Green Tea Extract (EGCG)
Camellia sinensis
Catechin-rich extract with modest metabolic and lipid effects—and a real high-dose liver caveat.
Evidence tier
Mixed
Research weight
Citations
19 verified / 19
Classification
Heart & Metabolic
❝
What the evidence says. Conflicting results across studies; benefit uncertain.
What is Green Tea Extract (EGCG)?
Green Tea Extract (EGCG) (Camellia sinensis) is a heart and metabolic supplement used for may modestly lower ldl and total cholesterol (roughly 5-6 mg/dl on average in pooled trials).. NutriDex grades the human evidence as Mixed. Green tea extract concentrates the catechins of Camellia sinensis, chiefly epigallocatechin gallate (EGCG), and is marketed for weight loss, cardiovascular health, and antioxidant support. The human evidence is mixed: pooled randomized trials show small but statistically significant reductions in LDL/total cholesterol and modest decreases in body weight, body fat, and waist circumference, but effects on blood pressure and on weight beyond what exercise alone achieves are weak and inconsistent. These benefits are real but modest, and brewed green tea delivers far lower catechin doses than concentrated extract capsules. The most important caveat is safety, not efficacy: high-dose green tea EXTRACTS (unlike brewed tea) have been linked to rare but serious idiosyncratic hepatotoxicity, with case reports spanning EGCG intakes of 140-1000 mg/day and elevated liver enzymes seen above about 800 mg/day. Susceptibility appears highly individual and may be genetically influenced, so taking the extract with food and at conservative doses is prudent.
Purported Benefits
✓May modestly lower LDL and total cholesterol (roughly 5-6 mg/dL on average in pooled trials).
✓Small reductions in waist circumference, body weight, and body fat, especially when paired with exercise or calorie restriction.
✓May slightly raise HDL and lower triglycerides in overweight/obese people, though effects are inconsistent.
✓Provides catechin antioxidants (notably EGCG) that scavenge free radicals in vitro; clinical longevity benefit is unproven.
✓Blood-pressure effects are weak and inconsistent—at most a small drop in diastolic pressure, with no reliable systolic effect.
Evidence by outcome
The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.
| Outcome | Evidence | Effect | Studies |
|---|---|---|---|
| Lower LDL / total cholesterolMultiple RCT meta-analyses show ~5-6 mg/dL LDL/TC reduction, but trials confined to overweight/obese sometimes find no LDL effect. | Moderate | ↑ benefit · small | 3 |
| Reduced body weight / fat / waist circumference59-RCT meta-analysis shows small but significant weight/BMI/body-fat reductions; benefit beyond exercise alone is minimal. | Moderate | ↑ benefit · small | 3 |
| Raised HDL / lowered triglyceridesSignificant in overweight/obese catechin trials but inconsistent across the broader RCT pool. | Mixed | ↔ mixed · small | 2 |
| Lower blood pressureAt most ~1 mmHg DBP/SBP reductions; systolic effect unreliable and clinically trivial. | Mixed | ↑ benefit · negligible | 2 |
| Improved glycemic control (HbA1c / fasting glucose)41-RCT meta-analysis found ~0.18% HbA1c and small glucose reductions; below clinical-importance threshold, no insulin effect. | Moderate | ↑ benefit · negligible | 2 |
| Idiosyncratic hepatotoxicity (high-dose extract)USP safety review links extract (not brewed tea) to rare serious liver injury above ~800 mg/day EGCG with high individual susceptibility. | Moderate | ⚠ risk | 2 |
Dosing & Compounds
Typical Dose
Commonly 250-500 mg/day of standardized extract providing roughly 100-300 mg EGCG. Take with food (not fasted) and avoid bolus doses; keep total EGCG well below 800 mg/day, the threshold associated with elevated liver enzymes.
Active Compounds
Safety & Cautions
Concentrated green tea EXTRACTS (unlike ordinary brewed tea) carry a rare but documented risk of serious idiosyncratic liver injury (hepatocellular pattern), reported across EGCG doses of 140-1000 mg/day; liver-enzyme elevations are more likely above ~800 mg/day EGCG. To reduce risk, take with food rather than fasted, avoid large single (bolus) doses, and discontinue immediately if you develop jaundice, dark urine, abdominal pain, or unusual fatigue. Avoid in people with existing liver disease or elevated liver enzymes; not recommended in pregnancy or breastfeeding (high catechin intake may reduce folate availability). Caffeinated extracts can cause insomnia, jitteriness, and raised heart rate—choose decaffeinated forms or limit other caffeine. Green tea may reduce absorption of iron (take apart from iron-rich meals/supplements and consider pairing with vitamin C) and can interact with anticoagulants/antiplatelets (it contains some vitamin K and affects platelet function), with the chemotherapy agent bortezomib (EGCG may blunt its effect), and with stimulant or blood-pressure medications. People on multiple medications, the elderly, and anyone with hepatic or cardiac conditions should consult a clinician before use. Educational only — always check with your doctor or pharmacist before combining Green Tea Extract (EGCG) with any medicine.
Green Tea Extract (EGCG) drug interactions
Known or theoretical interactions between Green Tea Extract (EGCG) and common medications — educational, not exhaustive. Always check with your doctor or pharmacist before combining Green Tea Extract (EGCG) with any medicine.
Caution
Nadolol (beta-blocker)
Green tea sharply reduces nadolol absorption (~85%), blunting its BP-lowering effect.
Catechins (EGCG) inhibit intestinal OATP1A2 uptake transporters, cutting nadolol bioavailability. MSKCC — Green Tea
Caution
Bortezomib & some chemotherapy
Green tea/EGCG can inactivate bortezomib and may interfere with some chemo — discuss with oncologist.
EGCG forms a boronate complex with bortezomib, blocking its action. MSKCC — Green Tea
Key Studies ★ 19 studies
GRADE-assessed systematic review and dose-response meta-analysis of RCTs
36 RCTs (GRADE-assessed dose-response)
✓ PubMed
In a 2025 GRADE-assessed dose-response meta-analysis, green tea supplementation modestly lowered systolic blood pressure (WMD -1.08 mmHg, 95% CI -1.98 to -0.18) and diastolic blood pressure (WMD -1.09 mmHg, 95% CI -1.67 to -0.50), with larger effects in participants with elevated baseline BP, doses under 500 mg/day, Asian populations, and women.
Meta-analysis
Xu 2023 (Front Nutr)
✓ Full text
Meta-analysis of 55 RCTs (4,874 participants) found green tea supplementation significantly reduced LDL cholesterol (WMD -5.80 mg/dL; 95% CI -8.30 to -3.30; P<0.001) and total cholesterol (WMD -7.62 mg/dL; 95% CI -10.51 to -4.73), and raised HDL (WMD +1.85 mg/dL).
Meta-analysis
Heliyon 2023
✓ Full text
Meta-analysis of 11 RCTs (613 participants) in overweight/obese adults found green tea catechins had NO significant effect on LDL (WMD -0.13; 95% CI -0.30 to -0.04; P=0.129) or total cholesterol (WMD -0.19; P=0.142), with benefit only for triglycerides and HDL.
Systematic review
Ferrari & Naponelli 2025 (Molecules)
✓ Full text
Systematic review of 17 recent clinical studies (2022-2024) on EGCG/green tea catechins covering metabolism, toxicity, pharmacokinetics, cognition and inflammation, summarizing therapeutic benefits and potential hepatotoxicity risks of high-dose EGCG.
Meta-analysis
Asbaghi et al. 2023 (British Journal of Nutrition)
✓ PubMed
GRADE-assessed dose-response meta-analysis of 59 RCTs (3802 participants): green tea extract supplementation significantly reduced body mass, BMI, body fat percentage and malondialdehyde, and increased adiponectin and total antioxidant capacity; no significant effect on fat mass, leptin or ghrelin.
Meta-analysis
Xu et al. 2020 (Nutrition & Metabolism)
✓ PubMed
Meta-analysis of 27 RCTs (2194 subjects): green tea consumption modestly lowered fasting blood glucose (WMD -1.44 mg/dL, 95% CI -2.26 to -0.62; low heterogeneity) but had no significant effect on fasting insulin or HbA1c.
Systematic review and meta-analysis of RCTs
55 RCTs, 4,874 participants
✓ Full text
Green tea supplementation produced small but significant reductions in LDL cholesterol (WMD -5.80 mg/dL) and diastolic blood pressure (-0.87 mmHg), with no significant effect on systolic blood pressure.
Meta-analysis of RCTs
11 RCTs, 613 overweight/obese participants
✓ PubMed
Green tea catechin significantly reduced triglycerides (-0.18 mmol/L), raised HDL (+0.07 mmol/L), and cut waist circumference (-1.37 cm), but did not significantly change blood pressure, LDL, or BMI.
Systematic review and meta-analysis of RCTs
10 RCTs, 476 overweight/obese participants
✓ PubMed
Adding green tea catechin to exercise training gave only minimal additional weight loss versus exercise alone (standardized mean difference about -0.30 for weight, -0.29 for fat mass) and no extra benefit on lipid profile.
Systematic review and meta-analysis of RCTs
20 RCTs (catechin doses 145-3,000 mg/day)
✓ PubMed
Green tea catechins significantly lowered LDL cholesterol by about 5.3 mg/dL and total cholesterol versus control, supporting a modest lipid-lowering effect.
Cochrane systematic review
142 studies, >1,100,000 participants (11 RCTs, 1,795 participants)
✓ PubMed
This Cochrane review found inconsistent and limited evidence that green tea prevents cancer; pooled observational data showed a modest reduction in overall cancer incidence (RR ~0.83) but no association with cancer mortality, with a possible benefit for prostate cancer (RR 0.50, 3 RCTs) of low certainty.
systematic review/meta-analysis of RCTs
41 RCTs
✓ PubMed
EGCG supplementation produced statistically significant but modest improvements in glycemic control, lowering HbA1c by about 0.18% (WMD -0.18%, 95% CI -0.35 to -0.02) and fasting glucose and HOMA-IR, while having no significant effect on fasting insulin (WMD -0.50, 95% CI -1.46 to 0.47).
meta-analysis of observational studies
18 studies, 58,929 participants
✓ PubMed
Higher green tea consumption was inversely associated with cognitive impairment (OR 0.63, 95% CI 0.54-0.73), including reduced odds of dementia (OR 0.74) and mild cognitive impairment (OR 0.64), with the strongest protection in adults aged 50-69 and in Asian populations.
Systematic review and meta-analysis of randomized clinical trials
15 RCTs
✓ PubMed
Across all participants green tea had no significant overall effect on liver enzymes (ALT SMD -0.17, 95% CI -0.42 to 0.08; AST SMD -0.07, 95% CI -0.43 to 0.29), but subgroup analysis showed a reduction in transaminases among people with NAFLD versus a small significant increase in healthy subjects, indicating effects depend on baseline liver status.
Meta-analysis of prospective cohort studies
38 prospective cohort data sets, 1,956,549 participants
✓ PubMed
Comparing highest versus lowest tea intake, consumption was associated with lower all-cause mortality (effect size 0.90, 95% CI 0.86-0.95) and cardiovascular mortality (0.86, 95% CI 0.79-0.94) but not cancer mortality (0.90, 95% CI 0.78-1.03), with the greatest benefit near about 2 cups/day and no further reduction at higher intake.
RCT
Pormlikul 2025 (Food Sci Nutr)
✓ Full text
Randomized double-blind placebo-controlled trial in 60 dyslipidemia adults found 6 weeks of green tea beverage (891 mg total catechins) reduced LDL cholesterol by 7.98% and total cholesterol by 4.96% versus placebo.
Systematic safety review (regulatory body)
USP comprehensive safety review
✓ PubMed
Case reports link green tea extract hepatotoxicity to EGCG intakes of 140-1000 mg/day with large inter-individual susceptibility; transaminase/cholestasis increases were seen above roughly 800 mg/day EGCG, prompting cautionary labeling to take with food.
RCT
Kumar et al. 2015 (Polyphenon E prostate trial)
✓ PubMed
Randomized, double-blind, placebo-controlled trial in 97 men with HGPIN/ASAP: 400 mg/day EGCG (Polyphenon E) for 1 year did not reduce 1-year prostate cancer incidence (5/49 vs 9/48, P=0.25); a secondary composite endpoint (cancer+ASAP in HGPIN-only men) was reduced (3/26 vs 10/25, P<0.024) and PSA fell (-0.87 ng/mL). Well tolerated.
prospective cohort study (Stroke, AHA journal)
46,213 Japanese adults (478 stroke and 1,214 MI survivors)
✓ PubMed
Among stroke and heart-attack survivors, greater green tea intake was associated with dose-dependent lower all-cause mortality (stroke survivors: HR 0.62 at 1-2 cups/day down to 0.38 at >=7 cups/day), whereas no protective association was seen in people without prior stroke or MI.