Green Tea Extract
Herb ·Exploratory record · not publication-reviewed ·Updated July 13, 2026
Rich in EGCG catechins for antioxidant, metabolic, and cognitive benefits.
Exploratory record, not a reviewed medical publication.
See the editorial and medical-review policies for the publication gate.
This generated database record has not completed a claim-level review by a qualified human medical reviewer. Bibliography links and evidence labels are not approval. The page remains available for reference and is excluded from search indexing.
What the research says.
A quick, data-only summary. The full evidence, dosing, and sources are below.
Green Tea Extract is a herb most often used for antioxidant, fat metabolism, cognitive function. NutriStack rates the overall evidence as strong. A typical adult dose is 250-500 mg extract daily, standardized to 50% EGCG (125-250 mg EGCG); keep total supplemental EGCG below 300 mg/day unless clinician-supervised, commonly taken as decaffeinated standardized extract. This profile indexes 19 sources.
- Antioxidant
- Fat metabolism
- Cognitive function13
- Cardiovascular health
The bottom line
Evidence rating strong. Most-documented uses: antioxidant, fat metabolism, cognitive function. 19 sources indexed (2009–2025), with 0 interaction records on file.
How it works, mechanistically.
Core mechanism
EGCG inhibits catechol-O-methyltransferase (COMT), extending catecholamine activity. Activates AMPK for fat oxidation and thermogenesis. Potent ROS scavenger.1,3
Dosing & protocol.
Take with food to reduce hepatotoxicity risk; avoid fasting use and avoid stacking multiple EGCG products3,4
What it actually costs.
Real-world pricing across three quality tiers. Assumes Decaffeinated EGCG Extract.
Assumes 250-500 mg/day. Vendor basis: NOW/iHerb, Vitacost, Life Extension, and Amazon marketplace; decaffeinated high-EGCG extracts cost more. Updated 2026-05-28.
The same dose, as food.
How much you'd eat to match a supplemental dose.
Extracts can be much more concentrated than tea and may carry higher liver-risk concerns when taken fasting.
Full safety detail.
Side effects
- Caffeine sensitivity (if not decaf)
- Hepatotoxicity risk increases with high EGCG dose, fasting use, or multiple EGCG products
- Iron absorption reduction
Sources, by evidence tier.
Numbered references. Citations throughout the page link here.
Meta-analyses & systematic reviews
12- 1Green Tea and Epigallocatechin Gallate (EGCG) for Cancer Prevention: A Systematic Review and Meta-AnalysisPMIDZhang Y, Xu Q, Hu J, Zhang F, Yu Y, Ma L · The American Journal of Chinese Medicine · 2025
Higher green tea consumption and EGCG intake were associated with reduced risk of several cancer types, with the strongest evidence for gastrointestinal and breast cancers.
- 2Effects 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 TrialsPMIDPayne ER, Aceves-Martins M, Dubost J et al. · Nutrition reviews · 2025
Payne ER, Aceves-Martins M, Dubost J et al.. 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. Nutrition reviews. 2025
- 3The effects of green tea extract supplementation on body composition, obesity-related hormones and oxidative stress markers: a grade-assessed systematic review and dose-response meta-analysis of randomised controlled trialsPMIDHosseinpour-Niazi S et al. · Br J Nutr · 2024
Daily consumption of EGCG 100-460 mg/day was effective for body fat and body weight reduction, especially in interventions of 12 weeks or more
- 4Chemoprophylaxis Effect of EGCG on the Recurrence of Colorectal Cancer: A Systematic Review and Meta-AnalysisPMIDHe B, Kang S, Su R et al. · Current Pharmaceutical Design · 2024
EGCG supplementation was associated with reduced recurrence rates of colorectal adenomas and metachronous cancers following polypectomy or resection.
- 5Therapeutic effects of epigallocatechin-3-gallate for inflammatory bowel disease: A preclinical meta-analysisPMIDWei F, Li D, Chen X et al. · Phytomedicine : international journal of phytotherapy and phytopharmacology · 2024
Wei F, Li D, Chen X et al.. Therapeutic effects of epigallocatechin-3-gallate for inflammatory bowel disease: A preclinical meta-analysis. Phytomedicine : international journal of phytotherapy and phytopharmacology. 2024
- 6Green tea and green tea extract in oncological treatment: A systematic reviewPMIDWiese F, Kutschan S, Doerfler J et al. · International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition · 2023
Wiese F, Kutschan S, Doerfler J et al.. Green tea and green tea extract in oncological treatment: A systematic review. International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition. 2023
- 7Salubrious Effects of Green Tea Catechins on Fatty Liver Disease: A Systematic ReviewPMIDAbunofal O, Mohan C · Medicines (Basel, Switzerland) · 2022
Abunofal O, Mohan C. Salubrious Effects of Green Tea Catechins on Fatty Liver Disease: A Systematic Review. Medicines (Basel, Switzerland). 2022
- 8Anti-Influenza with Green Tea Catechins: A Systematic Review and Meta-AnalysisPMIDRawangkan A, Kengkla K, Kanchanasurakit S, Duangjai A, Saokaew S · Molecules · 2021
Green tea catechins demonstrated protective effects against influenza infection and reduced the incidence of influenza-like illness in pooled analysis of clinical trials.
- 9Camellia Sinensis Mouthwashes in Oral Care: a Systematic ReviewPMIDTafazoli A, Tafazoli Moghadam E · Journal of dentistry (Shiraz, Iran) · 2020
Tafazoli A, Tafazoli Moghadam E. Camellia Sinensis Mouthwashes in Oral Care: a Systematic Review. Journal of dentistry (Shiraz, Iran). 2020
- 10Physiological effects of epigallocatechin-3-gallate (EGCG) on energy expenditure for prospective fat oxidation in humans: A systematic review and meta-analysisPMIDKapoor MP et al. · J Nutr Biochem · 2017
EGCG intake moderately accelerates energy expenditure and reduces respiratory quotient, increasing fat oxidation rates by approximately 17%
- 11The effects of green tea on weight loss and weight maintenance: a meta-analysisSource linkedPMIDHursel R, Viechtbauer W, Westerterp-Plantenga MS · Int J Obes · 2009
- 12Green tea consumption and the risk of type 2 diabetes mellitus: a systematic review and meta-analysisSource linkedPMIDJing Y, Han G, Hu Y et al. · J Intern Med · 2009
Randomized controlled trials
1- 13Acute neurocognitive effects of epigallocatechin gallate (EGCG)PMIDScholey A et al. · Appetite · 2012
EGCG administration was associated with significant increases in brain activity and increased self-rated calmness while reducing self-rated stress
Reviews & position papers
4- 14United States Pharmacopeia (USP) comprehensive review of the hepatotoxicity of green tea extractsPMIDOketch-Rabah HA et al. · Toxicol Rep · 2020
Hepatotoxicity associated with EGCG intake 140-1000 mg/day; safe intake level of 338 mg EGCG/day as bolus dose or 704 mg/day in beverage form
- 15Scientific opinion on the safety of green tea catechinsPMIDEFSA Panel (Younes M et al.) · EFSA J · 2018
Doses equal to or above 800 mg EGCG/day as a food supplement have been shown to induce significant increase of serum transaminases compared to control
- 16Green tea effects on cognition, mood and human brain function: A systematic reviewPMIDMancini E et al. · Phytomedicine · 2017
Green tea influences anxiety reduction, cognition including memory and attention benefits, and brain function activation
- 17Hepatotoxicity related to green tea: a systematic review and meta-analysisSource linkedPMIDMazzanti G, Di Sotto A, Vitalone A · Phytother Res · 2015
Reference material
2- 18Hu J, Webster D, Cao J et al.. The safety of green tea and green tea extract consumption in adults - Results of a systematic review. Regulatory toxicology and pharmacology : RTP. 2018Source linkedPMID
- 19Chen IJ, Liu CY, Chiu JP et al.. Therapeutic effect of high-dose green tea extract on weight reduction: A randomized, double-blind, placebo-controlled clinical trial. Clinical nutrition (Edinburgh, Scotland). 2016Source linkedPMID
Common questions.
Quick answers about Green Tea Extract, drawn from the data on this page.
What is Green Tea Extract?
Rich in EGCG catechins for antioxidant, metabolic, and cognitive benefits.
What is Green Tea Extract used for?
Commonly cited benefits of Green Tea Extract include: Antioxidant; Fat metabolism; Cognitive function; Cardiovascular health. NutriStack rates the overall evidence as strong.
What is a typical dose of Green Tea Extract?
A typical adult dose of Green Tea Extract is 250-500 mg extract daily, standardized to 50% EGCG (125-250 mg EGCG); keep total supplemental EGCG below 300 mg/day unless clinician-supervised. The commonly recommended form is Decaffeinated standardized extract. These are general ranges, not personalized advice; confirm the right dose with a clinician.
What are the side effects of Green Tea Extract?
Reported side effects include caffeine sensitivity (if not decaf), hepatotoxicity risk increases with high egcg dose, fasting use, or multiple egcg products, iron absorption reduction. This is educational information; check with a healthcare professional before use.
How strong is the evidence for Green Tea Extract?
NutriStack rates this as Strong, meaning multiple high-quality meta-analyses or systematic reviews converge on the same finding. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.
Use this with your stack
Green Tea Extract in NutriStack.
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