How much EGCG is in green tea?

One cup of brewed green tea contains approximately 50-90mg of EGCG, depending on brewing time and tea quality. Matcha powder contains higher concentrations, with about 130mg EGCG per gram of powder.

What is the optimal EGCG dosage for supplements?

Clinical studies typically use 300-600mg of EGCG daily, taken with meals to reduce gastric irritation. Doses above 800mg daily may increase risk of liver toxicity and should be avoided.

Does EGCG break down when heated?

EGCG is relatively heat-stable but can degrade at temperatures above 80°C (176°F) for extended periods. Cold brewing or moderate temperature brewing (70-80°C) preserves maximum EGCG content in tea.

Can EGCG supplements cause liver damage?

High-dose EGCG supplements (over 800mg daily) taken on empty stomach have been associated with hepatotoxicity in rare cases. Taking EGCG with food significantly reduces this risk.

How does EGCG compare to other antioxidants?

EGCG demonstrates 25-100 times stronger antioxidant activity than vitamins C and E in laboratory tests. It has a unique gallic acid ester group that enhances its radical scavenging capacity compared to other catechins.

Does EGCG interact with common medications?

EGCG may interact with medications metabolized by the CYP1A2 enzyme, potentially affecting how your body processes certain drugs like theophylline and some antiarrhythmics. If you take prescription medications, consult your healthcare provider before adding EGCG supplements, as timing and dosage adjustments may be necessary. Individual metabolic variation means interactions are not universal, but medical supervision is recommended for safety.

What is the most bioavailable form of EGCG?

EGCG absorption is typically highest from freshly brewed green tea, where it remains chemically intact and is absorbed in the small intestine at approximately 10–30% bioavailability. Isolated EGCG supplements may have variable bioavailability depending on formulation, with some products using phytosomes or other delivery systems to enhance absorption. Taking EGCG with vitamin C or on an empty stomach may modestly improve uptake, though individual differences in gut microbiota significantly influence actual bioavailability.

Who should avoid EGCG supplements?

Individuals with iron deficiency, liver disease, or those taking blood thinners should avoid high-dose EGCG supplementation without medical guidance, as EGCG may inhibit iron absorption and affect liver function or anticoagulant efficacy. Pregnant and breastfeeding women should limit intake to amounts found naturally in food rather than supplements, since safety data in these populations is limited. People with caffeine sensitivity should note that concentrated EGCG supplements may contain residual caffeine from green tea extraction.

Epigallocatechin gallate

Epigallocatechin gallate (EGCG) is the most abundant and potent catechin in green tea, representing up to 59% of total catechins. EGCG exerts its effects primarily through antioxidant mechanisms and modulation of cellular signaling pathways.

Category: Compound Evidence: 2/10 Tier: Emerging

Epigallocatechin gallate — Hermetica Encyclopedia

Origin & History

Epigallocatechin gallate (EGCG) is a polyphenol catechin ester derived from the leaves of the green tea plant, Camellia sinensis. It is extracted from unfermented dried leaves, achieving a purity of ≥80% by HPLC.

Historical & Cultural Context

The research does not provide any historical or traditional use information for EGCG. No traditional medicine systems or indications were mentioned.

Health Benefits

• Contains high levels of polyphenols, potentially beneficial for health [Preliminary evidence]. • May contribute to antioxidant activity, though specific human studies are lacking [Preliminary evidence]. • Potential interaction with CYP1A2 gene, suggesting metabolic effects [Preliminary evidence]. • Found in high concentrations in green tea, which is associated with various health claims [Preliminary evidence]. • Hazard classifications suggest caution in use, signaling a need for further safety studies [Preliminary evidence].

How It Works

EGCG functions as a potent antioxidant by scavenging reactive oxygen species and chelating metal ions. It modulates cellular pathways including NF-κB, MAPK, and PI3K/Akt signaling cascades. EGCG also inhibits DNA methyltransferases and may influence CYP1A2 enzyme activity, affecting caffeine metabolism.

Scientific Research

The research dossier lacks detailed clinical trials or meta-analyses on EGCG. No specific PMIDs or study designs were found.

Clinical Summary

Human studies on isolated EGCG remain limited compared to green tea extract research. Small-scale trials have examined EGCG doses ranging from 300-800mg daily for periods of 4-12 weeks. Preliminary evidence suggests potential metabolic benefits, but larger randomized controlled trials are needed. Most research focuses on green tea consumption rather than purified EGCG supplementation.

Nutritional Profile

Epigallocatechin gallate (EGCG) is a purified catechin compound, not a whole food, so traditional macronutrient/micronutrient profiling does not apply. As a bioactive polyphenol, its profile is characterized as follows: Molecular weight: 458.37 g/mol. Classified as a flavan-3-ol (catechin subclass) within the broader polyphenol superfamily. In standardized green tea extract supplements, EGCG is typically concentrated at 45–90% of total catechin content, with common doses ranging from 200–800 mg per capsule. In brewed green tea, EGCG concentration ranges approximately 50–100 mg per 240 mL serving, varying by steeping time, temperature, and tea grade. No caloric, protein, fat, or fiber content of significance. Contains no vitamins or minerals intrinsically. Bioavailability is notably limited: oral bioavailability in humans is estimated at less than 1–5% due to poor intestinal absorption, extensive first-pass metabolism, and rapid conjugation (glucuronidation, sulfation, methylation) in the gut and liver. Peak plasma concentration (Cmax) typically reached 1–2 hours post-ingestion. Food matrix effects are significant: absorption is reduced when consumed with milk proteins (casein binding) and enhanced in a fasted state. Colonic microbiota further metabolize unabsorbed EGCG into smaller phenolic acids (e.g., 4-hydroxybenzoic acid, protocatechuic acid), which may contribute secondary bioactivity. Stability is pH- and temperature-sensitive; EGCG degrades rapidly in alkaline conditions and at high temperatures.

Preparation & Dosage

No clinically studied dosage ranges or standardized forms were identified in the research. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Vitamin C, Resveratrol, Quercetin, Curcumin, Black Pepper Extract

Safety & Interactions

EGCG is generally well-tolerated at moderate doses but may cause hepatotoxicity at very high doses (over 800mg daily on empty stomach). It can enhance the effects of anticoagulant medications due to vitamin K antagonism. EGCG may interact with iron absorption and should be taken separately from iron supplements. Pregnant and breastfeeding women should limit intake due to potential caffeine content in green tea sources.