Not as clearly as its reputation suggests. A 2025 review of 38 randomized trials found green tea did not change CRP, IL-6 or TNF-alpha, three common inflammation markers. It did lower one, IL-1 beta. Some smaller reviews found drops in certain groups, such as people with type 2 diabetes.
Why people think green tea calms inflammation
Green tea is rich in plant compounds called catechins. The best known is EGCG (short for epigallocatechin gallate). Researchers have long thought catechins might lower the signals the body uses to keep inflammation running.
Those signals can be measured in a blood test. CRP (C-reactive protein) is a protein the liver makes when inflammation is up. IL-6 and TNF-alpha are messenger proteins that help drive it. Extra body fat tends to push all three up, which is the slow, low-grade kind of inflammation most of our readers care about.
So the question is simple. When people drink green tea, or take it as a pill, do these numbers go down?
Does green tea reduce inflammation in the body?
The biggest answer so far came in 2025. A research team pooled 38 randomized trials, the kind where people are assigned by chance to green tea or a comparison. They graded how much to trust each result.
A full year of high-dose green tea extract left CRP, IL-6 and TNF-alpha unchanged.From a 2026 randomized trial in Nutrients
Green tea did not lower CRP, IL-6 or TNF-alpha in a meaningful way. It did lower IL-1 beta, another inflammation signal, by a small amount. It also improved several signs of oxidative stress, a kind of cell wear and tear that often travels with inflammation. The authors summed it up plainly: no significant effect on inflammation markers "except for IL-1β."
An earlier meta-analysis, from 2019, pooled 16 trials. A meta-analysis is a study that combines the results of many studies. It also found no drop in CRP. It found TNF-alpha went down, but IL-6 went up. Its authors suggested green tea might not do much in people whose inflammation is already low, and that future trials should test people with high inflammation.
Where the signals show up
That idea, that green tea may matter more when inflammation is already high, has some support.
In people with type 2 diabetes, a 2019 review of 8 trials with 614 patients found CRP dropped after green tea, compared with control groups. And a 2026 network meta-analysis of 60 trials in adults with overweight or obesity found green tea extract lowered IL-6. That kind of review compares many supplements at once. Its authors still asked for caution, since doses, trial lengths and the people studied varied a lot.
Now the counterweight. The Minnesota Green Tea Trial gave postmenopausal women with overweight or obesity a high-dose extract (about 843 mg of EGCG a day) or a dummy pill for a full year. In a group of 97 of them, CRP, IL-6 and TNF-alpha did not change any differently between the two groups.
A year is a long, careful test. It came back flat.
Cup or capsule: why the form matters
Most of the trial evidence above mixes brewed tea and extract pills. For safety, the two are not the same thing.
In that same Minnesota trial, 1,021 women with normal liver tests took the extract or a dummy pill for 12 months. Liver enzymes rose in the extract group. 26 women on the extract (5.1%) developed moderate or worse liver test changes. The enzymes fell when the pills stopped and rose again when they restarted.
A 2018 safety review of 159 human studies found liver problems came from concentrated, catechin-rich products taken in large doses, "but not when consumed as brewed tea." It set a safe level of 338 mg of EGCG a day for pills and capsules, and 704 mg a day for tea drinks.
Brewed tea looks different. A 2021 umbrella review, which gathers many reviews into one, looked at 23 reviews on tea and heart health. It found tea as a drink did not seem harmful. It linked about 2 cups of unsweet tea a day to lower heart disease risk, with some trials showing lower TNF-alpha and IL-6. Many of those studies were too small to be sure.
Tea and the brain is murkier. In a 2026 study that followed two large US groups for years, moderate tea drinking was linked to lower dementia risk in one group but not the other.
What this means for you
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you have liver disease or have had abnormal liver tests; you take prescription medicines; you are pregnant or breastfeeding; or you notice dark urine, yellowing skin or eyes, or pain in your upper belly while taking a green tea extract.
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The bottom line
Green tea earned its calm reputation from a plausible idea: catechins should quiet inflammation. Pooled across 38 trials, they mostly didn't. A few groups, such as people with type 2 diabetes, showed drops, and one marker moved a little. But a full year of high-dose pills left CRP flat and pushed liver enzymes up. So keep the cup and question the capsule. Green tea is a fine drink, but it is not a fix for inflammation.
Common questions
Does green tea reduce inflammation in the body?
Not much, by the usual blood tests. A 2025 review of 38 randomized trials found green tea did not lower CRP, IL-6 or TNF-alpha, though it lowered IL-1 beta a little. Smaller reviews found drops in some groups, like CRP in people with type 2 diabetes. Trials in people with higher inflammation may show more.
Does green tea cause inflammation in the stomach?
The studies we read did not measure stomach inflammation. A 2021 review of tea and heart health found the main side effects reported in human studies were liver problems and stomach upset, such as vomiting and diarrhea, after high-dose supplements. It found tea as a drink did not seem harmful. If tea upsets your stomach, it is worth mentioning to your doctor.
Is green tea inflammatory or anti-inflammatory?
Neither label fits well. Across 38 trials, it did not move the main markers either way, and it lowered IL-1 beta slightly. One 2019 review saw TNF-alpha go down while IL-6 went up. Brewed tea looks safe in normal amounts. High-dose extract pills can raise liver enzymes.
Is green tea extract better than drinking green tea?
Not for inflammation, based on current trials. A year of high-dose extract did not change CRP, IL-6 or TNF-alpha in 97 women. Extract pills also carry a liver risk that brewed tea has not shown in studies. A 2026 review did find extract lowered IL-6 in adults with overweight or obesity.
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How this article was made
Researched and written from 9 peer-reviewed papers. Our automated check matched every claim against the exact words of its source, confirmed every paper exists in PubMed, and found none retracted. Checked November 2, 2026. Not individually reviewed by a doctor. Photos are illustrative; the people in them are not patients or readers.
Grades run Strong, Moderate, Emerging, Early and Not supported, and the grade decides the words we may use. How we grade evidence · Medical disclaimer
Sources
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- Meta-analysisThe effect of green tea on inflammatory mediators: A systematic review and meta-analysis of randomized clinical trials.Haghighatdoost F, Hariri M Phytother Res, 2019.PubMedFull paper
- Meta-analysisThe effect of green tea on C-reactive protein and biomarkers of oxidative stress in patients with type 2 diabetes mellitus: A systematic review and meta-analysis.Asbaghi O, Fouladvand F, Gonzalez MJ et al. Complement Ther Med, 2019.PubMedFull paper
- Randomized trialEffects of Green Tea Extract Supplementation on Inflammatory Cytokines Among Postmenopausal Women with Overweight or Obesity-A Secondary Analysis of a Randomized Controlled Trial.Cunningham A, Gomes A, Meng L et al. Nutrients, 2026.PubMedFull paper
- Meta-analysisEffects of Nutritional Supplements on Inflammatory Biomarkers in Overweight and Obese Adults: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials.Chen Z, Liu A, Bian S et al. Nutrients, 2026.PubMedFull paper
- Systematic reviewThe safety of green tea and green tea extract consumption in adults - Results of a systematic review.Hu J, Webster D, Cao J et al. Regul Toxicol Pharmacol, 2018.PubMedFull paper
- Randomized trialEffect of Green Tea Supplements on Liver Enzyme Elevation: Results from a Randomized Intervention Study in the United States.Yu Z, Samavat H, Dostal AM et al. Cancer Prev Res (Phila), 2017.PubMedFull paper
- Umbrella reviewTea intake and cardiovascular disease: an umbrella review.Keller A, Wallace TC Ann Med, 2021.PubMedFull paper
- CohortCoffee and tea intake, circulating inflammatory biomarkers, and long-term risk of dementia: findings from two longitudinal studies.Yan M, Shen J, Zhao M et al. Eur J Epidemiol, 2026.PubMedFull paper
