Outcome
    Moderate Evidence

    Green Tea Extract (EGCG) for Thermogenic Effect

    Green tea catechins raise energy expenditure slightly, with trivial weight effects.

    Overview

    Green tea catechins raise energy expenditure slightly, with trivial weight effects.

    Verdict

    Insufficient evidence

    How It Works

    EGCG inhibits catechol-O-methyltransferase, prolonging noradrenaline-driven thermogenesis, synergistically with caffeine.

    Dosing & Protocol

    Typical dose

    Recommended dose
    300-500mg EGCG daily with food
    Expected timeframe
    8-12 weeks

    Protocol

    form
    Not applicable
    duration
    Not applicable
    co factor
    Evidence is insufficient for a meaningful thermogenic effect. The effect itself is real and reproducible: metabolic chamber studies show catechin-caffeine combinations increase 24-hour energy expenditure by around 3-4%, roughly 60-100 kcal/day, via COMT inhibition prolonging noradrenaline action. What is insufficient is evidence that this matters. Partial tolerance develops over weeks, habitual caffeine consumers show attenuated responses, and the body compensates for small expenditure increases through reduced spontaneous movement and increased appetite - which is why the corresponding weight-loss trials show only about 1-1.5 kg over 12 weeks. Thermogenic marketing implies a mechanism that delivers far more than the trials show.
    titration
    Not applicable
    starting dose
    Not applicable as a treatment - the measured effect is too small to matter clinically

    Evidence

    What the studies say

    Meta-analyses show modest increases in energy expenditure and fat oxidation with average weight loss of well under 1.5kg. Effects diminish in habitual caffeine consumers.

    Green tea supplementation and body weight: a null randomized controlled trial in postmenopausal women

    Score: 9/10
    2016
    rct
    n=937

    Dostal AM, Samavat H, Bedell S +8 more

    Green tea extract produced no significant change in body weight, BMI or body composition compared with placebo over one year

    View source

    Green tea catechins with or without caffeine and energy expenditure: a meta-analysis

    Score: 7/10
    2011
    meta_analysis

    Hursel R, Viechtbauer W, Dulloo AG +4 more

    Catechin-caffeine mixtures significantly increased 24-hour energy expenditure by roughly 4-5%

    View source

    Effects of green tea catechins with or without caffeine on energy expenditure and fat oxidation: a meta-analysis

    Score: 8/10
    2011
    meta_analysis

    Hursel R, Viechtbauer W, Dulloo AG +3 more

    Catechin-caffeine mixtures raised 24-hour energy expenditure by roughly 4-5%

    View source

    Safety

    Caveats

    High-dose extracts have caused liver injury. Take with food, avoid fasted high doses.

    Less likely to help if

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

    Medical Disclaimer

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    Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.