Supplements

green tea extract causes liver injury

In plain terms: Can green tea extract supplements damage your liver?

Leans support Supplements 🔬 Includes disconfirming🔎 Limited evidence — fewer than 12 studies

RefutedContestedStrong support

consensus score 0.34

Yes, rarely — concentrated green-tea-extract supplements, especially high doses on an empty stomach, can cause serious liver injury; regulators added warning labels, and some people are genetically more susceptible. Brewed green tea is safe. Drink the tea; be cautious with the pills.

📅 Last reviewed: 2026-07-15 ⓘ

Evidence ladder

How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."

Top evidence so far: Human trials (RCT / n-of-1)

MechanismIn-vitroAnimalObservationalRCTMeta-analysis

How the studies fall

5 support 1 contradict 3 tested null 2 mixed · 11 sources, 6 independent groups

What the evidence shows

A real safety signal — but scoped tightly. Concentrated, high-dose green tea EXTRACT supplements (especially taken on an empty stomach) can cause idiosyncratic liver injury; the USP added cautionary labeling, an RCT was halted for liver-enzyme rises, and genetic susceptibility (COMT/UGT) raises risk. Brewed green tea as a beverage is considered safe — the concern is the concentrated pills.

Cochrane agrees with us see how our grade compares ▾

Cochrane review 2020 · not GRADE-rated for hepatotoxicity Agrees with our grade

adverse events reported narratively; primary outcome was cancer prevention)

“Adverse effects of green tea extract intake were reported, including gastrointestinal disorders, elevation of liver enzymes, and, more rarely, insomnia, raised blood pressure and skin/subcutaneous reactions. The studies also indicated the occurrence of several side effects associated with high intakes of green tea.”

Why we agree: we reached the same direction independently, from our own appraisal of 11 sources. Two methods landing in the same place is a stronger signal than either alone.

What is Cochrane, and why trust it?

Cochrane produces systematic reviews: instead of running a new study, they gather every trial ever done on a question, judge how well each was run, and pool the results. They take no commercial or industry funding, which is why the medical community treats their reviews as a gold standard — and why we check our own verdicts against theirs.

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The evidence (15)

Source	Grade	Stance	Quality	Finding
Zheng EX, Rossi S, Fontana RJ, Vuppalanchi R, Hoofnagle JH, Khan I, Navarro VJ 2016 · Drug Saf	observational	supports	high	DILIN prospective registry: 6 RUCAM-adjudicated liver-injury cases from GTE weight-loss products (extract, not beverage).
Patel SS, Beer S, Kearney DL, Phillips G, Carter BA 2013 · World J Gastroenterol	observational	supports	low	Case report: adolescent on a weight-loss GTE product - biopsy-confirmed acute hepatocellular injury / impending liver failure.
Ballotin VR, Bigarella LG, Brandão ABM, Balbinot RA, Balbinot SS, Soldera J 2021 · World J Clin Cases	observational	supports	moderate	Systematic review/meta of herb-induced liver injury: green tea extract among top implicated botanicals (hepatocellular pattern).
Sarma DN, Barrett ML, Chavez ML, Gardiner P, Ko R, Mahady GB, Marles RJ, Pellicore LS, Giancaspro GI, Low Dog T 2008 · Drug Saf	observational	supports	moderate	Original USP review (216 case reports): concentrated extract on an empty stomach more likely linked to liver injury than fed-state - prompted cautionary labeling.
Oketch-Rabah HA, Roe AL, Rider CV, Bonkovsky HL, Giancaspro GI, Navarro V, Paine MF, Betz JM, Marles RJ, Casper S, Gurley B, Jordan SA, He K, Kapoor MP, Rao TP, Sherker AH, Fontana RJ, Rossi S, Vuppalanchi R, Seeff LB, Stolz A, Ahmad J, Koh C, Serrano J, Low Dog T, Ko R 2020 · Toxicol Rep	observational	supports	high	USP comprehensive review: hepatotoxicity linked to bolus-dose/fasted concentrated EGCG (case reports 140-1000 mg/d), hepatocellular pattern, genetic susceptibility - concentrated EXTRACT, not brewed tea.
Rubab HH, Riaz N, Zubair F, Saleem M 2026 · Scientific reports	animal	contradicts	low	Mouse study explicitly evaluated hepatotoxicity of green tea extract alone (20 mg/kg/day, low dose) vs pesticide-induced injury; GT alone showed no hepatotoxic signal and mitigated pesticide-induced ALT/ALP rises.
Ferrari E, Naponelli V 2025 · Molecules (Basel, Switzerland)	observational	mixed	moderate	Systematic survey of 17 clinical studies of green tea extract/EGCG; concludes benefits outweigh risks but flags a 'toxicity and detoxification' category and stresses genotyping importance for interpreting liver-injury biomarkers from catech
Acosta L, Byham-Gray L, Kurzer M, Samavat H 2022 · J Diet Suppl	RCT	supports	moderate	Minnesota Green Tea Trial (n=1,075, 843 mg/d EGCG x12 mo): COMT/UGT genotype-dependent ALT/AST elevations - genetic susceptibility to extract hepatotoxicity.
Björnsson ES, Andrade RJ 2026 · Journal of internal medicine	observational	supports	moderate	DILI update review states HLA-B35:01 has been identified as a genetic risk factor for green-tea-extract-induced liver injury, grouped with other HDS causing DILI (turmeric, Garcinia, kratom, ashwagandha).
Nederveen JP, Mastrolonardo AJ, Xhuti D, Di Carlo A, Manta K, Fuda MR, Tarnopolsky MA 2023 · Nutrients	RCT	tested-null	low	RCT: multi-ingredient supplement incl. 500 mg GTE x12 wk - ALT/AST IMPROVED vs placebo, no hepatotoxic signal (GTE co-administered - confounded).
Lovera J, Ramos A, Devier D, Garrison V, Kovner B, Reza T, Koop D, Rooney W, Foundas A, Bourdette D 2015 · J Neurol Sci	RCT	supports	moderate	Phase II RCT Polyphenon E (800 mg/d EGCG) in MS: halted early after 5/7 treated developed abnormal liver enzymes - high-dose extract can cause serious hepatotoxicity.
Hu J, Webster D, Cao J, Shao A 2018 · Regul Toxicol Pharmacol	meta-analysis	mixed	moderate	Systematic review 159 trials: hepatic adverse events only with concentrated bolus catechins, NOT beverage/with-food; safe bolus intake ~338 mg EGCG/d (704 mg/d as beverage).
Zhao Y, Wang Z, Xu M, Wang M, Wang F, Pang H, Liu Y, Li X, Li H, Zhang W, Song H, Shi R, Lin J, Wang Z, Wang Y, Jiang H 2026 · Frontiers in medicine	animal	supports	low	Systematic review + meta-analysis of 63 animal studies (738 animals) of EGCG in digestive disease; explicitly reports high-dose EGCG alone induces hepatotoxicity, worsened under inflammatory conditions. Toxic doses substantially exceed norm
Isomura T, Suzuki S, Origasa H, Hosono A, Suzuki M, Sawada T, Terao S, Muto Y, Koga T 2016 · Eur J Clin Nutr	meta-analysis	tested-null	moderate	Meta 34 RCTs: liver-related adverse events (mild enzyme rises) rare, not significantly different from placebo (OR 2.1, CI 0.5-9.8).
He AR, Smith CI, Cruz-Correa M, Chakraborty R, Zhang S, Sang S, Cheng G, Hecht SS, Bazzi LA, Kocherginsky M, Benante KA, Schering T, Richmond E, Rodriguez LM, Khan SA, Chung FL 2025 · Cancer Prev Res	RCT	tested-null	high	Phase I dose-escalation (cirrhosis, Polyphenon E 400-2000 mg/d x24 wk): well-tolerated to 1600 mg, no serious hepatotoxicity reached.

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