Yerba Maté (Ilex paraguariensis) Herbal Monograph

What Is Yerba Maté?

Yerba maté is an evergreen holly tree whose dried leaves are brewed into maté, the everyday caffeinated drink of southern South America. The leaves are traditionally steeped in a gourd and sipped through a metal filter straw called a bombilla ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

Ilex paraguariensis grows wild in Paraguay, north-eastern Argentina, southern Brazil and Uruguay, and it is farmed across the same region ^{22,31Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →Reference 31Useful Tropical Plants (n.d.)Ilex paraguariensis — description, range, habitat and cultivation — species databaseView study →}. The Guaraní were the first to drink it, and Jesuit missionaries later grew it on plantations, which is why it is also called Jesuit’s tea ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

The leaf contains caffeine and theobromine, and it is rich in chlorogenic acid and related polyphenols ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. A 150 mL cup holds about 80 mg of caffeine, similar to a cup of coffee ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. Trials have tested maté for blood sugar, cholesterol and body fat ^{4,5,6,7Reference 4Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →Reference 5Klein et al. · 2011Clinical trialMate tea (Ilex paraguariensis) improves glycemic and lipid profiles of type 2 diabetes and pre-diabetes individuals: a pilot study — clinical trialView study →Reference 6de Morais et al. · 2009Clinical trialConsumption of yerba mate (Ilex paraguariensis) improves serum lipid parameters in healthy dyslipidemic subjects — controlled clinical trialView study →Reference 7Bravo et al. · 2025RCTYerba Mate (Ilex paraguariensis) tea may have cardiometabolic beneficial effects — a randomized, controlled, blind, crossover trial in nonhabitual consumersView study →}.

Maté is one of several caffeine plants, alongside coffee, tea, guarana and cacao. Its close relative guayusa (Ilex guayusa) is a separate species from Ecuador.

How Is Yerba Maté Used?

Maté is drunk throughout the day as a stimulant, and it is often shared around a group.

Maté or chimarrão — dried leaf packed into a gourd and topped up with hot water, 65–80 °C, many times over ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.
Tereré — the same leaf brewed with cold water, often with lemon or other citrus, popular in Paraguay and south-western Brazil ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.
Mate cocido — the leaf infused in hot water like an ordinary tea ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.
Capsules and extracts — concentrated leaf extracts, used in weight-management products and in some trials ^{1,2,3Reference 1Kim et al. · 2015RCTAnti-obesity effects of Yerba Maté (Ilex paraguariensis): a randomized, double-blind, placebo-controlled clinical trialView study →Reference 2Alkhatib · 2014RCTYerba Maté (Ilex paraguariensis) ingestion augments fat oxidation and energy expenditure during exercise — randomised crossover trialView study →Reference 3Alkhatib et al. · 2017RCTYerba Maté (Ilex paraguariensis) metabolic, satiety, and mood state effects at rest and during prolonged exercise — randomized trialView study →}.

The gourd method, tereré and other ways to brew it are set out in How to Prepare Yerba Maté, and choosing a brand in Best Yerba Maté.

Maté Terms

Bombilla — the drinking straw, a metal or cane tube with a perforated filter at the end that sits in the leaf ^{22,34Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →Reference 34Sulaiman N et al. · 2021Socio-cultural significance of yerba maté among Syrian residents and diaspora — ethnographic studyView study →}.
Mate — the drink, and also the gourd it is drunk from, usually a dried calabash (Lagenaria) ^{33,34Reference 33Kujawska M · 2018Yerba mate (Ilex paraguariensis) beverage: nutraceutical ingredient or conveyor for the intake of medicinal plants? Evidence from Paraguayan folk medicine — ethnobotanical field studyView study →Reference 34Sulaiman N et al. · 2021Socio-cultural significance of yerba maté among Syrian residents and diaspora — ethnographic studyView study →}.
Chimarrão — the Brazilian name for maté brewed with hot water ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.
Tereré — maté brewed with cold water, often with citrus, drunk in Paraguay and south-western Brazil on hot days ^{22,33Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →Reference 33Kujawska M · 2018Yerba mate (Ilex paraguariensis) beverage: nutraceutical ingredient or conveyor for the intake of medicinal plants? Evidence from Paraguayan folk medicine — ethnobotanical field studyView study →}.
Mate cocido — the leaf infused in hot water like an ordinary tea ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.
Yerba canchada — leaf crushed into large pieces, prepared especially for tereré ^{33Reference 33Kujawska M · 2018Yerba mate (Ilex paraguariensis) beverage: nutraceutical ingredient or conveyor for the intake of medicinal plants? Evidence from Paraguayan folk medicine — ethnobotanical field studyView study →}.
Despalada — maté with few stems, up to about 10% ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.
Elaborada — maté with about 35% stems ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

In Paraguayan folk medicine, medicinal plants are often added to the gourd or the water. Cooling plants, used for “hot” conditions, are always taken in tereré ^{33Reference 33Kujawska M · 2018Yerba mate (Ilex paraguariensis) beverage: nutraceutical ingredient or conveyor for the intake of medicinal plants? Evidence from Paraguayan folk medicine — ethnobotanical field studyView study →}.

Traditional Uses

Yerba maté comes from the lands of the Guaraní, who were the first people to drink it, and it is used above all as a stimulant drink taken through the day for energy and fatigue ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. Across South America the beverage is also the everyday vehicle for other medicinal plants, rather than a strongly medicinal plant in its own right ^{33Reference 33Kujawska M · 2018Yerba mate (Ilex paraguariensis) beverage: nutraceutical ingredient or conveyor for the intake of medicinal plants? Evidence from Paraguayan folk medicine — ethnobotanical field studyView study →}.

Jesuit missionaries cultivated and traded the leaf from the 17th century ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. In the early 20th century Syrian migrants returning from South America made it a staple drink in Syria ^{34Reference 34Sulaiman N et al. · 2021Socio-cultural significance of yerba maté among Syrian residents and diaspora — ethnographic studyView study →}. Europe recognises maté leaf as a traditional herbal medicine for fatigue and for flushing the urinary tract ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}.

Guaraní & South American Indigenous Medicine

The Guaraní were the first people to use yerba maté in its native range ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. The cured leaf is chewed or steeped in hot water and drunk through the day ^{26Reference 26Taylor · 2005The Healing Power of Rainforest Herbs: A Guide to Understanding and Using Herbal Medicinals}. Its central use is as a stimulant for energy, wakefulness and fatigue ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

Other uses include low mood, digestive complaints, nerve pain and weight management ^{26Reference 26Taylor · 2005The Healing Power of Rainforest Herbs: A Guide to Understanding and Using Herbal Medicinals}. A poultice of the leaf has been applied to anthrax skin ulcers ^{26Reference 26Taylor · 2005The Healing Power of Rainforest Herbs: A Guide to Understanding and Using Herbal Medicinals}.

Remnants of yerba maté powder have been found in Incan tombs, but whether Indigenous peoples used it widely before colonisation is disputed ^{27Reference 27Folch · 2010Stimulating consumption: yerba mate myths, markets, and meanings from conquest to present}.

Jesuit missionaries arrived in the region in the 16th century. By about 1670 they were cultivating yerba maté and trading its leaves, which is the origin of the name Jesuit’s tea. After the order was dissolved, their plantations were abandoned, and cultivation was taken up again only in the 20th century ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

Paraguayan Folk Medicine

Apart from the Guaraní, the Paraguayan Mestizo people have the longest tradition of drinking maté. In their folk medicine maté is not considered a medicinal plant in its own right, but it is the main way medicinal plants are taken ^{33Reference 33Kujawska M · 2018Yerba mate (Ilex paraguariensis) beverage: nutraceutical ingredient or conveyor for the intake of medicinal plants? Evidence from Paraguayan folk medicine — ethnobotanical field studyView study →}.

In a study of 100 Paraguayan migrants in Misiones, Argentina, 97 plant species were added to hot maté or to cold tereré. They were used for 18 categories of illness, including digestive complaints, humoral “hot” and “cold” conditions, and newer ones such as diabetes, high blood pressure and high cholesterol ^{33Reference 33Kujawska M · 2018Yerba mate (Ilex paraguariensis) beverage: nutraceutical ingredient or conveyor for the intake of medicinal plants? Evidence from Paraguayan folk medicine — ethnobotanical field studyView study →}.

The temperature of the brew is part of the remedy. Cooling plants, used for “hot” conditions, are always taken in cold tereré ^{33Reference 33Kujawska M · 2018Yerba mate (Ilex paraguariensis) beverage: nutraceutical ingredient or conveyor for the intake of medicinal plants? Evidence from Paraguayan folk medicine — ethnobotanical field studyView study →}.

Western Herbal Medicine

The European Medicines Agency recognises maté leaf as a traditional herbal medicinal product, a status based on long-standing use ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}.

Its two registered uses are for fatigue and a feeling of weakness, and to increase urine flow and flush the urinary tract in minor urinary complaints ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}. The dried leaf is taken as a tea, about 2–4 g a day for fatigue and 2.5–5 g a day for urinary flushing ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}.

The monograph limits both uses to adults and advises against them in heart, circulatory and thyroid conditions and in stomach ulcers ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}.

Indications

Fatigue and weakness [leaf tea; European traditional use]
Minor urinary complaints, to flush the urinary tract [leaf tea; European traditional use]
Energy and alertness [leaf infusion; South American traditional use]
Blood sugar in prediabetes and type 2 diabetes [roasted leaf infusion] Caution: A meta-analysis found lower after-meal glucose and HbA1c in prediabetes, based on two trials, and no effect on fasting glucose ⁴.
High LDL cholesterol [green or roasted leaf infusion] Caution: LDL fell in individual trials, most in people with high cholesterol or on statins, but a 2025 meta-analysis of randomised trials found no significant effect on cholesterol or triglycerides ^4,6.
Body fat [capsule extract] Caution: A meta-analysis found no effect on BMI or waist size, and brewed maté did not change energy use during exercise ^4,25.
Blood pressure [leaf infusion] Caution: Lowered in one 8-week crossover trial measuring surrogate markers; a single dose did not change blood pressure or heart rate ^7,8.
Bone density after menopause [habitual drinking] Caution: Drinkers had higher bone density in one cross-sectional study; a case-control study found no link with fractures ^15,16.
Low mood, digestive complaints and nerve pain [leaf; South American traditional use]
Anthrax skin ulcers [leaf poultice; South American traditional use]

Botany

Yerba maté is a small, slow-growing evergreen tree in the holly family (Aquifoliaceae), with a dense, oblong crown ^{31Reference 31Useful Tropical Plants (n.d.)Ilex paraguariensis — description, range, habitat and cultivation — species databaseView study →}. It can reach 15 m but is usually 4–8 m tall, with a short trunk 30–40 cm across ^{31Reference 31Useful Tropical Plants (n.d.)Ilex paraguariensis — description, range, habitat and cultivation — species databaseView study →}. The genus Ilex has about 450 species ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

The leaves are stiff and leathery, oval with a wedge-shaped base, a scalloped edge and a blunt tip, and about 8 cm long. They are olive green, darker on top ^{22,28Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →Reference 28Rodd · 2005Flora’s Trees & Shrubs}.

The trees are either male or female. The small white flowers usually have four petals and grow in clusters in spring (October to November in the Southern Hemisphere) ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. The fruit is a red or reddish-brown berry 5–8 mm across, with four or five hard-coated seeds that birds disperse ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

Distribution

Yerba maté is native to Argentina, Uruguay, Paraguay and southern, eastern and central Brazil ^{31Reference 31Useful Tropical Plants (n.d.)Ilex paraguariensis — description, range, habitat and cultivation — species databaseView study →}. It grows in cool, humid highlands near streams and river valleys, at elevations up to 1,500 m ^{31Reference 31Useful Tropical Plants (n.d.)Ilex paraguariensis — description, range, habitat and cultivation — species databaseView study →}.

It is both wild-harvested and cultivated in its native range, and it is also grown on the Iberian Peninsula ^{31Reference 31Useful Tropical Plants (n.d.)Ilex paraguariensis — description, range, habitat and cultivation — species databaseView study →}. Argentina is the largest producer, and Brazil and Paraguay are the other main producers ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

Growing Conditions

Cultivation snapshot for Yerba Maté

Lifeperennial, evergreen tree

Temperaturegrows best at 17–26 °C. Mature trees can be killed at −6 °C or below, and young growth is damaged at −1 °C ^{31Reference 31Useful Tropical Plants (n.d.)Ilex paraguariensis — description, range, habitat and cultivation — species databaseView study →}.

Rainfall1,200–2,000 mm a year is ideal; it tolerates 700–2,500 mm ^{31Reference 31Useful Tropical Plants (n.d.)Ilex paraguariensis — description, range, habitat and cultivation — species databaseView study →}.

Sunfull sun or light shade ^{31Reference 31Useful Tropical Plants (n.d.)Ilex paraguariensis — description, range, habitat and cultivation — species databaseView study →}.

Propagationby seed, which is very slow and can take 2–3 years to germinate. It must be sown fresh or stratified in warm, humid sand for 4–7 months ^{31Reference 31Useful Tropical Plants (n.d.)Ilex paraguariensis — description, range, habitat and cultivation — species databaseView study →}.

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Harvesting, Collection & Preparation

Leaves and stems 6–12 months old are harvested from wild trees and from plantations ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

The fresh leaves are first flash-heated (sapecado) for 10 seconds to 3 minutes, traditionally over an open wood fire, to stop the enzymes that would brown them. They are then dried (secado) for 8–24 hours at up to 100 °C, often in wood smoke. The dried leaf is crushed and aged for at least a year, which raises its caffeine and polyphenol content ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

Finally the leaves and twigs are sieved and remixed in set proportions. Despalada maté is sold with few stems, up to 10%, while elaborada contains about 35% ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

The smoke-drying steps form polycyclic aromatic hydrocarbons (PAHs). Benzo[a]pyrene has been measured at 11.9–99.3 µg/kg across maté products ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

Pharmacology & Research

Yerba maté has several dozen human studies, including a 2025 meta-analysis of 13 randomised trials, alongside a larger body of cell and animal work ^{4,22Reference 4Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

The most consistent human signal is on after-meal blood sugar in prediabetes and type 2 diabetes. Results for cholesterol, body weight and blood pressure are positive in individual trials but fall away when the randomised data are pooled ^{4,5,6,7Reference 4Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →Reference 5Klein et al. · 2011Clinical trialMate tea (Ilex paraguariensis) improves glycemic and lipid profiles of type 2 diabetes and pre-diabetes individuals: a pilot study — clinical trialView study →Reference 6de Morais et al. · 2009Clinical trialConsumption of yerba mate (Ilex paraguariensis) improves serum lipid parameters in healthy dyslipidemic subjects — controlled clinical trialView study →Reference 7Bravo et al. · 2025RCTYerba Mate (Ilex paraguariensis) tea may have cardiometabolic beneficial effects — a randomized, controlled, blind, crossover trial in nonhabitual consumersView study →}. An emerging cardiometabolic and anti-inflammatory profile rests on an 8-week crossover trial and a gene-expression study ^{7,9Reference 7Bravo et al. · 2025RCTYerba Mate (Ilex paraguariensis) tea may have cardiometabolic beneficial effects — a randomized, controlled, blind, crossover trial in nonhabitual consumersView study →Reference 9Ruskovska et al. · 2023RCTMultigenomic modifications in human circulating immune cells in response to consumption of polyphenol-rich extract of yerba mate — randomized controlled trialView study →}.

What the Evidence Supports

Best-supported: lower after-meal glucose and HbA1c in prediabetes (a meta-analysis of two trials, plus a roasted-leaf pilot) and a broad antioxidant, gene-modulating profile ^{4,5,9Reference 4Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →Reference 5Klein et al. · 2011Clinical trialMate tea (Ilex paraguariensis) improves glycemic and lipid profiles of type 2 diabetes and pre-diabetes individuals: a pilot study — clinical trialView study →Reference 9Ruskovska et al. · 2023RCTMultigenomic modifications in human circulating immune cells in response to consumption of polyphenol-rich extract of yerba mate — randomized controlled trialView study →}.
Emerging, worth watching: lower blood pressure and inflammatory cytokines over eight weeks ^{7Reference 7Bravo et al. · 2025RCTYerba Mate (Ilex paraguariensis) tea may have cardiometabolic beneficial effects — a randomized, controlled, blind, crossover trial in nonhabitual consumersView study →}, and higher bone mineral density in postmenopausal drinkers ^{15Reference 15Brun et al. · 2025ObservationalPositive effect of yerba mate (Ilex paraguariensis) consumption on bone mineral density in postmenopausal women — observational studyView study →}.
Mechanistically thin: antibacterial activity (in vitro and in silico only) ^{18,19Reference 18Rempe et al. · 2015In vitroComputational ranking of yerba mate small molecules based on predicted contribution to antibacterial activity against MRSA — in vitro / in silicoView study →Reference 19Prado Martin et al. · 2013In vitroAntimicrobial activity of yerba mate (Ilex paraguariensis StView study →}, and sustained weight loss, where acute fat-oxidation gains sit against null pooled body measurements ^{4,25Reference 4Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →Reference 25Zaki S et al. · 2026RCTAcute effects of commercial yerba mate products on cardiometabolic responses during submaximal cycling — randomized crossover trialView study →}.
The caveat: most trials are small and short and use different preparations, and the pooled randomised data are null for lipids, body weight and fasting glucose ^{4Reference 4Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →}.

The trials used different preparations. Green and roasted leaf, hot and cold infusions and capsule extracts were each tested at their own doses, and a result for one does not carry over to the others ^{4,6Reference 4Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →Reference 6de Morais et al. · 2009Clinical trialConsumption of yerba mate (Ilex paraguariensis) improves serum lipid parameters in healthy dyslipidemic subjects — controlled clinical trialView study →}.

Evidence by IndicationStrength of support

Antidiabetic / Glycemic ControlPromising

72%

AntioxidantPromising

68%

HypolipidemicPromising

60%

Cardiometabolic / CardioprotectivePromising

54%

Anti-Obesity / ThermogenicPromising

52%

Anti-InflammatoryPromising

50%

OsteoprotectivePromising

46%

AntibacterialShaky

38%

1. Antidiabetic / Glycemic Control

A 2025 meta-analysis of 13 randomised trials found that in people with prediabetes, maté lowered after-meal glucose by 12.76 mg/dL, HbA1c by 0.37% and the HOMA insulin-resistance index by 0.24. These results rest on two trials. There was no significant effect on fasting glucose, fasting insulin or blood lipids ^{4Reference 4Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →}.

In a 60-day pilot study of 58 people with type 2 diabetes or prediabetes, drinking 330 mL of roasted maté three times a day lowered fasting glucose by 25 mg/dL, HbA1c by 0.85% and LDL cholesterol in those with diabetes. In the prediabetes group, maté combined with dietary counselling lowered LDL, non-HDL cholesterol and triglycerides ^{5Reference 5Klein et al. · 2011Clinical trialMate tea (Ilex paraguariensis) improves glycemic and lipid profiles of type 2 diabetes and pre-diabetes individuals: a pilot study — clinical trialView study →}.

Gap: benefits concentrate in prediabetes and type 2 diabetes and in after-meal rather than fasting measures; no large, long-duration RCT confirms a durable HbA1c reduction, and the human glucose signal comes from roasted-leaf infusions, not green leaf or capsules.

2. Antioxidant

Maté is rich in caffeoylquinic acids and flavonols, and antioxidant activity has been shown across study types ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. In healthy middle-aged men at cardiovascular risk, four weeks of a standardised polyphenol-rich maté extract changed the expression of 2,635 genes in circulating immune cells, including genes involved in inflammation and cell signalling ^{9Reference 9Ruskovska et al. · 2023RCTMultigenomic modifications in human circulating immune cells in response to consumption of polyphenol-rich extract of yerba mate — randomized controlled trialView study →}.

In the nematode Caenorhabditis elegans, maté extracts extended lifespan and protected against paraquat toxicity ^{10Reference 10Lima et al. · 2014AnimalIlex paraguariensis extract increases lifespan and protects against paraquat toxicity in Caenorhabditis elegans — in vivo modelView study →}. In perimenopausal rats, maté lowered an oxidative-stress marker in bone ^{17Reference 17Pereira et al. · 2017AnimalIlex paraguariensis decreases oxidative stress in bone and mitigates damage in rats — in vivo studyView study →}.

Gap: the one substantial human study measured gene expression rather than an antioxidant or clinical endpoint ^{9Reference 9Ruskovska et al. · 2023RCTMultigenomic modifications in human circulating immune cells in response to consumption of polyphenol-rich extract of yerba mate — randomized controlled trialView study →}.

3. Hypolipidemic

In a single-blind controlled trial of 102 people drinking 330 mL of green or roasted maté three times a day for 40 days, LDL cholesterol fell by 8.7% in people with normal lipids and by 8.6% in people with dyslipidaemia. People already on statins had a further 10.0–13.1% fall in LDL and a 6.2% rise in HDL ^{6Reference 6de Morais et al. · 2009Clinical trialConsumption of yerba mate (Ilex paraguariensis) improves serum lipid parameters in healthy dyslipidemic subjects — controlled clinical trialView study →}.

The roasted-maté diabetes study also improved blood lipids ^{5Reference 5Klein et al. · 2011Clinical trialMate tea (Ilex paraguariensis) improves glycemic and lipid profiles of type 2 diabetes and pre-diabetes individuals: a pilot study — clinical trialView study →}.

The 2025 meta-analysis of randomised trials found no significant effect on total cholesterol, LDL, HDL or triglycerides ^{4Reference 4Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →}.

In cells and in 20 healthy women who drank it, maté raised the activity of paraoxonase-2, an antioxidant enzyme, and chlorogenic acid and caffeic acid had the same effect in cells ^{13Reference 13Fernandes et al. · 2012In vitroYerba mate (Ilex paraguariensis) enhances the gene modulation and activity of paraoxonase-2: in vitro and in vivo studiesView study →}.

Gap: benefit appears concentrated in dyslipidemic or statin-treated drinkers and specific infusion protocols; the pooled RCT evidence is null, so a general cholesterol-lowering claim is not supported.

4. Cardiometabolic / Cardioprotective

In a 2025 randomised, controlled, blinded crossover trial in people who did not usually drink maté, some healthy and some with high cholesterol, three servings a day for eight weeks lowered blood pressure and several inflammatory cytokines and chemokines in all participants. The control was a decaffeinated isotonic drink ^{7Reference 7Bravo et al. · 2025RCTYerba Mate (Ilex paraguariensis) tea may have cardiometabolic beneficial effects — a randomized, controlled, blind, crossover trial in nonhabitual consumersView study →}.

LDL cholesterol fell in the participants with normal cholesterol, while maté and the control drink had a similar effect in those with high cholesterol. Body-fat percentage fell in the healthy group ^{7Reference 7Bravo et al. · 2025RCTYerba Mate (Ilex paraguariensis) tea may have cardiometabolic beneficial effects — a randomized, controlled, blind, crossover trial in nonhabitual consumersView study →}.

In an acute crossover trial in 13 healthy adults, a single hot or cold maté infusion did not change endothelial function, blood pressure, heart rate or heart-rate variability ^{8Reference 8Filipini et al. · 2024RCTAcute ingestion of yerba mate (Ilex paraguariensis) infusion does not modify endothelial function, hemodynamics, or heart rate variability — a randomized crossover clinical trialView study →}.

Gap: the supporting trial is small and short, and the outcomes are surrogate markers.

5. Anti-Obesity / Thermogenic

In a 12-week randomised, double-blind, placebo-controlled trial in 30 obese Korean adults, 3 g a day of maté in capsules reduced body-fat mass, percent body fat and waist-hip ratio, with no significant adverse effects ^{1Reference 1Kim et al. · 2015RCTAnti-obesity effects of Yerba Maté (Ilex paraguariensis): a randomized, double-blind, placebo-controlled clinical trialView study →}.

In acute crossover trials, 1 g of maté raised fat oxidation during submaximal exercise by 24% ^{2Reference 2Alkhatib · 2014RCTYerba Maté (Ilex paraguariensis) ingestion augments fat oxidation and energy expenditure during exercise — randomised crossover trialView study →}, and 2 g raised fat oxidation during 30 minutes of cycling and reduced hunger ^{3Reference 3Alkhatib et al. · 2017RCTYerba Maté (Ilex paraguariensis) metabolic, satiety, and mood state effects at rest and during prolonged exercise — randomized trialView study →}.

In a 2026 crossover trial in 29 adults, two brands of brewed maté did not change energy expenditure or fuel use during cycling compared with water or water with caffeine ^{25Reference 25Zaki S et al. · 2026RCTAcute effects of commercial yerba mate products on cardiometabolic responses during submaximal cycling — randomized crossover trialView study →}. The 2025 meta-analysis found no significant effect on BMI or waist circumference ^{4Reference 4Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →}.

In mice on a high-fat diet, maté extract reduced weight gain and fat ^{14Reference 14Arçari et al. · 2009AnimalAntiobesity effects of yerba maté extract (Ilex paraguariensis) in high-fat diet–induced obese mice — animal modelView study →}. It also reduced abdominal fat and triglycerides in obese rats weaned early ^{24Reference 24Lima et al. · 2014AnimalIlex paraguariensis (yerba mate) improves endocrine and metabolic disorders in obese rats primed by early weaning — animal modelView study →}.

Gap: the one positive body-composition RCT used a concentrated capsule extract, not tea; acute fat-oxidation gains do not clearly translate to sustained weight loss, and the pooled human data are null on body measurements.

6. Anti-Inflammatory

In rats, maté tea and maté saponins reduced colon inflammation caused by a chemical carcinogen, lowering COX-2, iNOS and NF-κB signalling ^{11Reference 11Puangpraphant et al. · 2013AnimalYerba mate tea and mate saponins prevented azoxymethane-induced inflammation of rat colon through suppression of NF-κB signaling — rat in vivo studyView study →}.

The human polyphenol-extract study showed changes in inflammation-related genes ^{9Reference 9Ruskovska et al. · 2023RCTMultigenomic modifications in human circulating immune cells in response to consumption of polyphenol-rich extract of yerba mate — randomized controlled trialView study →}, and the 8-week trial reported lower inflammatory cytokines and chemokines ^{7Reference 7Bravo et al. · 2025RCTYerba Mate (Ilex paraguariensis) tea may have cardiometabolic beneficial effects — a randomized, controlled, blind, crossover trial in nonhabitual consumersView study →}.

A 2025 systematic review of maté and rheumatoid arthritis found preliminary anti-inflammatory and antioxidant signals, but no trials in people with the disease ^{12Reference 12Cassotta et al. · 2025Systematic reviewYerba Mate (Ilex paraguariensis) and rheumatoid arthritis: a systematic reviewView study →}.

Gap: no controlled trial has measured a clinical inflammatory-disease outcome.

7. Osteoprotective

In an Argentine cross-sectional study of 300 postmenopausal women (153 maté drinkers, 147 non-drinkers), the drinkers had higher total-hip bone mineral density, with both cortical and trabecular bone contributing. They also had less osteoporosis (3.3% vs 10.9%) and fewer low-impact fractures (5.9% vs 12.9%) ^{15Reference 15Brun et al. · 2025ObservationalPositive effect of yerba mate (Ilex paraguariensis) consumption on bone mineral density in postmenopausal women — observational studyView study →}.

A Brazilian case-control study of 95 postmenopausal women found no link between maté drinking and fractures, and no difference in markers of bone turnover ^{16Reference 16da Veiga et al. · 2018ObservationalYerba mate intake has a neutral effect on bone: a case-control study in postmenopausal women — observationalView study →}.

In perimenopausal rats, maté limited the loss of bone structure and lowered bone oxidative stress ^{17Reference 17Pereira et al. · 2017AnimalIlex paraguariensis decreases oxidative stress in bone and mitigates damage in rats — in vivo studyView study →}.

Gap: the positive bone data are cross-sectional and cannot establish causation; the one fracture-endpoint case-control study was neutral, and no interventional trial exists.

8. Antibacterial

Aqueous maté extract kills or inhibits methicillin-resistant Staphylococcus aureus (MRSA) in the laboratory. In a computational ranking of the extract’s fractions, 3,4-dihydroxybenzaldehyde was the most active compound, and quinic acid and quercetin were also ranked as likely contributors ^{18Reference 18Rempe et al. · 2015In vitroComputational ranking of yerba mate small molecules based on predicted contribution to antibacterial activity against MRSA — in vitro / in silicoView study →}.

Methanol and ethanol extracts inhibited S. aureus, Listeria monocytogenes and Salmonella Enteritidis, but not E. coli. The most active ethanol extract contained chlorogenic acid derivatives and caffeic acid ^{19Reference 19Prado Martin et al. · 2013In vitroAntimicrobial activity of yerba mate (Ilex paraguariensis StView study →}.

Gap: all of it is in vitro or in silico, with no animal-infection or clinical data.

Mechanisms

Caffeine and theobromine, with a trace of theophylline, are the stimulants in the leaf ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. The chlorogenic acids and flavonoids have been studied as antioxidants and for their effects on the enzyme paraoxonase-2 ^{13,22Reference 13Fernandes et al. · 2012In vitroYerba mate (Ilex paraguariensis) enhances the gene modulation and activity of paraoxonase-2: in vitro and in vivo studiesView study →Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

The maté saponins, built on ursolic acid, have been studied for their effect on inflammatory signalling in the colon ^{11,22Reference 11Puangpraphant et al. · 2013AnimalYerba mate tea and mate saponins prevented azoxymethane-induced inflammation of rat colon through suppression of NF-κB signaling — rat in vivo studyView study →Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

Mechanism	Drives	Key compounds
Free-radical scavenging; changes in antioxidant and inflammatory gene expression	antioxidantosteoprotectivecardiometabolic	chlorogenic acid, quercetin, rutin
Paraoxonase-2 expression and activity ↑	hypolipidemicantioxidant	chlorogenic acid, caffeic acid
NF-κB ↓, COX-2 ↓, iNOS ↓	anti-inflammatory	matesaponins
Central nervous system stimulation	energy/wakefulness	caffeine, theobromine
Fat oxidation ↑ during exercise	anti-obesitythermogenic	whole-leaf extract

Pharmacokinetics

A 150 mL cup of maté delivers about 80 mg of caffeine ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. Caffeine is cleared mainly by the liver enzyme CYP1A2, which metabolises about 95% of the caffeine taken in, and its clearance varies with genetics, smoking, liver disease, hormones and many medicines ^{38Reference 38Nehlig A · 2018ReviewInterindividual Differences in Caffeine Metabolism and Factors Driving Caffeine Consumption — reviewView study →}.

The chlorogenic acids have poor oral bioavailability ^{37Reference 37Li L et al. · 2020ReviewChlorogenic Acids in Cardiovascular Disease: A Review of Dietary Consumption, Pharmacology, and Pharmacokinetics — reviewView study →}.

Clinical Trials

The registered trials cluster on cardiometabolic and anti-obesity endpoints, with metabolic-syndrome and harvest-time studies still recruiting.

Completed	Planned	Terminated	Preclinical
7	2	0	~40+

Last checked: October 2026.

Phytochemistry

The leaf’s stimulants are the purine alkaloids caffeine, at about 1–2% of the dry weight, and theobromine, at 0.3–0.9%, with a trace of theophylline ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. They are concentrated in the leaves, with little in the stems ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. There is no separate compound called “mateine”; the stimulant in maté is caffeine.

The main polyphenols are phenolic acids, led by chlorogenic acid. Fresh leaves contain 46–81 µg/mg of it, about 5–8% of the dry weight, along with caffeic acid, quinic acid and the dicaffeoylquinic acids, including 3,5- and 4,5-dicaffeoylquinic acid ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. Total polyphenols usually run at about 4–10% of the dry leaf, measured as chlorogenic acid ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

The flavonoids include rutin and glycosides of quercetin and kaempferol, at about 70 mg/g of the dry leaf in total ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

The bitter maté saponins are triterpene glycosides of ursolic acid, at about 7.0 mg/g in green leaf and 6.6 mg/g in roasted leaf, with some analogues built on oleanolic acid ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

Roasting changes the aroma. Green maté’s essential oil is led by limonene, linalool and geranyl acetate, while roasting adds furfurals that give a smoky, sweet note ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

Constituent Summary

Share of the dried leaf unless noted. Content varies with origin, leaf age, processing (green or roasted) and brewing ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}.

Grouped by class · 21 compounds

Purine Alkaloid4 compounds3 with data

Purine AlkaloidCaffeine~1–2%; ~80 mg per 150 mL cup ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}

Purine AlkaloidTheobromine~0.3–0.9% ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}

Purine AlkaloidTheophyllinetrace ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}

Purine AlkaloidXanthine alkaloidsNo data

Phenolic Acid6 compounds1 with data

Phenolic AcidChlorogenic acid46–81 µg/mg (fresh leaf) ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}

Phenolic AcidCaffeic acidNo data

Phenolic AcidFerulic acidNo data

Phenolic AcidGallic acidNo data

Phenolic AcidSyringic acidNo data

Phenolic Acidp-Coumaric acidNo data

Phenolic1 compound1 with data

PhenolicPolyphenols~4–10% (as chlorogenic acid) ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}

Flavonoid3 compounds1 with data

FlavonoidRutinpart of ~70 mg/g total flavonoids ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}

FlavonoidQuercetinNo data

FlavonoidKaempferolNo data

Saponin2 compounds1 with data

SaponinMatesaponins~6.6–7.0 mg/g ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}

SaponinSaponinsNo data

Triterpene2 compoundsno data

TriterpeneUrsolic acidNo data

TriterpeneOleanolic acidNo data

Sterol1 compoundno data

SterolSterolsNo data

Organic Acid2 compoundsno data

Organic AcidCitric acidNo data

Organic AcidQuinic acidNo data

Dosage

Most trials used three 330 mL servings of infusion a day. The weight studies used capsules.

Indication	Preparation	Dose	Est. dried-herb equivalent	Source
Blood sugar (T2DM & pre-diabetes)	Roasted leaf infusion	330 mL × 3/day, 60 days	Not quantified	^{5Reference 5Klein et al. · 2011Clinical trialMate tea (Ilex paraguariensis) improves glycemic and lipid profiles of type 2 diabetes and pre-diabetes individuals: a pilot study — clinical trialView study →}
Cholesterol	Green or roasted infusion	330 mL × 3/day, 40 days	Not quantified	^{6Reference 6de Morais et al. · 2009Clinical trialConsumption of yerba mate (Ilex paraguariensis) improves serum lipid parameters in healthy dyslipidemic subjects — controlled clinical trialView study →}
Blood pressure, inflammation	Maté tea	3 servings/day, 8 weeks	Not quantified	^{7Reference 7Bravo et al. · 2025RCTYerba Mate (Ilex paraguariensis) tea may have cardiometabolic beneficial effects — a randomized, controlled, blind, crossover trial in nonhabitual consumersView study →}
Body fat	Capsules	3 g/day, 12 weeks	3 g/day	^{1Reference 1Kim et al. · 2015RCTAnti-obesity effects of Yerba Maté (Ilex paraguariensis): a randomized, double-blind, placebo-controlled clinical trialView study →}
Fat oxidation during exercise (acute)	Capsules	1–2 g, single dose before exercise	1–2 g	^{2,3Reference 2Alkhatib · 2014RCTYerba Maté (Ilex paraguariensis) ingestion augments fat oxidation and energy expenditure during exercise — randomised crossover trialView study →Reference 3Alkhatib et al. · 2017RCTYerba Maté (Ilex paraguariensis) metabolic, satiety, and mood state effects at rest and during prolonged exercise — randomized trialView study →}

Traditional Dosage

System	Preparation	Dose
European herbal (fatigue)	Leaf tea	2–4 g a day, taken as about 1 g three times a day ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}
European herbal (urinary flushing)	Leaf tea	2.5–5 g a day, taken as 2.5 g once or twice a day ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}
South American traditional (maté / chimarrão)	Gourd filled about a quarter full or more, topped up with water at 65–80 °C	Refilled many times; 12–23 g of leaf a day is typical in the region ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}
South American traditional (tereré)	Same, with cold water	Refilled many times ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}

Safety & Pregnancy

Maté is well tolerated as a drink, and its cautions are mostly those of caffeine. The one specific to maté is temperature: it is traditionally drunk very hot, and drinking any beverage very hot is a probable cause of oesophageal cancer.

Safety at a Glance

Low / no toxicityDrug interactionsCardiac cautionSedative interactionsNot for children

Drink it warm, not very hot. Drinking beverages above 65 °C is classed as probably carcinogenic, and maté is traditionally drunk at about 70 °C ^{29Reference 29International Agency for Research on Can · 2016ReviewIARC Monographs evaluate drinking coffee, maté, and very hot beverages — Press Release NoView study →}.
Caffeine. A full gourd session can exceed 260 mg of caffeine. EFSA considers up to 400 mg a day safe for healthy adults ^{22,32Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →Reference 32EFSA Panel on Dietetic Products et al. · 2015ReviewScientific opinion on the safety of caffeine — regulatory reviewView study →}.
Not with certain conditions. Avoid with stomach or duodenal ulcers, high blood pressure, heart-rhythm problems or an overactive thyroid ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}.
Not before bed, and not for under-18s. It can disturb sleep, and it is not recommended for children and teenagers ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}.
Drug interactions. Use with care alongside MAO inhibitors, sedatives and stimulant drugs ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}. Its caffeine is cleared by CYP1A2 ^{38Reference 38Nehlig A · 2018ReviewInterindividual Differences in Caffeine Metabolism and Factors Driving Caffeine Consumption — reviewView study →}.
Pregnancy and breastfeeding. Keep to moderate amounts as a drink; the EU herbal monograph advises avoiding medicinal maté products ^{30,32Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →Reference 32EFSA Panel on Dietetic Products et al. · 2015ReviewScientific opinion on the safety of caffeine — regulatory reviewView study →}.

Full Safety Detail

Side effects. Side effects reported in trials included mouth and throat irritation, sleeplessness, a fast heartbeat, angina, headache and stomach upset ^{4Reference 4Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →}.

Temperature and oesophageal cancer. In 2016 the International Agency for Research on Cancer classified drinking very hot beverages, above 65 °C, as probably carcinogenic to humans (Group 2A), based on higher oesophageal cancer rates where tea or maté is drunk at about 70 °C. Drinking maté that is not very hot was not classifiable (Group 3), and cold maté showed no carcinogenic effect in animal or human studies ^{29Reference 29International Agency for Research on Can · 2016ReviewIARC Monographs evaluate drinking coffee, maté, and very hot beverages — Press Release NoView study →}.

In two pooled South American case-control studies (1,400 cases), maté drinkers had a higher risk of oesophageal squamous cell carcinoma (OR 1.60). The risk rose with lifetime intake, and more steeply for maté drunk hot or very hot than warm ^{20Reference 20Lubin et al. · 2014ObservationalMaté drinking and esophageal squamous cell carcinoma in South America: pooled results from two case-control studies — observationalView study →}. In the UK Biobank, drinking tea or coffee hot or very hot was also linked to this cancer ^{21Reference 21Inoue-Choi et al. · 2025ObservationalHot beverage intake and oesophageal cancer in the UK Biobank — prospective cohort studyView study →}.

The authors of the pooled study named thermal injury and polycyclic aromatic hydrocarbons from smoke-drying as possible causes ^{20Reference 20Lubin et al. · 2014ObservationalMaté drinking and esophageal squamous cell carcinoma in South America: pooled results from two case-control studies — observationalView study →}. The EU monograph asks for PAH content to be controlled in medicinal maté ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}.

Caffeine. A 150 mL cup holds about 80 mg of caffeine, but the traditional gourd, refilled many times, can deliver more than 260 mg in one session ^{22Reference 22Gawron-Gzella et al. · 2021ReviewYerba Mate — a long but current history — reviewView study →}. EFSA considers up to 400 mg of caffeine a day from all sources safe for healthy adults, and notes that 100 mg near bedtime can disturb sleep ^{32Reference 32EFSA Panel on Dietetic Products et al. · 2015ReviewScientific opinion on the safety of caffeine — regulatory reviewView study →}.

Contraindications. The EU herbal monograph lists stomach and duodenal ulcers, heart and circulatory conditions such as high blood pressure and arrhythmia, an overactive thyroid, and conditions that call for reduced fluid intake, such as urinary obstruction. It does not recommend maté for under-18s, or before bedtime ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}.

MAO inhibitors, sedatives and stimulant drugs. The monograph advises care with MAO inhibitors. Caffeine weakens the effect of sedatives and adds to the side effects of stimulant (sympathomimetic) drugs ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}. In rats, an aqueous maté extract had an antidepressant-like effect without inhibiting monoamine oxidase ^{36Reference 36Reis Ede M et al. · 2014AnimalAntidepressant-like effect of Ilex paraguariensis in rats — ratView study →}.

Diabetes medicines. Maté lowered after-meal blood sugar in prediabetes ^{4,5Reference 4Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →Reference 5Klein et al. · 2011Clinical trialMate tea (Ilex paraguariensis) improves glycemic and lipid profiles of type 2 diabetes and pre-diabetes individuals: a pilot study — clinical trialView study →}, so an added effect with glucose-lowering drugs is plausible. The combination has not been studied.

Drug metabolism. In a laboratory study of nine standardised plant extracts, the maté extract inhibited CYP3A4, an enzyme that clears many medicines; this has not been tested in people ^{35Reference 35Feltrin C et al. · 2020In vitroEffects of Standardized Medicinal Plant Extracts on Drug Metabolism Mediated by CYP3A4 and CYP2D6 Enzymes — in vitroView study →}.

Maté’s caffeine is itself cleared mainly by CYP1A2, which metabolises about 95% of ingested caffeine ^{38Reference 38Nehlig A · 2018ReviewInterindividual Differences in Caffeine Metabolism and Factors Driving Caffeine Consumption — reviewView study →}. Medicines that block CYP1A2 can therefore raise caffeine levels and its stimulant effects, and smoking also changes its clearance ^{38Reference 38Nehlig A · 2018ReviewInterindividual Differences in Caffeine Metabolism and Factors Driving Caffeine Consumption — reviewView study →}.

Pregnancy & Lactation

Caution in pregnancy Caution while breastfeeding

Caution. As with coffee and tea, the concern is caffeine, which crosses the placenta and passes into breast milk. The EU herbal monograph advises avoiding medicinal maté products during pregnancy and breastfeeding, because data are limited ^{30Reference 30European Medicines Agency · 2010ReviewCommunity herbal monograph on Ilex paraguariensis StView study →}.

As a drink, maté counts toward total caffeine. EFSA considers up to 200 mg a day from all sources safe for the fetus ^{32Reference 32EFSA Panel on Dietetic Products et al. · 2015ReviewScientific opinion on the safety of caffeine — regulatory reviewView study →}.

References

Kim, S. Y., et al. (2015). Anti-obesity effects of Yerba Maté (Ilex paraguariensis): a randomized, double-blind, placebo-controlled clinical trial. BMC Complementary and Alternative Medicine. https://pubmed.ncbi.nlm.nih.gov/26408319/
Alkhatib, A. (2014). Yerba Maté (Ilex paraguariensis) ingestion augments fat oxidation and energy expenditure during exercise — randomised crossover trial. Nutrition & Metabolism. https://pubmed.ncbi.nlm.nih.gov/25342955/
Alkhatib, A., & Atcheson, R. (2017). Yerba Maté (Ilex paraguariensis) metabolic, satiety, and mood state effects at rest and during prolonged exercise — randomized trial. Nutrients. https://pubmed.ncbi.nlm.nih.gov/28809814/
Li, D., et al. (2025). Yerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTs. Frontiers in Endocrinology. https://pubmed.ncbi.nlm.nih.gov/41244043/
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de Morais, E. C., et al. (2009). Consumption of yerba mate (Ilex paraguariensis) improves serum lipid parameters in healthy dyslipidemic subjects — controlled clinical trial. Journal of Agricultural and Food Chemistry. https://pubmed.ncbi.nlm.nih.gov/19694438/
Bravo, L., et al. (2025). Yerba Mate (Ilex paraguariensis) tea may have cardiometabolic beneficial effects — a randomized, controlled, blind, crossover trial in nonhabitual consumers. Molecular Nutrition & Food Research. https://pubmed.ncbi.nlm.nih.gov/40263915/
Filipini, R. E., et al. (2024). Acute ingestion of yerba mate (Ilex paraguariensis) infusion does not modify endothelial function, hemodynamics, or heart rate variability — a randomized crossover clinical trial. Plant Foods for Human Nutrition. https://pubmed.ncbi.nlm.nih.gov/39708247/
Ruskovska, T., et al. (2023). Multigenomic modifications in human circulating immune cells in response to consumption of polyphenol-rich extract of yerba mate — randomized controlled trial. British Journal of Nutrition. https://pubmed.ncbi.nlm.nih.gov/35373729/
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Cassotta, M., et al. (2025). Yerba Mate (Ilex paraguariensis) and rheumatoid arthritis: a systematic review. Nutrients. https://pubmed.ncbi.nlm.nih.gov/41470797/
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