Matcha and Green Tea as Drinks

Camellia sinensis (L.) Kuntze · also called Green tea, powdered green tea, matcha

Matcha and green tea are drinks made from the leaf of the tea plant. Matcha is the whole leaf ground to a powder. Large studies link tea drinking with fewer deaths, but these cannot prove cause, and trials on blood pressure, cholesterol and weight are mixed or small. The main cautions are caffeine, pregnancy, some medicines, and liver injury from concentrated extract capsules, which is a different product from the drink.

General information, not medical advice. Last substantive update October 26, 2026 · Not medically reviewed. A named clinician has not signed off on this page. How this page is made

About Matcha and Green Tea as Drinks

Matcha and green tea are drinks made from the leaf of Camellia sinensis. Brewed green tea is a steeped leaf; matcha is the whole leaf in powder form. Both contain caffeine. The drink is not a proven remedy, and green tea extract capsules are a different product with liver cautions.

What it is

Green, black and oolong teas all come from Camellia sinensis, but are prepared differently. For green tea, NCCIH says the leaves are steamed, pan fried and dried but not fermented. Matcha is a powdered green tea from plants shaded as they grow, which raises theanine, caffeine, chlorophyll and catechins.

USDA lists brewed green tea (per 100 g) at 1 kcal, 0.22 g protein, no fat, no carbohydrate, no sugar, 12 mg caffeine, 8 mg potassium and 0.184 mg manganese. One cup (245 g) is about 2 kcal and about 29 mg of caffeine by our arithmetic. FDA lists a higher figure, 37 mg in a 12-fluid-ounce cup. No USDA item for matcha powder was found, so matcha nutrition is not given.

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The drink is not the extract

NCCIH says no safety concerns have been reported for green tea consumed as a beverage by adults, but that liver injury, although uncommon, has been reported with green tea products, mainly extracts in tablets or capsules. The liver cases in the sources are mainly capsules. Results for the drink do not carry over to an extract, and the reverse is also true.

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What the research shows

In 38 cohorts, the most tea drinkers had fewer deaths from any cause (0.90) and from heart and blood vessel disease (0.86). Cancer deaths showed no clear difference. In Japan, 5 or more cups of green tea a day went with HR 0.90 (men) and 0.82 (women). These are links; tea drinkers differ in other ways.

Trials are mixed. A 2020 pooled analysis of 14 trials found no significant change in blood pressure or cholesterol with green or black tea. Five trials in people with raised blood pressure found a fall of 4.81 mmHg (systolic). A 2011 analysis of drinks and extracts found LDL 2.19 mg/dL lower. A Cochrane review found no meaningful weight loss. Fourteen trials in type 2 diabetes found no blood sugar effect.

For matcha itself, there are small trials: one in 39 adults with a matcha chosen for its ingredient ratio found lower anxiety, and one of 61 older adults found a higher memory score in women only. Fluoride is high in matcha by lab measure; no harm has been shown.

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Drink versus extract

The deaths and heart links are for brewed tea. Several cholesterol and weight results mix drinks and extracts. The liver cautions apply mainly to extracts and capsules. Matcha trials used matcha powder and are small.

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At a glance

Traditional uses history, not proof

Drunk as a daily beverage for a very long time in China and Japan
Matcha is used in Japanese tea ceremony
Long use as a drink is not proof that it treats any condition

Studied for research

Tea drinking and deaths, heart disease: low certainty (observational)
Blood pressure: mixed
Cholesterol: low certainty
Body weight: low certainty, small at most
Blood sugar in type 2 diabetes: low certainty, no clear effect
Stress and focus (matcha): low certainty
Memory: very-low certainty
Cancer: insufficient evidence

Main compounds

Catechins, mainly EGCG
Caffeine
L-theanine
Chlorophyll (more in matcha)
Fluoride

Common forms

Brewed green tea (USDA nutrition read)
Matcha powder whisked into a drink (no USDA figures read)
Green tea extract capsules are a different product and are covered only for safety

Research links: 2024 pooled study: tea and deaths (38 cohorts) · 2012 Cochrane review: green tea and weight · NCCIH: green tea usefulness and safety · Research Library · Genes & Biomarkers Library

What it is and its history

Accepted scientific name: Camellia sinensis (L.) Kuntze
Naming authority: (L.) Kuntze; GBIF accepted name
Common names: Green tea (English); Matcha (Japanese loanword in English); Powdered green tea (English)
Family or group: Theaceae (tea family), per GBIF
Classification: Plantae > Tracheophyta > Magnoliopsida > Ericales > Theaceae > Camellia > Camellia sinensis
Native range: Not verified from a source read here, beyond NCCIH saying the tea plant was first cultivated in China thousands of years ago.
Habitat: Not verified from a source read.
What it looks like: Roots: Not verified.; Stems: Not verified.; Leaves: The leaf is the part used for tea.; Flowers: Not verified.
Cultivation: Matcha comes from tea plants shaded while they grow, which raises theanine, caffeine, chlorophyll and catechins (matcha review abstract).
Harvest and processing: NCCIH says green tea leaves are steamed, pan fried and dried but not fermented; black tea is fermented and oolong partly fermented. Matcha is the leaf ground to a fine powder and drunk with the leaf.
Look-alikes and adulterants: Name: Black tea, oolong tea; Note: Same plant, different processing; see their own pages.; Name: Herbal teas; Note: Made from other plants such as chamomile or peppermint and have their own pages.; Name: Green tea extract capsules; Note: Concentrated catechins; a different product with liver cautions.
Sustainability and conservation: Not assessed.

Photographs

Matcha and green tea leaf close-up — Green tea leaf and powdered matcha.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
		s-nccih-green-tea

Traditional use shows how it was used. It does not show that it works or is safe today.

What is inside, and how it may work

What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.

Main compounds

Compound	Family	Where it is concentrated	Activity studied	Level of evidence
Catechins, mainly EGCG PubChem 65064	polyphenol (catechin)	Leaf EFSA estimates mean EGCG intake from infusions of 90 to 300 mg a day in EU adults. A matcha review calls matcha the best condensed source of the main catechins.	The main compound studied for health and the one linked to liver cautions at high supplement intakes. ^{28 5 14}	Human data
Caffeine PubChem 2519	methylxanthine	Leaf USDA: 12 mg per 100 g brewed green tea. FDA: 37 mg per 12 fluid ounces. No matcha figure read.	Stimulant; works against theanine in the mouse stress experiments. ^{27 30 22 20}	Human data
L-theanine PubChem 439378	amino acid	Leaf (more in shaded leaf) Higher in matcha than other tea per the matcha papers; no figure read.	Thought to be calming; mouse and a small human trial are the evidence. ^{29 20 14}	Animal research
Chlorophyll	pigment	Leaf (more in shaded leaf) Not read.	Raised by shading, per the matcha review. No health finding read. ¹⁴	Lab
Fluoride	mineral	Leaf Matcha infusions 3.36 to 4.03 mg/L; powder 118.39 to 121.65 mg/kg.	Hard-tissue role at low levels; accumulates with long exposure per the authors. ¹⁰	Lab

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Theanine to caffeine ratio and stress	Not specified in the sources read	In mice, the stress-reducing effect of matcha needed a molar ratio of caffeine and EGCG to theanine and arginine of less than two. ²⁰	Animal research
Catechins and body weight	Not specified in the sources read	NCCIH says the catechins and caffeine may have a modest effect on body weight; this was not tested as a mechanism here. ²⁵	Human data
Polyphenols and iron absorption	Not specified	Polyphenol-rich drinks cut iron absorption from a test meal in a 1999 trial. ⁸	Human data

Absorption, metabolism and elimination

Absorption: Not found for the drink in the sources read.
Distribution: Not found.
Metabolism: Not found.
Elimination: Not found.
Bioavailability: Not established in the sources read.

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Isolated compounds versus whole extracts

The deaths and heart disease links are for brewed tea. The cholesterol and weight results mix drinks with extracts. The liver cautions apply mainly to concentrated extracts and capsules, not the drink. Matcha is the whole leaf in a drink, which makes it different from a steeped tea.

Nutritional composition

Source: USDA FoodData Central, SR Legacy item "Beverages, tea, green, brewed, regular" (FDC ID 171917), read 2026-10-26 from USDA data files. Per 100 g: 1 kcal, protein 0.22 g, no fat, no carbohydrate, no sugar, caffeine 12 mg, potassium 8 mg, magnesium 1 mg, sodium 1 mg, manganese 0.184 mg, iron 0.02 mg. One cup is 245 g, which works out to about 2 kcal, about 29 mg of caffeine and about 0.45 mg of manganese (our arithmetic from the per-100 g values). FDA lists a higher figure, 37 mg per 12 fluid ounces; sources differ because tea varies. No USDA SR Legacy item for matcha powder was found, so matcha nutrition is not given. Sweetened bottled and cafe tea drinks are different foods; check the label.

8benefits and uses looked at

30studies and sources checked

Low certaintybest evidence rating found

6lab markers tracked in trials

1 mixed findings5 low certainty1 very low certainty1 not enough evidence

What was looked at

The 8 benefits and uses checked for Matcha and Green Tea as Drinks, each with how strong the evidence is. Tap one to open it.

Living longer and heart disease (tea drinking, observational)Low certainty
Blood pressure (green tea and tea drinks)Mixed findings
Cholesterol (green tea drinks and extracts)Low certainty
Body weight (green tea preparations)Low certainty
Blood sugar in type 2 diabetes (green tea intake)Low certainty
Stress, attention and focus (matcha)Low certainty
Memory and thinking in older adults (matcha trial; green tea observational)Very low certainty
Cancer (population studies)Not enough evidence

Lab markers tracked in the studies

LDL cholesterolSystolic blood pressure (top number)Diastolic blood pressure (bottom number)Body weightFasting blood glucose and HbA1cMontreal Cognitive Assessment (MoCA) score

What is Matcha and Green Tea as Drinks good for?

The main studied uses and how strong the human evidence is for each. Many results are for green tea in general or for extracts, not for matcha.

Living longer and heart disease (tea drinking, observational)Low certaintyIn large cohorts, more tea went with fewer deaths from any cause (0.90) and from heart and blood vessel disease (0.86); cancer deaths showed no clear difference. Green tea at 5 or more cups a day in Japan went with HR 0.90 (men) and 0.82 (women). Links, not proof. Blood pressureMixed findingsOne analysis of 14 trials found no change; another of 5 trials in people with raised pressure found systolic -4.81 mmHg. A newer one, mostly supplements, found about -1 mmHg. Not reliable. CholesterolLow certaintyGreen tea drinks and extracts lowered LDL by 2.19 mg/dL in a 2011 analysis; a 2020 analysis of tea drinks found no significant change. Most trials used extracts. Body weightLow certaintyA Cochrane review found no meaningful weight loss from green tea preparations; any loss was small. Blood sugar in type 2 diabetesLow certaintyFourteen trials of green tea intake found no significant effect on blood sugar measures. Stress and focus (matcha)Low certaintySmall trials of matcha found lower anxiety or better attention under mild stress. The best-known trial used a matcha chosen for its ingredient ratio. Memory in older adultsVery low certaintyOne small matcha trial found a higher memory score in women only; observational studies on dementia are mixed. CancerNot enough evidenceNCCIH calls the overall results inconsistent.

Benefits, one by one

Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.

Living longer and heart disease (tea drinking, observational)

Low certainty

In large groups followed over time, people who drank more tea had fewer deaths from any cause and from heart and blood vessel disease. For cancer deaths the range included no difference. These are links, not proof that tea caused the difference.

3 studiesBrewed tea, mostly green or black. Matcha was not separately studied.

Studies, doses and limits

What the trials found

A 2024 pooled analysis of 38 cohort data sets (1,956,549 people) found highest versus lowest tea intake went with fewer deaths from any cause (0.90) and from heart and blood vessel disease (0.86). For cancer deaths the range crossed 1 (0.90, 0.78 to 1.03). The biggest all-cause drop was at about 2 cups a day, with no more benefit beyond that. In eight Japanese cohorts (313,381 people), green tea at 5 cups or more a day went with 0.90 (men) and 0.82 (women) all-cause death risk compared with under 1 cup.

Results

A modest link with fewer deaths, in people who report drinking tea. Healthy habits of tea drinkers may play a part.

Effect sizes as reported

All tea: all-cause 0.90 (0.86 to 0.95); heart and blood vessel 0.86 (0.79 to 0.94); cancer 0.90 (0.78 to 1.03). Green tea, Japan, 5 or more cups a day: all-cause HR 0.90 men, 0.82 women.

Why this rating

Low because all the data are observational and tea drinking was self-reported. Tea types were not separated in the all-tea analysis, and the green tea cohorts are Japanese only.

Form and dose studied

Brewed tea, mostly green or black. Matcha was not separately studied.

Who was studied

Adults in cohort studies, mainly in Asia and the West (all tea) and Japan (green tea).

Limits

Cannot show cause. Self-reported intake. Other lifestyle differences between tea drinkers and others.

Why researchers looked

Tea is one of the most drunk drinks in the world, so researchers compare drinkers and non-drinkers.

Traditional use

Green tea has been drunk in China and Japan for a very long time. Long use is not proof that it treats anything.

Proposed mechanism Other

Not shown. Authors often point to tea polyphenols, but the studies read are observational and do not test a mechanism.

A proposed mechanism does not show that the effect happens in people.

See the Safety tab for caffeine, pregnancy and medicine cautions.

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Blood pressure (green tea and tea drinks)

Mixed findings

Results are mixed. One pooled analysis of 14 trials of green or black tea found no significant change. Another of five trials in people with raised blood pressure found a fall. A newer analysis, mostly of supplements, found a very small fall.

5 studiesBrewed green or black tea; green tea extracts and capsules in some an…

Studies, doses and limits

What the trials found

In 14 trials (798 people, 4 to 24 weeks), green or black tea did not significantly change blood pressure, but the authors say the trials were too small. In 5 trials of tea as a drink in 408 people with raised blood pressure, systolic fell by 4.81 mmHg and diastolic by 1.98 mmHg; leaving out the most uneven trials gave smaller falls. A Cochrane review of 7 green tea trials (3 months or more) found systolic -3.18 and diastolic -3.42 mmHg, but results changed when trials were left out and forms were mixed. A 2025 analysis of 36 trials of green tea "supplementation" found about -1 mmHg.

Results

Possibly a small fall, strongest in people who start with higher blood pressure. Not reliable enough to count on.

Effect sizes as reported

Raised-pressure trials: systolic -4.81 mmHg (-8.40 to -1.58); diastolic -1.98 (-3.77 to -0.20). Cochrane green tea: systolic -3.18 (-5.25 to -1.11); diastolic -3.42 (-4.54 to -2.30). 36 trials: systolic -1.08; diastolic -1.09.

Why this rating

Mixed because different analyses disagree, trials are small and short, and drinks and extracts are pooled in several of them. The authors of the null analysis rate their evidence low to moderate by GRADE.

Form and dose studied

Brewed green or black tea; green tea extracts and capsules in some analyses. Matcha was not tested for blood pressure.

Who was studied

Healthy adults, adults at risk, and adults with raised blood pressure.

Limits

Short trials, small samples, heavy differences between trials, mixed forms.

Why researchers looked

High blood pressure is a main risk factor for heart disease, and tea polyphenols are thought to help blood vessels.

Traditional use

Not a traditional use. Long use as a drink is not proof of an effect.

Proposed mechanism Other

Not shown. The authors of the 2025 analysis mention blood vessel function and inflammation as ideas, not findings.

A proposed mechanism does not show that the effect happens in people.

If you take blood pressure medicine, NCCIH says high-dose green tea lowered blood levels of nadolol. See the Safety tab.

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Cholesterol (green tea drinks and extracts)

Low certainty

A small fall in total and LDL cholesterol in pooled trials of green tea drinks and extracts, but a later pooled analysis of tea drinks found no significant change. NCCIH notes most trials used extracts, not the drink.

4 studiesDrinks and extracts mixed. Matcha was not tested.

Studies, doses and limits

What the trials found

A 2011 pooled analysis of 14 trials (1,136 people) of green tea drinks or extracts found total cholesterol 7.20 mg/dL lower and LDL 2.19 mg/dL lower, with no change in HDL. The 2020 analysis of 14 trials of green or black tea found no significant effect on total, LDL or HDL cholesterol or triglycerides. The Cochrane review found falls for green tea of about 0.6 mmol/L, but the result was not stable. NCCIH says most trials tested extracts rather than the drink.

Results

If there is an effect of the drink it is small. The evidence mostly comes from extracts.

Effect sizes as reported

2011: total -7.20 mg/dL (-8.19 to -6.21); LDL -2.19 mg/dL (-3.16 to -1.21). Cochrane green tea: total -0.62 mmol/L; LDL -0.64 mmol/L.

Why this rating

Low because the pooled results disagree, most trials used extracts or mixed forms, and the benefits were not stable in sensitivity checks.

Form and dose studied

Drinks and extracts mixed. Matcha was not tested.

Who was studied

Adults, healthy and at risk.

Limits

Mixed forms; short trials; older pooled analyses; later null result.

Why researchers looked

High LDL cholesterol is a heart risk, and green tea catechins were proposed to lower it.

Traditional use

Not a traditional use.

Proposed mechanism Other

Not shown in the sources read.

A proposed mechanism does not show that the effect happens in people.

Extracts carry liver cautions that the drink does not; see the Safety tab. NCCIH says green tea extract can lower blood levels of atorvastatin.

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Body weight (green tea preparations)

Low certainty

A Cochrane review found no meaningful weight loss from green tea preparations. NCCIH says a modest effect is possible and did not separate drink from extract.

2 studiesGreen tea preparations of different kinds. Matcha was not tested.

Studies, doses and limits

What the trials found

In trials outside Japan (six trials, 532 people), the weight difference was -0.04 kg (95% CI -0.5 to 0.4). The eight Japanese trials (1,030 people) ranged from -0.2 kg to -3.5 kg and could not be pooled. The authors concluded any weight loss was small and unlikely to matter. This 2012 review covered green tea preparations of several kinds.

Results

No clear weight loss from the studies of 12 weeks or more outside Japan.

Effect sizes as reported

Outside Japan: weight -0.04 kg (-0.5 to 0.4); BMI -0.2 (-0.5 to 0.1); waist -0.2 cm (-1.4 to 0.9). All not significant.

Why this rating

Low because trials were short, preparations differed, and the Japanese trials could not be pooled. The pooled non-Japan result was null.

Form and dose studied

Green tea preparations of different kinds. Matcha was not tested.

Who was studied

Overweight and obese adults.

Limits

Older review (2012), mixed forms, short trials.

Why researchers looked

Catechins and caffeine in green tea are thought to raise energy use.

Traditional use

Not a traditional use.

Proposed mechanism Authoritative guidance

NCCIH says catechins and caffeine may have a modest effect on body weight. The mechanism was not shown in the sources read.

A proposed mechanism does not show that the effect happens in people.

Weight-loss products with green tea extract carry the liver cautions on the Safety tab.

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Blood sugar in type 2 diabetes (green tea intake)

Low certainty

A pooled analysis of 14 trials in people with type 2 diabetes found no significant effect of green tea on blood sugar measures.

1 studiesNot stated in the abstract.

Studies, doses and limits

What the trials found

Fourteen trials of "supplementary" green tea intake found no significant change in fasting glucose, fasting insulin, HbA1c or insulin resistance (HOMA-IR). The abstract does not describe the forms used.

Results

No clear effect.

Effect sizes as reported

No significant effect on any of the four measures.

Why this rating

Low: a null result, with the forms of green tea not described in the abstract.

Who was studied

Adults with type 2 diabetes.

Limits

Forms not described; no figures in the abstract.

Why researchers looked

Catechins have been proposed to affect blood sugar.

Traditional use

Not a traditional use.

Proposed mechanism Other

Not shown in the sources read.

A proposed mechanism does not show that the effect happens in people.

If you take diabetes medicine, ask your pharmacist about tea.

Stress, attention and focus (matcha)

Low certainty

A few small trials of matcha found lower anxiety, or better attention and work output on tests under mild stress, compared with a look-alike matcha or caffeine alone. The trials are small, short and the abstracts give few numbers.

2 studiesMatcha powder as a drink. The chosen matcha is not a typical product.

Studies, doses and limits

What the trials found

In 39 adults, a matcha chosen for its ingredient ratios gave lower anxiety than a placebo matcha. In a trial that compared matcha with caffeine alone under mild lab stress, caffeine improved attention after a single dose; matcha with continued intake improved work output more than caffeine. The abstract gives no numbers or group sizes.

Results

A possible small calming or focus effect for a specially chosen matcha. Not shown for matcha in general.

Effect sizes as reported

Anxiety significantly lower than placebo (size not given in the abstract). No numbers for the caffeine comparison.

Why this rating

Low because the trials are small, short, partly in mice, and the abstracts lack numbers. The best-known trial used a matcha chosen for its ingredient ratio.

Form and dose studied

Matcha powder as a drink. The chosen matcha is not a typical product.

Who was studied

Healthy adults.

Limits

Few participants; mild laboratory stress; funding not stated in the abstracts.

Why researchers looked

Matcha has a lot of theanine as well as caffeine, and theanine is thought to be calming.

Traditional use

Matcha has long been drunk in Japan, including in tea ceremony. Long use is not proof that it treats anything.

Proposed mechanism Animal research

In mice, the stress effect needed a low ratio of caffeine and EGCG to theanine and arginine. This is an animal finding.

A proposed mechanism does not show that the effect happens in people.

Matcha has caffeine; see the Safety tab.

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Memory and thinking in older adults (matcha trial; green tea observational)

Very low certainty

One small trial of matcha powder in older adults found a higher memory test score in women only. A review of observational studies found mixed results on green tea and dementia.

2 studiesMatcha powder in the trial; brewed green tea in the observational stu…

Studies, doses and limits

What the trials found

In a 12-week trial of 61 older adults, matcha powder (3 g a day) versus placebo gave a higher MoCA score in women in a sex-split analysis; the abstract reports no overall effect. In a review of 3 cohort and 5 cross-sectional studies, four supported a benefit, two partly, and two found no link.

Results

Not enough to say matcha or green tea protects memory.

Effect sizes as reported

No numbers in the abstracts.

Why this rating

Very low because the trial is small and the finding came from a sex-split analysis, and the review is observational with mixed results.

Form and dose studied

Matcha powder in the trial; brewed green tea in the observational studies.

Who was studied

Older adults in Japan.

Limits

Small, single-country trial; observational review; no cause shown.

Why researchers looked

Green tea compounds were proposed to protect the brain, and observational studies hinted at a link.

Traditional use

Not a traditional use.

Proposed mechanism Other

Not shown in the sources read.

A proposed mechanism does not show that the effect happens in people.

Matcha contains vitamin K; see the warfarin note on the Safety tab.

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Cancer (population studies)

Not enough evidence

NCCIH calls the overall results of cancer studies on green tea inconsistent. The 2024 pooled analysis of tea and cancer deaths included no difference.

3 studiesBrewed tea in population studies.

Studies, doses and limits

What the trials found

NCCIH says many studies looked at green tea and cancer risk, with inconsistent results. In the 2024 pooled analysis, cancer deaths were 0.90 (0.78 to 1.03) for highest versus lowest tea intake, a range that includes no difference. In eight Japanese cohorts, moderate green tea went with fewer cancer deaths in women only.

Results

No clear effect either way.

Effect sizes as reported

Cancer deaths, all tea: 0.90 (0.78 to 1.03).

Why this rating

Insufficient because NCCIH calls the results inconsistent and the pooled range includes no difference.

Form and dose studied

Brewed tea in population studies.

Who was studied

Adults in cohorts.

Limits

Observational; many cancer types lumped.

Why researchers looked

Catechins have shown activity in the lab, which led to many population studies.

Traditional use

Not a traditional use.

Proposed mechanism Other

Not assessed here.

A proposed mechanism does not show that the effect happens in people.

None specific for the drink.

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Connections to the rest of health

How Matcha and Green Tea as Drinks connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.

Explore every connection: goals, body systems, organs, symptoms, genes

Kind of connection Connected to Search

A. Wellness goals

Connected to	Evidence status	Context	Studies
Heart Health	Low certainty	Living longer and heart disease (tea drinking, observational): In large groups followed over time, people who drank more tea had fewer deaths from any cause and from heart and blood vessel disease. For cancer deaths the range included no difference. These are links, not proof that tea caused the difference.	^{13 1 25}
Healthy Aging	Low certainty	Living longer and heart disease (tea drinking, observational): In large groups followed over time, people who drank more tea had fewer deaths from any cause and from heart and blood vessel disease. For cancer deaths the range included no difference. These are links, not proof that tea caused the difference.	^{13 1 25}
Blood Pressure Support	Mixed findings	Blood pressure (green tea and tea drinks): Results are mixed. One pooled analysis of 14 trials of green or black tea found no significant change. Another of five trials in people with raised blood pressure found a fall. A newer analysis, mostly of supplements, found a very small fall.	^{9 15 6 17 25}
Heart Health	Mixed findings	Blood pressure (green tea and tea drinks): Results are mixed. One pooled analysis of 14 trials of green or black tea found no significant change. Another of five trials in people with raised blood pressure found a fall. A newer analysis, mostly of supplements, found a very small fall. Cholesterol (green tea drinks and extracts): A small fall in total and LDL cholesterol in pooled trials of green tea drinks and extracts, but a later pooled analysis of tea drinks found no significant change. NCCIH notes most trials used extracts, not the drink.	^{9 15 6 17 25 21}
Cholesterol Balance	Low certainty	Cholesterol (green tea drinks and extracts): A small fall in total and LDL cholesterol in pooled trials of green tea drinks and extracts, but a later pooled analysis of tea drinks found no significant change. NCCIH notes most trials used extracts, not the drink.	^{21 9 6 25}
Weight Management	Low certainty	Body weight (green tea preparations): A Cochrane review found no meaningful weight loss from green tea preparations. NCCIH says a modest effect is possible and did not separate drink from extract.	^{11 25}
Metabolic Health	Low certainty	Body weight (green tea preparations): A Cochrane review found no meaningful weight loss from green tea preparations. NCCIH says a modest effect is possible and did not separate drink from extract.	^{11 25}
Blood Sugar Balance	Low certainty	Blood sugar in type 2 diabetes (green tea intake): A pooled analysis of 14 trials in people with type 2 diabetes found no significant effect of green tea on blood sugar measures.	³
Metabolic Health	Low certainty	Blood sugar in type 2 diabetes (green tea intake): A pooled analysis of 14 trials in people with type 2 diabetes found no significant effect of green tea on blood sugar measures.	³
Stress Reduction	Low certainty	Stress, attention and focus (matcha): A few small trials of matcha found lower anxiety, or better attention and work output on tests under mild stress, compared with a look-alike matcha or caffeine alone. The trials are small, short and the abstracts give few numbers.	^{20 4}
Better Focus	Low certainty	Stress, attention and focus (matcha): A few small trials of matcha found lower anxiety, or better attention and work output on tests under mild stress, compared with a look-alike matcha or caffeine alone. The trials are small, short and the abstracts give few numbers.	^{20 4}
Memory Support	Very low certainty	Memory and thinking in older adults (matcha trial; green tea observational): One small trial of matcha powder in older adults found a higher memory test score in women only. A review of observational studies found mixed results on green tea and dementia.	^{18 12}
Brain Health	Very low certainty	Memory and thinking in older adults (matcha trial; green tea observational): One small trial of matcha powder in older adults found a higher memory test score in women only. A review of observational studies found mixed results on green tea and dementia.	^{18 12}
Preventive Wellness	Not enough evidence	Cancer (population studies): NCCIH calls the overall results of cancer studies on green tea inconsistent. The 2024 pooled analysis of tea and cancer deaths included no difference.	^{25 13 1}

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Cardiovascular System	Biological association	Low certainty	Studied for: Living longer and heart disease (tea drinking, observational) Studied for: Blood pressure (green tea and tea drinks)	^{13 1 25 9 15 6 17 21}
Metabolism Weight	Biological association	Low certainty	Studied for: Body weight (green tea preparations)	^{11 25}
Endocrine System	Biological association	Low certainty	Studied for: Blood sugar in type 2 diabetes (green tea intake)	³
Nervous System	Biological association	Low certainty	Studied for: Stress, attention and focus (matcha) Studied for: Memory and thinking in older adults (matcha trial; green tea observational)	^{20 4 18 12}
Stress Mood	Biological association	Low certainty	Studied for: Stress, attention and focus (matcha)	^{20 4}
Immune System	Biological association	Not enough evidence	Studied for: Cancer (population studies)	^{25 13 1}

C. Body parts and organs

Connected to	Kind of connection	Evidence status	Context	Studies
Liver	Adverse effect or risk	Uncommon reports, mainly extracts	NCCIH and EFSA report liver injury with green tea products, mainly concentrated extracts. Liver injury has been reported with green tea products, mainly concentrated extract capsules; the drink is not the main concern. Preparation or compound: Green tea extracts and capsules (not the drink)	^{25 5}

E. Health conditions

Connected to	Kind of connection	Evidence status	Context	Studies
High blood pressure		Mixed findings	Small falls in some trials, none in others; not a treatment. Preparation or compound: Green or black tea as a drink	^{15 9}

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
LDL cholesterol	Biological association	Low certainty	Measured in trials: lowered a little in some analyses, no significant change in another. A lab change is not the same as a health benefit.	^{21 9}
Systolic blood pressure (top number)	Biological association	Mixed findings	Measured in trials: lowered a little in some analyses, no significant change in another. A lab change is not the same as a health benefit.	^{15 9 17}
Diastolic blood pressure (bottom number)	Biological association	Mixed findings	Measured in trials: lowered a little in some analyses, no significant change in another. A lab change is not the same as a health benefit.	^{15 9}
Body weight	Biological association	Low certainty	Measured in trials: no significant change outside Japan. A lab change is not the same as a health benefit.	¹¹
Fasting blood glucose and HbA1c	Biological association	Low certainty	Measured in trials: no significant change. A lab change is not the same as a health benefit.	³
Montreal Cognitive Assessment (MoCA) score	Biological association	Very low certainty	Measured in trials: higher in women in the matcha group in a sex-split analysis. A lab change is not the same as a health benefit.	¹⁸

K. Biological pathways

Connected to	Kind of connection	Evidence status	Context	Studies
Caffeine	Preliminary mechanism	Human	Present in green tea and matcha; see the Safety tab.	^{30 22}

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Catechins, mainly EGCG	Biological association	Human	The main compound studied for health and the one linked to liver cautions at high supplement intakes. Preparation or compound: Leaf	^{28 5 14}
Caffeine	Biological association	Human	Stimulant; works against theanine in the mouse stress experiments. Preparation or compound: Leaf	^{27 30 22 20}
L-theanine	Biological association	Animal	Thought to be calming; mouse and a small human trial are the evidence. Preparation or compound: Leaf (more in shaded leaf)	^{29 20 14}
Chlorophyll	Biological association	Lab	Raised by shading, per the matcha review. No health finding read. Preparation or compound: Leaf (more in shaded leaf)	¹⁴
Fluoride	Biological association	Lab	Hard-tissue role at low levels; accumulates with long exposure per the authors. Preparation or compound: Leaf	¹⁰

Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 26, 2026).

Evidence at a glance: what the research found for 8 outcomes

5Low certainty

1Very low certainty

1Mixed findings

1Not enough evidence

Each outcome below is one thing researchers measured. Certainty is how far the evidence can be trusted, not how well it works. The full studies are on the next tab.

Living longer and heart disease (tea drinking, observational) 3 studies Low certainty Blood pressure (green tea and tea drinks) 5 studies Mixed findings Cholesterol (green tea drinks and extracts) 4 studies Low certainty Body weight (green tea preparations) 2 studies Low certainty Blood sugar in type 2 diabetes (green tea intake) 1 study Low certainty Stress, attention and focus (matcha) 2 studies Low certainty Memory and thinking in older adults (matcha trial; green tea observational) 2 studies Very low certainty Cancer (population studies) 3 studies Not enough evidence

The evidence

The research centre for Matcha and Green Tea as Drinks. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.

Evidence by outcome

Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).

How we rate evidence

High certainty

Several well-run trials or reviews agree; further research is unlikely to change the picture much.

Moderate certainty

Good trials point the same way, but some doubt remains.

Low certainty

Small, short or inconsistent trials. The finding could change with better research.

Very low certainty

Very little or very weak human data. Treat as a possibility only.

Mixed findings

Trials or reviews disagree with each other.

Not enough evidence

Not enough human research to say either way.

Evidence against

Good research found no benefit, or found harm.

We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We started from our older page on this drink, re-read every PubMed abstract (summary and abstract) and the NCCIH, FDA, NHS and IARC pages, and took nutrition from USDA FoodData Central. Only abstracts were read for studies. Items we could not verify are flagged in the research gaps.

Study library: every study we checked 30

Design Research type Year from Search

Study	Design	People	Product, dose, length	Result
Abe 2019 Green tea consumption and mortality in Japanese men and women: a pooled analysis of eight population-based cohort studies in Japan. Eur J Epidemiol · PMID 31392470 · DOI	Cohort pooled	313381 Adults in eight Japanese population-based cohorts, mean follow-up 17.3 years, 52,943 deaths	Green tea drinking from self-report at the start of each study Brewed green tea as drunk Mean 17.3 years of follow-up · vs Fewer than 1 cup a day	The highest green tea group went with fewer deaths from any cause, heart disease and stroke. Among women moderate drinking also went with fewer cancer deaths. Highest group (5 or more cups a day) versus under 1 cup: all-cause HR 0.90 in men and 0.82 in women; heart disease HR 0.82 men, 0.75 women; stroke-type (cerebrovascular) HR 0.76 men, 0.78 women. (All-cause 0.87 to 0.94 men, 0.74 to 0.90 women; heart disease 0.75 to 0.90 men, 0.68 to 0.84 women) Methods, limits and funding Outcomes: Deaths from any cause and from specific causes Limitations: Observational, in Japan only. Tea drinking was reported once at the start. Other habits of tea drinkers may explain part of the link. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Abiri 2023 Tea's anti-obesity properties, cardiometabolic health-promoting potentials, bioactive compounds, and adverse effects: A review focusing on white and green teas. Food Sci Nutr · PMID 37823174 · DOI	Narrative review n/a	Review of white and green tea research	Not applicable Green and white tea drinks and extracts	The review mentions possible toxic effects and suggests reducing tea during the last trimester of pregnancy. Gut effects are described as new evidence. No numbers in the abstract. (Not applicable) Methods, limits and funding Outcomes: Health effects, adverse effects, pregnancy Limitations: A narrative review. The abstract does not say which studies lie behind the pregnancy suggestion. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Asbaghi 2021 Effect of green tea on glycemic control in patients with type 2 diabetes mellitus: A systematic review and meta-analysis. Diabetes Metab Syndr · PMID 33285391 · DOI	Systematic review meta analysis	14 randomised trials in adults with type 2 diabetes	Supplementary green tea intake (forms not described in the abstract) · vs Control	No significant effect on any of the blood sugar measures. No significant effect on fasting glucose, fasting insulin, HbA1c or HOMA-IR. (Not stated in the abstract) Methods, limits and funding Outcomes: Fasting blood glucose, fasting insulin, HbA1c, insulin resistance (HOMA-IR) Limitations: Forms of green tea were not described in the abstract; the word "supplementary" suggests extracts or capsules were included. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Baba 2021 Effects of Daily Matcha and Caffeine Intake on Mild Acute Psychological Stress-Related Cognitive Function in Middle-Aged and Older Adults: A Randomized Placebo-Controlled Study. Nutrients · PMID 34067795 · DOI	Randomized trial	Adults under mild induced stress (Japan)	Matcha versus caffeine alone Powdered green tea (matcha) Single dose and continued intake compared · vs Caffeine	Caffeine alone improved attention. The quicker reaction after one matcha dose was likely caused by its caffeine. After continued intake, the matcha group did more work on the test than the caffeine group did. Narrative result only in the abstract: matcha with caffeine improved attention and work performance more than caffeine alone. (Not stated in the abstract) Methods, limits and funding Outcomes: Attention and work output on stress tests Limitations: The abstract gives no numbers or group sizes. Mild laboratory stress, not daily life. Registered as UMIN000036578. Funding and conflicts: Funding is not stated in the abstract. Registration: UMIN000036578 Read: abstract
EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) 2018 Scientific opinion on the safety of green tea catechins. EFSA J · PMID 32625874 · DOI	Regulatory opinion n/a	EU adult population	Green tea catechins from infusions, reconstituted drinks and food supplements	Traditional green tea infusions at usual European intakes are considered safe. Rare liver injury has been reported after infusions, most likely an unusual personal reaction. In trials, supplements giving 800 mg EGCG a day or more raised liver enzymes. Mean EGCG intake from infusions 90 to 300 mg a day; high drinkers up to 866 mg a day; supplements 5 to 1,000 mg a day. (Not applicable) Methods, limits and funding Outcomes: Safety of green tea catechins, liver effects Limitations: Read through the PubMed abstract (the EFSA site was not opened). Covers catechins from all green tea products, not matcha specifically. Funding and conflicts: An EFSA scientific panel opinion. Read: abstract
Hartley 2013 Green and black tea for the primary prevention of cardiovascular disease. Cochrane Database Syst Rev · PMID 23780706 · DOI	Cochrane systematic review	821 11 randomised trials of 3 months or longer in healthy adults or adults at high risk of heart and blood vessel disease; 7 trials tested green tea	Green tea (and, in separate analyses, black tea), as drinks or extracts Tea drinks and tea extracts (forms differed between trials) Differed between trials 3 months or longer · vs No treatment, placebo or minimal treatment	No trial reported heart and blood vessel events. Green tea lowered total and LDL cholesterol and blood pressure, but few trials fed each result and the results were not stable when trials were left out. The reviewers advise caution. Green tea: total cholesterol -0.62 mmol/L, LDL -0.64 mmol/L, systolic -3.18 mmHg, diastolic -3.42 mmHg. (Total cholesterol -0.77 to -0.46; LDL -0.77 to -0.52; systolic -5.25 to -1.11; diastolic -4.54 to -2.30) Methods, limits and funding Outcomes: Heart events, cholesterol, blood pressure Limitations: Few trials per result, risk of bias, results not stable on sensitivity checks. Drinks and extracts were mixed. Published 2013. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Hu 2018 The safety of green tea and green tea extract consumption in adults - Results of a systematic review. Regul Toxicol Pharmacol · PMID 29580974 · DOI	Systematic review	Toxicology studies and 159 human intervention studies	Green tea as brewed tea, in beverages, in food, and as concentrated preparations Differed between studies Differed between studies	Liver side effects came from concentrated, catechin-rich preparations taken in large single doses. They were not seen with brewed tea, extracts in drinks, or tea in food. No pooled number. Authors derived safe intake levels for EGCG by form. (Not applicable) Methods, limits and funding Outcomes: Liver adverse events with green tea products Limitations: A review by authors in the food and toxicology field. The abstract does not state funding. Case reports of liver injury after drinking infusions exist (see the EFSA opinion). Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Hurrell 1999 Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages. Br J Nutr · PMID 10999016	Clinical trial	Adult volunteers	Polyphenol-containing drinks (black tea, peppermint, camomile, vervain, lime flower, pennyroyal, cocoa, coffee) with a bread meal Beverages; green tea was not tested By total polyphenols per serving Single meals · vs Water	All the tested drinks reduced iron absorption from the meal, more with more polyphenols. Black tea cut it by 79 to 94 percent. Green tea was not in this study. Black tea 79 to 94 percent lower iron absorption; peppermint tea 84 percent; cocoa 71 percent. (Not stated in the abstract) Methods, limits and funding Outcomes: Iron absorption from a meal Limitations: Green tea itself was not tested, so this is an indirect link. Single-meal study from 1999. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Igho-Osagie 2020 Short-Term Tea Consumption Is Not Associated with a Reduction in Blood Lipids or Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Nutr · PMID 33188386 · DOI	Systematic review meta analysis	798 14 randomised trials in healthy adults and at-risk adults (obesity, prediabetes, borderline high cholesterol, metabolic syndrome)	Green tea or black tea drinks Brewed tea or tea in other drink or product forms (not separated in the abstract) 4 to 24 weeks (mean 7.4 weeks) · vs Placebo or control	No significant effect of tea on any of these measures. The authors say many trials were too small to detect a change. No significant effect on systolic or diastolic blood pressure, total, LDL or HDL cholesterol or triglycerides. (Not stated in the abstract) Methods, limits and funding Outcomes: Blood pressure, total, LDL and HDL cholesterol, triglycerides Limitations: Short trials. Low to moderate strength of evidence by GRADE because of small sample sizes and low power. Green and black tea were analysed together. Funding and conflicts: Funding is not stated in the abstract. Registration: PROSPERO CRD42020134513 Read: abstract
Jakubczyk 2022 Fluoride Content of Matcha Tea Depending on Leaf Harvest Time and Brewing Conditions. Nutrients · PMID 35745280 · DOI	Food analysis n/a	Matcha powder of different harvest times and infusions made at 25, 70, 80 and 90 degrees C	Matcha infusions, tested in the laboratory Matcha powder	Matcha infusions held 3.36 to 4.03 mg/L of fluoride, and the dry powder 118 to 122 mg/kg. The authors call this a high fluoride content. Infusions 3.36 to 4.03 mg/L; powder 118.39 to 121.65 mg/kg. (Not applicable) Methods, limits and funding Outcomes: Fluoride content Limitations: A laboratory measurement. It does not show any harm to people, and the abstract sets no limit. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Jurgens 2012 Green tea for weight loss and weight maintenance in overweight or obese adults. Cochrane Database Syst Rev · PMID 23235664 · DOI	Cochrane systematic review	1562 14 randomised trials of 12 weeks or longer in overweight or obese adults (six outside Japan, 532 people; eight in Japan, 1,030 people)	Green tea preparations (drinks, extracts and others) Green tea preparations Differed between trials 12 to 13 weeks · vs Control	Outside Japan, no difference in weight loss. In Japan the results ranged from about no effect to a few kilograms but the trials were too different to pool. The authors judged any weight loss small and unlikely to matter. Outside Japan: weight -0.04 kg; BMI -0.2 kg/m2; waist -0.2 cm, none significant. (Weight -0.5 to 0.4 kg; BMI -0.5 to 0.1; waist -1.4 to 0.9) Methods, limits and funding Outcomes: Body weight, BMI, waist size Limitations: Short trials, preparations differed, and the Japanese trials could not be pooled. Published 2012. Two people in the green tea groups were hospitalised in trials that said it was not linked to the intervention. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Kakutani 2019 Green Tea Intake and Risks for Dementia, Alzheimer's Disease, Mild Cognitive Impairment, and Cognitive Impairment: A Systematic Review. Nutrients · PMID 31137655 · DOI	Systematic review	3 cohort studies and 5 cross-sectional studies on green tea and dementia or thinking problems	Green tea intake from questionnaires Brewed green tea as drunk Varied · vs Lower intake	Four of the eight studies supported a benefit, two partly, and two found no link. The authors say better cohort studies are needed. No pooled number in the abstract. (Not applicable) Methods, limits and funding Outcomes: Dementia, Alzheimer disease, mild cognitive impairment, cognitive impairment Limitations: Mostly cross-sectional or small observational studies. They cannot show cause. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Kim 2024 Tea consumption and risk of all-cause, cardiovascular disease, and cancer mortality: a meta-analysis of thirty-eight prospective cohort data sets. Epidemiol Health · PMID 38938012 · DOI	Systematic review meta analysis	1956549 38 prospective cohort data sets (27 papers), adults	Tea drinking, all types together, from questionnaires Brewed tea as drunk Follow-up varied by cohort · vs Lowest tea intake	Highest versus lowest tea intake went with fewer deaths from any cause and from heart and blood vessel disease. For cancer deaths the range included no difference. The biggest all-cause drop was at about 2 cups a day. All-cause 0.90; heart and blood vessel disease 0.86; cancer 0.90 (pooled effect sizes). At 2.0 cups a day, all-cause 0.91. (All-cause 0.86 to 0.95; heart and blood vessel disease 0.79 to 0.94; cancer 0.78 to 1.03) Methods, limits and funding Outcomes: Deaths from any cause, heart and blood vessel disease, and cancer Limitations: Observational, so it cannot show cause. Tea types were not separated in the abstract. Authors call for better prospective studies. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Kochman 2020 Health Benefits and Chemical Composition of Matcha Green Tea: A Review. Molecules · PMID 33375458 · DOI	Narrative review n/a	Review of matcha research	Not applicable Matcha powder	Describes matcha as a powdered green tea from shaded plants, rich in theanine, caffeine, chlorophyll and catechins, and as the best condensed source of the main catechins. It says regular matcha "may" help physical and mental health, which is a hope, not a finding. No numbers in the abstract. (Not applicable) Methods, limits and funding Outcomes: Matcha composition and reported health effects Limitations: A review of composition and early studies. The composition claim is not proof of health benefit. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Mahdavi-Roshan 2020 The effects of regular consumption of green or black tea beverage on blood pressure in those with elevated blood pressure or hypertension: A systematic review and meta-analysis. Complement Ther Med · PMID 32507441 · DOI	Systematic review meta analysis	408 5 randomised trials in people with raised blood pressure or high blood pressure	Regular green or black tea as a drink Tea beverage Trial length varied; longer than 3 months gave bigger falls · vs Control	Regular tea went with lower blood pressure. When the most uneven trial was left out, the falls were smaller. The green tea trials showed bigger falls than black tea. No side effects were reported in the trials. Systolic -4.81 mmHg (weighted mean difference); diastolic -1.98 mmHg. Without the most heterogeneous trials, about -3.53 and -0.99 mmHg. (Systolic -8.40 to -1.58; diastolic -3.77 to -0.20) Methods, limits and funding Outcomes: Systolic and diastolic blood pressure Limitations: Only five trials, nine measurements. The authors found the trials differed a lot. Green and black tea were mixed in the headline result. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Pillukat 2014 Concentrated green tea extract induces severe acute hepatitis in a 63-year-old woman--a case report with pharmaceutical analysis. J Ethnopharmacol · PMID 24862489 · DOI	Case report	1 A 63-year-old woman	Green tea capsules (very high EGCG, 93.2% EGCG on analysis) Capsule extract Very high, per the case report	Severe hepatitis judged probably linked to the capsules. She recovered after stopping them and after treatment with albumin dialysis. No contaminants were found in the capsules. RUCAM causality: probable. (Not applicable) Methods, limits and funding Outcomes: Severe liver inflammation (hepatitis) Limitations: One case. It involved concentrated capsules, not a drink. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Rezaei 2025 Effect of green tea supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomised controlled trials. Blood Press · PMID 40497293 · DOI	Systematic review meta analysis	36 randomised trials in adults	Green tea "supplementation" compared with control or placebo; the forms are not described in the abstract and a subgroup by milligrams a day suggests capsules or extracts were included Subgroups of 8 weeks or less and longer · vs Control or placebo	A very small average fall in blood pressure, with large differences between trials. The authors call green tea a complementary approach only. Systolic -1.08 mmHg; diastolic -1.09 mmHg (weighted mean differences, random effects). (Systolic -1.98 to -0.18; diastolic -1.67 to -0.50) Methods, limits and funding Outcomes: Systolic and diastolic blood pressure Limitations: High heterogeneity (I2 85% and 74%). Not clear which results are for tea drinks and which for extracts. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Sakurai 2020 Effects of Matcha Green Tea Powder on Cognitive Functions of Community-Dwelling Elderly Individuals. Nutrients · PMID 33256220 · DOI	Randomized trial	61 61 community-dwelling older adults in Japan	Matcha powder in a drink Powdered green tea (matcha) 3 g of powder a day was the trial amount 12 weeks · vs Placebo powder	In an analysis split by sex, women in the matcha group had a higher MoCA score. The abstract reports no overall effect in the whole group. Higher MoCA in women who drank matcha (size not given in the abstract). Vitamin K from the rest of the diet was linked to MoCA change. (Not stated in the abstract) Methods, limits and funding Outcomes: Thinking and memory tests, including the MoCA score Limitations: Small trial. The finding came from a sex-split analysis, which raises the chance of a chance result. Needs repeating. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Taylor 1999 Probable antagonism of warfarin by green tea. Ann Pharmacother · PMID 10332534 · DOI	Case report	1 A 44-year-old man taking warfarin after a mechanical heart valve	Green tea drink, one-half to one gallon a day Brewed tea One-half to one gallon a day (the case) About one week before the low INR	His INR fell from 3.79 to 1.37, then to 1.14. After he stopped the green tea it rose to 2.55. The authors suggest the vitamin K in green tea was the cause. INR 3.79 down to 1.37, then back up to 2.55 after stopping green tea. (Not applicable) Methods, limits and funding Outcomes: INR (blood clotting test) while on warfarin Limitations: One case with a very large amount of tea. Not proof of cause. Does not show what usual amounts do. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Unno 2018 Stress-Reducing Function of Matcha Green Tea in Animal Experiments and Clinical Trials. Nutrients · PMID 30308973 · DOI	Randomized trial plus animal human and mouse	39 39 participants in the human trial; mice in the animal work	Matcha chosen for its mix of ingredients (test matcha) versus a placebo matcha Powdered green tea (matcha) · vs Placebo matcha	Anxiety was lower in the test-matcha group than in the placebo group. In mice, the stress effect needed a low ratio of caffeine and EGCG to theanine and arginine. Not every matcha has that mix. Anxiety significantly lower in the test-matcha group (size not given in the abstract). Mouse effect needed a molar ratio under two. (Not stated in the abstract) Methods, limits and funding Outcomes: Anxiety (human); stress-related adrenal enlargement (mice) Limitations: Small trial. Not every matcha has the tested ratio, so it does not show that matcha in general reduces anxiety. Part of the paper is in mice. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
Zheng 2011 Green tea intake lowers fasting serum total and LDL cholesterol in adults: a meta-analysis of 14 randomized controlled trials. Am J Clin Nutr · PMID 21715508 · DOI	Meta-analysis	1136 14 randomised trials in adults	Green tea drinks or green tea extracts Tea beverages and extracts Differed between trials Differed between trials · vs Control	Green tea drinks or extracts lowered total and LDL cholesterol a little and did not change HDL cholesterol. Total cholesterol -7.20 mg/dL; LDL -2.19 mg/dL; HDL no significant change. (Total -8.19 to -6.21; LDL -3.16 to -1.21) Methods, limits and funding Outcomes: Total, LDL and HDL cholesterol Limitations: Drinks and extracts were pooled, so it does not tell you about the drink alone. Published 2011; later pooled work (2020) found no significant lipid effect. Funding and conflicts: Funding is not stated in the abstract. Read: abstract
s-fda-caffeine FDA: Spilling the Beans: How Much Caffeine Is Too Much? (content current as of 08/28/2024) · Source	Health agency n/a			Methods, limits and funding Read: full-text
s-gbif-camellia-sinensis GBIF Backbone: Camellia sinensis (L.) Kuntze (usageKey 3189635) · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-iarc-hot-drinks IARC (WHO): Press release 244: coffee, mate and very hot beverages (15 June 2016) · Source	Health agency n/a			Methods, limits and funding Read: full-text
s-nccih-green-tea NCCIH (NIH): Green Tea: Usefulness and Safety (last updated February 2025) · Source	Health agency n/a			Methods, limits and funding Read: full-text
s-nhs-pregnancy-foods NHS (UK): Foods to avoid in pregnancy (page last reviewed 15 June 2026) · Source	Health agency n/a			Methods, limits and funding Read: full-text
s-pubchem-caffeine PubChem: Caffeine (CID 2519), C8H10N4O2 · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-pubchem-egcg PubChem: Epigallocatechin Gallate (CID 65064), C22H18O11 · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-pubchem-theanine PubChem: L-Theanine (CID 439378), C7H14N2O3 · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-usda-fdc-171917 USDA FoodData Central (SR Legacy): Beverages, tea, green, brewed, regular (FDC ID 171917) · Source	Reference database n/a			Methods, limits and funding Read: full-text

What we do not know yet

No trial of matcha for blood pressure, cholesterol, weight or blood sugar was found.
No head-to-head health trial of matcha against brewed green tea was found.
Matcha caffeine, heavy metals, lead and pesticides were not found in the sources read.
Children, teens and kidney disease advice for tea was not researched.
The matcha trials are small and their abstracts give few numbers.

How new research is added

New studies are found by a saved PubMed search and placed in a review queue before the page changes.

Lab markers

What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".

Metabolic 2

●

LDL cholesterol

Lowered a little in some analyses, no significant change in another in trials

The 'bad' cholesterol carried in the blood. Higher levels go with higher heart risk.

Low certainty

Results and what it means

Why it was measured

It is the usual blood marker used to test diet effects on heart risk.

Statistical vs. clinical meaning

A small average change at best, and not consistent between analyses.

Safety implication

Extract capsules carry a liver caution; see Safety.

Study	Result	People	Product
²¹	LDL -2.19 mg/dL (95% CI -3.16 to -1.21) with green tea drinks or extracts	14 randomised trials, 1,136 adults	Green tea drinks or extracts
⁹	No significant effect on LDL	14 randomised trials, 798 adults	Green or black tea, 4 to 24 weeks

^{21 9}

●

Body weight

No significant change outside Japan in trials

Weight in kilograms.

Low certainty

Results and what it means

Why it was measured

The main outcome in weight-loss trials.

Statistical vs. clinical meaning

No meaningful weight loss in the pooled trials outside Japan.

Safety implication

Extract products carry a liver caution; see Safety.

Study	Result	People	Product
¹¹	Weight -0.04 kg (95% CI -0.5 to 0.4), not significant	6 trials outside Japan, 532 people	Green tea preparations, 12 to 13 weeks

¹¹

Other 4

●

Systolic blood pressure (top number)

Lowered a little in some analyses, no significant change in another in trials

The pressure in the arteries when the heart beats.

Mixed findings

Results and what it means

Why it was measured

Blood pressure is a standard heart risk marker in tea trials.

Statistical vs. clinical meaning

A fall of a few mmHg at most, strongest where blood pressure starts higher.

Safety implication

None specific for the drink.

Study	Result	People	Product
¹⁵	Systolic -4.81 mmHg (95% CI -8.40 to -1.58)	5 trials, 408 people with raised or high blood pressure	Green or black tea as a drink
⁹	No significant effect	14 trials, 798 adults	Green or black tea, 4 to 24 weeks
¹⁷	Systolic -1.08 mmHg (95% CI -1.98 to -0.18)	36 trials in adults	Green tea supplementation (forms not described)

^{15 9 17}

●

Diastolic blood pressure (bottom number)

Lowered a little in some analyses, no significant change in another in trials

The pressure in the arteries between heartbeats.

Mixed findings

Results and what it means

Why it was measured

Reported alongside systolic pressure in tea trials.

Statistical vs. clinical meaning

Very small falls, if any.

Safety implication

None specific.

Study	Result	People	Product
¹⁵	Diastolic -1.98 mmHg (95% CI -3.77 to -0.20)	5 trials, 408 people with raised or high blood pressure	Green or black tea as a drink
⁹	No significant effect	14 trials, 798 adults	Green or black tea, 4 to 24 weeks

^{15 9}

●

Fasting blood glucose and HbA1c

No significant change in trials

Blood sugar after fasting, and the average over about three months.

Low certainty

Results and what it means

Why it was measured

Standard measures of blood sugar control in diabetes.

Statistical vs. clinical meaning

No clear effect.

Safety implication

None specific.

Study	Result	People	Product
³	No significant effect on fasting glucose, insulin, HbA1c or HOMA-IR	14 trials in adults with type 2 diabetes	Supplementary green tea (forms not described)

●

Montreal Cognitive Assessment (MoCA) score

Higher in women in the matcha group in a sex-split analysis in trials

A short memory and thinking test used to screen for mild cognitive impairment.

Very low certainty

Results and what it means

Why it was measured

The main thinking-test score in the matcha trial.

Statistical vs. clinical meaning

Small trial and a sex-split finding that needs repeating.

Safety implication

None specific.

Study	Result	People	Product
¹⁸	Higher MoCA in women in the matcha group (size not given in the abstract)	61 older adults, Japan	Matcha powder, 3 g a day, 12 weeks, versus placebo powder

¹⁸

Safety

What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.

Main points to know 4

The drink and the capsules are not the same thing for the liver. NCCIH says no safety concerns have been reported for green tea as a drink in adults, but liver injury, although uncommon, has been reported in some people using green tea products, mainly extracts in tablets or capsules. EFSA found traditional infusions at usual European intakes safe overall, yet noted rare liver injury after infusions, most likely an unusual personal reaction. A 159-study review found liver effects only from concentrated, catechin-rich preparations in large single doses. Authoritative guidance ^{25 5 7}
It contains caffeine. FDA lists green tea at 37 mg of caffeine in a 12-fluid-ounce drink. USDA lists brewed green tea at 12 mg per 100 g. Matcha is described as rich in caffeine in a trial paper, but no caffeine figure for matcha powder was found in the sources read. People who are pregnant, trying to become pregnant or breastfeeding are advised to ask a health care provider about limiting caffeine. Authoritative guidance ^{22 30 20}
Medicine questions. A case report describes a man on warfarin whose INR fell sharply after drinking very large amounts of green tea. NCCIH reports that high-dose green tea lowered blood levels of nadolol, and that green tea extract lowered atorvastatin levels. Ask your prescriber or pharmacist. Case report ^{19 25}
Pregnancy and breastfeeding. NCCIH says caffeine should not exceed moderate levels in pregnancy and that high caffeine can make a breastfed baby fussy and sleep poorly, though babies usually have no problems when the mother has low to moderate caffeine. NHS sets 200 mg of caffeine a day in pregnancy and counts a cup of black or green tea at 75 mg. One 2023 review suggests reducing tea in the last trimester. Ask your midwife or doctor. Authoritative guidance ^{25 26 2}

Side effects 3

Effect	How often	Severity and recovery	Evidence
Caffeine effects such as restlessness or poor sleep in people sensitive to caffeine FDA says sensitivity to caffeine varies a lot between people, and conditions and some medicines can raise sensitivity.	Not given in the sources read.	Usually mild Not described in the sources read.	Authoritative guidance ²²
Liver injury from green tea products, mainly concentrated extracts in tablets or capsules NCCIH says people with a certain immune gene variant seem especially susceptible, and puts it at 5 to 15 percent of Americans. The case report was of concentrated capsules, not a drink.	NCCIH calls it uncommon; no figure given.	Can be severe (one case needed albumin dialysis, then recovered) The case recovered after stopping the capsules and treatment.	Case report ^{25 16 5}
Lower iron absorption from a meal when polyphenol-rich drinks are drunk with it The study tested black tea, herbal teas, cocoa and coffee, not green tea. Green tea is also rich in polyphenols, so this is an indirect link.	Not applicable.	Not graded Applies to the meal; not studied beyond single meals in the paper read.	Controlled trial ⁸

Liver

NCCIH says liver injury has been reported in some people who used green tea products, primarily extracts in tablet or capsule form. The drink itself is not the problem product in these reports. EFSA noted rare cases after infusions, most probably an unusual personal reaction, and found that supplements giving 800 mg EGCG a day or more raised liver enzymes in trials. One published case report describes severe hepatitis with very high-EGCG capsules. ^{25 5 16 7}

How often. NCCIH calls it uncommon; EFSA says rare. No numerical rate was found.

Monitoring. No agency advice on liver tests for drinking the tea was found.

This is a safety connection. It is not evidence that Matcha and Green Tea as Drinks supports liver health.

Medicines and supplements 5

With	Why it matters	Importance	Evidence	What to do
Warfarin prescription	Green tea can be a source of vitamin K, which works against warfarin. Matcha is whole leaf and a trial paper lists vitamin K in matcha.	A 1999 case report: INR fell from 3.79 to 1.37 after one-half to one gallon of green tea a day, and rose to 2.55 once he stopped.	Case report Very low certainty ^{19 18}	If you take warfarin, tell your clinic before changing how much green tea or matcha you drink.
Nadolol (a beta-blocker) prescription	Not described in the source.	NCCIH says green tea at high doses reduced blood levels of nadolol and so its effect.	Authoritative guidance Low certainty ²⁵	Ask your prescriber or pharmacist.
Atorvastatin (a cholesterol medicine) prescription	Not described in the source.	NCCIH says green tea extract can lower atorvastatin blood levels. This is for extract, not the drink.	Authoritative guidance Low certainty ²⁵	Ask your prescriber or pharmacist before using green tea extract.
Raloxifene (an osteoporosis medicine) prescription	Not described in the source.	NCCIH reports that an NCCIH-funded study showed an interaction between green tea and raloxifene.	Authoritative guidance Low certainty ²⁵	Ask your prescriber or pharmacist.
Iron supplements and iron in food nutrient	Polyphenols in drinks bind iron in the gut.	Black tea and herbal teas cut iron absorption from a meal in a 1999 trial. Green tea was not tested.	Controlled trial Low certainty ⁸	If you are low in iron, ask your clinician about tea timing with meals.

Who should check first 2

Situation	Advice	Evidence
Liver disease, or any past liver reaction to a green tea product	Avoid green tea extract and capsules. Ask your clinician about the drink. No agency advice on the drink was found.	Authoritative guidance ²⁵
Pregnancy, trying to become pregnant, or breastfeeding	Ask your health care provider about caffeine. NCCIH says caffeine should not exceed moderate levels in pregnancy; NHS gives a daily caffeine limit and counts a cup of black or green tea at about 75 mg.	Authoritative guidance ^{25 26 22}

Overdose, product quality and regulators

Summary. No toxicity from green tea as a drink was found in the sources read. Toxicology work points to the liver and to concentrated catechin-rich preparations in large single doses.

Animal. A review of laboratory studies named the liver as the target organ, tied to bolus dosing and fasting. Animal results are not a guide to drinking tea.

High dose or long term signals. Supplements giving 800 mg EGCG a day or more raised liver enzymes in trials, per EFSA. A very large daily amount of tea was linked to a warfarin problem in one case.

Overdose response. Not found.

Genotoxicity. Not researched.

Fluoride in matcha was measured in the lab. Heavy metals (lead, cadmium) in matcha and pesticide residues were not found in the sources read.

Fluoride. Matcha infusions held 3.36 to 4.03 mg/L of fluoride and the dry powder 118 to 122 mg/kg; the authors call this high. No harm to people was shown and no limit is given in the abstract. ¹⁰

Very hot drinks. IARC classed drinks above 65 degrees C as probably carcinogenic to humans for oesophageal cancer. It is the temperature, not the tea. ²⁴

Body	Action	Date
US NCCIH (NIH) (United States)	Green Tea: Usefulness and Safety. No safety concerns reported for the drink in adults; liver injury uncommon, mainly with extracts in tablets or capsules; interactions with nadolol, atorvastatin and raloxifene; caffeine moderate in pregnancy. source	2025-02
US FDA (United States)	How Much Caffeine Is Too Much? Green tea 37 mg in 12 fluid ounces; 400 mg a day cited for most adults as an amount not generally associated with negative effects. source	2024-08-28
EFSA (European Union)	Safety of green tea catechins. Traditional infusions generally considered safe at usual intakes; rare liver injury after infusions; 800 mg EGCG a day or more as a supplement raised liver enzymes. source	2018
NHS (United Kingdom)	Foods to avoid in pregnancy: no more than 200 mg of caffeine a day; a cup of black or green tea about 75 mg. source	2026-06-15
IARC (WHO) (International)	Very hot beverages (above 65 degrees C) probably cause oesophageal cancer (Group 2A). source	2016-06-15

When to get medical help

Yellow skin or eyes, dark urine, pale stools, severe tiredness, nausea, or pain in the upper right belly after using green tea products: stop the product and contact a clinician promptly.
Fast or uneven heartbeat, chest pain or severe shaking after caffeine: seek urgent care.
If you take warfarin and notice unusual bruising or bleeding, contact your clinic.

Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.

General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.

Frequently asked questions

What is matcha, and how is it different from green tea?

Both come from the leaf of Camellia sinensis. Matcha is made from plants shaded while they grow and is ground to a fine powder that you drink with the leaf. Shading raises theanine, caffeine, chlorophyll and catechins. Brewed green tea is a steeped leaf, strained out.

^{14 25}

Is matcha healthier than brewed green tea?

Not shown. A review calls matcha the best condensed source of catechins, which is a statement about what is in it, not proof of benefit. No trial comparing matcha with brewed green tea for a health outcome was found.

¹⁴

Does green tea or matcha lower blood pressure?

Results are mixed. One analysis of 14 trials found no change. Another of 5 trials in people with raised blood pressure found a small fall. Matcha was not tested for blood pressure.

^{9 15 17}

Does green tea lower cholesterol?

Maybe a little. A 2011 analysis found LDL 2.19 mg/dL lower with drinks and extracts, but a 2020 analysis of tea drinks found no significant effect. NCCIH says most trials used extracts.

^{21 9 25}

Does green tea help with weight loss?

A Cochrane review found no meaningful weight loss from green tea preparations. NCCIH says catechins and caffeine may have a modest effect and did not separate the drink from extracts.

^{11 25}

Does green tea help with type 2 diabetes?

A pooled analysis of 14 trials found no significant effect on fasting glucose, insulin, HbA1c or insulin resistance. The abstract does not say which forms of green tea were used.

Does matcha help with stress or focus?

Small trials suggest it might. One of 39 adults found lower anxiety with a matcha chosen for its ingredient ratio, and another found better work output than caffeine alone under mild stress. These are small and not proof for matcha in general.

^{20 4}

Do tea drinkers live longer?

In big cohort studies, more tea went with fewer deaths from any cause, and the biggest drop was at about 2 cups a day. These are links, and tea drinkers may differ in other habits.

^{13 1}

Can green tea harm the liver?

NCCIH says no safety concerns have been reported for green tea as a drink in adults, but liver injury, although uncommon, has been reported with green tea products, mainly extracts in capsules. EFSA noted rare cases after infusions too. Capsules are a different product from the drink.

^{25 5 16}

Does matcha or green tea contain caffeine?

Yes. FDA lists green tea at 37 mg of caffeine in a 12-fluid-ounce drink, and USDA lists brewed green tea at 12 mg per 100 g. A trial paper describes matcha as rich in caffeine, but no figure for matcha powder was found in the sources read.

^{22 30 20}

Is green tea safe in pregnancy and while breastfeeding?

NCCIH says caffeine should not exceed moderate levels in pregnancy, and NHS sets a daily caffeine limit and counts a cup of black or green tea at about 75 mg. Ask your midwife or doctor.

^{25 26}

Does green tea interact with medicines?

Possibly. One case report describes a drop in INR on warfarin after very large amounts of green tea. NCCIH reports lower blood levels of nadolol with high-dose green tea, and of atorvastatin with extract. Ask your prescriber or pharmacist.

^{19 25}

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Editorial transparency

Written by: AlternativeMed editorial team. Research compiled with AI assistance, then checked against the sources listed.
Medical review: None. This page has not been reviewed by a physician or pharmacist.
First published: 2026-10-26
Last substantive update: 2026-10-26
How we research: We started from our older page on this drink, re-read every PubMed abstract (summary and abstract) and the NCCIH, FDA, NHS and IARC pages, and took nutrition from USDA FoodData Central. Only abstracts were read for studies. Items we could not verify are flagged in the research gaps.
How we rate evidence: See "How we rate evidence" in the Evidence tab.
Independence: No product is promoted on this page. No affiliate links are shown. Funding is not stated in most of the abstracts read.

Sources 30

Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.

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.. Eur J Epidemiol. 2019. PMID 31392470. DOI 10.1007/s10654-019-00545-y. (abstract)
Abiri B, Amini S, Hejazi M, et al.. Tea's anti-obesity properties, cardiometabolic health-promoting potentials, bioactive compounds, and adverse effects: A review focusing on white and green teas.. Food Sci Nutr. 2023. PMID 37823174. DOI 10.1002/fsn3.3595. (abstract)
Asbaghi O, Fouladvand F, Gonzalez MJ, et al.. Effect of green tea on glycemic control in patients with type 2 diabetes mellitus: A systematic review and meta-analysis.. Diabetes Metab Syndr. 2021. PMID 33285391. DOI 10.1016/j.dsx.2020.11.004. (abstract)
Baba Y, Inagaki S, Nakagawa S, et al.. Effects of Daily Matcha and Caffeine Intake on Mild Acute Psychological Stress-Related Cognitive Function in Middle-Aged and Older Adults: A Randomized Placebo-Controlled Study.. Nutrients. 2021. PMID 34067795. DOI 10.3390/nu13051700. (abstract)
EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), Younes M, Aggett P, et al.. Scientific opinion on the safety of green tea catechins.. EFSA J. 2018. PMID 32625874. DOI 10.2903/j.efsa.2018.5239. (abstract)
Hartley L, Flowers N, Holmes J, et al.. Green and black tea for the primary prevention of cardiovascular disease.. Cochrane Database Syst Rev. 2013. PMID 23780706. DOI 10.1002/14651858.CD009934.pub2. (abstract)
Hu J, Webster D, Cao J, et al.. The safety of green tea and green tea extract consumption in adults - Results of a systematic review.. Regul Toxicol Pharmacol. 2018. PMID 29580974. DOI 10.1016/j.yrtph.2018.03.019. (abstract)
Hurrell RF, Reddy M, Cook JD. Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages.. Br J Nutr. 1999. PMID 10999016. (abstract)
Igho-Osagie E, Cara K, Wang D, et al.. Short-Term Tea Consumption Is Not Associated with a Reduction in Blood Lipids or Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.. J Nutr. 2020. PMID 33188386. DOI 10.1093/jn/nxaa295. (abstract)
Jakubczyk K, Ligenza A, Gutowska I, et al.. Fluoride Content of Matcha Tea Depending on Leaf Harvest Time and Brewing Conditions.. Nutrients. 2022. PMID 35745280. DOI 10.3390/nu14122550. (abstract)
Jurgens TM, Whelan AM, Killian L, et al.. Green tea for weight loss and weight maintenance in overweight or obese adults.. Cochrane Database Syst Rev. 2012. PMID 23235664. DOI 10.1002/14651858.CD008650.pub2. (abstract)
Kakutani S, Watanabe H, Murayama N. Green Tea Intake and Risks for Dementia, Alzheimer's Disease, Mild Cognitive Impairment, and Cognitive Impairment: A Systematic Review.. Nutrients. 2019. PMID 31137655. DOI 10.3390/nu11051165. (abstract)
Kim Y, Je Y. Tea consumption and risk of all-cause, cardiovascular disease, and cancer mortality: a meta-analysis of thirty-eight prospective cohort data sets.. Epidemiol Health. 2024. PMID 38938012. DOI 10.4178/epih.e2024056. (abstract)
Kochman J, Jakubczyk K, Antoniewicz J, et al.. Health Benefits and Chemical Composition of Matcha Green Tea: A Review.. Molecules. 2020. PMID 33375458. DOI 10.3390/molecules26010085. (abstract)
Mahdavi-Roshan M, Salari A, Ghorbani Z, et al.. The effects of regular consumption of green or black tea beverage on blood pressure in those with elevated blood pressure or hypertension: A systematic review and meta-analysis.. Complement Ther Med. 2020. PMID 32507441. DOI 10.1016/j.ctim.2020.102430. (abstract)
Pillukat MH, Bester C, Hensel A, et al.. Concentrated green tea extract induces severe acute hepatitis in a 63-year-old woman--a case report with pharmaceutical analysis.. J Ethnopharmacol. 2014. PMID 24862489. DOI 10.1016/j.jep.2014.05.015. (abstract)
Rezaei M, Akhavan N, Fathi F, et al.. Effect of green tea supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomised controlled trials.. Blood Press. 2025. PMID 40497293. DOI 10.1080/08037051.2025.2517122. (abstract)
Sakurai K, Shen C, Ezaki Y, et al.. Effects of Matcha Green Tea Powder on Cognitive Functions of Community-Dwelling Elderly Individuals.. Nutrients. 2020. PMID 33256220. DOI 10.3390/nu12123639. (abstract)
Taylor JR, Wilt VM. Probable antagonism of warfarin by green tea.. Ann Pharmacother. 1999. PMID 10332534. DOI 10.1345/aph.18238. (abstract)
Unno K, Furushima D, Hamamoto S, et al.. Stress-Reducing Function of Matcha Green Tea in Animal Experiments and Clinical Trials.. Nutrients. 2018. PMID 30308973. DOI 10.3390/nu10101468. (abstract)
Zheng XX, Xu YL, Li SH, et al.. Green tea intake lowers fasting serum total and LDL cholesterol in adults: a meta-analysis of 14 randomized controlled trials.. Am J Clin Nutr. 2011. PMID 21715508. DOI 10.3945/ajcn.110.010926. (abstract)
. FDA: Spilling the Beans: How Much Caffeine Is Too Much? (content current as of 08/28/2024). . . (full-text)
. GBIF Backbone: Camellia sinensis (L.) Kuntze (usageKey 3189635). . . (full-text)
. IARC (WHO): Press release 244: coffee, mate and very hot beverages (15 June 2016). . . (full-text)
. NCCIH (NIH): Green Tea: Usefulness and Safety (last updated February 2025). . . (full-text)
. NHS (UK): Foods to avoid in pregnancy (page last reviewed 15 June 2026). . . (full-text)
. PubChem: Caffeine (CID 2519), C8H10N4O2. . . (full-text)
. PubChem: Epigallocatechin Gallate (CID 65064), C22H18O11. . . (full-text)
. PubChem: L-Theanine (CID 439378), C7H14N2O3. . . (full-text)
. USDA FoodData Central (SR Legacy): Beverages, tea, green, brewed, regular (FDC ID 171917). . . (full-text)

Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.