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Research · Food and drink

Green tea

In Japanese and Chinese cohorts, drinking more green tea was linked to lower death and fewer heart attacks and strokes. In trials of catechin-enriched green tea drinks, total cholesterol fell about 3 mg/dL and LDL did not change significantly. A Cochrane review found inconsistent cancer results. Very hot tea with alcohol or smoking was linked to esophageal cancer.

Add to Bio HackChecked 2026-11-13
Status
A food, not a regulated health product. FDA allows one qualified claim on green tea and cancer, that drinking green tea may reduce the risk of breast or prostate cancer, with the required disclaimer "FDA does not agree that green tea may reduce that risk because there is very little scientific evidence for the claim". It found no credible evidence for gastric, lung, colorectal, esophageal, pancreatic, ovarian or combined cancers [1].
Also called
green tea, brewed green tea, sencha, matcha, Japanese green tea, Chinese green tea, Camellia sinensis tea, catechin-rich green tea drink, decaffeinated green tea
Studied for
weight loss, metabolism, heart health, longer life, blood pressure, cholesterol, blood sugar, type 2 diabetes prevention, cancer prevention, antioxidants

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help6

Reported risks3

What it was studied for, and what was found

Shown to help6

Moderate

Death from any cause

Linked to 10% lower death in men and 18% lower in women at 5 or more cups a day than under 1 cup, in 8 pooled Japanese cohorts.

Compared with people drinking under 1 cup a day [2]

The numbers and sources
Effect
At 5 or more cups a day, death from any cause was lower in men (HR 0.90, 95% CI 0.87 to 0.94) and women (HR 0.82, 95% CI 0.74 to 0.90), as was death from heart disease (HR 0.82 in men, 0.75 in women) and cerebrovascular disease (HR 0.76 in men, 0.78 in women). In women, 1 to 4 cups a day was linked to slightly lower cancer death [2].
Population
313,381 Japanese adults with 52,943 deaths over a mean 17.3 years in 8 cohorts [2].
Sources
[2]
Caveats
Observational, with intake reported once at the start. All participants were Japanese, where green tea is a daily habit, so the results may not carry to other populations.
Strong

Heart attack and stroke

Linked to 19% lower heart attack and 36% lower stroke at 1 to 3 cups a day than under 1 cup, in pooled studies, mostly from Asia.

Compared with people drinking under 1 cup a day [3][2]

The numbers and sources
Effect
At 1 to 3 cups a day, heart attack (OR 0.81, 95% CI 0.67 to 0.98) and stroke (OR 0.64, 95% CI 0.47 to 0.86) were lower than at under 1 cup, and heart attack was lower at 4 or more cups (OR 0.68, 95% CI 0.56 to 0.84). Non-drinkers had higher cardiovascular disease (OR 1.19, 95% CI 1.09 to 1.29) than people drinking under 1 cup a day [3]. In Japanese cohorts, 5 or more cups a day was linked to lower heart disease and cerebrovascular death [2].
Population
259,267 people in 9 studies [3]. 313,381 Japanese adults [2].
Sources
[3], [2]
Caveats
Observational. The pooled analysis mixed observational studies and trials, and the abstract gives no study count by design [3].
Moderate

Cholesterol

Shown to lower total cholesterol by 2.8 mg/dL in trials of catechin-enriched green tea drinks. LDL, HDL and triglycerides did not change significantly in those trials.

Compared with water or other placebo drinks, no intervention, or green tea drinks low in catechins [4]

The numbers and sources
Effect
In the 9 trials that gave green tea as a drink, total cholesterol fell by 2.80 mg/dL (95% CI 0.16 to 5.43). LDL changed by -2.61 mg/dL (95% CI -5.49 to 0.27), HDL by -0.84 mg/dL and triglycerides by -0.77 mg/dL, none significant. Across all 31 trials of drinks and capsules, LDL fell by 4.55 mg/dL (95% CI 2.80 to 6.31) [4].
Population
3,321 participants in 31 randomized trials, 9 of them using a green tea drink [4].
Sources
[4]
Caveats
The drinks in these trials were green tea beverages made with extract, carrying 400 to 928 mg of catechins a day, not ordinary brewed tea. Meta-regression found no significant difference between drinks and capsules [4]. Capsule trials are on the green tea extract page.
Moderate

Blood pressure

Shown to lower blood pressure by about 2 mmHg in pooled trials of green tea drinks and extracts, with no separate result for the drink.

Compared with control groups, including placebo capsules, water and low-catechin green tea drinks [5]

The numbers and sources
Effect
Systolic pressure fell by 1.98 mmHg (95% CI 1.01 to 2.94) and diastolic by 1.92 mmHg (95% CI 0.68 to 3.17). Falls were larger in people with stage 1 hypertension (3.52 mmHg systolic) and were seen only in trials that removed the effect of caffeine, used lower polyphenol doses or lasted longer [5].
Population
1,367 participants in 13 randomized trials, several using green tea drinks [5].
Sources
[5]
Caveats
The pooled trials mixed drinks and capsules. Polyphenol doses ranged from 208 to 1,207 mg a day [5].
Limited

Type 2 diabetes

Limited evidence: one Japanese cohort linked 6 or more cups a day to 33% lower odds of type 2 diabetes than under 1 cup a week.

Compared with people drinking under 1 cup a week [6]

The numbers and sources
Effect
At 6 or more cups a day, the odds of new diabetes over 5 years were lower (OR 0.67, 95% CI 0.47 to 0.94). Black and oolong tea were not linked to diabetes [6].
Population
17,413 Japanese adults aged 40 to 65 [6].
Sources
[6]
Caveats
Diabetes was self-reported and follow-up was low, at 49% of the original study population [6].
Limited

Weight and waist size

One small trial found a larger drop in waist size with a catechin-rich green tea drink than a low-catechin one, in people with type 2 diabetes.

Compared with a green tea drink with 96.3 mg of catechins a day [8]

The numbers and sources
Effect
After 12 weeks, waist circumference fell more with 582.8 mg of catechins a day than with 96.3 mg, and adiponectin rose only in the high-catechin group [8].
Population
23 adults on the catechin-rich drink and 20 on the control drink, all with type 2 diabetes [8].
Sources
[8]
Caveats
One small double-blind trial of a drink richer in catechins than brewed tea. The abstract gives no weight change. Pooled weight-loss trials, mostly of extracts, are on the green tea extract page.

Mixed results1

Moderate

Blood sugar in trials

Mixed results: pooled trials of green tea and extracts found small falls in fasting glucose and HbA1c, while a trial of a catechin-rich drink found no difference.

Compared with control groups in randomized trials [7]; a green tea drink with 96.3 mg of catechins a day [8]

The numbers and sources
Effect
Across 17 trials, green tea lowered fasting glucose by 0.09 mmol/L (95% CI 0.03 to 0.15) and HbA1c by 0.30% (95% CI 0.22 to 0.37), and fasting insulin in higher-quality trials [7]. In people with type 2 diabetes, a drink with 582.8 mg of catechins a day for 12 weeks showed no apparent difference in glucose or HbA1c from a low-catechin drink, except in people on insulin-releasing drugs [8].
Population
1,133 participants in 17 randomized trials of green tea or green tea extract [7]. 43 adults with type 2 diabetes not on insulin [8].
Sources
[7], [8]
Caveats
The pooled trials included extracts, and the abstract gives no separate result for the drink [7].

Not shown to help1

Moderate

Cancer

Not shown to lower cancer risk: a Cochrane review found inconsistent results and no link between green tea drinking and cancer death.

Compared with the lowest intake [9]

The numbers and sources
Effect
At the highest against the lowest intake, overall cancer incidence was 0.83 (95% CI 0.65 to 1.07) in 3 studies and cancer death 0.99 (95% CI 0.91 to 1.07) in 8 studies, both low-certainty. Cohort and case-control studies conflicted for esophageal, prostate and urinary tract cancer and leukemia, with higher risk in cohorts [9].
Population
More than 1,100,000 participants in 46 cohort and 85 case-control studies, and 1,795 in 11 trials of green tea extract [9].
Sources
[9]
Caveats
Most studies were in Asian populations with high green tea intake [9].

Amounts studied

Cohorts grouped people from under 1 cup a week to 6 or more cups a day [6], and from under 1 cup to 5 or more cups a day [2]. Drink trials included 700 mL a day for 14 days [10] and catechin-rich drinks of 582.8 mg catechins a day for 12 weeks [8]. Polyphenol doses in blood pressure trials ranged from 208 to 1,207 mg a day [5].

Risks

Reported risks3

LimitedHow often is not known

Esophageal cancer with very hot tea

Linked to five times the esophageal cancer risk when burning-hot tea was combined with 15 g or more of alcohol a day, in one large Chinese cohort.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Against people drinking tea less than weekly and under 15 g of alcohol a day, those drinking burning-hot tea with 15 g or more of alcohol daily had higher esophageal cancer risk (HR 5.00, 95% CI 3.64 to 6.88). Current smokers who drank burning-hot tea daily had HR 2.03 (95% CI 1.55 to 2.67) [11]. In the Cochrane review, cohort studies found higher esophageal cancer risk with more green tea, while case-control studies did not [9].
Population
456,155 Chinese adults aged 30 to 79 followed a median 9.2 years [11].
Sources
[11], [9]
Caveats
Observational, with tea temperature self-reported once. The cohort abstract does not say which type of tea people drank [11].
LimitedHow often is not known

Interaction with nadolol

One small study found 700 mL a day of brewed green tea cut blood levels of the beta-blocker nadolol by about 85% and weakened its effect on blood pressure.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
After 14 days of green tea, peak nadolol levels fell 85.3% and total exposure 85.0% against water, and nadolol's lowering of systolic pressure was reduced [10].
Population
10 healthy volunteers [10].
Sources
[10]
Caveats
One small study of a single drug. The green tea extract page reports the same study.
LimitedHow often is not known

Interaction with warfarin

Case reports: a man on warfarin drinking half to one gallon of green tea a day saw his INR fall from 3.79 to 1.14, rising again when he stopped.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
INR fell to 1.37 about a week after he began drinking large amounts of green tea, and to 1.14 a month later. After stopping, it rose to 2.55. The authors attribute this to vitamin K in green tea [12].
Population
One 44-year-old man with a mechanical heart valve [12].
Sources
[12]
Caveats
A single case at very high intake.

Claims tested and not found

  1. That green tea lowers cancer death. In a Cochrane review, cancer death did not differ between the highest and lowest intake (RR 0.99) [9].
  2. That drinking green tea lowers LDL cholesterol. In 8 trials of catechin-enriched green tea drinks, LDL did not fall significantly [4].

Related

Green tea extractCaffeine

Sources

  1. US Food and Drug Administration. Letter Responding to Health Claim Petition dated January 27, 2004: Green Tea and Reduced Risk of Cancer Health Claim. FDA Qualified Health Claims, Letters of Enforcement Discretion. 2011. http://wayback.archive-it.org/7993/20171114183649/https://www.fda.gov/Food/IngredientsPackagingLabeling/LabelingNutrition/ucm072774.htm
  2. Abe SK, Saito E, Sawada N, et al. Green tea consumption and mortality in Japanese men and women: a pooled analysis of eight population-based cohort studies in Japan. European Journal of Epidemiology. 2019. https://doi.org/10.1007/s10654-019-00545-y
  3. Pang J, Zhang Z, Zheng TZ, et al. Green tea consumption and risk of cardiovascular and ischemic related diseases: A meta-analysis. International Journal of Cardiology. 2016. https://doi.org/10.1016/j.ijcard.2014.12.176
  4. Xu R, Yang K, Li S, et al. Effect of green tea consumption on blood lipids: a systematic review and meta-analysis of randomized controlled trials. Nutrition Journal. 2020. https://doi.org/10.1186/s12937-020-00557-5
  5. Peng X, Zhou R, Wang B, et al. Effect of green tea consumption on blood pressure: a meta-analysis of 13 randomized controlled trials. Scientific Reports. 2014. https://doi.org/10.1038/srep06251
  6. Iso H, Date C, Wakai K, et al. The relationship between green tea and total caffeine intake and risk for self-reported type 2 diabetes among Japanese adults. Annals of Internal Medicine. 2006. https://doi.org/10.7326/0003-4819-144-8-200604180-00005
  7. Liu K, Zhou R, Wang B, et al. Effect of green tea on glucose control and insulin sensitivity: a meta-analysis of 17 randomized controlled trials. The American Journal of Clinical Nutrition. 2013. https://doi.org/10.3945/ajcn.112.052746
  8. Nagao T, Meguro S, Hase T, et al. A catechin-rich beverage improves obesity and blood glucose control in patients with type 2 diabetes. Obesity. 2009. https://doi.org/10.1038/oby.2008.505
  9. Filippini T, Malavolti M, Borrelli F, et al. Green tea (Camellia sinensis) for the prevention of cancer. Cochrane Database of Systematic Reviews. 2020. https://doi.org/10.1002/14651858.cd005004.pub3
  10. Misaka S, Yatabe J, Müller F, et al. Green tea ingestion greatly reduces plasma concentrations of nadolol in healthy subjects. Clinical Pharmacology and Therapeutics. 2014. https://doi.org/10.1038/clpt.2013.241
  11. Yu C, Tang H, Guo Y, et al. Hot Tea Consumption and Its Interactions With Alcohol and Tobacco Use on the Risk for Esophageal Cancer: A Population-Based Cohort Study. Annals of Internal Medicine. 2018. https://doi.org/10.7326/m17-2000
  12. Taylor JR, Wilt VM. Probable antagonism of warfarin by green tea. The Annals of Pharmacotherapy. 1999. https://doi.org/10.1345/aph.18238

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