Green Tea Extract (EGCG) for Fatty Acid Oxidation

Green tea catechins produce a small, real increase in fat oxidation, but the magnitude is too small to matter for body composition on its own.

Overview

Green tea catechins produce a small, real increase in fat oxidation, but the magnitude is too small to matter for body composition on its own.

Verdict

Mixed evidence

A measurable metabolic effect that does not translate into meaningful fat loss.

How It Works

EGCG inhibits catechol-O-methyltransferase, prolonging noradrenaline signalling and increasing lipolysis and thermogenesis, an effect amplified by caffeine.

Dosing & Protocol

Typical dose

Recommended dose: 250-500 mg EGCG daily with food
Expected timeframe: 8-12 weeks

Protocol

form: Extract standardised for EGCG; brewed tea at 3-5 cups daily is a safer equivalent
duration: 8-12 weeks
co factor: Take with food, and where the goal is exercise fat oxidation, 60-90 minutes beforehand. Evidence is mixed. Several crossover studies using indirect calorimetry report that green tea extract increases fat oxidation during moderate-intensity exercise by around 10-17%, with EGCG inhibiting catechol-O-methyltransferase and prolonging noradrenaline signalling as the mechanism. Other trials find no effect, results differ by training status and habitual caffeine intake, and the absolute quantities involved are small - a shift of a few grams of fat per hour of exercise. Crucially, higher fat oxidation during exercise does not equal greater fat loss, which is governed by total energy balance across the day.
titration: Up to 400 mg/day of extract; never above 800 mg/day EGCG
starting dose: 300 mg/day of standardised extract with food

Evidence

What the studies say

Meta-analyses show increased 24-hour energy expenditure of roughly 100 kcal and modest increases in fat oxidation, with weight loss averaging under 1.5 kg over 12 weeks. Effects are smaller in habitual caffeine consumers and in East Asian populations.

Physiological effects of epigallocatechin-3-gallate (EGCG) on energy expenditure for prospective fat oxidation in humans: A systematic review and meta-analysis

Score: 8/10

2017

meta_analysis

Kapoor MP, Sugita M, Fukuzawa Y

Green tea catechins (GTCs) are known to improve fat oxidation (FOX) during fasted, rested and exercise conditions

View source

Safety

Caveats

High-dose concentrated extracts have caused hepatotoxicity; take with food and avoid fasted high doses. Interacts with nadolol and reduces non-haem iron absorption.

Less likely to help if

Habitual caffeine consumers and anyone expecting a substitute for a calorie deficit.

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