Home Ingredients EGCG (Epigallocatechin Gallate)
AntioxidantWeight ManagementLongevity

EGCG (Epigallocatechin Gallate)

Evidence Level
Moderate
2 Clinical Trials
5 Documented Benefits
3/5 Evidence Score

EGCG (epigallocatechin gallate) is the most abundant and most studied catechin in green tea — accounts for 50-80% of total green tea catechins. Standalone EGCG supplements provide concentrated doses without caffeine or other tea compounds. Studied for weight management, antioxidant effects, cancer prevention, neuroprotection. Critical hepatotoxicity warning: EGCG at supplemental doses (especially fasted, >800 mg/day) has caused liver injury — EFSA established 800 mg/day safety limit for supplemental EGCG.

Studied Dose 200-400 mg/day general use; 400-800 mg/day weight management trials; CRITICAL — EFSA safety limit 800 mg/day for supplemental EGCG due to hepatotoxicity
Active Compound (-)-Epigallocatechin-3-gallate (EGCG)

Benefits

Antioxidant Activity

EGCG is one of the most potent natural antioxidants — neutralizes reactive oxygen species directly and supports endogenous antioxidant systems (Nrf2 pathway). In vitro activity exceptional; clinical translation more modest.

Supported by Trial 1, Trial 2

Weight Management Modest Effects

Hursel 2011 and Phung 2010 meta-analyses show EGCG (especially with caffeine) modestly increases energy expenditure (~4-5% increase) and fat oxidation — translating to modest weight loss (~1-2 kg) over 12 weeks. Effect small; lifestyle intervention foundational.

Supported by Trial 1

Cardiovascular Risk Reduction

Green tea consumption (especially Asian populations) associated with reduced CV mortality in observational studies. EGCG may reduce LDL oxidation, improve endothelial function. RCT evidence less robust than observational.

Supported by Trial 2, Trial 1

Cancer Prevention Research

Extensive in vitro and animal evidence for cancer prevention via multiple mechanisms (apoptosis induction, angiogenesis inhibition, DNA methylation). Human clinical trials more modest. Not established cancer therapy.

Supported by Trial 1

Neuroprotection Research

EGCG crosses blood-brain barrier and has neuroprotective effects in animal models of Alzheimer's, Parkinson's. Human translation limited; popular component of nootropic stacks.

Supported by Trial 2

Mechanism of action

1

Direct Antioxidant Activity

EGCG's gallate group makes it one of the most potent direct antioxidants in nature — directly scavenges hydroxyl radicals, peroxyl radicals, superoxide. Particularly effective at neutralizing peroxynitrite.

2

Catechol-O-Methyltransferase (COMT) Inhibition

EGCG inhibits COMT — the enzyme that degrades catecholamines and EGCG itself. Slows norepinephrine breakdown, prolonging thermogenic effects (basis for weight management mechanism).

3

Multiple Cellular Targets

EGCG modulates: Nrf2 (antioxidant response), NF-κB (inflammation), AMPK (energy sensing), PI3K/Akt (growth signaling), MAPK pathways. Pleiotropic effects basis for diverse health claims.

4

Pro-Oxidant at High Doses (Hepatotoxicity)

Paradoxically, at high concentrations EGCG can act as pro-oxidant — generating reactive oxygen species. May explain hepatotoxicity at supplemental megadoses, particularly in fasted state when liver concentrations peak.

Clinical trials

1
EGCG/Green Tea for Weight Loss

Pooled analysis of green tea catechins (with and without caffeine) for weight loss across multiple clinical trials.

Pooled across weight loss clinical trials.

Catechins (with caffeine) modestly reduce weight (~1.3 kg over 12 weeks), waist circumference, BMI vs placebo. Effect smaller without caffeine. Catechins alone less effective than combination with caffeine.

2
EGCG Hepatotoxicity — EFSA Safety Assessment

EFSA 2018 scientific opinion on safety of green tea catechins, particularly supplemental EGCG hepatotoxicity.

Safety assessment.

Supplemental EGCG ≥800 mg/day associated with hepatotoxicity cases (elevated liver enzymes, hepatitis, rare acute liver failure); risk increased when taken fasted. EFSA established 800 mg/day as safety limit for supplemental EGCG. Tea consumption itself generally safe due to lower bioavailability.

Side effects and drug interactions

Common Potential side effects

Hepatotoxicity — most concerning; supplemental EGCG (especially ≥800 mg/day, fasted) has caused liver injury; symptoms include nausea, abdominal pain, jaundice, dark urine, fatigue; can be severe; obtain LFTs at baseline and periodically with chronic high-dose use.
GI distress (nausea, vomiting) — particularly with fasted high doses.
Headache.
Insomnia (typically from caffeine in green tea, not EGCG itself).
Increased blood pressure occasionally.
Rare allergic reactions.

Important Drug interactions

Bortezomib (chemotherapy) — EGCG may reduce bortezomib activity; avoid combination during chemotherapy; consult oncologist.
Anticoagulants (warfarin) — EGCG/catechins may modestly affect coagulation; theoretical interaction.
Beta-blockers — green tea catechins may interfere; theoretical.
Iron — catechins reduce non-heme iron absorption (~50%); separate iron supplements by 1-2 hours.
Folic acid — EGCG inhibits dihydrofolate reductase; theoretical concern.
Caffeine — additive stimulant effects (relevant when EGCG is from green tea).
Hepatotoxic drugs (acetaminophen, methotrexate, isoniazid) — additive liver toxicity risk.

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Frequently asked questions about EGCG (Epigallocatechin Gallate)

How much EGCG or green tea extract should I take?

Studies use a range, often 250 to 500 mg of EGCG per day, which a standardized green tea extract supplies in a capsule or two. To stay on the safe side, keep EGCG from supplements at or below about 800 mg per day.

What is EGCG used for?

EGCG (epigallocatechin gallate) is the main catechin in green tea, studied for antioxidant support, metabolism and weight management, and cardiovascular health. It is the compound behind much of green tea's reputation.

Should I take green tea extract with or without food?

For safety, take green tea extract with food. While taking it on an empty stomach may slightly increase absorption, doing so has been linked to a higher risk of liver irritation, so taking it with a meal is the prudent choice.

Is green tea extract safe for the liver?

Drinking green tea is very safe, but concentrated EGCG supplements have, in rare cases, been linked to liver injury, especially at high doses on an empty stomach. Take it with food, keep doses moderate, and stop if you notice symptoms like dark urine or yellowing skin.

What is EGCG?

EGCG (epigallocatechin gallate) is the most abundant and most studied catechin in green tea — accounts for 50-80% of total green tea catechins. Standalone EGCG supplements provide concentrated doses without caffeine or other tea compounds.

What is the recommended dosage of EGCG?

The clinically studied dose is 200-400 mg/day general use; 400-800 mg/day weight management trials; Critical — EFSA safety limit 800 mg/day for supplemental EGCG due to hepatotoxicity Always follow the product label and check with a healthcare provider for personal advice.

Is EGCG safe, and does it have side effects?

For most healthy adults, EGCG is well tolerated at studied doses. Reported effects can include: Hepatotoxicity — most concerning; supplemental EGCG (especially ≥800 mg/day, fasted) has caused liver injury; symptoms include nausea, abdominal pain, jaundice, dark urine, fatigue; can be severe; obtain LFTs at baseline and periodically with chronic high-dose use. It may also interact with some medications. EGCG is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does EGCG interact with any medications?

Possible interactions include: Bortezomib (chemotherapy) — EGCG may reduce bortezomib activity; avoid combination during chemotherapy; consult oncologist. Anticoagulants (warfarin) — EGCG/catechins may modestly affect coagulation; theoretical interaction. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for EGCG?

NutraSmarts rates the evidence for EGCG as Moderate (3 out of 5). It is backed by 2 clinical trials and 1 cited reference summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(1 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Kapoor MP, Sugita M, Fukuzawa Y, et al. Physiological effects of epigallocatechin-3-gallate (EGCG) on energy expenditure for prospective fat oxidation in humans: A systematic review and meta-analysis. J Nutr Biochem. 2017;43:1-10..PubMedUsed to support: Meta-analysis on EGCG, energy expenditure, and fat oxidation in humans.