Yerba Mate for Weight Loss: A Small Positive Trial, and No BMI Change When Trials Are Pooled
Yerba mate is sold as a fat burner. The trials show a bump in fat burning during exercise and little measurable change in body weight.
By Kymata Health Editorial Published Last checked
Key takeaways
From 13 sources- A 2025 meta-analysis of 13 randomized trials found no significant effect of yerba mate on BMI or waist circumference1.
- The best-known positive trial had 30 Korean adults with obesity, ran 12 weeks at 3 g/day, and acknowledged financial support from the company that supplied the product2.
- The 5.1 kg weight-loss figure often quoted came from a three-herb blend, not yerba mate alone3.
- Single doses raised fat burning during moderate exercise in lab studies of 12 to 14 people, which is not the same as losing fat45.
- Mate adds caffeine: the FDA cites 400 mg a day from all sources as an amount not generally linked to negative effects for most adults6.
What this article covers
1 evidence profileThe evidence, graded
Pulled from the trial tables in our evidence profiles. Grades follow our evidence-grading policy.
Graded findings
1 row- DGrade DBody fat in adults with obesityImproved Body fat mass, percent body fat and waist-hip ratio fell more than with placebo; no clinically significant safety changes.Yerba Mate · RCT · n=30 · 2015 · PMID 26408319
Where the fat-burner reputation comes from
Yerba mate is a caffeinated South American drink brewed from the leaves of Ilex paraguariensis. A 2023 systematic review of 32 studies reported benefits for body weight and composition among other outcomes, but it rated the risk of bias as high in 22 studies and the certainty of evidence as moderate to very low7.
What the weight trials show
The strongest test is a 2025 meta-analysis of 13 randomized trials in people with normal weight, overweight, obesity or high cholesterol1. It found no significant effect on BMI, waist circumference, fasting glucose, fasting insulin or blood lipids1.
In a 2015 Korean trial, 30 adults with obesity took 3 g/day of yerba mate capsules or placebo for 12 weeks, 15 per group2. Body fat mass, percent body fat and waist-to-hip ratio fell more than with placebo, with no clinically significant safety changes2. The authors thanked Bluegreenlink Co. for providing the yerba mate and for financial support, alongside a government grant2.
A 2001 Danish study is the source of the large weight-loss figures: overweight patients lost 5.1 kg over 45 days versus 0.3 kg on placebo3. The capsules combined yerba mate with guarana and damiana, so the result cannot be credited to mate alone3.
Burning more fat during exercise is not the same as losing fat
In a crossover study of 14 adults, 1,000 mg of yerba mate taken 60 minutes before exercise raised fat oxidation by 24% at intensities below 70% of peak oxygen uptake4.
In 12 active women, 2 g of yerba mate raised fat oxidation during 30 minutes of cycling and lowered hunger ratings compared with placebo5.
These were single-dose lab sessions lasting hours, and neither measured body weight45. The longer trials that did measure body size found no significant change in BMI or waist circumference1.
The one metabolic signal: blood sugar
In the 2025 meta-analysis, people with prediabetes had lower post-meal glucose, HbA1c and insulin-resistance scores with yerba mate, but each of those estimates rested on just 2 trials1.
Safety and who should be careful
Adverse events reported in yerba mate trials included mucosal irritation, insomnia, fast heart rate, angina, headache and stomach upset1.
Who should be careful:
- Caffeine-sensitive people, and anyone stacking mate with coffee, energy drinks or pre-workouts: the FDA cites 400 mg a day as an amount not generally linked to negative effects for most adults, and notes some medicines and conditions make people more sensitive6. See how much caffeine is too much.
- People who drink it very hot: IARC classifies drinking beverages hotter than 65 °C as probably carcinogenic to humans (Group 2A), based on oesophageal cancer studies that included places where mate is traditionally drunk at about 70 °C; mate drunk at lower temperatures was not classifiable (Group 3)8.
- Regular drinkers, hot or cold: mate leaves are often dried with smoke, and commercial samples have carried high levels of polycyclic aromatic hydrocarbons (PAHs), including the carcinogen benzo[a]pyrene1213. Some of these pass into both hot and cold infusions, with reported transfer rates of 1 to 50% depending on the method1213.
- People with low iron: in 14 patients with hereditary haemochromatosis, a mate infusion taken with a meal significantly reduced the rise in blood iron compared with water9. Applying this to people with low iron is an inference; see iron supplements every other day.
- Pregnant or breastfeeding women: a premature newborn whose mother drank homemade mate during pregnancy had withdrawal symptoms, with high caffeine and theobromine levels found in samples including breast milk10.
Quick answers
Common questions
3 answersHow much yerba mate was used in weight trials?
Does cold yerba mate (tereré) have less caffeine?
Not in a lab simulation: cold-water tereré extracted about 2.5 times more methylxanthines, the caffeine family, than the strongest hot preparation tested11.
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References
13 sources. Numbers in the text link here.
Sources cited in this article
13 sources- 1Yerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysisFront Endocrinol (Lausanne), 2025 · PMID 41244043
- 2Anti-obesity effects of Yerba Mate (Ilex Paraguariensis): a randomized, double-blind, placebo-controlled clinical trialBMC Complement Altern Med, 2015 · PMID 26408319
- 3Weight loss and delayed gastric emptying following a South American herbal preparation in overweight patientsJ Hum Nutr Diet, 2001 · PMID 11424516
- 4Yerba Maté (Illex Paraguariensis) ingestion augments fat oxidation and energy expenditure during exercise at various submaximal intensitiesNutr Metab (Lond), 2014 · PMID 25342955
- 5Yerba Maté (Ilex paraguariensis) Metabolic, Satiety, and Mood State Effects at Rest and during Prolonged ExerciseNutrients, 2017 · PMID 28809814
- 6Spilling the Beans: How Much Caffeine is Too Much?U.S. Food and Drug Administration, 2024
- 7Physiological effects of yerba maté (Ilex paraguariensis): a systematic reviewNutr Rev, 2023 · PMID 36647770
- 8IARC Monographs evaluate drinking coffee, maté, and very hot beverages (Press release No. 244)International Agency for Research on Cancer (WHO), 2016
- 9Ilex paraguariensis (A. St.-Hil.) leaf infusion decreases iron absorption in patients with hereditary hemochromatosis: a randomized controlled crossover studyFood Funct, 2021 · PMID 34173816
- 10Neonatal withdrawal syndrome after chronic maternal drinking of mateTher Drug Monit, 2007 · PMID 17304161
- 11Methylxanthines and phenolics content extracted during the consumption of mate (Ilex paraguariensis St. Hil) beveragesJ Agric Food Chem, 2010 · PMID 20058928
- 12High levels of carcinogenic polycyclic aromatic hydrocarbons in mate drinksCancer Epidemiol Biomarkers Prev, 2008 · PMID 18483349
- 13Polycyclic aromatic hydrocarbons as a potential source of carcinogenicity of mateJ Environ Sci Health C Environ Carcinog Ecotoxicol Rev, 2019 · PMID 30596334
Yerba Mate and other dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Talk to your clinician or pharmacist before starting a supplement, especially if you take prescription medicines. This page has no product or affiliate links.