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Green tea extract (EGCG) at 400-500 mg/day modestly increases metabolic rate and fat oxidation. A Cochrane review found green tea catechins reduced body weight by ~1.3 kg over 12 weeks. Effects are modest but consistent. Caffeine-containing formulations show stronger effects.
Green tea extract is one of the better-studied natural thermogenic agents, with a Cochrane review confirming modest but statistically significant weight loss. The mechanism involves COMT inhibition, which prolongs norepinephrine signaling and increases energy expenditure. Effects are enhanced by caffeine and exercise. Safety concerns center on rare hepatotoxicity at high doses — staying under 800 mg EGCG/day and taking with food mitigates this risk.
Green tea extract is one of the better-studied natural thermogenic agents, with a Cochrane review confirming modest but statistically significant weight loss.
| Form | Bioavailability | Best For |
|---|---|---|
| Standardized EGCG Extract | Moderate | Concentrated catechins without excessive caffeine |
| Green Tea Extract (with caffeine) | Moderate | Synergistic formula — caffeine enhances EGCG thermogenic effects |
| Decaffeinated Green Tea Extract | Moderate | Caffeine-sensitive individuals — still provides EGCG benefits |
General recommendation: 400-500 mg EGCG daily, or 500-1,000 mg green tea extract (standardized to 50% EGCG)
Timing: Take between meals or before exercise; avoid on empty stomach if sensitive
| Condition | Recommended Dose | Evidence |
|---|---|---|
| Weight management | 400-500 mg EGCG daily | Moderate |
| Fat oxidation during exercise | 300-400 mg EGCG 60-90 min before exercise | Moderate |
Upper limit: 800 mg EGCG/day; higher doses associated with liver toxicity reports
Safety profile: Generally Safe
Clinical trials show modest weight loss of 1-2 kg over 12 weeks beyond what diet alone achieves. This is not dramatic, but combined with exercise and calorie control, green tea extract provides a consistent thermogenic boost. The combination with caffeine and exercise amplifies results.
At standard doses (400-500 mg EGCG/day), green tea extract is safe for most people. Rare liver injury reports are associated with high-dose (>800 mg EGCG) fasted supplementation. To minimize risk: stay under 800 mg EGCG/day, take with food, and avoid combining with other hepatotoxic substances.
Studies show EGCG + caffeine is more effective for fat oxidation than EGCG alone. If you tolerate caffeine well, choose a formula that includes both. If caffeine-sensitive, decaffeinated EGCG still provides benefits, just slightly less thermogenic effect.