EGCG

non-nutrient/non-botanicalEGCG Octaacetate

What is it

EGCG (epigallocatechin gallate) is the most abundant and most studied catechin polyphenol in green tea. It is a flavan-3-ol with potent antioxidant activity and is responsible for many of the bioactive effects attributed to green tea.

How it works

EGCG works through several biological mechanisms. As an antioxidant, it directly scavenges free radicals and chelates redox-active metals such as iron and copper, reducing oxidative stress. It also modulates intracellular signaling, including activation of AMP-activated protein kinase (AMPK), inhibition of fatty acid synthase, and suppression of NF-kB-mediated inflammatory responses. Research suggests EGCG can inhibit angiogenesis and certain proteasome activity, which has prompted ongoing investigation into anticancer applications. It also influences insulin signaling and glucose metabolism, contributing to potential metabolic benefits. In the cardiovascular system, EGCG may improve endothelial nitric oxide production and reduce LDL oxidation. Bioavailability is the main limitation. Plasma EGCG levels after oral dosing are low (typically 0.1-1 micromolar) and the compound is rapidly cleared. Co-administration with food generally lowers plasma levels but improves safety. Fasting administration produces higher peak concentrations but is associated with hepatotoxicity in case reports.

Evidence for 5 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Antioxidant status

Grade B

Good evidence

EGCG reliably increases antioxidant capacity markers in plasma and reduces oxidative damage markers in short-term human trials.

Cardiovascular markers

Grade C

Moderate evidence

Small trials show modest reductions in LDL cholesterol and improvements in endothelial function with EGCG supplementation. Effects on blood pressure are inconsistent and typically small.

Weight management

Grade C

Moderate evidence

EGCG, particularly in combination with caffeine, has been shown to slightly increase energy expenditure and fat oxidation. Weight loss effects are modest and variable across trials.

Glucose regulation

Grade D

Mixed evidence

Some trials show modest improvements in fasting glucose or insulin sensitivity; others show no effect. Clinical relevance for diabetes management is uncertain.

Cancer prevention

Grade F

Limited evidence

Preclinical evidence is substantial but human RCTs have not consistently demonstrated cancer prevention benefits. EGCG remains an active research target rather than an evidence-based intervention.

3 commercial forms

Standardized green tea extract

EGCG content typically 45-90% by weight; absorption is improved when caffeine is present and reduced by food.

The most common supplemental form. Choose products that disclose EGCG content per serving rather than total polyphenols.

Decaffeinated EGCG extract

Plasma EGCG levels may be lower without caffeine co-administration.

Suitable for caffeine-sensitive individuals or evening use.

EGCG with piperine or phospholipid carriers

Some formulations claim improved bioavailability; clinical data are limited.

Marketed for enhanced absorption; evidence for meaningful clinical improvement remains preliminary.

Dosage

Typical supplement doses range from 200-400 mg of EGCG per day. Most clinical trials use 300-800 mg per day. The European Food Safety Authority has identified 800 mg per day from supplements as the threshold above which liver-related safety concerns become significant. There is no established RDA.

When and how to take it

Take EGCG with food to reduce the risk of liver injury and gastrointestinal upset. Earlier in the day is preferable if the formulation contains caffeine. Separate EGCG from iron supplements and iron-rich meals by 1-2 hours if iron status is a concern. Avoid taking on an empty stomach, particularly at higher doses.

Food sources

Food	Amount	%DV
Brewed green tea (1 cup)	50-100 mg EGCG	—
Matcha (1 tsp)	60-80 mg EGCG	—
White tea (1 cup)	10-50 mg EGCG	—
Black tea (1 cup)	5-20 mg EGCG	—
Oolong tea (1 cup)	10-40 mg EGCG	—

Safety

Low-to-moderate doses are generally well tolerated. Higher doses, especially when taken on an empty stomach, have been linked to liver injury in case reports. Symptoms of liver stress include nausea, abdominal pain, fatigue, dark urine, and jaundice. EGCG can also cause gastrointestinal upset, headache, and in caffeine-containing extracts, jitteriness. Iron absorption from food may be reduced when EGCG is taken with meals.

Who should be cautious

People with liver disease or elevated liver enzymes should avoid concentrated EGCG supplements. Pregnant and breastfeeding women lack adequate safety data and should avoid high-dose extracts. Individuals taking medications metabolized by CYP enzymes, those receiving cancer treatment with bortezomib, and people with iron-deficiency anemia should consult a clinician before use.

Interactions

EGCG inhibits several drug-metabolizing enzymes and transporters, with potential interactions with statins, certain beta-blockers (notably nadolol), and chemotherapy agents such as bortezomib (where EGCG may reduce efficacy). Combining EGCG with other hepatotoxic agents, including high-dose acetaminophen or alcohol, may increase liver risk. Concurrent use with iron supplements should be separated by 1-2 hours.

Frequently asked questions

What is the difference between EGCG and green tea extract?⌄

Green tea extract contains multiple catechins and other polyphenols, with EGCG being the most abundant. Standardized extracts will specify the EGCG percentage on the label.

How much EGCG is safe?⌄

Most experts consider up to 300-400 mg per day from supplements safe when taken with food. The 800 mg daily threshold from EFSA is a conservative limit above which liver risk rises.

Can EGCG cause liver damage?⌄

Rare cases of liver injury have been reported with concentrated EGCG supplements, particularly at high doses or on an empty stomach. Take with food and avoid mega-dosing to minimize risk.

Should I take EGCG with or without food?⌄

Take it with food. While fasting produces higher blood levels, it also raises the risk of liver toxicity and gastrointestinal upset.

Does EGCG really burn fat?⌄

It modestly increases energy expenditure and fat oxidation, especially when combined with caffeine. The effect is small and works best alongside diet and exercise.

References

EFSA: EGCG Safety — European Food Safety Authority link
Wikidata: EGCG — Wikidata link
PubChem: EGCG — PubChem link

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Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition.