IngredientsYerba mate or yerba maté (Ilex paraguariensis) is a plant species of the holly genus native to South America. Its leaves are classified within the family Aquifoliaceae. The plant was named by the French botanist Augustin Saint-Hilaire. The full accepted taxonomic binomial is Ilex paraguariensis A. St.-Hil.
The plant and the beverage prepared from it go by a range of common and regional names. It is commonly called "mate" or "yerba mate" and is used for the preparation of the most popular tea-like beverage of South America. The Guarani name for yerba mate is ka'a, which means "a plant" or "a herb." Yerba mate was also known as Jesuit tea or Paraguayan tea and was shipped as such to Europe. It is also known as chimarrão in Portuguese, cimarrón in Spanish, and ka'ay in Guarani.
Yerba mate is a native tree growing in the subtropics of South America, present in Southern Brazil, Northeastern Argentina, Eastern Paraguay, and Uruguay. The yerba mate plant is grown and processed in its native regions of South America, specifically in Paraguay, some parts of northern Argentina (Misiones), Uruguay, and southern Brazil (Rio Grande do Sul, Santa Catarina, Paraná, and Mato Grosso do Sul).
I. paraguariensis has seven local congeneric substitutes or adulterants: I. brevicuspis; I. theezans; I. microdonta; I. dumosa var. dumosa; I. taubertiana; I. pseudobuxus; I. integerrima; and I. argentina. I. paraguariensis shows a higher content of flavonoids and caffeoyl derivatives than these other assayed species.
Traditional consumption of Ilex paraguariensis occurs through three different beverages: chimarrão, tereré, and mate-tea.
Mate is traditionally served with a metal straw (bombilla) in a container typically made from a calabash gourd, from water-resistant hardwoods such as Lapacho or Palo Santo, and also made from a cattle horn (guampa) in some areas. The process of adding water to the gourd is repeated several times and the total drink consumption is estimated at approximately 1 liter.
Beyond traditional beverage use, yerba mate is gaining rapid introduction into the world market, either as tea itself or as an ingredient in formulated foods or dietary supplements. Today, mate is also sold commercially in tea bags and as bottled iced tea.
Industrial processing of yerba mate involves multiple steps. Three different steps constitute the basic yerba mate processing: "Zapeca," a pre-drying process where the green yerba is exposed directly to high temperatures to decrease humidity and inactivate oxidative enzymes; drying, in which the material is exposed to hot air in rotating drums heated by gas or wood until 3% of moisture is reached; and milling, in which the yerba is triturated and receives additional drying. Afterwards, it can be either directed to crushing, aging, and packing for commercialization, or to roasting.
Hot-prepared infusions on average contain considerably more active compounds than cold-prepared infusions, which results in greater antioxidant activity of hot-prepared beverages.
The yerba mate beverage has been consumed traditionally by Guarani indigenous people since before the conquest of South America by the Spaniards. The indigenous Guaraní and some Tupi communities — whose territory covered modern Paraguay — first cultivated and consumed yerba mate prior to European colonization of the Americas. Its consumption was exclusive to the natives of two regions of the territory that became Paraguay, specifically the departments of Amambay and Alto Paraná.
In the Guarani language, yerba mate is called Ka'a, meaning "the forest inside the tree." For both the Guarani and the Kaingang, the tree is a sacred aspect of daily life, and it is used and consumed in a range of different rituals.
The commercial potential of this plant was discovered by the Jesuits, who brought wild-growing yerba mate into cultivation. Pedro de Montenegro, a Jesuit monk, in his Materia Medica Misionera described the use of the most important species for the Guarani people, in which yerba mate appeared at the top of the list.
After the Jesuits discovered its commercialization potential, yerba mate became widespread throughout the province and even elsewhere in the Spanish Crown. With the Spanish colonization of Paraguay in the late 16th century, the consumption of yerba mate spread to Spanish settlers, and in the 17th century to the Río de la Plata and from there to Peru and Chile. This widespread consumption turned it into Paraguay's main commodity above other wares such as tobacco, cotton, and beef.
In the mid-17th century, Jesuits managed to domesticate the plant and establish plantations in their Indian reductions in the Argentine province of Misiones, sparking severe competition with the Paraguayan harvesters of wild stands. After their expulsion in the 1770s, the Jesuit missions — along with the yerba mate plantations — fell into ruins.
In terms of traditional medicinal use, popular medicine and herbalists have recommended mate for arthritis, migraines, constipation, rheumatism, hemorrhoids, obesity, fatigue, retention of liquid, hypertension, and for stomach and liver diseases.
In ethnobotanical traditions, plants associated with mate beverages are used in the treatment of 18 medicinal categories, including illnesses traditionally treated with plants such as digestive system disorders, humoral medicine, and relatively new health conditions such as diabetes, hypertension, and high levels of cholesterol.
Tereré — the cold-water infusion of mate — holds particular cultural recognition: practices and traditional knowledge of tereré in the culture of Pohã Ñana have been recognized as a UNESCO Intangible Cultural Heritage.
Yerba Mate is a rich source of methylxanthines, especially caffeine (1–2% of dry weight), theobromine (0.3–0.9%), and trace amounts of theophylline. These compounds are found mainly in leaves (3.15–3.5 mg/g) and in small concentrations in stems. They are responsible for the characteristic bitter taste and stimulating effect of the drinks.
The caffeine content in a cup (about 150 mL) of yerba mate tea is comparable to that in a cup of coffee and is about 80 mg. However, the amount of alkaloids in beverages is variable and depends on the type of raw materials used and how the brew is prepared. In a study of teas from Uruguay, Argentina, and Brazil, Uruguayan teas had the highest contents of caffeine and theobromine, followed by Argentine teas and the lowest Brazilian. Caffeine content in yerba mate can vary from 25 to 175 mg/g and theobromine from 6 to 28 mg/g of dry mass.
In traditional yerba mate brewing, the volume of the beverage consumed sometimes reaches even 500 mL, and this amount of the beverage may contain approximately 260 mg or more of caffeine.
In yerba mate, the xanthine derivatives caffeine, theobromine, and theophylline — also known as methylxanthines — are important active components. Caffeine and theobromine are the dominating alkaloids in all beverages, and the total level of alkaloids (methylxanthines and trigonelline) results between 29 and 76 µg/mL in hot-brewed beverages and between 5.9 and 40 µg/mL in cold-brewed beverages.
The predominant bioactive fraction consists of chlorogenic acids, which account for 71–76% of total polyphenols, together with methylxanthines, saponins, and flavonoids.
Identified caffeoyl derivatives include caffeic acid, chlorogenic acid, 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid, while flavonoids include quercetin, rutin, and kaempferol.
The yerba mate samples contain at least five free sugars, five organic acids, eighteen fatty acids, one tocopherol, nine hydroxycinnamoyl derivatives, and two flavonols.
Spray-dried yerba mate extract presents high polyphenol content, namely high concentrations of caffeic acid (1.54 mg/g), 5-caffeoylquinic acid (91.40 mg/g), rutin (5.38 mg/g), and total phenolics (178.32 mg/g).
The polyphenol levels in I. paraguariensis extracts are higher than those of green tea and parallel to those of red wines.
Phenolic substances are the major constituents of Ilex paraguariensis, followed by saponins and methylxanthines. The chemical profiles of yerba mate infusions include saponins (matesaponins 1–5). Saponins are believed to contribute to mate's bitter flavor and its proposed effects on lipid metabolism.
The contents of antioxidant compounds assessed in mate include neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, caffeic acid, 4-feruloylquinic acid, isochlorogenic acid, rutoside, astragalin, caffeine, and indole derivatives. All tested samples show the presence of elements such as magnesium, zinc, copper, iron, and manganese.
Chlorogenic acid is noteworthy as a lipid regulator and lipid oxidizing reduction that may be beneficial in preventing cardiovascular disease. Polyphenols combat oxidative stress and inflammation by neutralizing reactive oxygen species; saponins may influence lipid metabolism by modulating intestinal lipid absorption.
The probable mechanism of LDL lowering by Yerba Mate is the blockade of cholesterol absorption in the small intestine and/or inhibition of cholesterol synthesis in the liver, which may be attributed to the presence of saponins, polyphenolic compounds, and caffeine.
The leaf extract reveals the highest antioxidant activity, correlating with its highest levels of phenolic compounds. Phenols and flavonoids have been shown to bolster antioxidant defenses via direct scavenging of free radicals and to reduce inflammation by inhibiting the expression of proinflammatory cytokines.
The flavones, caffeine, theobromine, and theophylline present in yerba mate and in its infusions have a neuroprotective effect, improve mood, cognitive functions, and concentration, stimulate and support mental work, as well as affect the increase in the number of synapses and extend the life of nerve cells.
This is arguably the best-studied clinical area for mate.
Epidemiological and clinical studies indicate Yerba Maté may influence lipid homeostasis, decreasing total cholesterol, LDL-C, and triglycerides as well as increasing HDL-C.
A key human trial was conducted by Borges et al. (published in the Journal of Agricultural and Food Chemistry): the objective was to verify the effect of yerba mate consumption on lipid and lipoprotein levels in humans. One hundred and two individuals participated in this single-blind controlled trial. Normolipidemic (n = 15), dyslipidemic (n = 57), and hypercholesterolemic subjects on long-term statin therapy (n = 30) ingested 330 mL, 3 times/day, of green or roasted yerba mate infusions for 40 days. After 40-day consumption of 1 L/day of Yerba Mate in three doses, a decrease in LDL fraction was observed in all subjects (in groups I and II by about 8.5%, and in group III by 13%) and an increase in HDL fraction was observed in group II by 4.4% and in group III by 6.2%.
The demonstration that drinking Yerba Mate provides additional reduction in LDL cholesterol in hypercholesterolemic subjects who were on stable statin therapy suggests that the beverage may not only reduce the risk of cardiovascular disease but may also be used in anti-atherosclerotic therapy.
Ex vivo studies of LDL obtained from human plasma before and after drinking Yerba Mate have shown that, due to the presence of antioxidants absorbed into the bloodstream after consuming the drink, there is reduced oxidation of LDL, leading to a reduction in the accumulation of cholesterol in the walls of blood vessels.
A 2025 randomized, controlled, crossover trial in Molecular Nutrition & Food Research found that yerba mate intake shows cardiometabolic beneficial effects decreasing blood pressure, blood lipids, inflammatory biomarkers, and body fat in healthy and hypercholesterolemic non-habitual consumers. Yerba mate could exert cardiometabolic protective effects in healthy consumers and in subjects at moderate cardiovascular risk.
A post-hoc analysis of a cohort of postmenopausal women found that the ingestion of more than 1 L/day of mate infusion was associated with fewer self-reported cardiovascular diseases and lower serum levels of glucose. The authors noted that longitudinal studies are needed to evaluate the association between yerba mate infusion and reduction of cardiovascular diseases in postmenopausal women.
Strength of evidence: Moderate. Several human clinical trials and one cohort study support lipid-lowering effects, particularly reduction of LDL-C. However, many trials are small, of short duration, and not all are double-blinded. Results from a 2025 crossover RCT are encouraging but require replication in larger populations.
A randomized, double-blind, placebo-controlled trial was conducted to investigate the efficacy and safety of Yerba Mate supplementation in Korean subjects with obesity. Subjects with a BMI ≥ 25 but < 35 kg/m² and waist-hip ratio ≥ 0.90 for men and ≥ 0.85 for women were given oral supplements of Yerba Mate capsules (n = 15) or placebos (n = 15) for 12 weeks. Subjects took three capsules per each meal, total three times in a day (3 g/day). During 12 weeks of Yerba Mate supplementation, decreases in body fat mass (P = 0.036) and percent body fat (P = 0.030) compared to the placebo group were statistically significant. Waist-hip ratio was significantly decreased (P = 0.004) in the Yerba Mate group compared to the placebo group. No clinically significant changes in any safety parameters were observed.
Strength of evidence: Preliminary. The above trial was small (n = 30), conducted in a single ethnicity, and of modest duration. Additional well-powered, multicenter RCTs are needed to confirm these findings.
A 2025 PRISMA-compliant systematic review and meta-analysis of RCTs retrieved from MEDLINE, EMBASE, and the Cochrane Central Register — encompassing studies published up to January 2025 — evaluated the effects of Yerba Maté on metabolic health outcomes. Although there is preliminary evidence that suggests Yerba Maté may play a role in modulating postprandial glycemic responses and decreasing HbA1c (glycated hemoglobin) levels, the authors argued that these effects are likely due to the psychostimulant effect of the included xanthines. The systematic review concluded that existing evidence remains inconclusive.
In a randomized clinical trial, 148 patients orally administered I. paraguariensis leaves (1000 mg) once daily in combination with Morus alba (50 mg) and chromium picolinate (100 μg), and after a period of 3 months, improvements in glycemic parameters were observed. (Note: this study used a combination product, making it difficult to isolate mate's independent contribution.)
Strength of evidence: Weak to preliminary. The evidence for glycemic benefit is mechanistically plausible (via chlorogenic acids inhibiting glucose absorption and the role of methylxanthines) but clinically unconfirmed at the level of high-quality RCTs.
The antioxidant potential of Yerba Mate was demonstrated in a study involving fourteen healthy volunteers who ingested orally 3 × 750 mg of spray-dried raw material extract over a period of 60 days. There was an increase in the antioxidant capacity of blood serum by about 16% on the 7th and 30th day of the study and an increase in antioxidant biomarkers (GSH, SOD, CAT) with a simultaneous decrease in lipid peroxidation biomarkers.
Yerba Mate protects DNA from oxidation and inhibits in vitro low-density lipoprotein lipoperoxidation, and has a high antioxidant capacity.
Strength of evidence: Moderate for in vitro and preliminary human evidence of improved antioxidant biomarkers. Larger clinical trials specifically assessing antioxidant endpoints are limited.
The bone health of 146 postmenopausal women who drank at least 1 L of Yerba Mate tea daily for at least 4 years was compared with the bone health of the same number of women (same age and time after menopause) who did not drink Yerba Mate. The Yerba Mate drinkers had 9.7% higher bone mineral density (BMD) of the lumbar spine and 6.2% higher BMD of the femoral neck.
However, findings across studies are not uniform. The WebMD natural medicines database references a study by da Veiga et al. (2018, Phytotherapy Research) suggesting that yerba mate intake has a neutral effect on bone in postmenopausal women, as per a case-control study.
Strength of evidence: Mixed and preliminary. The observational data suggesting benefit are countered by other case-control evidence of no effect. Controlled intervention trials specifically targeting bone outcomes are needed.
A systematic review on yerba mate and rheumatoid arthritis that identified 23 studies (11 human, 7 human-based in vitro, 5 animal) found that interventions with yerba mate infusions or standardized extracts suggest reductions in inflammatory markers (e.g., C-reactive protein, interleukin-6) and indicate improvements in glutathione-related oxidative balance. Yerba mate and its constituents show preliminary indications of anti-inflammatory and antioxidant effects with potential relevance to RA pathophysiology.
Stem extract showed the highest anti-inflammatory potential and was also the most potent against MCF-7 and HepG2 cell lines, probably due to the presence of other phytochemicals. This finding is from in vitro work and does not directly translate to clinical benefit.
Strength of evidence: Preliminary. Anti-inflammatory mechanisms are well-characterized in vitro and in preclinical models; clinical translation in human inflammatory disease requires further, larger, rigorously designed trials.
Experimental studies have shown that yerba mate enhances antioxidant defenses, increases chaperonin expression, and reduces AChE activity and Aβ expression. A pilot study based at two Argentine hospitals examined the potential association between yerba mate consumption and risk of developing cognitive impairment in individuals aged ≥50 years who underwent neurocognitive testing. The study was conducted at the Trinidad Mitre Hospital and Favaloro Foundation in Buenos Aires, Argentina, from January 2023 to December 2024, and administered a structured survey to individuals aged ≥50 years who underwent neurocognitive testing.
Strength of evidence: Very preliminary. This remains largely an area of preclinical (animal and cell-based) research and a small pilot study. No large-scale human RCTs have yet confirmed cognitive benefits.
Several smaller human studies have examined mate in the context of exercise. One study, referenced in the WebMD natural medicines database, by Alkhatib and Atcheson (2017) examined yerba mate's metabolic, satiety, and mood state effects at rest and during prolonged exercise. Additional research has been conducted in well-trained cyclists.
Strength of evidence: Weak. Studies in this area are small and heterogeneous. Effects attributed to exercise performance may largely reflect the caffeine content of mate rather than unique properties of the plant.
Dosage forms and amounts in the published clinical literature vary considerably:
Drinking mate has been associated with an increased risk of esophageal cancer. This increased risk may be attributed to drinking mate very hot, or to mate's potentially carcinogenic contaminants, such as polycyclic aromatic hydrocarbons (PAHs).
Drinking hot beverages — especially maté, a type of tea traditionally consumed in South America at very hot temperatures (≥65 °C = 149 °F) — was classified as "probably carcinogenic to humans (Group 2A)" by the International Agency for Research on Cancer (IARC), based on limited evidence for esophageal cancer. Evidence came mainly from hospital-based case-control studies in South America.
Researchers concluded that "the observed links between mate drinking and cancer of the esophagus seem to be largely driven by drinking mate very hot." Similar associations are seen for other very hot beverages, like tea or coffee.
Mate leaves are often dried via smoking, and therefore commercial samples may have high amounts of PAHs. A review of original articles that measured PAHs in commercial dry samples found that nearly all found very high mass fractions. Most studies found benzo[a]pyrene mass fractions to be over 25 ng/g, and some found levels up to 600 ng/g.
However, the very high margin of exposure (MOE) for PAH suggests that the human dosage is considerably below the lowest effective dose in animals, and the very similar PAH exposure levels from mate and tea consumption offer indirect further support for IARC's conclusion that temperature, rather than PAH content per se, is the primary driver of risk.
Paraguayans have a tradition of mixing mate with crushed leaves, stems, and flowers of the plant known as flor de agosto (plants of the genus Senecio, particularly Senecio grisebachii), which contain pyrrolizidine alkaloids. This represents a distinct risk from adulteration or co-preparation, not from pure mate itself.
Monoamine Oxidase Inhibitors (MAOIs): Yerba mate contains caffeine. There is concern that caffeine can interact with MAOIs, and if caffeine is taken with these medications, it might increase the risk for serious side effects including fast heartbeat and very high blood pressure. Some common MAOIs include phenelzine (Nardil), selegiline (Zelapar), and tranylcypromine (Parnate).
Stimulant medications / beta-adrenergic agonists: Combination effects with beta-adrenergic agonists and monoamine oxidase inhibitors may include nervousness, high blood pressure, and a fast heart rate.
Anticoagulant / antiplatelet drugs: Yerba mate contains caffeine. Caffeine is reported to have antiplatelet activity. Theoretically, it might increase the risk of bleeding when used concomitantly with anticoagulant/antiplatelet agents; however, this interaction has not been reported in humans.
CYP3A4 substrates: Theoretically, yerba mate might increase the levels and clinical effects of CYP3A4 substrates. In vitro research shows that yerba mate extract inhibits CYP3A4 enzymes. Theoretically, taking yerba mate may increase levels and adverse effects of CYP3A4 substrates.
Diabetes medications: Caffeine can either increase or decrease blood sugar. Diabetes medications are used to lower blood sugar. Taking some medications for diabetes along with caffeine might change the effects of the diabetes medications.
Quinolones, cimetidine, and estrogens: Prescription medication drug interactions with yerba mate include quinolones, cimetidine, and estrogens, causing jitteriness, increased heart rate, and headaches. There is also a pharmacokinetic drug interaction with yerba mate and terbinafine (Lamisil), which alters metabolism and may increase the chances for adverse effects.
In the 12-week Korean obesity RCT (3 g/day capsules), no clinically significant changes in any safety parameters were observed. The absence of hepatotoxicity in yerba mate extracts was confirmed in porcine liver primary cells. In a comparative study of chimarrão, tereré, and mate-tea extracts, no sign of toxicity was observed.
Health conditions that Mate may help support.
Body systems that Mate may help support.
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