24 hours before a cardiac stress test.

  • Disulfiram (Antabuse) interacts with GUARANA

    The body breaks down caffeine to get rid of it. Disulfiram (Antabuse) can decrease how quickly the body gets rid of caffeine. Taking guarana (which contains caffeine) along with disulfiram (Antabuse) might increase the effects and side effects of caffeine including jitteriness, hyperactivity, irritability, and others.

  • Estrogens interacts with GUARANA

    The body breaks down the caffeine in guarana to get rid of it. Estrogens can decrease how quickly the body breaks down caffeine. Taking guarana along with estrogens can cause jitteriness, headache, fast heartbeat, and other side effects. If you take estrogens limit your caffeine intake.<br/><br/> Some estrogen pills include conjugated equine estrogens (Premarin), ethinyl estradiol, estradiol, and others.

  • Fluvoxamine (Luvox) interacts with GUARANA

    The body breaks down the caffeine in guarana to get rid of it. Fluvoxamine (Luvox) can decrease how quickly the body breaks down caffeine. Taking guarana along with fluvoxamine (Luvox) might cause too much caffeine in the body, and increase the effects and side effects of caffeine.

  • Lithium interacts with GUARANA

    You body naturally gets rid of lithium. The caffeine in guarana can increase how quickly your body gets rid of lithium. If you take products that contain caffeine and you take lithium, stop taking caffeine products slowly. Stopping caffeine too quickly can increase the side effects of lithium.

  • Medications for depression (MAOIs) interacts with GUARANA

    Guarana contains caffeine. Caffeine can stimulate the body. Some medications used for depression can also stimulate the body. Taking guarana with these medications used for depression might cause serious side effects including fast heartbeat, high blood pressure, nervousness, and others.<br/><br/> Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others.

  • Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs) interacts with GUARANA

    Guarana contains caffeine. Caffeine might slow blood clotting. Taking guarana along with medications that also slow clotting might increase the chances of bruising and bleeding.<br/><br/> Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, warfarin (Coumadin), and others.

  • Nicotine interacts with GUARANA

    Stimulant drugs such as nicotine speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and increase your heart rate. The caffeine in guarana might also speed up the nervous system. Taking guarana along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with caffeine.

  • Pentobarbital (Nembutal) interacts with GUARANA

    The stimulant effects of the caffeine in guarana can block the sleep-producing effects of pentobarbital.

  • Phenylpropanolamine interacts with GUARANA

    The caffeine in guarana can stimulate the body. Phenylpropanolamine can also stimulate the body. Taking guarana along with phenylpropanolamine might cause too much stimulation and increase heartbeat, blood pressure and cause nervousness.

  • Riluzole (Rilutek) interacts with GUARANA

    The body breaks down riluzole (Rilutek) to get rid of it. Taking guarana can decrease how fast the body breaks down riluzole (Rilutek) and increase the effects and side effects of riluzole.

  • Theophylline interacts with GUARANA

    Guarana contains caffeine. Caffeine works similarly to theophylline. Caffeine can also decrease how quickly the body gets rid of theophylline. Taking guarana along with theophylline might increase the effects and side effects of theophylline.

  • Verapamil (Calan, Covera, Isoptin, Verelan) interacts with GUARANA

    The body breaks down the caffeine in guarana to get rid of it. Verapamil (Calan, Covera, Isoptin, Verelan) can decrease how quickly the body gets rid of caffeine. Taking guarana along with verapamil (Calan, Covera, Isoptin, Verelan) can increase the risk of caffeine side effects including jitteriness, headache, and an increased heartbeat.

Minor Interaction

Be watchful with this combination

  • Alcohol interacts with GUARANA

    The body breaks down the caffeine in guarana to get rid of it. Alcohol can decrease how quickly the body breaks down caffeine. Taking guarana along with alcohol might cause too much caffeine in the bloodstream and caffeine side effects including jitteriness, headache, and fast heartbeat.

  • Birth control pills (Contraceptive drugs) interacts with GUARANA

    The body breaks down the caffeine in guarana to get rid of it. Birth control pills can decrease how quickly the body breaks down caffeine. Taking guarana along with birth control pills can cause jitteriness, headache, fast heartbeat, and other side effects.<br/><br/> Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.

  • Fluconazole (Diflucan) interacts with GUARANA

    Guarana contains caffeine. The body breaks down caffeine to get rid of it. Fluconazole (Diflucan) might decrease how quickly the body gets rid of caffeine Taking guarana along with fluconazole (Diflucan) might increase the risk of caffeine side effects such as nervousness, anxiety, and insomnia.

  • Medications for diabetes (Antidiabetes drugs) interacts with GUARANA

    Guarana might increase blood sugar. Diabetes medications are used to lower blood sugar. By increasing blood sugar, guarana might decrease the effectiveness of diabetes medications. Monitor your blood sugar closely. The dose of your diabetes medication might need to be changed.<br/><br/> Some medications used for diabetes include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others.

  • Mexiletine (Mexitil) interacts with GUARANA

    Guarana contains caffeine. The body breaks down caffeine to get rid of it. Mexiletine (Mexitil) can decrease how quickly the body breaks down caffeine. Taking mexiletine (Mexitil) along with guarana might increase the caffeine effects and side effects of guarana.

  • Terbinafine (Lamisil) interacts with GUARANA

    The body breaks down caffeine (contained in guarana) to get rid of it. Terbinafine (Lamisil) can decrease how fast the body gets rid of caffeine and increase the risk of side effects including jitteriness, headache, increased heartbeat, and other effects.



The appropriate dose of guarana depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for guarana. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

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