Supplements

green tea causes liver injury

In plain terms: Is green tea bad for your liver?

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

RefutedContestedStrong support

consensus score 0.34

Brewed green tea is safe. The risk is with concentrated green-tea-EXTRACT supplements — especially high doses on an empty stomach — which can, rarely, cause serious liver injury (regulators added warning labels, and some people are genetically more susceptible). 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

9 support 1 contradict 3 tested null 2 mixed · 15 sources, 10 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 15 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.

About Cochrane ↗ · Get involved / support ↗

Read the Cochrane review ↗

The evidence (15)

Source	Grade	Stance	Quality	Finding
Zheng EX et al. 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 et al. 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 et al. 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 et al. 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 et al. 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 et al 2026 · study_type: animal	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 et al 2025 · study_type: observational	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 et al. 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 et al 2026 · study_type: observational	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 et al. 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 et al. 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 et al. 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 et al 2026 · study_type: meta-analysis	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 et al. 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 L et al. 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.

Disagree, or know a study we missed?

We grade by evidence, not opinions. The way to weigh in is to point us to a study we haven't cited (check the evidence table above first), or to flag a problem with one we have. Every submission is reviewed; if it holds up, the grade updates and shows in Science Changes Its Mind.

📚 Suggest a study ⚑ Flag / request reclassification

Opens a short form. You'll sign in with Google so submissions are tied to a real account — we don't display your identity, and we only accept a link we can verify (PubMed, DOI, ClinicalTrials.gov).

Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.