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Beverages · Teas

Green Tea: Benefits, Caffeine, How Much to Drink & Side Effects

What green tea is, what a cup supplies, what the research shows for longevity, stroke, cholesterol, blood pressure, focus, blood sugar and weight, how much to drink and how to brew it, and who should be careful with extracts.

By Dr. Josh Axe, DC, DNM, CNS·25-min read
Meet the Medical Advisory Board
Evidence-based71 sources citedUpdated October 13, 2026
Published Oct 13, 2026Last updated Oct 13, 2026Editorial policyMedical review policyFact-checking policy
Two clear glass cups of brewed green tea, each holding a fresh tea leaf, beside fresh green leaves on a wooden table
Green tea is brewed from the leaves of the tea plant, Camellia sinensis, steamed or pan-fired soon after picking so they stay green.
The Dr. Axe Score™
7.3/10
Overall Dr. Axe Score · Green Tea

Green tea scores 7.3 for a large body of human research, a rich supply of catechins that strengthened the body's antioxidant defenses in trials, and its place as a daily drink in Dr. Axe's protocols.

Scientific Evidence
8.2/10
Cohort studies of hundreds of thousands of adults and pooled randomized trials on cholesterol, blood pressure, blood sugar and weight.
Antioxidant & Anti-Inflammatory
8.0/10
Rich in catechins led by EGCG; across 38 trials, antioxidant enzymes rose and a marker of oxidative damage fell, while CRP held steady.
Clinical Effectiveness
8.6/10
A daily drink in Dr. Axe's protocols; 2 to 3 cups a day sits in the range linked with the lowest stroke risk, and its caffeine with L-theanine sharpened focus in trials.
Nutrient Density
3.4/10
Rated drink against drink: about 2 calories, 0.45 mg of manganese (20% DV) and 0.14 mg of riboflavin (11% DV) per cup.
Why this score?
Why Green Tea scores 7.3 / 10

    Weighting: Evidence 30% · Antioxidant & Anti-Inflammatory 25% · Clinical Effectiveness 25% · Nutrient Density 20% (8.2×0.30 + 8.0×0.25 + 8.6×0.25 + 3.4×0.20 = 2.46 + 2.00 + 2.15 + 0.68 = 7.29, shown as 7.3). How we score

    A transparent, weighted index built for foods. See how it’s calculated →

    Interaction check: High for nadolol, a beta-blocker, and for lisinopril taken with green tea extract. Moderate for atorvastatin, rosuvastatin, digoxin, fexofenadine, raloxifene, folic acid, celiprolol, nintedanib and sildenafil. The study details are in the box below. Interactions are rated separately and don't change the score.

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    Green tea at a glance

    Green tea is the lightly processed leaf of the tea plant, and it's one of the daily drinks in my Mitochondrial Longevity Protocol, at 2 to 3 cups a day before 2 p.m.1 A cup has about 2 calories and 29.4 milligrams of caffeine, along with catechins such as EGCG and the calming amino acid L-theanine.23

    • Longer life: in 8 Japanese cohort studies of 313,381 adults followed for an average of 17 years, 5 or more cups a day went with a 10% lower risk of death from any cause in men and 18% lower in women, against less than a cup4
    • Stroke: across cohort studies of 645,393 adults, the highest green tea intake was linked with a 26% lower risk of stroke5
    • Cholesterol and blood pressure: in pooled randomized trials, LDL cholesterol fell 4.55 mg/dL and systolic pressure 1.17 points67
    • Calm focus: caffeine and L-theanine together sharpened attention in placebo-controlled studies8
    • Who should be careful: if you take nadolol or lisinopril, or use concentrated extracts, read the safety section first

    Green tea is one of the oldest drinks in the world, and after water, tea is the most widely consumed drink there is.1011

    In Heal Your Cells, Dr. Will Cole and I note that green tea contains one of the highest levels of antioxidants, with polyphenols making up about 30 percent of the leaf's dry weight, led by the catechin EGCG.39 Green tea also brings a modest dose of caffeine together with L-theanine, an amino acid that promotes relaxation without drowsiness and smooths out caffeine's jittery side, the combination we call calm energy.3

    I'm a huge tea fan, and I drink a lot more matcha and green tea than coffee.1213 Cohort studies that followed hundreds of thousands of adults in East Asia link regular green tea with a lower risk of stroke and of dying from heart disease,45 and randomized trials show modest drops in LDL cholesterol, blood pressure and blood sugar.6714

    I drink green tea in the form of matcha many mornings to give me energy before my workouts as well as to energize me throughout the day.Dr. Josh Axe, DC, DNM, CNSFrom The Biblio Diet (2025), ebook p. 113

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    Did you know?

    • L-theanine, the amino acid behind tea's calm energy, is found almost exclusively in tea.3 In a lab analysis of 37 commercial teas, green tea averaged 6.56 milligrams per gram of dry leaf, a little more than white tea (6.26), oolong (6.09) or black tea (5.13).15

    • As tea leaves are oxidized into oolong and then black tea, their catechins join together into larger compounds called theaflavins, so the three teas may act differently in your body.9

    • A green tea's EGCG peaks within minutes of steeping. In a study of one Turkish green tea brewed at 85°C (185°F), EGCG and its close relatives rose over the first 3 to 5 minutes and then declined, and 30- to 45-minute steeps were rated very bitter.16

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    What is green tea?

    Quick answer

    Green tea is made from the leaves of the tea plant, Camellia sinensis, the same plant that gives us oolong and black tea, and its leaves are steamed or pan-fired right after picking, which keeps them green and preserves their natural polyphenols.959 Most of those polyphenols are catechins, and the most abundant is EGCG.9

    That quick heat stops the enzymes that would break down the leaf's color pigments, so the leaves stay green through rolling and drying.9 I list green tea among my herbs for heart and circulation, alongside turmeric, hawthorn and garlic.3

    Green tea vs. matcha

    Matcha is green tea in its most concentrated form: a powder made from whole green tea leaves that you whisk into water and drink, rather than leaves you steep and set aside.3 It's the form of green tea I like best, because its high theanine content pairs the energy and focus of caffeine with a calming effect on the body, and the highest-quality matcha, ceremonial grade, is prized in Japan.3 Our matcha guide covers its nutrition and how to prepare it, and a matcha green tea latte is an easy place to start.

    A short history of green tea

    Tea began in ancient China around 2700 B.C., valued from early on for its healing properties, and trade routes carried it far beyond China over the centuries that followed.11 In Okinawa, a region of Japan associated with longevity, daily green tea is considered essential.17 Our guide to the Okinawa diet covers the rest of that traditional way of eating.

    A leaf steeped for your health brings to mind the close of Ezekiel's vision of trees growing beside a river that flows from the sanctuary: "and the fruit thereof shall be for meat, and the leaf thereof for medicine" (Ezekiel 47:12).18

    Green tea nutrition facts

    Quick answer

    An 8-ounce cup of brewed green tea has about 2 calories, 29.4 milligrams of caffeine, 0.45 milligrams of manganese (20% of the daily value) and 0.14 milligrams of riboflavin (11%).219 Its bigger contribution comes from compounds the USDA record doesn't list: catechins such as EGCG, and L-theanine.2015

    Values from USDA FoodData Central, FDC ID 171917 (brewed green tea, SR Legacy), for an 8-fluid-ounce cup weighing 245 grams; % Daily Value uses FDA label reference values.219

    NutrientOne 8-ounce cup (245 g)Per 100 g
    CaloriesAbout 21
    Protein0.54 g0.22 g
    Fat, carbohydrate and sugar0 g0 g
    Manganese0.45 mg (20% DV)0.184 mg
    Riboflavin (vitamin B2)0.14 mg (11% DV)0.058 mg
    Potassium19.6 mg8 mg
    Magnesium2.45 mg1 mg
    Caffeine29.4 mg12 mg

    Published lab analyses fill in what the USDA record leaves out. Per-cup amounts below are calculated for 8 fluid ounces (237 mL) from the per-liter values.

    CompoundMeasured amountAbout per 8-ounce cup

    EGCG

    117 to 442 mg per liter of commercial green tea infusions20

    28 to 105 mg

    Caffeine

    141 to 338 mg per liter of the same infusions20

    33 to 80 mg

    L-theanine

    6.56 mg per gram of dry leaf, on average15

    Depends on how much leaf you use

    Those ranges are wide because the leaf and the way it's brewed both change what ends up in your cup, which is why the brewing section below matters.2016

    Does green tea have caffeine?

    Yes. USDA lists 29.4 milligrams of caffeine in an 8-ounce cup of brewed green tea.2 The FDA's typical figures for a 12-ounce serving put green tea at about 37 milligrams, black tea at 71 and regular brewed coffee at 113 to 247.21 On my show, I've explained that matcha never bothers me even though it has caffeine, in part because tea also carries theanine, which brings calmness to the body at the same time.13

    What is green tea good for?

    Quick answer

    Green tea is best studied for heart health: in large cohort studies, regular drinkers had a lower risk of stroke, heart disease and early death, and in randomized trials, green tea lowered LDL cholesterol and blood pressure by a few points.5467 Trials also point to calmer focus, slightly lower blood sugar, modest weight loss and stronger antioxidant defenses.8142223

    Where the research stands

    Green tea has a large human research record: cohort studies that followed hundreds of thousands of adults for years, and pooled analyses of dozens of randomized trials.456 Most of the cohort studies come from Japan and other parts of East Asia, where green tea is a daily habit, and they show associations rather than cause and effect.2425 Many of the randomized trials used green tea extracts or catechin-enriched drinks rather than brewed cups, so each result below names the form studied.7 Researchers at companies that sell tea wrote several of the reviews behind the focus, artery and cold-and-flu results.83826

    Green tea benefits, graded by evidence (updated October 2026). Grades compare these uses with each other; they aren't formal certainty ratings.
    UseEvidenceForm studiedWhat the research shows

    Longer life

    		Moderate

    Brewed green tea, cups a day

    Death from any cause 10% lower in men and 18% lower in women at 5 or more cups a day4

    Stroke and heart disease

    		Moderate

    Brewed green tea

    Stroke risk 26% lower at the highest intake; heart disease risk 16% lower at 2 cups (600 mL) a day525

    LDL cholesterol

    		Moderate

    Mostly extracts and catechin-enriched drinks

    LDL down 4.55 mg/dL and total cholesterol down 4.66 mg/dL6

    Blood pressure

    		Moderate

    Brewed tea in 8 trial comparisons; extract capsules in 17

    Systolic pressure down 1.08 to 2.08 points72728

    Calm focus

    		Moderate

    L-theanine and caffeine, taken together

    Sharper attention switching in the 2 hours after a dose829

    Blood sugar

    		Mixed

    Green tea and extracts

    Fasting blood sugar and HbA1c down slightly; no change in trials of people with type 2 diabetes1430

    Brain aging

    		Emerging

    Brewed green tea

    37% lower odds of cognitive impairment in green tea drinkers31

    Weight

    		Mixed

    Mostly extracts and catechin drinks, usually with caffeine

    Weight down 0.44 to 1.78 kg in four pooled analyses, with the clearest results in trials from Japan3233452234

    Antioxidant defenses

    		Moderate

    Green tea supplements

    Antioxidant capacity and enzymes up, a marker of oxidative damage down; CRP unchanged23

    Liver enzymes in fatty liver disease

    		Emerging

    Green tea and catechins

    Liver enzymes down in fatty liver disease; a small rise in healthy people35

    Colds and flu

    		Emerging

    Tea and catechins, drunk or gargled

    26% lower risk of flu and upper respiratory infections26

    Cancer risk

    		Mixed

    Brewed tea in studies of tea drinkers; extracts in trials

    Lower risk for some cancers in studies of tea drinkers; trial results differ by cancer2436

    How does green tea work in your body?

    I describe green tea's catechins as compounds that improve the elasticity of your blood vessels and reduce oxidative stress.3 Here's how researchers think that unfolds, with lab and animal studies behind the early steps and human trials and cohort studies behind the later ones:

    1Catechins move into your cup

    When you steep green tea, its catechins, led by EGCG, move into the water; the nutrition section above shows how much a cup can carry.20

    2EGCG signals the vessel lining

    In rat arteries and in cow blood-vessel cells, EGCG switched on the enzyme that makes nitric oxide, a signal that relaxes blood vessels.37

    3Arteries widen more easily

    In a pooled analysis of 9 placebo-controlled studies of green and black tea, about 2 to 3 cups a day improved flow-mediated dilation, a measure of how well an artery widens, by 2.6 percentage points, a gain of about 40% over the usual reading.38

    4Less cholesterol gets absorbed

    In rats, EGCG lowered the share of dietary cholesterol absorbed from the gut from 79.3% to 62.7%.39

    5Cholesterol and blood pressure come down

    In randomized trials, mostly of extracts, LDL cholesterol and blood pressure fell by a few points; the benefit cards below give the numbers.67

    6Fewer strokes over the years

    In cohort studies, people who drank green tea regularly had fewer strokes and fewer deaths from heart disease.54

    In trials, green tea also strengthened the body's own antioxidant defenses. In a pooled analysis of 38 randomized trials of green tea supplements, total antioxidant capacity rose by 0.09 mmol/L, and the antioxidant enzymes superoxide dismutase and glutathione peroxidase rose by 17.21 and 3.90 units per liter. CRP, IL-6 and TNF-α didn't change, while the inflammatory signal IL-1β dipped slightly and malondialdehyde, a marker of oxidative damage to fats, fell by 0.40 µmol/L.23

    Green tea benefits, ranked by evidence

    Ordered by the strength of the human research, green tea's benefits start with longer life and fewer strokes, followed by cholesterol and blood pressure, with calm focus, blood sugar and brain aging close behind.

    1

    Longer life

    Moderate evidenceHuman study8 pooled cohorts · 313,381 adults; Ohsaki cohort · 40,530 adults

    In a pooled analysis of 8 Japanese cohort studies that followed 313,381 adults for an average of 17.3 years, people who drank 5 or more cups of green tea a day had a 10% lower risk of death from any cause if they were men and 18% lower if they were women than those who drank less than a cup (hazard ratios 0.90 and 0.82). Deaths from heart disease were 18% lower in men and 25% lower in women.4

    The earlier Ohsaki study, which followed 40,530 Japanese adults aged 40 to 79 for up to 11 years, found the link was stronger in women. Women who drank 3 to 4 cups a day had a hazard ratio of 0.82 for death from any cause, and those who drank 5 or more, 0.77, against 1.00 for less than a cup; for men, 5 or more cups came to 0.88. At 1 to 2 cups (0.98 for women and 0.93 for men), and for men at 3 to 4 cups (0.95), the differences weren't statistically significant.40

    Study takeaway: in 313,381 Japanese adults, 5 or more cups of green tea a day went with a 10% lower risk of death from any cause in men and 18% lower in women.

    In 40,530 Japanese adults, more cups of green tea a day went with a lower risk of death

    In 40,530 Japanese adults, more cups of green tea a day went with a lower risk of deathOhsaki cohort, adults aged 40 to 79, followed up to 11 years · hazard ratio for death from any cause vs less than 1 cup a day. Less than 1 cup: Women 1 hazard ratio, death from any cause, Men 1 hazard ratio, death from any cause; 1 to 2 cups: Women 0.98 hazard ratio, death from any cause, Men 0.93 hazard ratio, death from any cause; 3 to 4 cups: Women 0.82 hazard ratio, death from any cause, Men 0.95 hazard ratio, death from any cause; 5 or more cups: Women 0.77 hazard ratio, death from any cause, Men 0.88 hazard ratio, death from any causeOhsaki cohort, adults aged 40 to 79, followed up to 11 years· hazard ratio for death from any cause vs less than 1 cup aday10.980.820.77Women (hazard ratio, death from any cause)10.930.950.88Men (hazard ratio, death from any cause)Less than 1cup1 to 2 cups3 to 4 cups5 or more cups
    Source: Kuriyama et al. · JAMA, 2006 [40]The link was stronger in women. A hazard ratio below 1.00 means a lower risk than in people who drank less than a cup a day.
    2

    Lower risk of stroke and heart disease

    Moderate evidenceHuman study2 pooled analyses of cohort studies · 645,393 and 772,922 adults

    Across 5 cohort studies of 645,393 adults with 11,421 strokes, people who drank the most green tea had a 26% lower risk of stroke than those who drank the least (relative risk 0.74).5 The benefit followed a curve. Compared with people who drank none, risk was 0.91 at 150 mL a day, 0.84 at 300 mL, 0.79 at 500 mL, 0.77 at 900 mL and 0.84 at 1,500 mL, so moderate drinkers did best.5 Two to three 8-ounce cups is about 475 to 710 mL, which overlaps the lowest-risk stretch of that curve.

    For coronary heart disease, 7 East Asian cohort studies of 772,922 adults found the lowest risk at 2 cups a day, with the researchers counting a cup as 300 mL: 16% lower than in people who drank none (relative risk 0.84).25 Our guide to improving heart health covers the rest of the plan.

    Study takeaway: the highest green tea intake went with a 26% lower risk of stroke across 645,393 adults.

    Stroke risk fell as green tea rose to 900 mL a day, then edged back up

    Stroke risk fell as green tea rose to 900 mL a day, then edged back up5 cohort studies · 645,393 adults · 11,421 strokes · relative risk vs people who drank no green tea. 150 mL a day: Green tea drinkers 0.91 relative risk of stroke; 300 mL a day: Green tea drinkers 0.84 relative risk of stroke; 500 mL a day: Green tea drinkers 0.79 relative risk of stroke; 900 mL a day: Green tea drinkers 0.77 relative risk of stroke; 1,500 mL a day: Green tea drinkers 0.84 relative risk of stroke5 cohort studies · 645,393 adults · 11,421 strokes ·relative risk vs people who drank no green tea0.910.840.790.770.84Green tea drinkers (relative risk of stroke)150 mL a day300 mL a day500 mL a day900 mL a day1,500 mL a day
    Source: Wang et al. · Nutrition, 2023 [5]A relative risk below 1 means a lower risk than in people who drank no green tea. Moderate drinkers had the lowest risk.
    3

    Lower LDL cholesterol

    Moderate evidenceHuman studyPooled analyses of 31 and 13 randomized trials · 3,321 adults in the larger

    In a pooled analysis of 31 randomized trials with 3,321 adults, green tea lowered LDL cholesterol by 4.55 mg/dL and total cholesterol by 4.66 mg/dL compared with control. HDL didn't change, and triglycerides fell 3.77 mg/dL, a difference that wasn't statistically significant. Most of the trials used extracts or catechin-enriched drinks rather than brewed cups.6 A second pooled analysis of 13 trials found LDL 0.16 mmol/L lower, about 6 mg/dL.27 EGCG may help in part by limiting how much cholesterol your gut absorbs, as the step diagram above shows. Our guide to lowering cholesterol naturally has the full plan.

    Study takeaway: across 31 randomized trials, green tea lowered LDL cholesterol by 4.55 mg/dL.

    4

    Lower blood pressure

    Moderate evidenceHuman studyPooled analyses of 24, 13 and 36 randomized trials

    In a pooled analysis of 24 randomized trials with 1,697 adults, green tea lowered systolic pressure by 1.17 points and diastolic by 1.24 points over 3 to 16 weeks; 8 of the trial comparisons used brewed green tea and 17 used extract capsules.7 A pooled analysis of 13 trials found larger drops, 2.08 points systolic and 1.71 diastolic, with the biggest effects in people whose systolic pressure started at 130 or higher, and a 2025 analysis of 36 trials found drops of 1.08 and 1.09 points.2728 See more natural ways to lower blood pressure.

    Study takeaway: across 24 randomized trials, green tea lowered systolic pressure by 1.17 points and diastolic by 1.24.

    5

    Calm, focused energy

    Moderate evidenceHuman studyReview of 50 trials (15 pooled) and pooled analysis of 11 placebo-controlled studies; trials of 29 and 35 adults

    Green tea pairs caffeine with L-theanine, and the two work well together. In a pooled analysis of 11 placebo-controlled studies, caffeine with L-theanine improved alertness and the accuracy of switching attention between tasks in the first 2 hours.29 A 2025 review of 50 randomized trials, which pooled the ones that measured each outcome, found the pair improved the accuracy of switching attention in the second hour after a dose, a small-to-moderate effect (effect size 0.33).8 In a placebo-controlled study of 29 adults in which each person tried both, 97 mg of theanine with 40 mg of caffeine improved task switching.418 And in 35 young adults, 50 mg of theanine, an amount its researchers called realistic for the diet, raised alpha brain waves, the pattern of relaxed alertness, more than a placebo did.10

    As I've explained on my show, caffeine works by blocking adenosine, a brain messenger that signals relaxation and sleepiness, and the theanine in tea balances it.13423 For more foods that support focus, see brain foods.

    Study takeaway: caffeine and L-theanine together sharpened attention switching in pooled placebo-controlled studies.

    6

    Steadier blood sugar

    Mixed evidenceHuman studyPooled analyses of 17 and 14 randomized trials

    In a pooled analysis of 17 randomized trials with 1,133 people, green tea and its extracts lowered fasting blood sugar by 0.09 mmol/L (about 1.6 mg/dL) and HbA1c by 0.30%, and in the higher-quality trials, fasting insulin fell too.14 A pooled analysis of 14 trials limited to people with type 2 diabetes found no significant change in fasting blood sugar, insulin or HbA1c.30 In my Healthy Weight & Metabolic Reset protocol, 3 cups of green tea and a tablespoon of vinegar are two daily habits that support blood sugar.43 Our guide to normal blood sugar explains the numbers to watch.

    Study takeaway: across 17 randomized trials, green tea lowered fasting blood sugar and HbA1c slightly.

    7

    Healthier brain aging

    Emerging evidenceHuman studyPooled analysis of 18 studies of tea drinkers · 58,929 people; study of 3,868 adults

    In a 2026 pooled analysis of 18 observational studies with 58,929 people, green tea drinkers had 37% lower odds of cognitive impairment (odds ratio 0.63), including 26% lower odds of dementia and 36% lower odds of mild cognitive impairment; the link was strongest in people aged 50 to 69 and showed up in Asian populations rather than European ones.31 In a Chinese study that measured 3,868 middle-aged and older adults at one point in time, green tea drinkers had lower odds of cognitive impairment (odds ratio 0.36) than drinkers of other teas (0.59), each compared with people who didn't drink tea.44

    Study takeaway: green tea drinkers had 37% lower odds of cognitive impairment in a pooled analysis of 58,929 people.

    Three markers for your heart and metabolic picture

    These markers show where your heart and blood sugar stand and give you a baseline to track as green tea and other food changes become part of your day. They can't tell you whether a food is right for you, so go over your numbers with your practitioner.

    • ApoB: A measure of how many LDL and related cholesterol-carrying particles are in your blood.
    • hs-CRP: Low-grade inflammation anywhere in the body.
    • HbA1c: Your average blood sugar over about three months.

    See the cellular bloodwork panel

    Have results? Analyze them free →

    Does green tea help you lose weight?

    Quick answer

    Yes, modestly: in four pooled analyses of randomized trials, green tea and its catechins lowered body weight by 0.44 to 1.78 kilograms (about 1 to 4 pounds) more than the comparison, with the clearest results in trials from Japan.3233452234 In my Healthy Weight & Metabolic Reset protocol, I describe green tea as a habit that helps modestly, not dramatically, with its catechins and caffeine working together and doing the most when paired with exercise.43

    Green tea's catechins and caffeine work together on weight. In a 2010 pooled analysis of 15 randomized trials with 1,243 people, catechins taken with caffeine lowered body weight by 1.38 kg, BMI by 0.55 and waist size by 1.93 cm compared with caffeine alone, and lowered weight by 0.44 kg compared with a caffeine-free control; catechins taken without caffeine showed no benefit on any measure.32 A cup of brewed green tea delivers both together.220

    A 2009 pooled analysis of 11 studies found catechins lowered weight by 1.31 kg, with larger effects in people who habitually took in less caffeine (1.60 kg, against 0.27 kg in heavy caffeine users) and in Asian participants (1.51 kg, against 0.82 kg in Caucasian participants), though neither difference was statistically significant on its own.45 The newest graded analysis of randomized trials, from 2025, found green tea supplements lowered weight by 0.74 kg, waist size by 1.04 cm and body fat by 0.65 percentage points, along with lower leptin, a hormone that helps regulate appetite and fat stores.22 A 2020 dose-response analysis of randomized trials found 1.78 kg, with the larger weight effect at under 500 mg a day and at 12 weeks.33

    The Cochrane review drew the sharpest line between countries. In 8 trials from Japan with 1,030 people, weight loss ranged from 0.2 to 3.5 kg in favor of green tea, though the trials were too different to pool; in 6 trials outside Japan with 532 people, the pooled difference was 0.04 kg, which wasn't statistically significant.34

    Weight change in pooled trials of green tea: 0.04 to 1.78 kg

    Weight change in pooled trials of green tea: 0.04 to 1.78 kgReviews of randomized trials in adults, mostly green tea extracts or catechin-rich drinks · green tea vs the comparison in each review. Dose-response review of trials (Lin): -1.78 kg weight change vs comparison; Catechins with caffeine vs caffeine alone (Phung): -1.38 kg weight change vs comparison; 11 studies of catechins (Hursel): -1.31 kg weight change vs comparison; Graded review of supplement trials (Dehzad): -0.74 kg weight change vs comparison; Catechins with caffeine vs caffeine-free control (Phung): -0.44 kg weight change vs comparison; 6 trials outside Japan (Cochrane): -0.04 kg weight change vs comparisonReviews of randomized trials in adults, mostly green teaextracts or catechin-rich drinks · green tea vs thecomparison in each reviewDose-responsereview of trials(Lin)-1.78 kg weight change vscomparisonCatechins withcaffeine vscaffeine alone(Phung)-1.38 kg weight change vscomparison11 studies ofcatechins(Hursel)-1.31 kg weight change vscomparisonGraded review ofsupplementtrials (Dehzad)-0.74 kg weight change vscomparisonCatechins withcaffeine vscaffeine-freecontrol (Phung)-0.44 kg weight change vscomparison6 trials outsideJapan (Cochrane)-0.04 kg weight change vscomparison
    Source: Lin et al., Phytotherapy Research 2020 · Phung et al., American Journal of Clinical Nutrition 2010 · Hursel et al., International Journal of Obesity 2009 · Dehzad et al., International Journal of Food Sciences and Nutrition 2025 · Jurgens et al., Cochrane Database of Systematic Reviews 2012 [33, 32, 45, 22, 34]Negative values mean more weight lost than in the comparison group. Japanese trials in the Cochrane review ranged from 0.2 to 3.5 kg in favor of green tea but were too different to pool.

    At 3 cups a day, green tea is one of the top metabolic boosters in my Healthy Weight & Metabolic Reset protocol.43 Our guide to metabolism boosters covers the others.

    Can green tea lower cancer risk?

    Green tea's cancer research is large, and it's best read in two parts: studies of people who drink tea, and trials of concentrated extracts. As I've written, research links regular green tea with a lower risk of chronic diseases, including certain cancers.17 A 2025 review that covered both kinds, 36 cohort studies and 7 randomized trials, linked green tea with a 9% lower overall cancer risk (relative risk 0.91), with the clearest results for prostate, oral, gallbladder and blood cancers.36

    Studies of tea drinkers. Across 18 studies of stomach cancer, risk was 14% lower at the highest intake (0.86, a borderline result), and 32% lower (0.68) in the 6 studies where the heaviest drinkers had 5 or more cups a day more than the lightest.46 The 2020 Cochrane review, which included more than 1.1 million people in 46 cohort and 85 case-control studies, found lower risk at most individual cancer sites but no difference in cancer deaths (0.99), with results that differed between studies.24 In the Ohsaki cohort, cancer deaths weren't lower at any intake, while in the pooled Japanese cohorts, women who drank 1 to 4 cups a day had slightly lower cancer mortality (0.89 to 0.91).404

    Trials of green tea extracts. These four trials gave catechin capsules or extracts rather than brewed tea:

    • Prostate: In a placebo-controlled trial of 60 men with high-grade prostatic intraepithelial neoplasia, a precancerous change, 600 mg of green tea catechins a day for a year was followed by prostate cancer in 1 of 30 men, against 9 of 30 on placebo.47 A placebo-controlled trial of 97 men with similar changes, using a decaffeinated catechin mix with 400 mg of EGCG a day, found 5 cancers in 49 men against 9 in 48, a difference that wasn't statistically significant; among the men who started with only the high-grade changes, a combined count of cancer and atypical cell findings was lower (3 of 26, against 10 of 25).48
    • Colon: In 176 Korean adults who'd had precancerous colon polyps removed (143 finished), 0.9 grams of green tea extract a day for a year cut new polyps to 23.6%, against 42.3% in people who took no supplement (relative risk 0.56). There was no placebo, so people knew which group they were in, and three of the authors worked at a cosmetics company's research center.49
    • Breast: In a placebo-controlled trial of 1,075 postmenopausal women at higher risk of breast cancer (932 finished), an extract with 843 mg of EGCG a day for a year didn't change breast density overall; in women aged 50 to 55, density fell 4.40%, against a 1.02% rise on placebo.50

    If you're in cancer treatment, my Breast Cancer Support Protocol is clear that concentrated green tea extracts, like other high-dose antioxidants, shouldn't be taken during active chemotherapy or radiation unless your oncology team approves.51 Brewed tea is a different exposure from those capsules, and it's the form the studies of tea drinkers describe; our guide to cancer-fighting drinks covers it alongside others.

    How much green tea should you drink a day?

    Quick answer

    I recommend 2 to 3 cups of green tea a day, before 2 p.m., the amount in my Mitochondrial Longevity Protocol.1 If caffeine affects your sleep, keep it to the morning: my Deep Sleep Protocol has green tea before noon only.52

    Your goalDr. Axe's amountProtocol

    Everyday health and energy

    2 to 3 cups, before 2 p.m.

    The Mitochondrial Longevity Protocol1

    Weight and blood sugar

    3 cups a day

    Healthy Weight & Metabolic Reset43

    Better sleep

    Green tea before noon only

    The Deep Sleep Protocol52

    Hormone balance

    1 to 2 cups, before noon

    Hormone Balance for Women53

    In the stroke analysis above, risk was lowest at 500 to 900 mL a day, and an umbrella review of 96 meta-analyses of tea drinking found the largest reductions in death, heart disease, stroke and type 2 diabetes at about 2 to 3 cups a day.554 At 29.4 mg of caffeine a cup, 3 cups add up to about 88 mg, well under the 400 mg a day the FDA cites as not generally associated with negative effects for most adults.221

    On my show, I've encouraged people to listen to their bodies and not lean on caffeine as a crutch, and my wife and I often take a day or two off caffeine each week.55 If you use a green tea extract in place of cups, my Healthy Weight & Metabolic Reset protocol gives 250 to 500 mg of EGCG a day, taken with food; the safety section explains why the food matters.43

    How to brew green tea

    Quick answer

    Steep loose green tea in water heated to about 85°C (185°F), well below boiling, for about 3 minutes; in a study of one Turkish green tea, that combination gave the most EGCG and the best taste scores.16 Then let the cup cool for a few minutes before you sip.

    1. Measure the leaves. The brewing study used 1.6 grams of tea for 110 mL of water, which works out to about 3.5 grams for an 8-ounce cup.16

    2. Heat the water to about 85°C (185°F). Without a thermometer, let just-boiled water cool briefly before you pour.

    3. Steep about 3 minutes, then strain out the leaves.16

    4. Cool. Give the cup a few minutes before drinking: in an umbrella review, tea drunk hotter than 55 to 60°C (131 to 140°F) was linked with esophageal and stomach cancer.54

    When you buy green tea, I recommend certified organic tea or ceremonial-grade matcha, and for loose-leaf green tea, sencha is one of my favorites.12 Buying loose leaf also keeps plastic out of your cup. My advice on my show is to drink lots of tea and buy it loose, or in bags without plastic.56 When researchers steeped one plastic tea bag at brewing temperature, 95°C (203°F), it shed roughly 11.6 billion microplastic particles and 3.1 billion nanoplastic particles into the water.57 Our news story on plastic pieces in tea has the details.

    Drink it hot, or brew it and chill it for iced tea. If you like it sweeter, stir in a little raw local honey or Manuka honey; 1 teaspoon to 1 tablespoon of honey a day is plenty.58 Some bottled green teas are sweetened, so check the label for added sugar. For more ideas, try these ways to spice up your green tea, and see our list of healthy drinks.

    Want help fitting green tea into your day?

    Ask Dr. Axe AI. Answers are grounded in this library, with sources shown.

    Green tea side effects and who should be careful

    Quick answer

    Brewed green tea is safe for most adults at everyday amounts: Europe's food safety agency, EFSA, judged traditionally brewed green tea generally safe.59 The cautions are concentrated extracts and your liver, caffeine and sleep, tea at meals if you're prone to low iron, and a few medicines, nadolol above all.

    The liver concern centers on concentrated extracts. When EFSA reviewed the evidence in 2018, it found that extract doses of 800 mg of EGCG a day or more raised liver enzymes compared with placebo in trials, while it found no evidence of liver injury below 800 mg a day in trials lasting up to 12 months. Brewed tea usually supplies much less: European green tea drinkers average 90 to 300 mg of EGCG a day from their cups. EFSA also concluded that it couldn't identify an EGCG dose from extracts that could be considered safe.59 A U.S. Pharmacopeia review linked case reports of liver injury to EGCG intakes from 140 mg to about 1,000 mg a day and found that susceptibility varies widely between people, possibly for genetic reasons.60

    The clearest trial is the breast density study described in the cancer section above, in which postmenopausal women took an extract with 843 mg of EGCG a day, or a placebo, for a year. Raised ALT, a liver enzyme, showed up in 6.7% of the women on the extract against 0.7% on placebo, and 5.1% of the extract group developed moderate or worse liver abnormalities; ALT returned to normal when the extract was stopped.6162 Timing matters too: taking an extract on an empty stomach raises the amount of EGCG that reaches your blood, which is why the U.S. Pharmacopeia's label for green tea extract says to take it with food.60 My Healthy Weight & Metabolic Reset protocol follows that rule, with 250 to 500 mg of EGCG a day taken with food, below the 800 mg level where EFSA saw liver enzymes rise in trials.4359

    Good to know before you drink green tea or take an extract

    • Liver warning signs: If you take green tea extract and develop abdominal pain, dark urine, or yellowing of your skin or eyes, stop it and see a doctor right away. Skip extracts if you have liver disease.60

    • Nadolol and lisinopril (High): In 10 healthy volunteers who drank 700 mL of brewed green tea a day for 2 weeks, the peak blood level of nadolol, a beta-blocker, fell 85.3% and its effect on blood pressure weakened.63 In a study in which 10 healthy volunteers each tried both and knew which drink they got, an extract drink with about 300 mg of EGCG cut exposure to lisinopril, a blood pressure drug, by about two-thirds.64 If you take either one, review green tea with your prescriber or pharmacist before you drink it regularly, and don't change your medicine on your own.

    • Other medicines (Moderate): In clinical studies, green tea lowered blood levels of atorvastatin, rosuvastatin, digoxin, fexofenadine, raloxifene, folic acid, celiprolol and nintedanib, by 18% to 99% across the analyses that found a change, and raised levels of sildenafil.65 If you take any of these, tell your prescriber how much green tea you drink.

    • Iron: Tea polyphenols can lower how much iron you absorb from plant foods. In a study of 10 young women who each ate both versions of a meal, they absorbed 8.9% of the nonheme iron when green tea extract was added, against 12.1% without it.66 As I've said on my show, “When you drink tea, don't drink it at a meal; drink it between your meals if you're suffering with low iron levels.”67 For iron from food, see these iron-rich foods.

    • Caffeine: Sensitivity varies widely, the FDA notes, and some medicines make people more sensitive to caffeine.21 If tea keeps you up, keep it to the morning, and learn the signs of too much caffeine.

    • Pregnancy and nursing: Brewed green tea counts toward your daily caffeine. ACOG found that under 200 mg a day doesn't appear to be a major factor in miscarriage or preterm birth, and a cup of green tea has about 29 mg; confirm your amount with your OB.682 Skip green tea extracts while pregnant or nursing.

    • Fluoride: Tea leaves carry some fluoride. In a Danish lab analysis that brewed teas in fluoride-free water, loose green teas released 1.28 to 1.50 mg per liter, so 2 to 3 cups supply roughly 0.6 to 1.1 mg from the leaf itself.69 I'm not a fan of fluoride in large amounts or in drinking water, so brew with water from a filter that removes it.3

    The bottom line

    Is green tea good for you?

    Yes. Green tea is a nearly calorie-free drink with a large body of human research behind it: big cohort studies link it with longer life and fewer strokes, and randomized trials show modest gains for cholesterol, blood pressure, blood sugar, weight and focus. People in China have drunk it for thousands of years, and in Japan it plays a central role in daily life, a long record I give real weight. The heart and longevity findings are the best established; the brain, weight and cancer findings are promising.

    Drink 2 to 3 cups a day of loose-leaf green tea or matcha before 2 p.m. A few cups of a steeped leaf, enjoyed every day, is one of the easiest healthy traditions you can make your own.

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    Green tea: frequently asked questions

    Is green tea good for you?

    Yes. In large studies, people who drank green tea regularly had a lower risk of stroke, heart disease and early death, and in randomized trials it lowered LDL cholesterol and blood pressure by a few points.4567

    Does green tea have caffeine?

    Yes, about 29.4 milligrams in an 8-ounce cup of brewed green tea, by USDA data.2 The FDA's typical figure for a 12-ounce serving is 37 milligrams, against 113 to 247 for regular brewed coffee.21

    How many cups of green tea should you drink a day?

    I recommend 2 to 3 cups a day, before 2 p.m., the amount in my Mitochondrial Longevity Protocol.1 In cohort studies, stroke risk was lowest at about 500 to 900 mL a day, roughly 2 to 4 cups.5

    What is the best time to drink green tea?

    Morning to early afternoon: my protocols set green tea before 2 p.m., or before noon if caffeine affects your sleep.152 If your iron runs low, drink it between meals rather than with them.67

    What is the difference between green tea and matcha?

    Matcha is a concentrated powder made from whole green tea leaves, so you drink the leaf instead of steeping and setting it aside.3 It's the form of green tea I like best, and our matcha guide covers it in full.3

    Is green tea better than black tea?

    Both are good choices from the same plant: green tea is steamed or pan-fired right after picking, while black tea is oxidized, which joins many of its catechins into theaflavins.959 I drink a lot of green tea and matcha, along with other teas and a little black tea.13

    Does green tea help you lose weight?

    Yes, modestly: in four pooled analyses of randomized trials, green tea and its catechins lowered body weight by 0.44 to 1.78 kilograms more than the comparison,32334522 with the clearest results in trials from Japan.34 It works best as part of a full plan and paired with exercise, as in my Healthy Weight & Metabolic Reset protocol.43

    Does green tea lower blood pressure?

    Yes, slightly: in a pooled analysis of 24 randomized trials, green tea lowered systolic pressure by 1.17 points and diastolic by 1.24 over 3 to 16 weeks.7 In a pooled analysis of 13 trials, the drops were larger in people whose systolic pressure started at 130 or above.27

    Is green tea good for women?

    Yes. In the Ohsaki study of 40,530 Japanese adults, the link between green tea and a lower risk of death was stronger in women, with a hazard ratio of 0.77 at 5 or more cups a day.40 My Hormone Balance for Women protocol keeps green tea to 1 to 2 cups before noon, and the safety section covers pregnancy.53

    Is green tea extract safe?

    In trials, it has usually been well tolerated below 800 mg of EGCG a day: EFSA found no evidence of liver injury below that level in trials of up to 12 months, though it couldn't name an extract dose it considered safe.59 Take extracts with food, skip them if you have liver disease, and stop for abdominal pain, dark urine, or yellowing of your skin or eyes.60

    Does green tea block iron absorption?

    It can when you drink it with a meal: in a study of 10 young women who each ate the same meal with and without green tea extract, nonheme iron absorption fell from 12.1% to 8.9%.66 If your iron runs low, drink green tea between meals.67

    Can you drink green tea while pregnant?

    Yes, within your daily caffeine limit: ACOG found that under 200 mg of caffeine a day doesn't appear to be a major factor in miscarriage or preterm birth, and a cup of green tea has about 29 mg.682 Confirm your amount with your OB, and skip green tea extracts while pregnant or nursing.

    Does green tea interact with medications?

    Yes, with a few: in 10 healthy volunteers, 700 mL of brewed green tea a day for 2 weeks cut peak blood levels of the beta-blocker nadolol by about 85%, and in 10 volunteers who each tried both, an extract drink lowered lisinopril exposure by about two-thirds.6364 It also lowered levels of several other medicines in clinical studies, and the safety section lists them.

    Can green tea slow aging?

    It may help at the level of your cells: in a 6-year study of 1,952 Korean adults, drinking at least a cup of green tea a day was linked with less shortening of telomeres, the protective caps on your chromosomes.70 In my view, a daily cup of green tea may help keep your cells younger for longer.3

    Is green tea good for your skin?

    It may help from the inside: in a 12-week placebo-controlled trial of 60 women, a catechin-rich green tea drink supplying 1,402 mg of catechins a day cut skin redness after UV exposure by 25% and improved elasticity, roughness and hydration.71 Our guide to natural skin care covers the rest of a skin routine.

    Freshness & update log

    October 13, 2026 — Rewrote the page in full under Dr. Axe's byline. The previous version, titled "Green Tea: the No. 1 Anti-Aging Beverage?", credited green tea with protecting against Alzheimer's disease, bone loss and eye disease on the strength of lab and rodent studies, gave counts of "beta-blocking," "calcium channel blocking" and "diuretic" compounds without a source, quoted ORAC antioxidant scores, listed theobromine among green tea's compounds, recommended three to four cups a day and advised "no more than one or two cups" in pregnancy for an unsourced heart-rhythm reason; those claims are gone. This version adds the Dr. Axe Score (7.3) with an interaction check (High for nadolol, and for lisinopril with green tea extract); USDA nutrition facts per 8-ounce cup and measured EGCG, caffeine and L-theanine; the cohort studies on longer life, stroke and heart disease and the randomized trials on cholesterol, blood pressure, focus, blood sugar, weight and antioxidant defenses, each labeled by design and size, with three charts and a step diagram of how green tea works; observational and trial cancer research reported separately; Dr. Axe's amounts from his protocols, 2 to 3 cups a day before 2 p.m.; brewing at about 85°C (185°F) for 3 minutes from loose leaf; and one safety section on extracts and the liver, medicines, iron, caffeine, pregnancy and fluoride.

    January 30, 2023 — Previous version published.

    References

    1. Axe J. Heal Your Cells: The Mitochondrial Longevity Protocol. DrAxe.com protocol. 2026 (section 21, 7-day meal plan, Daily drinks: "Green tea — 2–3 cups before 2pm").
    2. U.S. Department of Agriculture, Agricultural Research Service. Beverages, tea, green, brewed, regular. FoodData Central, SR Legacy, FDC ID 171917 (NDB 14278). April 1, 2019.
    3. Axe J, Cole W. Heal Your Cells. Avery; 2026 (chapter "Herbs That Boost Cellular Energy and Resilience," green tea and matcha section; p. 159, table of herbs by system: "Heart and circulation: green tea, turmeric, hawthorn, garlic"; p. 344, "Precision Healing Protocols": "Matcha (green tea extract)... Dosage: 2–3 cups/day or 300–500 mg extract").
    4. Abe SK, Saito E, Sawada N, Tsugane S, Ito H, Lin Y, 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;34(10):917-926. doi:10.1007/s10654-019-00545-y. PMID:31392470
    5. Wang ZM, Chen B, Zhou B, Zhao D, Wang LS. Green tea consumption and the risk of stroke: A systematic review and meta-analysis of cohort studies. Nutrition. 2023;107:111936. doi:10.1016/j.nut.2022.111936. PMID:36599267
    6. Xu R, Yang K, Li S, Dai M, Chen G. Effect of green tea consumption on blood lipids: a systematic review and meta-analysis of randomized controlled trials. Nutr J. 2020;19(1):48. doi:10.1186/s12937-020-00557-5. PMID:32434539
    7. Xu R, Yang K, Ding J, Chen G. Effect of green tea supplementation on blood pressure: A systematic review and meta-analysis of randomized controlled trials. Medicine (Baltimore). 2020;99(6):e19047. doi:10.1097/MD.0000000000019047. PMID:32028419
    8. Payne ER, Aceves-Martins M, Dubost J, Greyling A, de Roos B. Effects of Tea (Camellia sinensis) or its Bioactive Compounds l-Theanine or l-Theanine plus Caffeine on Cognition, Sleep, and Mood in Healthy Participants: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutr Rev. 2025;83(10):1873-1891. doi:10.1093/nutrit/nuaf054. PMID:40314930
    9. Chacko SM, Thambi PT, Kuttan R, Nishigaki I. Beneficial effects of green tea: a literature review. Chin Med. 2010;5:13. doi:10.1186/1749-8546-5-13. PMID:20370896
    10. Nobre AC, Rao A, Owen GN. L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pac J Clin Nutr. 2008;17 Suppl 1:167-8. PMID:18296328
    11. Huda HS, Majid NBA, Chen Y, Adnan M, Ashraf SA, Roszko M, et al. Exploring the ancient roots and modern global brews of tea and herbal beverages: A comprehensive review of origins, types, health benefits, market dynamics, and future trends. Food Sci Nutr. 2024;12(10):6938-6955. doi:10.1002/fsn3.4346. PMID:39479640
    12. Axe J. Top 12 Foods & Herbs for Weight Loss (BETTER THAN OZEMPIC). The Dr. Josh Axe Show. 2025 (tea, metabolism, quality and sencha at 41:58 to 42:53; https://www.youtube.com/watch?v=-Uq92QA3MKw&t=2518s).
    13. Axe J. How Coffee Affects Your Brain, Hormones, and Gut. The Dr. Josh Axe Show. 2025 (at 2:48, 5:04, 5:38, 24:31 and 25:04; https://www.youtube.com/watch?v=BuM1ceuyUlk&t=1471s).
    14. Liu K, Zhou R, Wang B, Chen K, Shi LY, Zhu JD, et al. Effect of green tea on glucose control and insulin sensitivity: a meta-analysis of 17 randomized controlled trials. Am J Clin Nutr. 2013;98(2):340-8. doi:10.3945/ajcn.112.052746. PMID:23803878
    15. Boros K, Jedlinszki N, Csupor D. Theanine and Caffeine Content of Infusions Prepared from Commercial Tea Samples. Pharmacogn Mag. 2016;12(45):75-9. doi:10.4103/0973-1296.176061. PMID:27019564
    16. Saklar S, Ertas E, Ozdemir IS, Karadeniz B. Effects of different brewing conditions on catechin content and sensory acceptance in Turkish green tea infusions. J Food Sci Technol. 2015;52(10):6639-46. doi:10.1007/s13197-015-1746-y. PMID:26396411 (methods: 1.6 g of tea brewed in 110 mL of water).
    17. Axe J, Rubin J. The Biblio Diet. Hachette Book Group; 2025. ISBN 9781546008439 (green tea entry, ebook p. 113).
    18. The Holy Bible, King James Version. Ezekiel 47:12. Project Gutenberg eBook #10.
    19. U.S. Food and Drug Administration. Daily Value on the Nutrition and Supplement Facts Labels.
    20. Reto M, Figueira ME, Filipe HM, Almeida CM. Chemical composition of green tea (Camellia sinensis) infusions commercialized in Portugal. Plant Foods Hum Nutr. 2007;62(4):139-44. doi:10.1007/s11130-007-0054-8. PMID:17899383
    21. U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine Is Too Much? Consumer Update.
    22. Dehzad MJ, Ghalandari H, Fahimzad FS, Maghsoudi Z, Makhtoomi M, Nouri M, et al. Effects of green tea supplementation on obesity indices and adipokines in adults: a grade-assessed systematic review and dose-response meta-analysis of randomised controlled trials. Int J Food Sci Nutr. 2025;76(4):340-369. doi:10.1080/09637486.2025.2496400. PMID:40326418
    23. Dehzad MJ, Ghalandari H, Nouri M, Makhtoomi M, Askarpour M. Effects of green tea supplementation on antioxidant status and inflammatory markers in adults: a grade-assessed systematic review and dose-response meta-analysis of randomised controlled trials. J Nutr Sci. 2025;14:e25. doi:10.1017/jns.2025.13. PMID:40160899
    24. Filippini T, Malavolti M, Borrelli F, Izzo AA, Fairweather-Tait SJ, Horneber M, et al. Green tea (Camellia sinensis) for the prevention of cancer. Cochrane Database Syst Rev. 2020;3(3):CD005004. doi:10.1002/14651858.CD005004.pub3. PMID:32118296
    25. Wang ZM, Zhao D, Wang H, Wang QM, Zhou B, Wang LS. Green tea consumption and the risk of coronary heart disease: A systematic review and meta-analysis of cohort studies. Nutr Metab Cardiovasc Dis. 2023;33(4):715-723. doi:10.1016/j.numecd.2023.01.017. PMID:36849317
    26. Umeda M, Tominaga T, Kozuma K, Kitazawa H, Furushima D, Hibi M, et al. Preventive effects of tea and tea catechins against influenza and acute upper respiratory tract infections: a systematic review and meta-analysis. Eur J Nutr. 2021;60(8):4189-4202. doi:10.1007/s00394-021-02681-2. PMID:34550452
    27. Khalesi S, Sun J, Buys N, Jamshidi A, Nikbakht-Nasrabadi E, Khosravi-Boroujeni H. Green tea catechins and blood pressure: a systematic review and meta-analysis of randomised controlled trials. Eur J Nutr. 2014;53(6):1299-311. doi:10.1007/s00394-014-0720-1. PMID:24861099
    28. Rezaei M, Akhavan N, Fathi F, Alavi SM, Fadaii M, Dehzad MJ, 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;34(1):2517122. doi:10.1080/08037051.2025.2517122. PMID:40497293
    29. Camfield DA, Stough C, Farrimond J, Scholey AB. Acute effects of tea constituents L-theanine, caffeine, and epigallocatechin gallate on cognitive function and mood: a systematic review and meta-analysis. Nutr Rev. 2014;72(8):507-22. doi:10.1111/nure.12120. PMID:24946991
    30. Asbaghi O, Fouladvand F, Gonzalez MJ, Ashtary-Larky D, Choghakhori R, Abbasnezhad A. Effect of green tea on glycemic control in patients with type 2 diabetes mellitus: A systematic review and meta-analysis. Diabetes Metab Syndr. 2021;15(1):23-31. doi:10.1016/j.dsx.2020.11.004. PMID:33285391
    31. Zhou S, Zhu Y, Ren N, Wu M, Liu Y. The Association between Green Tea Consumption and Cognitive Function: A Meta-Analysis of Current Evidence. Neuroepidemiology. 2026;60(1):178-199. doi:10.1159/000543784. PMID:39947165
    32. Phung OJ, Baker WL, Matthews LJ, Lanosa M, Thorne A, Coleman CI. Effect of green tea catechins with or without caffeine on anthropometric measures: a systematic review and meta-analysis. Am J Clin Nutr. 2010;91(1):73-81. doi:10.3945/ajcn.2009.28157. PMID:19906797
    33. Lin Y, Shi D, Su B, Wei J, Găman MA, Sedanur Macit M, et al. The effect of green tea supplementation on obesity: A systematic review and dose-response meta-analysis of randomized controlled trials. Phytother Res. 2020;34(10):2459-2470. doi:10.1002/ptr.6697. PMID:32372444
    34. Jurgens TM, Whelan AM, Killian L, Doucette S, Kirk S, Foy E. Green tea for weight loss and weight maintenance in overweight or obese adults. Cochrane Database Syst Rev. 2012;12(12):CD008650. doi:10.1002/14651858.CD008650.pub2. PMID:23235664
    35. Mahmoodi M, Hosseini R, Kazemi A, Ofori-Asenso R, Mazidi M, Mazloomi SM. Effects of green tea or green tea catechin on liver enzymes in healthy individuals and people with nonalcoholic fatty liver disease: A systematic review and meta-analysis of randomized clinical trials. Phytother Res. 2020;34(7):1587-1598. doi:10.1002/ptr.6637. PMID:32067271
    36. Zhang Y, Xu Q, Hu J, Zhang F, Yu Y, Ma L. Green Tea and Epigallocatechin Gallate (EGCG) for Cancer Prevention: A Systematic Review and Meta-Analysis. Am J Chin Med. 2025;53(6):1755-1784. doi:10.1142/S0192415X2550065X. PMID:40832777
    37. Kim JA, Formoso G, Li Y, Potenza MA, Marasciulo FL, Montagnani M, et al. Epigallocatechin gallate, a green tea polyphenol, mediates NO-dependent vasodilation using signaling pathways in vascular endothelium requiring reactive oxygen species and Fyn. J Biol Chem. 2007;282(18):13736-45. doi:10.1074/jbc.M609725200. PMID:17363366
    38. Ras RT, Zock PL, Draijer R. Tea consumption enhances endothelial-dependent vasodilation; a meta-analysis. PLoS One. 2011;6(3):e16974. doi:10.1371/journal.pone.0016974. PMID:21394199
    39. Raederstorff DG, Schlachter MF, Elste V, Weber P. Effect of EGCG on lipid absorption and plasma lipid levels in rats. J Nutr Biochem. 2003;14(6):326-32. doi:10.1016/s0955-2863(03)00054-8. PMID:12873714
    40. Kuriyama S, Shimazu T, Ohmori K, Kikuchi N, Nakaya N, Nishino Y, et al. Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan: the Ohsaki study. JAMA. 2006;296(10):1255-65. doi:10.1001/jama.296.10.1255. PMID:16968850
    41. Einöther SJ, Martens VE, Rycroft JA, De Bruin EA. L-theanine and caffeine improve task switching but not intersensory attention or subjective alertness. Appetite. 2010;54(2):406-9. doi:10.1016/j.appet.2010.01.003. PMID:20079786
    42. Fredholm BB, Bättig K, Holmén J, Nehlig A, Zvartau EE. Actions of caffeine in the brain with special reference to factors that contribute to its widespread use. Pharmacol Rev. 1999;51(1):83-133. PMID:10049999
    43. Axe J. Healthy Weight & Metabolic Reset. DrAxe.com protocol. 2026 (p. 20, "Top 8 metabolic boosters": "Green tea (EGCG) 250–500 mg or 3 cups daily · Catechins plus caffeine modestly raise fat burning; best paired with exercise"; Burn phase: "Green tea extract (EGCG) — 250–500 mg daily with food"; p. 22: "Green tea & vinegar 3 cups / 1 tbsp"; p. 31, How to read the evidence: "vinegar, green tea and cinnamon help modestly, not dramatically").
    44. Zhang J, Wang A, Zhang X, Chen S, Wu S, Zhao X, et al. Association between tea consumption and cognitive impairment in middle-aged and older adults. BMC Geriatr. 2020;20(1):447. doi:10.1186/s12877-020-01848-6. PMID:33148194
    45. Hursel R, Viechtbauer W, Westerterp-Plantenga MS. The effects of green tea on weight loss and weight maintenance: a meta-analysis. Int J Obes (Lond). 2009;33(9):956-61. doi:10.1038/ijo.2009.135. PMID:19597519
    46. Kang H, Rha SY, Oh KW, Nam CM. Green tea consumption and stomach cancer risk: a meta-analysis. Epidemiol Health. 2010;32:e2010001. doi:10.4178/epih/e2010001. PMID:21191454
    47. Bettuzzi S, Brausi M, Rizzi F, Castagnetti G, Peracchia G, Corti A. Chemoprevention of human prostate cancer by oral administration of green tea catechins in volunteers with high-grade prostate intraepithelial neoplasia: a preliminary report from a one-year proof-of-principle study. Cancer Res. 2006;66(2):1234-40. doi:10.1158/0008-5472.CAN-05-1145. PMID:16424063
    48. Kumar NB, Pow-Sang J, Egan KM, Spiess PE, Dickinson S, Salup R, et al. Randomized, Placebo-Controlled Trial of Green Tea Catechins for Prostate Cancer Prevention. Cancer Prev Res (Phila). 2015;8(10):879-87. doi:10.1158/1940-6207.CAPR-14-0324. PMID:25873370
    49. Shin CM, Lee DH, Seo AY, Lee HJ, Kim SB, Son WC, et al. Green tea extracts for the prevention of metachronous colorectal polyps among patients who underwent endoscopic removal of colorectal adenomas: A randomized clinical trial. Clin Nutr. 2018;37(2):452-458. doi:10.1016/j.clnu.2017.01.014. PMID:28209333
    50. Samavat H, Ursin G, Emory TH, Lee E, Wang R, Torkelson CJ, et al. A Randomized Controlled Trial of Green Tea Extract Supplementation and Mammographic Density in Postmenopausal Women at Increased Risk of Breast Cancer. Cancer Prev Res (Phila). 2017;10(12):710-718. doi:10.1158/1940-6207.CAPR-17-0187. PMID:28904061
    51. Axe J. The Breast Cancer Support Protocol. DrAxe.com protocol. 2026 (p. 16, immune and estrogen stack: "Green tea extract (EGCG) 300–500 mg standardized, food"; "concentrated green-tea or curcumin extracts... should not be taken during active chemo or radiation unless your oncology team approves").
    52. Axe J. The Deep Sleep Protocol. DrAxe.com protocol. 2026 (p. 16: "Caffeine only before noon — one or two cups, after breakfast"; Daily drinks: "Coffee or green tea — before noon only").
    53. Axe J. Hormone Balance for Women. DrAxe.com protocol. 2026 (Daily drinks: "Green tea — 1–2 cups before noon").
    54. Yi M, Wu X, Zhuang W, Xia L, Chen Y, Zhao R, et al. Tea Consumption and Health Outcomes: Umbrella Review of Meta-Analyses of Observational Studies in Humans. Mol Nutr Food Res. 2019;63(16):e1900389. doi:10.1002/mnfr.201900389. PMID:31216091
    55. Axe J. Why SLEEP is Medicine: My 4 Tips to Improve Energy. The Dr. Josh Axe Show. 2026 (matcha and caffeine breaks at 25:44; theanine at 46:29; https://www.youtube.com/watch?v=ZmTNCfQO8_g&t=1544s).
    56. Axe J. Reverse Microplastic Toxicity NATURALLY (Heals Mitochondria, Gut, Brain) | Dr. Josh Axe. The Dr. Josh Axe Show. 2026 (tea bags and loose-leaf tea at 14:01; matcha for breakfast at 36:46; https://www.youtube.com/watch?v=oIBpaNxBaMg&t=841s).
    57. Hernandez LM, Xu EG, Larsson HCE, Tahara R, Maisuria VB, Tufenkji N. Plastic Teabags Release Billions of Microparticles and Nanoparticles into Tea. Environ Sci Technol. 2019;53(21):12300-12310. doi:10.1021/acs.est.9b02540. PMID:31552738
    58. Axe J. What Happens In Your Body If You Eat Honey Every Day? The Dr. Josh Axe Show. 2025 (raw local honey or Manuka honey as the sweetener to buy; "A teaspoon up to a tablespoon," at 20:40).
    59. EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), Younes M, Aggett P, Aguilar F, Crebelli R, Dusemund B, et al. Scientific opinion on the safety of green tea catechins. EFSA J. 2018;16(4):e05239. doi:10.2903/j.efsa.2018.5239. PMID:32625874
    60. Oketch-Rabah HA, Roe AL, Rider CV, Bonkovsky HL, Giancaspro GI, Navarro V, et al. United States Pharmacopeia (USP) comprehensive review of the hepatotoxicity of green tea extracts. Toxicol Rep. 2020;7:386-402. doi:10.1016/j.toxrep.2020.02.008. PMID:32140423
    61. Dostal AM, Samavat H, Bedell S, Torkelson C, Wang R, Swenson K, et al. The safety of green tea extract supplementation in postmenopausal women at risk for breast cancer: results of the Minnesota Green Tea Trial. Food Chem Toxicol. 2015;83:26-35. doi:10.1016/j.fct.2015.05.019. PMID:26051348
    62. Yu Z, Samavat H, Dostal AM, Wang R, Torkelson CJ, Yang CS, et al. Effect of Green Tea Supplements on Liver Enzyme Elevation: Results from a Randomized Intervention Study in the United States. Cancer Prev Res (Phila). 2017;10(10):571-579. doi:10.1158/1940-6207.CAPR-17-0160. PMID:28765194
    63. Misaka S, Yatabe J, Müller F, Takano K, Kawabe K, Glaeser H, et al. Green tea ingestion greatly reduces plasma concentrations of nadolol in healthy subjects. Clin Pharmacol Ther. 2014;95(4):432-8. doi:10.1038/clpt.2013.241. PMID:24419562
    64. Misaka S, Ono Y, Uchida A, Ono T, Abe O, Ogata H, et al. Impact of Green Tea Catechin Ingestion on the Pharmacokinetics of Lisinopril in Healthy Volunteers. Clin Transl Sci. 2021;14(2):476-480. doi:10.1111/cts.12905. PMID:33048477
    65. Kyriacou NM, Gross AS, McLachlan AJ. Green Tea Catechins as Perpetrators of Drug Pharmacokinetic Interactions. Clin Pharmacol Ther. 2025;118(1):45-61. doi:10.1002/cpt.3547. PMID:39748104
    66. Samman S, Sandström B, Toft MB, Bukhave K, Jensen M, Sørensen SS, et al. Green tea or rosemary extract added to foods reduces nonheme-iron absorption. Am J Clin Nutr. 2001;73(3):607-12. doi:10.1093/ajcn/73.3.607. PMID:11237939
    67. Axe J. 10 Signs You Have an Iron Deficiency (How to Boost Iron Naturally). The Dr. Josh Axe Show. 2024 (tea polyphenols and iron at 23:41; tea between meals at 24:08; https://www.youtube.com/watch?v=JjlsPil8ZSE&t=1448s).
    68. [No authors listed]. ACOG CommitteeOpinion No. 462: Moderate caffeine consumption during pregnancy. Obstet Gynecol. 2010;116(2 Pt 1):467-468. doi:10.1097/AOG.0b013e3181eeb2a1. PMID:20664420
    69. Krishnankutty N, Storgaard Jensen T, Kjær J, Jørgensen JS, Nielsen F, Grandjean P. Public-health risks from tea drinking: Fluoride exposure. Scand J Public Health. 2022;50(3):355-361. doi:10.1177/1403494821990284. PMID:33557697
    70. Sohn I, Shin C, Baik I. Associations of green tea, coffee, and soft drink consumption with longitudinal changes in leukocyte telomere length. Sci Rep. 2023;13(1):492. doi:10.1038/s41598-022-26186-y. PMID:36627320
    71. Heinrich U, Moore CE, De Spirt S, Tronnier H, Stahl W. Green tea polyphenols provide photoprotection, increase microcirculation, and modulate skin properties of women. J Nutr. 2011;141(6):1202-8. doi:10.3945/jn.110.136465. PMID:21525260
    Dr. Josh Axe

    Dr. Josh Axe, DC, DNM, CNS

    Doctor of Natural Medicine · Founder, DrAxe.com

    Dr. Axe is a certified doctor of natural medicine, clinical nutritionist, and multiple New York Times bestselling author. He has spent 20+ years in clinical practice helping people heal at the root cause and founded one of the most-visited natural-health platforms in the world.

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