Yerba Mate: Health Benefits, Side Effects, Uses, Dose & Precautions

Overview
Mate is used as a stimulant to relieve mental and physical tiredness (fatigue), as well as chronic fatigue syndrome (CFS). It is also used for heart-related complaints including heart failure, irregular heartbeat, and low blood pressure.
Some people use mate to improve mood and depression; to relieve headache and joint pains; to treat urinary tract infections (UTIs), and bladder and kidney stones; for weight loss; and as a laxative.
In foods, mate is used to make a tea-like beverage, known as maté or Yerba Maté, which is very popular in Brazil, Paraguay, and Argentina.
How does it work?
Mate contains caffeine and other chemicals which stimulate the brain, heart, muscles lining blood vessels, and other parts of the body.
Uses & Effectiveness
Insufficient Evidence to Rate Effectiveness for...
Mental function. Early research suggests that drinking a beverage containing yerbe mate does not affect mental performance in healthy females.
Diabetes. Early research suggests that drinking yerba mate tea three times daily for 60 days can lower blood sugar in people with diabetes.
High lipid (fat) levels in the blood. Early research suggests that drinking tea containing yerba mate three times daily for 40 days can lower total cholesterol and low-density lipoprotein (LDL or “bad”) cholesterol in people with high levels of lipids (fats) in the blood. Also, drinking yerba mate tea appeasr to reduce LDL (“bad”) cholesterol and increase high-density lipoprotein (HDL or “good”) cholesterol in people with high cholesterol who are also taking statin drugs.
Obesity. Early research shows that taking yerba mate by mouth might cause weight loss when used in combination with guarana and damiana.
Prediabetes. Early research suggests that drinking yerba mate tea three times daily for 60 days does not reduce blood sugar before eating in people with prediabetes. However, it might reduce glycated hemoglobin (HbA1C), a measure of average blood sugar.
Constipation.
Depression.
Urinary tract infections (UTIs).
Heart conditions.
Kidney and bladder stones.
Mental and physical tiredness (fatigue).
Chronic fatigue syndrome (CFS).
Fluid retention.
Headaches.
Low blood pressure (hypotension).
Other conditions.
More evidence is needed to rate the effectiveness of yerba mate for these uses.
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).
Side Effects
Yerba mate is POSSIBLY SAFE for most people, when taken by mouth for short periods of time. It contains caffeine, which can cause some side effects such as inability to sleep (insomnia), nervousness and restlessness, stomach upset, nausea and vomiting, increased heart rate and breathing, high blood pressure, headache, ringing in the ears, irregular heartbeats, and other side effects.
When taken in large amounts or for long periods of time, yerba mate is POSSIBLY UNSAFE. It increases the risk of mouth, esophageal, laryngeal, kidney, bladder, and lung cancer. This risk is especially high for people who smoke or drink alcohol.
When taken in very large amounts, yerba mate is LIKELY UNSAFE, due to its caffeine content.
Special Precautions & Warnings
Children: Yerba mate is POSSIBLY UNSAFE for children when taken by mouth. Yerba mate is linked with an increased risk of mouth cancer, esophageal cancer, laryngeal cancer, kidney cancer, bladder cancer, and lung cancer.
Pregnancy and breast-feeding: Yerba mate is POSSIBLY UNSAFE when taken by mouth during pregnancy. One concern is that using yerba mate seems to increase the risk of getting cancer. It's not known whether that risk is transferred to the developing fetus. Another concern is the caffeine content of yerba mate. Caffeine crosses the placenta and enters the fetus' bloodstream, producing caffeine levels in the fetus that resemble the caffeine level in the mother. In general, mothers should avoid consuming more than 200 mg of caffeine daily; that's about 2 cups of coffee or tea. Infants born to mothers who consume a lot of caffeine during pregnancy sometimes show symptoms of caffeine withdrawal after birth. High doses of caffeine have also been linked with miscarriage, premature delivery, and low birth weight. However, researchers studied mothers who drank yerba mate tea during pregnancy and found no strong link between drinking yerba mate and premature delivery or small birth weight. But this study has been criticized because it did not consider the amount of yerba mate or caffeine used by the mothers; it looked only at how often they used yerba mate.
Yerba mate is also POSSIBLY UNSAFE during breast-feeding. It is not known whether the cancer-causing chemicals in yerba mate pass into breast milk, but that is a concern. The caffeine in yerba mate is also a problem. It might cause irritability and increased bowel movements in nursing infants.
Alcoholism: Heavy alcohol use combined with long-term yerba mate use increases the risk of cancer from 3-fold to 7-fold.
Bleeding disorders: Caffeine might slow clotting. As a result, there is a concern that the caffeine in yerba mate might make bleeding disorders worse. But so far, this effect has not been reported in people.
Heart conditions: Caffeine in yerba mate can cause irregular heartbeats in certain people. If you have a heart condition, discuss using yerba mate with your healthcare provider.
Diabetes: Some research suggests that the caffeine in yerba mate may affect the way people with diabetes process sugar and may complicate blood sugar control. There is also some interesting research that suggests caffeine may make the warning symptoms of low blood sugar in people with type 1 diabetes more noticeable. 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 people with diabetes 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 using yerba mate.
Diarrhea. Yerba mate contains caffeine. The caffeine in yerba mate, especially when taken in large amounts, can worsen diarrhea.
Irritable bowel syndrome (IBS): Yerba mate contains caffeine. The caffeine in yerba mate, especially when taken in large amounts, can worsen diarrhea and might worsen symptoms of IBS.
Glaucoma: Using yerba mate increases the pressure inside the eye due to the caffeine it contains. The increase in pressure occurs within 30 minutes and lasts for at least 90 minutes. If you have glaucoma, discuss your use of yerba mate with your healthcare provider.
High blood pressure: The caffeine in yerba mate might increase blood pressure in people with high blood pressure. Consuming 250 mg of caffeine can increase blood pressure in healthy people, but this doesn't seem to happen in people who use caffeine all the time.
Weak bones (osteoporosis): Some researchers have found that postmenopausal women who drink a liter or more daily of a traditional South American yerba mate tea have higher bone density. However, the caffeine in yerba mate tends to flush calcium out of the body in the urine. This can contribute to weak bones. For this reason, many experts recommend that caffeine intake be limited to less than 300 mg per day (approximately 2-3 cups of yerba mate). Taking extra calcium may help to make up for the calcium that is flushed out.
There are some women who are at special risk for weak bones. These women have an inherited condition that makes it hard for them to use vitamin D properly. Vitamin D works with calcium to build strong bones. These women should be especially careful to limit the amount of caffeine they get from yerba mate as well as other sources.
Smoking: The risk of getting cancer is 3 to 7 times higher in people who smoke and use yerba mate for long periods of time.
Interactions
AmphetaminesInteraction Rating: Major Do not take this combination.
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 yerba mate might also speed up the nervous system. Taking yerba mate along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with yerba mate.
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 yerba mate might also speed up the nervous system. Taking yerba mate along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with yerba mate.
Stimulant drugs speed up the nervous system. Caffeine (contained in yerba mate) and ephedrine are both stimulant drugs. Taking caffeine 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.
Adenosine (Adenocard)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Yerba mate contains caffeine. The caffeine in yerba mate might block the effects 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 yerba mate or other caffeine-containing products at least 24 hours before a cardiac stress test.
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 yerba mate can increase the risk of side effects including jitteriness, headache, increased heart rate, and other side effects.
Cimetidine (Tagamet)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Yerba mate 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 yerba mate might increase the chance of caffeine side effects including jitteriness, headache, fast heartbeat, and others.
Clozapine (Clozaril)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
The body breaks down clozapine (Clozaril) to get rid of it. The caffeine in yerba mate seems to decrease how quickly the body breaks down clozapine (Clozaril). Taking yerba mate along with clozapine (Clozaril) can increase the effects and side effects of clozapine (Clozaril).
Dipyridamole (Persantine)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Yerba mate contains caffeine. The caffeine in yerba mate might block the effects 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 yerba mate or other caffeine-containing products at least 24 hours before a cardiac stress test.
Disulfiram (Antabuse)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
The body breaks down caffeine to get rid of it. Disulfiram (Antabuse) can decrease how quickly the body gets rid of caffeine. Taking yerba mate (which contains caffeine) along with disulfiram (Antabuse) might increase the effects and side effects of caffeine including jitteriness, hyperactivity, irritability, and others.
EstrogensInteraction Rating: Moderate Be cautious with this combination.Talk with your health provider.
The body breaks down caffeine (contained in yerba mate) to get rid of it. Estrogens can decrease how quickly the body breaks down caffeine. Decreasing the breakdown of caffeine can cause jitteriness, headache, fast heartbeat, and other side effects. If you take estrogens, limit your caffeine intake.
Fluvoxamine (Luvox)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
The body breaks down the caffeine in yerba mate to get rid of it. Fluvoxamine (Luvox) can decrease how quickly the body breaks down caffeine. Taking yerba mate along with fluvoxamine (Luvox) might cause too much caffeine in the body, and increase the effects and side effects of yerba mate.
LithiumInteraction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Your body naturally gets rid of lithium. The caffeine in yerba mate 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 yerba mate too quickly can increase the side effects of lithium.
Medications for asthma (Beta-adrenergic agonists)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Yerba mate contains caffeine. Caffeine can stimulate the heart. Some medications for asthma can also stimulate the heart. Taking caffeine with some medications for asthma might cause too much stimulation and cause heart problems.
Medications for depression (MAOIs)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
The caffeine in yerba mate can stimulate the body. Some medications used for depression can also stimulate the body. Drinking yerba mate and taking some medications for depression might cause too much stimulation to the body and serious side effects including fast heartbeat, high blood pressure, nervousness, and others could occur.
Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others.
NicotineInteraction Rating: Moderate Be cautious with this combination.Talk with your health provider.
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 yerba mate might also speed up the nervous system. Taking yerba mate along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with yerba mate.
Pentobarbital (Nembutal)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
The stimulant effects of the caffeine in yerba mate can block the sleep-producing effects of pentobarbital.
PhenylpropanolamineInteraction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Yerba mate contains caffeine. Caffeine can stimulate the body. Phenylpropanolamine can also stimulate the body. Taking yerba mate and phenylpropanolamine together might cause too much stimulation and increase heartbeat and blood pressure and cause nervousness.
Riluzole (Rilutek)Interaction Rating: Moderate Be cautious with this combination.Talk with your health provider.
The body breaks down riluzole (Rilutek) to get rid of it. Taking yerba mate can decrease how fast the body breaks down riluzole (Rilutek) and increase the effects and side effects of riluzole.
Stimulant drugsInteraction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Stimulant drugs speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and speed up your heartbeat. The caffeine in yerba mate can also speed up the nervous system. Consuming yerba mate along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with yerba mate.
TheophyllineInteraction Rating: Moderate Be cautious with this combination.Talk with your health provider.
Yerba mate contains caffeine. Caffeine works similarly to theophylline. Caffeine can also decrease how quickly the body gets rid of theophylline. Taking yerba mate along with theophylline might increase the effects and side effects of theophylline.
The body breaks down the caffeine in yerba mate to get rid of it. Verapamil (Calan, Covera, Isoptin, Verelan) can decrease how quickly the body gets rid of caffeine. Drinking yerba mate and taking verapamil (Calan, Covera, Isoptin, Verelan) can increase the risk of side effects for caffeine including jitteriness, headache, and an increased heartbeat.
AlcoholInteraction Rating: Minor Be cautious with this combination.Talk with your health provider.
The body breaks down the caffeine in yerba mate to get rid of it. Alcohol can decrease how quickly the body breaks down caffeine. Taking yerba mate 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)Interaction Rating: Minor Be cautious with this combination.Talk with your health provider.
The body breaks down the caffeine in yerba mate to get rid of it. Birth control pills can decrease how quickly the body breaks down caffeine. Taking yerba mate along with birth control pills can cause jitteriness, headache, fast heartbeat, and other side effects.
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)Interaction Rating: Minor Be cautious with this combination.Talk with your health provider.
Yerba mate contains caffeine. The body breaks down caffeine to get rid of it. Fluconazole (Diflucan) might decrease how quickly the body gets rid of caffeine. This could cause caffeine to stay in the body too long and increase the risk of side effects such as nervousness, anxiety, and insomnia.
Medications for diabetes (Antidiabetes drugs)Interaction Rating: Minor Be cautious with this combination.Talk with your health provider.
Mexiletine (Mexitil)Interaction Rating: Minor Be cautious with this combination.Talk with your health provider.
Yerba mate 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 yerba mate might increase the caffeine effects and side effects of yerba mate.
Terbinafine (Lamisil)Interaction Rating: Minor Be cautious with this combination.Talk with your health provider.
The body breaks down caffeine (contained in yerba mate) 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.
Dosing
The appropriate dose of mate 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 mate. 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.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Institute of Medicine. Caffeine for the Sustainment of Mental Task Performance: Formulations for Military Operations. Washington, DC: National Academy Press, 2001. Available at: http://books.nap.edu/books/0309082587/html/index.html.