- Inflammation marker (CRP)No clear difference0.09 mg/L higher1 review of trials2015 study ↗
supplement
Green Tea Extract (EGCG)
Also known as EGCG, Catechins, Camellia sinensis
Concentrated catechin polyphenols from Camellia sinensis, chiefly epigallocatechin gallate (EGCG); modestly increases thermogenesis and fat oxidation when combined with caffeine, and provides broad antioxidant activity.
Be careful if: certain health conditions
Ask first if you take: blood-pressure medicines, statins, blood thinners (anticoagulants or antiplatelets)
Upper limit: 800 mg EGCG per day — per day for adults — EFSA 2018 identified supplemental intakes at or above 800 mg EGCG/day as associated with increased serum transaminases (not a formal UL: EFSA set no tolerable upper intake level)
Suspect a side effect? Report it to the MHRA Yellow Card scheme ↗
2linked conditions
20linked studies
Evidence
What the research actually shows
We link to relevant studies and leave interpretation to you and your healthcare professional.
What studies found
The headline results, condition by condition
The large figures are what the studies reported for each thing they measured. Open a card for every result.
Colour keyReported a benefitNo clear benefitUnclearPossible harmAmber is for highlights, such as where the most research is. It never means a result was good.
Safety
Safety and considerations
What sources report about side effects, who should be careful, and medicines to ask about first.
Serious effects reported
| Reported effect | How often | Basis | Sources |
|---|---|---|---|
| Dose-related liver signal: supplemental intakes of >=800 mg EGCG/day were associated with increased serum transaminases; infusion-based (brewed tea) consumption was not a safety concern in EFSA's assessment | unknown | Listed by EFSA / SACN / COT upper levels | EFSA NDA Panel. Scientific Opinion on the safety of green tea catechins. EFSA Journal 2018;16(4):5239 (doi:10.2903/j.efsa.2018.5239) |
Be careful if you…
| Applies to | What sources say | Sources |
|---|---|---|
| certain health conditions | Anyone with an existing liver condition or raised liver enzymes should ask a clinician before using concentrated catechin extracts, given the transaminase signal EFSA identified at high supplemental doses. | EFSA NDA Panel. Scientific Opinion on the safety of green tea catechins. EFSA Journal 2018;16(4):5239 (doi:10.2903/j.efsa.2018.5239) |
Medicines to ask about
| Severity | Medicine | Sources |
|---|---|---|
| ask first | blood-pressure medicines — Repeated green tea consumption reduced plasma concentrations of the beta-blocker nadolol by roughly 85% (Cmax and AUC) and blunted its blood-pressure effect in an RCT; the review of cardiovascular drug interactions lists nadolol among documented cases. | Misaka S, et al. Green tea ingestion greatly reduces plasma concentrations of nadolol in healthy subjects. Clin Pharmacol Ther 2014;95(4):432-438 (PMID 24419562)Werba JP, et al. Overview of green tea interaction with cardiovascular drugs. Curr Pharm Des 2015;21(9):1213-1219 (PMID 25312732) |
| caution | statins — Human interaction data (review) document mild-to-modest average effects of green tea on simvastatin bioavailability/activity; people on statins drinking large volumes or taking catechin-enriched products should watch for unexpected drug responses. | Werba JP, et al. Overview of green tea interaction with cardiovascular drugs. Curr Pharm Des 2015;21(9):1213-1219 (PMID 25312732) |
| caution | blood thinners (anticoagulants or antiplatelets) — Warfarin is among the cardiovascular drugs with documented (mild-to-modest average) green tea interaction effects in human data reviewed by Werba et al. | Werba JP, et al. Overview of green tea interaction with cardiovascular drugs. Curr Pharm Des 2015;21(9):1213-1219 (PMID 25312732) |
How much is too much
800 mg EGCG per day — per day for adults — EFSA 2018 identified supplemental intakes at or above 800 mg EGCG/day as associated with increased serum transaminases (not a formal UL: EFSA set no tolerable upper intake level)
Sources
EFSA NDA Panel. Scientific Opinion on the safety of green tea catechins. EFSA Journal 2018;16(4):5239 (doi:10.2903/j.efsa.2018.5239)Misaka S, et al. Green tea ingestion greatly reduces plasma concentrations of nadolol in healthy subjects. Clin Pharmacol Ther 2014;95(4):432-438 (PMID 24419562)Werba JP, et al. Overview of green tea interaction with cardiovascular drugs. Curr Pharm Des 2015;21(9):1213-1219 (PMID 25312732)
Evidence analytics
Where the evidence is concentrated
Audited published research for Green Tea Extract (EGCG) by condition. Drill into a pair page for the full breakdown.
Green Tea Extract (EGCG): findings by condition
What this means: Bars count reported findings, not treatment effectiveness or certainty.
One study may report several findings or appear in more than one pairing. Counts do not show the size of an effect. Comparable numerical estimates are not established for this summary.
View the full data table
| Compound and condition | Findings (count) | Studies (count) | Reported results (finding counts) | How sure? |
|---|---|---|---|---|
| Inflammation | 1 | 1 | Benefit: 0; no benefit: 1; harm: 0; unclear: 0; not recorded / unrecognised: 0 | Not formally graded |
Suggested uses (unproven)
Where people report using it and what trials suggest
- Moderate evidenceLDL-cholesterol reduction
- Moderate evidenceBlood pressure (small effect)
- Moderate evidenceFat oxidation (acute, modest)
Where the evidence is negative
Common claims the trials do not support
- Weight-loss meta-analyses show trivial (~1 kg) effects at best.
- Cancer prevention trials null.
- EFSA flagged liver injury risk above ~800 mg/day EGCG, especially fasted.
Concentrated EGCG catechin; beverage-level intake is safe, but high-dose extracts carry a liver warning and benefits are modest.
Evidence grades reflect study quality and consistency, not marketing claims.
20studies referenced
14journals
2012–2026publication range
Ordered by strength of evidence, then result direction.
01Effectiveness of Herbal Medicines with Anti-Inflammatory, Antimicrobial, and Antioxidant Properties in Improving Oral Health and Treating Gingivitis and Periodontitis: A Systematic ReviewMalcangi G, et al. · Nutrients · 2025PMID 40077632 ↗02The Antiobesity Effects and Potential Mechanisms of TheaflavinsFang Y, et al. · Journal of medicinal food · 2024PMID 38060708 ↗03Does green tea catechin enhance weight-loss effect of exercise training in overweight and obese individuals? a systematic review and meta-analysis of randomized trialsGholami F, et al. · Journal of the International Society of Sports Nutrition · 2024PMID 39350601 ↗04Polyphenol Intervention Ameliorates Non-Alcoholic Fatty Liver Disease: An Updated Comprehensive Systematic ReviewRanneh Y, et al. · Nutrients · 2024PMID 39683546 ↗05Non-pharmacological factors for hypertension management: a systematic review of international guidelinesManiero C, et al. · European journal of preventive cardiology · 2023PMID 35947982 ↗06Efficacy and safety of dietary polyphenols in rheumatoid arthritis: A systematic review and meta-analysis of 47 randomized controlled trialsLong Z, et al. · Frontiers in immunology · 2023PMID 37033930 ↗Show all 20 studies
07Green tea promotes weight loss in women with polycystic ovary syndrome: Systematic review and meta-analysisColonetti L, et al. · Nutrition research (New York, N.Y.) · 2022PMID 35504067 ↗08Does tea extract supplementation benefit metabolic syndrome and obesity? A systematic review and meta-analysisLi X, et al. · Clinical nutrition (Edinburgh, Scotland) · 2020PMID 31174941 ↗09The effect of green tea supplementation on obesity: A systematic review and dose-response meta-analysis of randomized controlled trialsLin Y, et al. · Phytotherapy research : PTR · 2020PMID 32372444 ↗10Oral galactagogues (natural therapies or drugs) for increasing breast milk production in mothers of non-hospitalised term infantsFoong SC, et al. · The Cochrane database of systematic reviews · 2020PMID 32421208 ↗11Appetite-Suppressing and Satiety-Increasing Bioactive Phytochemicals: A Systematic ReviewStuby J, et al. · Nutrients · 2019PMID 31533291 ↗12A review on phytochemical and pharmacological properties of Litsea coreanaJia X, et al. · Pharmaceutical biology · 2017PMID 28301985 ↗13Polyphenols and Their Role in Obesity Management: A Systematic Review of Randomized Clinical TrialsFarhat G, et al. · Phytotherapy research : PTR · 2017PMID 28493374 ↗14Effects of dietary polyphenols on metabolic syndrome features in humans: a systematic reviewAmiot MJ, et al. · Obesity reviews : an official journal of the International Association for the Study of Obesity · 2016PMID 27079631 ↗15Effects of supplementation with green tea catechins on plasma C-reactive protein concentrations: A systematic review and meta-analysis of randomized controlled trialsSerban C, et al. · Nutrition (Burbank, Los Angeles County, Calif.) · 2015PMID 26233863 ↗16Preterm birth and body composition at term equivalent age: a systematic review and meta-analysisJohnson MJ, et al. · Pediatrics · 2012PMID 22891222 ↗17Effects of Green Tea Extract Supplementation on Inflammatory Cytokines Among Postmenopausal Women with Overweight or Obesity-A Secondary Analysis of a Randomized Controlled TrialCunningham A, et al. · Nutrients · 2026PMID 41515260 ↗18Anti-Inflammatory, Antithrombotic and Antioxidant Efficacy and Synergy of a High-Dose Vitamin C Supplement Enriched with a Low Dose of Bioflavonoids; In Vitro Assessment and In Vivo Evaluation Through a Clinical Study in Healthy SubjectsChrysikopoulou V, et al. · Nutrients · 2025PMID 40871671 ↗19Effects of 2-year cocoa extract supplementation on inflammaging biomarkers in older US adults: findings from the COcoa Supplement and Multivitamin Outcomes Study randomised clinical trialLi S, et al. · Age and ageing · 2025PMID 40966617 ↗20A green tea extract confection decreases circulating endotoxin and fasting glucose by improving gut barrier function but without affecting systemic inflammation: A double-blind, placebo-controlled randomized trial in healthy adults and adults with metabolic syndromeZeng M, et al. · Nutrition research (New York, N.Y.) · 2024PMID 38430822 ↗
Published research results
Reported results grouped by condition. Values and units are preserved as recorded; missing information is not estimated.
How to read this table
- Benefit
- What the trial saw happen: whether the measured outcome moved in the helpful direction in that one study (the tag on each row: “Benefit seen”, “No clear benefit”, “Possible harm” or “Unclear”). It is a study result — not advice, and not a promise it will work for you.
- Evidence
- Study design describes how research was conducted. It is not a formal certainty assessment.
- Effect size
- The result recorded in this summary. “Not reported” means the value is missing from the summary; it does not establish that the publication omitted it.
Reported direction, numerical results and study design are separate. Certainty has not been formally graded in this table.
Inflammation (1 outcome)
| What was measured | Reported findings | Result and units | Reported sample and duration | Study / source |
|---|---|---|---|---|
| plasma C-reactive protein concentrations | Green tea catechins showed no significant effect on plasma CRP vs control in 11 RCT arms. (95% CI, -0.225 to 0.395; P = 0.592)No clear benefit | 0.085 mg/L Recorded unit: mg/L | Sample (as reported): 11 RCTs arms Follow-up: <8 wk and ≥8 wk | Meta-analysis · 2015 Study detailsEffects of supplementation with green tea catechins on plasma C-reactive protein concentrations: A systematic review and meta-analysis of randomized controlled trials. Meta-Analysis |
Important: This page reflects observational, aggregate-only community reporting and independent published research. It is not medical advice, and it does not claim any compound treats, cures, or is effective for any condition. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or treatment.
Outcomes & conditions
Outcomes & conditions →Why people look into Green Tea Extract (EGCG) — and what they report
Associated conditions and community-reported outcomes, wrapped together on one page. Aggregates appear only once enough reports arrive.
Important: This page reflects observational, aggregate-only community reporting and independent published research. It is not medical advice, and it does not claim any compound treats, cures, or is effective for any condition. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or treatment.
Availability
Where to get Green Tea Extract (EGCG) (UK)
How this compound is sold in the UK, and where our readers typically find it.
Retailer search links — we may earn commission on purchases at no cost to you. Commission never affects our evidence ratings.