Green Tea Extract
Green Tea Extract (EGCG)
Concentrated catechins from green tea that support metabolism, fat oxidation, brain health, and antioxidant defense.
Green Tea Extract provides concentrated catechins, particularly EGCG (epigallocatechin gallate), the most bioactive compound in green tea. Research supports benefits for fat oxidation, metabolic rate, cognitive function, and cardiovascular health. One of the most popular and well-researched herbal extracts worldwide.
Mechanisms of Action
Thermogenesis
Increases metabolic rate and fat burning
Antioxidant Activity
Powerful free radical scavenging
Cognitive Support
Supports brain function and neuroprotection
Recommended Dose
250-500mg EGCG (or 500-1000mg green tea extract)
Optimal Timing
- With meals
- Morning or pre-exercise
Take with food
Best Form
Standardized extract (45-50% EGCG)
Alternatives: Decaffeinated extract, Matcha powder
Look for extracts standardized to EGCG content. Decaf versions available for caffeine-sensitive individuals.
Duration
Minimum: 4 weeks
Optimal: 12 weeks
Cycling: 8-12 weeks on, 2-4 weeks off recommended due to liver considerations.
Note: CRITICAL: Take with food to protect liver. Avoid on empty stomach. Contains caffeine unless decaffeinated.
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Increased Fat Oxidation
Enhanced fat burning during exercise
Metabolic Boost
Modest increase in metabolic rate
Mental Clarity
Improved focus and alertness
Limit to moderate tea consumption; avoid high-dose extracts
Avoid concentrated extracts
Who Should NOT Take This
- Liver disease
- Iron deficiency anemia (take separately from iron)
- Active Liver Disease - use with caution
Drug Interactions
Reduces iron absorption — take 2+ hours apart
May reduce drug absorption
Additive stimulant effects
May have mild antiplatelet effects — may affect platelet aggregation or vitamin K-dependent clotting factors, altering anticoagulant efficacy
Reduced chemotherapy effectiveness
Possible Side Effects
Tip: Always take with food
Tip: Take earlier in day; use decaf version
Tip: Take with food; cycle usage; monitor liver enzymes
Warnings
- ALWAYS take with food — fasting use linked to liver toxicity
- Rare but serious liver injury reported with high doses on empty stomach
- Cycle usage; don't use continuously for extended periods
- Inhibits iron absorption — separate from iron supplements
Top studies from 40+ peer-reviewed papers
Filippini T et al. • The Cochrane database of systematic reviews (2020)
“Overall, findings from experimental and nonexperimental epidemiological studies yielded inconsistent results, thus providing limited evidence for the beneficial effect of green tea consumption on the overall risk of cancer or on specific cancer sites.”
Key Findings:
- For incident prostate cancer, the summary risk ratio (RR) in the green tea-supplemented participants was 0.50 (95% confidence interval (CI) 0.18 to 1.36), based on three studies and involving 201 participants (low-certainty evidence).
- The summary RR for gynaecological cancer was 1.50 (95% CI 0.41 to 5.48; 2 studies, 1157 participants; low-certainty evidence).
- No evidence of effect of non-melanoma skin cancer emerged (summary RR 1.00, 95% CI 0.06 to 15.92; 1 study, 1075 participants; low-certainty evidence).
- When comparing the highest intake of green tea with the lowest, we found a lower overall cancer incidence (summary RR 0.83, 95% CI 0.65 to 1.07), based on three studies, involving 52,479 participants (low-certainty evidence).
Lagou V et al. • European journal of preventive cardiology (2025)
“Flavan-3-ol-rich foods considerably reduce elevated BP and improve endothelial function independent of blood pressure supporting their use for cardiovascular prevention.”
Key Findings:
- Flavan-3-ol interventions included epicatechin, epigallocatechin-gallate, cocoa products, tea, grape extract, and apples delivering 586 mg (95% CI 510, 662) total flavan-3-ols.
- Interventions decreased office (-2.8 [95% CI -3.9, -1.7]/-2.0 [-2.6, -1.3] mmHg) and 24 h-ambulatory BP (-3.7 [-5.8, -1.6]/-2.6 [-4.5, -0.8] mmHg) after chronic repetitive consumption.
- Flow-mediated dilation increased after acute (+2.0% [1.6, 2.3]) and repetitive (+1.7% [1.3, 2.2]) consumption independent of BP.
- Reported adverse events were minor and low (0.4%).
Asbaghi O et al. • The British journal of nutrition (2024)
“Moreover, GTE as a nutraceutical dietary supplement can increase TAC and adiponectin.”
Key Findings:
- Pooled effect sizes indicated that BM, BFP, BMI and MDA significantly reduced following GTE supplementation.
- In addition, GTE supplementation increased adiponectin and TAC, with no effects on FM, leptin and ghrelin.
- Certainty of evidence across outcomes ranged from low to high.
- Our results suggest that GTE supplementation can attenuate oxidative stress, BM, BMI and BFP, which are thought to negatively affect human health.
He B et al. • Current pharmaceutical design (2024)
“This study demonstrated that long-term EGCG can prevent CRC recurrence to a certain extent.”
Key Findings:
- The results showed no significant publication bias or heterogeneity in the five studies (I2 = 38%; p = 0.17).
- The results were statistically significant (Z=2.83, p < 0.05).
- This study demonstrated that long-term EGCG can prevent CRC recurrence to a certain extent.
Ranneh Y et al. • Nutrients (2024)
“Still, the inconsistent results across the included RCTs require further clinical research to establish optimal dosage and duration.”
Key Findings:
- Most studies on silymarin showed a reduction in liver enzymes and lipid profile; however, no changes were observed in inflammatory cytokine levels.
- The dietary supplementation of hesperidin and naringenin or green tea extract caused improvements in liver enzyme, lipid profile, and inflammatory cytokine, while genistein supplementation did not modulate blood lipid profile.
- In conclusion, dietary supplementation of polyphenols could potentially prevent and ameliorate NAFLD.
- Still, the inconsistent results across the included RCTs require further clinical research to establish optimal dosage and duration.
Study Type Distribution
Goals This Supplement Supports
Related Goals
This information is for educational purposes only and is not intended as medical advice. Always consult a qualified healthcare provider before starting any supplement.