🔬 Science & Research  | 7 min read
What Yerba Mate's Newest Research Actually Found (Including the Cancer Question)
Most yerba mate content recycles the same three claims — clean energy, no crash, packed with antioxidants — without ever pointing to an actual study. In 2025, two pieces of real research changed that: a controlled clinical trial and a systematic review pooling over a decade of data. Neither is a marketing department's dream. Both are more interesting than the usual copy, because they show where the evidence is genuinely strong, where it's thin, and where the popular claims get ahead of the data.
The 2025 Clinical Trial: What 8 Weeks of Yerba Mate Did to Real Bodies
Published in Molecular Nutrition & Food Research in August 2025, this was a proper randomized, controlled, blinded, crossover trial — the closest thing nutrition science has to a gold standard. Researchers recruited 52 adults: 25 healthy participants and 27 with hypercholesterolemia (high cholesterol, putting them at moderate cardiovascular risk). Each person drank 3 grams of yerba mate tea, three times a day, for 8 weeks — then, after a washout period, switched to a placebo beverage for another 8 weeks, so each person acted as their own control.
The results, after 8 weeks of yerba mate:
- Blood pressure dropped significantly in both groups (p < 0.001) — a consistent, statistically strong effect.
- Inflammatory markers fell, including circulating cytokines linked to blood vessel health.
- LDL cholesterol dropped in the healthy group, and total cholesterol, LDL, and triglycerides all fell in the at-risk group.
- Ghrelin and GIP — hormones that drive hunger and fat storage — decreased, while GLP-1 (a satiety hormone) stayed flat.
- Body fat percentage dropped in healthy participants (p = 0.001), even though total body weight didn't change.
The researchers were upfront about the limits, too: only 52 people, an 8-week window, and — importantly — the placebo group in the at-risk subgroup showed similar cholesterol improvements, which makes it hard to say the lipid results were purely down to yerba mate rather than other diet changes during the study. That kind of caveat is rare in supplement marketing and exactly why this trial is worth taking seriously.
The Bigger Picture: A 13-Study Meta-Analysis on Blood Sugar
A second 2025 paper, published in Frontiers in Endocrinology, pooled 13 randomized controlled trials on yerba mate and metabolic health — the largest synthesis of this evidence to date. The honest headline: yerba mate's effect on blood sugar depends heavily on who's drinking it.
In people with pre-diabetes specifically, the pooled data showed meaningful improvements: postprandial (after-meal) glucose dropped by an average of 12.76 mg/dL, HbA1c fell by 0.37 percentage points, and insulin resistance (measured by HOMA-IR) improved. But those numbers came from just 2 of the 13 trials, and the authors rated the certainty of that evidence as low to moderate under the GRADE framework — the standard system researchers use to grade how much confidence to place in a finding.
Across the wider population, the picture was flatter: no significant effect on fasting glucose, fasting insulin, triglycerides, HDL, LDL, waist circumference, or BMI. The authors' own conclusion is worth quoting directly: yerba mate "may demonstrate favorable effects on glycemic control, though its impact on lipid profiles and weight management appears to be limited." That's a meaningfully more measured claim than "burns fat" or "melts belly fat" — phrases that show up constantly in yerba mate marketing but aren't what this data actually supports.
Wait — Doesn't Yerba Mate Cause Cancer?
This comes up in almost every yerba mate search, so it's worth answering directly instead of ignoring it. Several South American studies have linked heavy mate drinking with a higher risk of esophageal cancer. The detail that usually gets lost: the studies showing risk involved people drinking more than 2.5 liters a day at very high temperatures — traditionally sipped scalding hot through a metal straw (a bombilla), for hours, daily, for years.
When researchers isolated temperature as a variable, the picture became clearer: beverages above 65°C (149°F) are associated with increased esophageal cancer risk — and that holds true for tea and coffee drunk that hot as well, not just mate. Cold mate preparations showed no increased risk at all. The scientific consensus is that this is a temperature effect from repeated thermal injury to esophageal tissue, not a property of the yerba mate plant itself.
Practically, this means the concern applies to scalding-hot traditional mate consumed in large volumes over years — not to a chilled kombucha, a gummy, or a tablet dissolved in room-temperature water.
What About All the Antioxidant Claims?
This part holds up reasonably well. Yerba mate genuinely does carry a dense polyphenol profile — including chlorogenic acid, rutin, and quercetin — at concentrations roughly 2 to 2.5 times higher than green tea, putting it in the same range as red wine for antioxidant content. That's consistent with, and likely part of the mechanism behind, the anti-inflammatory effects seen in the 2025 clinical trial above.
The Honest Takeaway
Putting it together: the strongest evidence right now is for blood pressure and inflammation, backed by an actual randomized trial with a real placebo arm. The blood-sugar story is promising but preliminary, and mostly relevant if you already have elevated blood sugar rather than as a general metabolic booster. The cancer scare is real but is about serving temperature and volume, not the plant. And the weight-loss and cholesterol claims — the ones that show up most in marketing — are the parts of the story the evidence supports the least.
This article is for informational purposes only and is not medical advice. If you have an existing health condition or are making changes to your diet, talk to a healthcare professional first.
Meet the Yerba Mate Behind the Research
Truyerba's Power Gummies, Effervescent Tablets, and Kombucha are all built on the same standardized yerba mate extract studied above — third-party lab tested, 100% vegan, and never served scalding hot.
Sources
Bravo L, et al. "Yerba Mate (Ilex paraguariensis St. Hill.) Tea May Have Cardiometabolic Beneficial Effects in Healthy and At-Risk Subjects." Molecular Nutrition & Food Research, 2025. onlinelibrary.wiley.com/doi/10.1002/mnfr.70065
Li D, et al. "Yerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis." Frontiers in Endocrinology, 2025. pmc.ncbi.nlm.nih.gov/articles/PMC12611702
"Comparative oesophageal cancer risk assessment of hot beverage consumption (coffee, mate and tea)." pmc.ncbi.nlm.nih.gov/articles/PMC5831222
"Maté Drinking and Esophageal Squamous Cell Carcinoma in South America." Cancer Epidemiology, Biomarkers & Prevention. aacrjournals.org/cebp/article/23/1/107