EGCG — Epigallocatechin Gallate (Flavan-3-ol · Metabolic Health · Antioxidant)

Compound	EGCG (Epigallocatechin Gallate)
Chemical class	Polyphenol — Flavan-3-ol Gallate
CAS	989-51-5
Primary source	Camellia sinensis (green tea leaves)
Key applications	Metabolic health, antioxidant, immune modulation
Claim strength	Moderate
Typical form	Green tea extract standardised to EGCG 50%

Name origin: EGCG is the abbreviation for epigallocatechin-3-gallate — a gallated flavan-3-ol comprising the epigallocatechin backbone with a gallic acid ester at C-3. It is the most abundant and most studied catechin in green tea. Traditional use: Inseparable from green tea’s multi-millennial use in Chinese and Japanese medicine for longevity, mental clarity, weight management, and cancer prevention. EGCG is now understood to be the primary bioactive underpinning most of green tea’s attributed benefits. Research trajectory: EGCG has one of the largest phytochemical research bodies globally, with documented activity in metabolic syndrome, obesity, oncology (preclinical), immune modulation, and antioxidant contexts. Human clinical evidence is extensive but effect sizes are often modest. Commercial source: Herbuno supplies EGCG 50% powder (standardised by HPLC) — one of the most commercially established botanical isolates.

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Evidence for EGCG Applications

Metabolic health and weight management: Multiple meta-analyses of human RCTs confirm EGCG-rich green tea extract modestly reduces body weight (mean ~1.3 kg), body fat percentage, and waist circumference. Mechanisms include sympathomimetic thermogenesis (catechol-O-methyltransferase inhibition, increasing norepinephrine), fat oxidation enhancement, and appetite modulation. Effect sizes are clinically modest but consistent. Claim strength: High.

Antioxidant and DNA protection: EGCG is one of the most potent natural antioxidants characterised, with ORAC values exceeding vitamin C and E on a molar basis. Human intervention studies show reductions in 8-OHdG (DNA oxidation marker) and plasma lipid peroxidation. Antioxidant mechanistic action is well-validated. Claim strength: High.

Immune modulation and anti-inflammatory: EGCG inhibits NF-κB, reduces pro-inflammatory cytokines, and modulates T-regulatory cell activity. Human studies in inflammatory conditions show modest but consistent anti-inflammatory effects. The gallate moiety is considered key to EGCG’s superior activity versus non-gallated catechins. Claim strength: Moderate.

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Dosage & Formulator Specification

Clinically studied range: 300–800 mg/day EGCG for metabolic and antioxidant applications, typically in two to three divided doses with meals. The EFSA safe upper level guidance is 800 mg/day EGCG from supplements; higher doses have been associated with rare hepatotoxic events particularly in fasted state.

Herbuno’s EGCG 50% powder: 1 g of extract delivers 500 mg EGCG. For a 400 mg/day EGCG dose, 800 mg extract per day (divided doses). Specify minimum 45–50% EGCG by HPLC with full catechin profile; ensure caffeine content is declared (green tea extract naturally contains residual caffeine unless decaffeinated).

EGCG bioavailability is best in a fasted state but hepatotoxicity risk is also higher fasted. Recommend with food for long-term use. Aqueous solubility is reasonable; suitable for capsule, tablet, and powder sachets. Sensitive to oxidation — use nitrogen-flushed packaging; avoid iron- or copper-containing co-ingredients.

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Frequently Asked Questions — EGCG

Why is EGCG considered superior to other green tea catechins?
EGCG has a gallic acid ester group at C-3 that non-gallated catechins lack. This significantly increases its binding affinity for target proteins (including COMT, eNOS, and various kinases), radical-scavenging capacity, and membrane interaction. EGCG accounts for approximately 50–80% of total catechin content in green tea and has the most extensive clinical evidence of any single tea catechin.

What is the hepatotoxicity risk with EGCG and how do formulators manage it?
Rare idiosyncratic hepatotoxic events have been reported with concentrated EGCG supplements, predominantly at doses above 800 mg/day and when taken on an empty stomach. Risk mitigation: keep EGCG at or below 400–600 mg/day per serving, recommend taken with food, include liver health advisory language for long-term use, and specify decaffeinated extract if targeting populations sensitive to caffeine co-load.

Does EGCG interact with chemotherapy agents?
Preclinical data suggest EGCG may potentiate or antagonise certain chemotherapy drugs depending on the agent and concentration. This is an area of active oncology research. Formulators should include advisory language recommending consultation with an oncologist for individuals undergoing cancer treatment.

Is decaffeinated green tea extract equivalent to standard EGCG extract?
For EGCG-specific benefits, yes. Decaffeination removes methylxanthines (caffeine, theobromine) but preserves catechin content if done via CO2 or water-based processes. Solvent decaffeination can also remove some catechins. For stimulant-free supplement formulations, specify CO2-decaffeinated green tea extract with verified EGCG content by HPLC.

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Claim-strength scale – High = multiple human RCTs; Moderate = limited trials or strong preclinical convergence; Emerging = early-stage lab or animal data.

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