Does green tea help with weight loss?

Barely. Pooled trials of green tea supplements put the effect at about a kilogram: 1.6 lb (0.74 kg) less than placebo in a 2025 meta-analysis of adults, and 2.8 lb (1.25 kg) in a 2023 network meta-analysis that rated the certainty low. The Cochrane review found that in six trials run outside Japan, with 532 overweight or obese adults, the difference was 0.09 lb (0.04 kg), with an interval from minus 0.5 to plus 0.88 lb (0.4 kg). Almost all of this comes from extracts and capsules, in trials of a few months.

Myth. Green tea is not a fat burner. The Cochrane authors judged the loss small, statistically non-significant and unlikely to be clinically important, and found no effect on keeping weight off. The EU did not authorize the label claim that a green tea and guarana extract helps to burn fat, which means the evidence did not meet the bar when it was assessed.

What the trials found

The pooled reviews

The Cochrane review covered randomized trials of green tea preparations in overweight or obese adults lasting at least 12 weeks. It pooled the six trials from outside Japan and found a difference of 0.09 lb (0.04 kg) (95% CI minus 0.5 to 0.4). The Japanese trials were too different from one another to pool, and the search ended in early 2012, so newer trials are not in it.

The newer reviews find a small effect that does reach significance. A 2025 dose-response meta-analysis found 1.6 lb (0.74 kg) less body weight (1.1 to 2.1 lb / 0.51 to 0.97 kg) and about 0.39 in (1 cm) off the waist. Its abstract does not say how many trials it pooled or how it rated their quality. A 2023 network meta-analysis of 111 trials across 18 supplements found 2.8 lb (1.8 to 3.7; metric: 1.25 kg, 0.82 to 1.68) for green tea, with the certainty rated low. A 2024 meta-analysis limited to women with overweight or obesity found 2.7 lb (0.73 to 4.7; metric: 1.23 kg, 0.33 to 2.13), and an umbrella review pooling 13 earlier meta-analyses put the figure at 0.89. These reviews draw on overlapping trials, so their agreement counts for less than it looks.

Unsettled. Why the Cochrane result differs from the newer reviews is not settled. The newer reviews include trials published after 2012 and do not separate Japanese from other trials in their abstracts. Nobody has explained whether the gap comes from catechin dose, caffeine habits or trial quality.

The longest trial

In the Minnesota Green Tea Trial, 121 overweight or obese postmenopausal women aged 50 to 70 took decaffeinated green tea extract with 843 mg of EGCG a day, or placebo, for 12 months. BMI changed by minus 0.13 against minus 0.05 (P = 0.61), and total fat mass by minus 0.66 lb (0.30 kg) against minus 0.26 lb (0.12 kg) (P = 0.40). The extract was decaffeinated, so any part of the effect that comes from caffeine was absent. It is still the only year-long trial on this page, and it found nothing.

The mechanism, measured

A meta-analysis of 8 randomized trials found EGCG raised energy expenditure by about 158 kJ, or 38 calories, a day, and that fat burning did not change significantly. That figure comes from a fixed-effect model in short metabolic studies, and its lower bound sits near zero (4.72 kJ). Even taken at face value, 38 calories a day is a small number, and it fits an effect of about a kilogram over a few months.

Women with polycystic ovary syndrome

In 6 randomized trials with 235 women with polycystic ovary syndrome, tea supplements on top of treatment lowered body weight by 6 lb (1 to 11; metric: 2.71 kg, 0.46 to 4.95). The review pooled green and herbal teas in small trials, and BMI did not change. The comparison of side effects was too imprecise to tell either way (RR 1.45, 0.30 to 6.90).

Who should be careful

Not for everyone. High-dose green tea extract can harm the liver. In the Minnesota trial, 1,021 women with normal liver tests took 843 mg of EGCG a day as capsules, far above what cups of tea give, for 12 months. Liver enzyme ALT rose by 5.4 U/L more than on placebo, and 26 of 513 women (5.1%) developed moderate or worse liver test abnormalities, an odds ratio of 7.0 (2.4 to 20.3). The enzymes fell after stopping and rose again on rechallenge.

The European Food Safety Authority reached the same point from clinical trials: supplements giving 800 mg of EGCG a day or more raised liver enzymes. It found traditional green tea safe at usual intakes and could not set a safe dose for supplements, and the EU has since restricted foods that deliver 800 mg a day or more.

Not for everyone. Green tea can block the beta-blocker nadolol. In 10 healthy volunteers who drank 24 fl oz (700 mL) of green tea a day for 14 days before a single 30 mg dose, nadolol blood levels fell by 85% and its effect on blood pressure was blunted. Nobody has measured this in patients taking nadolol long term, so if you take it, ask before making green tea a daily habit.

We did not find trial evidence on green tea for weight loss in pregnancy or in children, so this page says nothing about them either way.

What expert bodies say

The US National Center for Complementary and Integrative Health says the catechins and caffeine in green tea and its extracts may have a modest effect on body weight. EFSA's 2018 opinion is about safety and sets the 800 mg EGCG line above. The EU register of health claims lists the claim that a green tea and guarana extract helps to burn fat as non-authorized.

How we searched

What would change this answer

• A trial longer than a year with weight as the main outcome. Most trials last 8 to 13 weeks, and the only 12-month trial, with decaffeinated extract in postmenopausal women, found no change in fat.
• A trial of brewed green tea in ordinary cups against water. Nearly all the evidence is about extracts and capsules.
• An explanation for the Japanese trials. The Cochrane review could not pool them, and the newer reviews do not report them apart.
• A settled dose. The 2024 review in women saw more weight loss in trials using 1000 mg or more of green tea preparation a day, while EFSA ties 800 mg of EGCG a day or more to raised liver enzymes. No trial here tests one dose for both benefit and liver safety.

ClinicalTrials.gov lists no ongoing green tea trial with weight as an outcome.

Everything else about the drink, from caffeine to the other trials, is on the green tea page.

Sources

1. ev-gtwl-01 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = 532
   Meta-analysis of six studies conducted outside Japan showed a mean difference (MD) in weight loss of -0.04 kg (95% CI -0.5 to 0.4; P = 0.88; I(2) = 18%; 532 participants).
   
   Who: overweight or obese adults in RCTs of green tea preparations lasting at least 12 weeks
   Effect: weight MD -0.09 lb (95% CI -1.1 to 0.88; metric: -0.04 kg, -0.5 to 0.4), I2 18%, 6 trials outside Japan, 532 participants; Japanese trials not pooled
   Certainty: Search to early 2012; the Japanese trials were too different to pool; weight maintenance data from only 2 trials.
   Cochrane Database of Systematic Reviews, 2012, CD008650, Green tea for weight loss and weight maintenance in overweight or obese adults · checked 2026-10-06 · we read the abstract
2. ev-gtwl-02 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = —
   Green tea preparations appear to induce a small, statistically non-significant weight loss in overweight or obese adults. Because the amount of weight loss is small, it is not likely to be clinically important. Green tea had no significant effect on the maintenance of weight loss.
   
   Who: overweight or obese adults in RCTs of green tea preparations
   Effect: small non-significant weight loss; no significant effect on weight maintenance
   Certainty: Authors' conclusion; based on trials up to 2012.
   Cochrane Database of Systematic Reviews, 2012, CD008650, Green tea for weight loss and weight maintenance in overweight or obese adults · checked 2026-10-06 · we read the abstract
3. ev-gtwl-03 · Meta-analysis or systematic review · systematic review and dose-response meta-analysis of randomized controlled trials, GRADE-assessed · n = —
   Green tea supplementation reduced BW (WMD: -0.74 kg; 95% CI: -0.97, -0.51), BMI (WMD: -0.29 kg/m2; 95% CI: -0.38, -0.19), WC (WMD: -1.04 cm; 95% CI: -1.55, -0.53), BFP (WMD: -0.65%; 95% CI: -1.03, -0.27), and leptin (WMD: -0.92 ng/ml; 95% CI: -1.71, -0.14), but did not change adiponectin levels (WMD: 0.20 µg/ml; 95% CI: -0.17, 0.57).
   
   Who: adults in randomized controlled trials of green tea supplementation
   Effect: body weight WMD -1.6 lb (95% CI -2.1 to -1.1; metric: -0.74 kg, -0.97 to -0.51); BMI -0.29 kg/m2; waist -0.41 in (-1.04 cm); body fat -0.65%
   Certainty: Abstract does not give the number of trials or the GRADE rating; search to February 2024.
   Int J Food Sci Nutr, 2025 · checked 2026-10-06 · we read the abstract
4. ev-gtwl-04 · Meta-analysis or systematic review · systematic review and network meta-analysis of randomized controlled trials · n = 6171
   Supplementations with green tea (MD: -1.25 kg, 95%CI: -1.68, -0.82) and glucomannan (MD: -1.36 kg, 95%CI: -2.17, -0.54) demonstrated small weight loss, also the certainty of evidence was rated low.
   
   Who: adults with overweight or obesity in randomized trials of nutraceuticals
   Effect: green tea vs placebo MD -2.8 lb (95% CI -3.7 to -1.8; metric: -1.25 kg, -1.68 to -0.82), low certainty
   Certainty: Low certainty (GRADE) for green tea; N is for the whole network, not green tea alone.
   Pharmacol Res, 2023 · checked 2026-10-06 · we read the abstract
5. ev-gtwl-05 · Meta-analysis or systematic review · time and dose-response meta-analysis of randomized controlled trials · n = 16 RCT arms
   GT supplementation significantly decreases body weight (WMD: -1.23 kg, 95% CI: -2.13 to -0.33, p = 0.007), BMI (WMD: -0.47 kg/m2, 95% CI: -0.87 to -0.07, p = 0.020) and WC (WMD: -3.46 cm, 95% CI: -6.75 to -0.16, p = 0.040).
   
   Who: overweight and obese women in randomized controlled trials
   Effect: body weight WMD -2.7 lb (95% CI -4.7 to -0.73; metric: -1.23 kg, -2.13 to -0.33); BMI -0.47 kg/m2; waist -1.4 in (-3.46 cm); doses of 1000 mg/day or more WMD -3 lb (-1.38 kg)
   Certainty: Women only; the abstract gives no risk-of-bias or certainty rating.
   Crit Rev Food Sci Nutr, 2024 · checked 2026-10-06 · we read the abstract
6. ev-gtwl-06 · Meta-analysis or systematic review · umbrella review and meta-meta-analysis of systematic reviews and meta-analyses · n = 13 meta-analyses
   Meta-meta-analysis revealed significant effects of GT on weight and waist circumference with weighted mean difference (WMD) of -0.89 (95% CI -1.43 to -0.34, p < 0.001) and -1.01 (95% CI -1.63 to -0.39, p < 0.001)
   
   Who: 13 meta-analyses of green tea intake and cardiometabolic risk factors
   Effect: weight WMD -0.89 (95% CI -1.43 to -0.34); waist WMD -1.01 (95% CI -1.63 to -0.39)
   Certainty: Overlapping trials across the pooled meta-analyses.
   Nutr Metab Cardiovasc Dis, 2022 · checked 2026-10-06 · we read the abstract
7. ev-gtwl-07 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials · n = 8 trials
   The meta-analysis results of verities of studies in terms of dose and length of duration revealed that EGCG supplementation provided significant mean difference (MD) when compared with placebo for RQ [MD: -0.02; 95% confidence intervals (95% CI), -0.04 to 0.00; I2=67%; P=.01] and EE [MD: 158.05 kJ/day; 95% CI, 4.72 to 311.38; I2=0%; P=.04] in fixed-effect approach. Changes in FOX did not reach the level of statistical significance.
   
   Who: randomized controlled trials of EGCG in humans
   Effect: energy expenditure MD 158.05 kJ/day (95% CI 4.72 to 311.38); respiratory quotient MD -0.02; fat oxidation not significant
   Certainty: Fixed-effect result with a lower bound near zero; short metabolic studies, not weight outcomes.
   J Nutr Biochem, 2017 · checked 2026-10-06 · we read the abstract
8. ev-gtwl-08 · Randomized controlled trial(s) · randomized double-blind placebo-controlled trial (substudy) · n = 121
   There were no differences in changes in BMI (-0.13 ± 0.11 compared with -0.05 ± 0.11; P = 0.61), total fat mass (-0.30 ± 0.16 compared with -0.12 ± 0.15 kg; P = 0.40), percentage of body fat (-0.15% ± 0.17% compared with -0.15% ± 0.16%; P = 0.99), or BMD (-0.006 ± 0.002 compared with -0.003 ± 0.002 g/cm(2); P = 0.49) over 12 mo between women taking GTE (n = 61) and those taking a placebo (n = 60).
   
   Who: overweight or obese postmenopausal women aged 50 to 70 in the Minnesota Green Tea Trial
   Effect: BMI change -0.13 vs -0.05 (P = 0.61); total fat mass -0.66 vs -0.26 lb (-0.30 vs -0.12 kg) (P = 0.40); body fat -0.15% vs -0.15% over 12 months
   Certainty: Substudy of a breast cancer prevention trial; decaffeinated extract, so the caffeine part of the effect is absent.
   Journal of Nutrition, 2016, Long-Term Supplementation of Green Tea Extract Does Not Modify Adiposity or Bone Mineral Density in a Randomized Trial of Overweight and Obese Postmenopausal Women · checked 2026-10-06 · we read the abstract
9. ev-gtwl-09 · Randomized controlled trial(s) · randomized double-blind placebo-controlled phase II trial · n = 1,021
   Overall, 26 (5.1%) women in GTE developed moderate or more severe abnormalities in any liver function measure during the intervention period, yielding an OR of 7.0 (95% CI, 2.4-20.3) for developing liver function abnormalities as compared with those in the placebo arm.
   
   Who: women with normal baseline liver enzymes in a randomized placebo-controlled trial of green tea extract for 12 months
   Effect: ALT +5.4 U/L (95% CI 3.6 to 7.1) vs placebo; 26 of 513 (5.1%) with moderate or worse abnormalities; OR 7.0 (95% CI 2.4 to 20.3)
   Certainty: Dose was 843 mg EGCG a day as capsules (Minnesota Green Tea Trial), far above what cups of tea give; enzymes fell after stopping and rose on rechallenge.
   Cancer Prev Res (Phila), 2017 · checked 2026-10-06 · we read the abstract
10. ev-gtwl-10 · Position of an expert body · EFSA ANS Panel scientific opinion · n = —
    Based on the available data on the potential adverse effects of green tea catechins on the liver, the Panel concluded that there is evidence from interventional clinical trials that intake of doses equal or above 800 mg EGCG/day taken as a food supplement has been shown to induce a statistically significant increase of serum transaminases in treated subjects compared to control.
    
    Who: adults in the EU consuming green tea infusions or green tea catechin food supplements
    Effect: usual intake from tea 90 to 300 mg EGCG/day; supplements 5 to 1,000 mg/day; 800 mg EGCG/day or more raised serum transaminases
    Certainty: The Panel could not set a safe supplement dose; in 2022 the EU restricted foods with EGCG at 800 mg/day or more (Regulation (EU) 2022/2340, not quoted here).
    EFSA Journal, 2018, 16(4):5239, Scientific opinion on the safety of green tea catechins (EFSA ANS Panel) · checked 2026-10-06 · we read the abstract
11. ev-gtwl-11 · Randomized controlled trial(s) · randomized crossover pharmacokinetic trial · n = 10
    Green tea markedly decreased the maximum plasma concentration (C(max)) and area under the plasma concentration-time curve (AUC(0-48)) of nadolol by 85.3% and 85.0%, respectively (P < 0.01), without altering renal clearance of nadolol.
    
    Who: healthy volunteers given a single 30 mg dose of nadolol after 14 days of green tea or water
    Effect: nadolol Cmax -85.3% and AUC -85.0% (P < 0.01); smaller drop in systolic blood pressure
    Certainty: Small healthy-volunteer study; effect on patients taking nadolol long term not measured.
    Clin Pharmacol Ther, 2014 · checked 2026-10-06 · we read the abstract
12. ev-gtwl-12 · Position of an expert body · agency consumer fact sheet · n = —
    The catechins and caffeine in green tea and its extracts may have a modest effect on body weight.
    
    Who: general public
    Effect: modest effect on body weight
    Certainty: Fact sheet without its own analysis, last updated February 2025.
    NCCIH (NIH), Green Tea, last updated February 2025 · checked 2026-10-06 · we read the section
13. ev-gtwl-13 · Position of an expert body · EU Register on nutrition and health claims, claim POL-HC-8415, snapshot of 2026-09-21 · n = —
    POL-HC-8415 A combination of Paullinia cupana Kunth (guarana) and Camellia sinensis (L.) Kuntze (green tea) extracts Helps to burn fat -/- Non-authorised
    
    Who: foods sold in the EU
    Effect: claim status: non-authorized
    Certainty: Non-authorized means the evidence did not meet the bar at assessment, not that there is no effect.
    EU Register on nutrition and health claims, claim POL-HC-8415, snapshot 2026-09-21 · checked 2026-10-06 · we read the section
14. ev-gtwl-14 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials · n = 235
    Tea supplements as adjuvant therapy led to greater improvement in body weight (WMD -2.71, 95% CI -4.95 to -0.46, P = 0.02, I2 = 0%), fasting blood glucose (FBG: WMD -0.40, 95% CI -0.59 to -0.20, P < 0.0001, I2 = 0%) and fasting insulin (FINS: WMD -3.40, 95% CI -4.76 to -2.03, P < 0.00001, I2 = 0%) when compared with placebo.
    
    Who: women with polycystic ovary syndrome in randomized controlled trials of tea versus placebo
    Effect: body weight WMD -6 lb (95% CI -11 to -1; metric: -2.71 kg, -4.95 to -0.46), I2 0%; no difference in BMI or waist; adverse reactions RR 1.45 (95% CI 0.30 to 6.90)
    Certainty: Pools green and herbal teas; small trials; BMI did not change despite the weight result.
    Front Endocrinol (Lausanne), 2021 · checked 2026-10-06 · we read the abstract