Green Tea Extract Research
52 peer-reviewed studies · Evidence score: 9/10
Impact of flavan-3-ols on blood pressure and endothelial function in diverse populations: a systematic review and meta-analysis of randomized controlled trials
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.
- 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.
The effects of green tea extract supplementation on body composition, obesity-related hormones and oxidative stress markers: a grade-assessed systematic review and dose-response meta-analysis of randomised controlled trials
Asbaghi O et al. • The British journal of nutrition (2024)
Moreover, GTE as a nutraceutical dietary supplement can increase TAC and adiponectin.
- 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.
Chemoprophylaxis Effect of EGCG on the Recurrence of Colorectal Cancer: A Systematic Review and Meta-Analysis
He B et al. • Current pharmaceutical design (2024)
This study demonstrated that long-term EGCG can prevent CRC recurrence to a certain extent.
- 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.
A network meta-analysis on the comparative effect of nutraceuticals on lipid profile in adults
Osadnik T et al. • Pharmacological research (2022)
All rights reserved.
- Evidence for bergamot effect was based on relatively small study group and may require further investigations.
- Policosanols have no effect on the lipid profile.Copyright © 2022 The Authors.
- Published by Elsevier Ltd..
Anti-Influenza with Green Tea Catechins: A Systematic Review and Meta-Analysis
Rawangkan A et al. • Molecules (Basel, Switzerland) (2021)
To confirm the findings before implementation, longitudinal clinical trials with specific doses of green tea consumption are warranted.
- Similarly, in three cohort studies with 2,223 participants treated with GTCs, there were also statistically significant effects (RR 0.52, 95%CIs 0.35-0.77, P = 0.001) with very low evidence of heterogeneity (I2 = 3%, P = 0.358).
- Additionally, the overall effect in the subgroup analysis of gargling and orally ingested items (taking capsules and drinking) showed a pooled RR of 0.62 (95% CIs 0.49-0.77, P = 0.003) without heterogeneity (I2= 0%, P = 0.554).
- There were no obvious publication biases (Egger's test (P = 0.138) and Begg's test (P = 0.103)).
Polyphenols for the Prevention or Management of Preeclampsia: A Systematic Review and Meta-Analysis
Nguyen PY et al. • BJOG : an international journal of obstetrics and gynaecology (2025)
ECGC and resveratrol supplements have been investigated for potential effects in managing clinical signs and symptoms of preeclampsia; however, evidence on the clinical and adverse effects of polyphenols is limited and uncertain.
- ECGC and resveratrol supplements have been investigated for potential effects in managing clinical signs and symptoms of preeclampsia; however, evidence on the clinical and adverse effects of polyphenols is limited and uncertain.
- Published in BJOG : an international journal of obstetrics and gynaecology (2025)
- Further research warranted to confirm findings
Green tea (Camellia sinensis) for the prevention of cancer
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.
- 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).
Effect of green tea extract on body weight, body composition, and antioxidant status: A systematic review and meta-analysis of randomized controlled trials
Lin Y et al. • Phytomedicine (2020)
Green tea extract supplementation significantly reduced body weight and BMI while improving antioxidant status in pooled RCT analysis.
- Significant reduction in body weight (mean -1.78 kg) vs placebo
- Significant reduction in BMI across intervention periods
- Enhanced total antioxidant capacity and reduced malondialdehyde levels
Effects of green tea catechin extract on cardiovascular risk factors: A systematic review and meta-analysis
Xu R et al. • Critical Reviews in Food Science and Nutrition (2020)
Green tea catechins significantly reduced LDL cholesterol, total cholesterol, and blood pressure in randomized controlled trials.
- Significant reduction in LDL cholesterol and total cholesterol
- Modest but significant blood pressure lowering effects
- EGCG doses of 400-500 mg/day showed optimal cardiovascular benefits
Effects of green tea or green tea extract on insulin sensitivity and glycaemic control in populations at risk of type 2 diabetes mellitus: a systematic review and meta-analysis of randomised controlled trials
Wang X et al. • Journal of human nutrition and dietetics : the official journal of the British Dietetic Association (2014)
The consumption of green tea did not decrease the levels of fasting plasma glucose, fasting serum insulin, OGTT-2 h glucose, haemoglobin A₁c and HOMA(IR) in populations at risk of T2DM.
- The consumption of green tea did not decrease the levels of fasting plasma glucose, fasting serum insulin, OGTT-2 h glucose, haemoglobin A₁c and HOMA(IR) in populations at risk of T2DM.
- Larger, longer-term and high-quality RCTs are needed to further definitely determine the effect of green tea or green tea extract on insulin sensitivity and glycaemic control in populations at risk of T2DM.
- Further research warranted to confirm findings
Green Tea and Epigallocatechin Gallate (EGCG) for Cancer Prevention: A Systematic Review and Meta-Analysis
Zhang Y et al. • The American journal of Chinese medicine (2025)
However, given the heterogeneity of the included studies, our findings still need to be validated by conducting higher-quality studies.
- The results of the meta-analysis showed that green tea (relative risk [RR]: 0.91, 95% confidence interval [CI]: 0.86-0.96) and EGCG (RR: 0.72, 95% CI: 0.54-0.97) could reduce the risk of cancer to a certain extent compared to controls.
- It had an especially notable effect in reducing the risk of prostate cancer (RR: 0.43, 95% CI: 0.22-0.83), oral cancer (RR: 0.44, 95% CI: 0.01-0.87), gallbladder cancer (RR: 0.72, 95% CI: 0.51-0.94), and hematological cancers (RR: 0.72, 95% CI: 0.49-0.95), with statistically significant differences.
- Additionally, the dose-response meta-analysis revealed a significant negative linear correlation between high doses, long-term consumption of green tea, and cancer risk.
Risk reduction and precision prevention across the Alzheimer's disease continuum: a systematic review of clinical trials combining multidomain lifestyle interventions and pharmacological or nutraceutical approaches
Bereczki E et al. • The journal of prevention of Alzheimer's disease (2025)
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- Findings suggest that well-designed interventions - tailored to the right individuals, implemented at the optimal time - may effectively improve cognition.
- However, further refinement of the RCT methodology is warranted, for better alignment with the multifaceted nature of dementia prevention and management.Copyright © 2025 The Authors.
- Published by Elsevier Masson SAS..
Preclinical evidence construction for epigallocatechin-3-gallate against non-alcoholic fatty liver disease: a meta-analysis and machine learning study
Zhang Y et al. • Phytomedicine : international journal of phytotherapy and phytopharmacology (2025)
The efficacy of EGCG in treating NAFLD has been predicted within a time frame of 10-15 weeks.
- Our analysis indicates that EGCG significantly reduces ALT, AST, hepatic triglyceride, serum TG, hepatic TC, serum TC.
- The efficacy of EGCG in treating NAFLD has been predicted within a time frame of 10-15 weeks.
- It may exert its effects primarily through the NF-κB and Nrf2 pathways, which regulate the ROS phenotype.
Green tea and green tea extract in oncological treatment: A systematic review
Wiese F et al. • International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition (2023)
Due to limitations, further studies with higher methodological quality and larger sample sizes are needed.
- T0: 9.9±8.5 ng/ml, T1: 10.0±9.0 ng/ml; p=0.04), whereas in a second study only a trend was seen.
- Radiotherapy-induced diarrhea was lower in the green tea intervention group compared to placebo (1 study; N=42; week 4+5: without diarrhea p=0.002).
- Conclusions: The studies suggest that EGCG is as effective as a local antibiotic in malodorous control and improvement of QoL of fungating malignant wounds.
Green tea promotes weight loss in women with polycystic ovary syndrome: Systematic review and meta-analysis
Colonetti L et al. • Nutrition research (New York, N.Y.) (2022)
Published by Elsevier Inc.
- We found a significantly lower body weight (kg) for green tea group (mean difference, -2.80; 95% confidence interval, -5.25 to -0.35; P = .03; I² = 0%; 4 studies, 169 participants, very low-quality evidence).
- Green tea has potential positive effects for the reduction of weight, and future studies will be needed to confirm the estimated effect size; we reasonably expect this to be an option of adjuvant treatment in PCOS clinical management.
- Registration number: CRD42021226296.Copyright © 2022.
Polyphenol Intervention Ameliorates Non-Alcoholic Fatty Liver Disease: An Updated Comprehensive Systematic Review
Ranneh Y et al. • Nutrients (2024)
Still, the inconsistent results across the included RCTs require further clinical research to establish optimal dosage and duration.
- 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.
Effect of Green Tea on Blood Pressure in Healthy Individuals: A Meta-Analysis
Yıldırım Ayaz E et al. • Alternative therapies in health and medicine (2023)
In healthy individuals, green tea supplementation reduced systolic blood pressure by 2.99 mmHg and diastolic blood pressure by 0.95 mmHg.
- The completion rate of the consumption of green tea ranged from 85-100%.
- The combined results of the studies showed that green tea was effective in lowering systolic and diastolic blood pressure in individuals (MD: -2.99, 95%; CI: -3.77 to -2.22; Z = 7.57; P < .00001; I2 = 0%, MD: -0.95, 95%; CI: -1.62 to -0.27; Z = 2.75; P = .006; I2 = 0%).
- In healthy individuals, green tea supplementation reduced systolic blood pressure by 2.99 mmHg and diastolic blood pressure by 0.95 mmHg.
Potential therapeutic effects of green tea on obese lipid profile - a systematic review
Macêdo APA et al. • Nutrition and health (2022)
In human studies, green tea has not been shown to be effective in controlling obese lipids.
- In humans' studies green tea was not shown to be effective for obese lipid control.
- Because supplementation with green tea extract reduced total cholesterol, triglycerides, low-density lipoprotein for three months at a specific dose.
- Conclusion: Therefore, green tea appears to act as a protective agent for dyslipidemia in obesity-induced animals.
Pharmaceuticals targeting signaling pathways of endometriosis as potential new medical treatment: A review
Hung SW et al. • Medicinal research reviews (2021)
Medicinal Research Reviews published by Wiley Periodicals LLC.
- N-acetyl cysteine, curcumin, and ginsenoside exert antioxidant and anti-inflammatory effects via radical scavenging activity.
- Natural products have high efficacy with minimal side effects; for example, resveratrol and epigallocatechin gallate have multiple targets and provide synergistic efficacy to resolve the complexity of the pathophysiology of EM, showing promising efficacy in treating EM.
- Although new medical treatments are currently being developed, more detailed pharmacological studies and large sample size clinical trials are needed to confirm the efficacy and safety of these treatments in the near future.© 2021 The Authors.
Green tea and lung cancer: a systematic review
Fritz H et al. • Integrative cancer therapies (2013)
Although some evidence suggests that chemopreventative benefits can be accrued from green tea, there is currently insufficient evidence to support green tea as a treatment or preventative agent for lung cancer.
- Although some evidence suggests that chemopreventative benefits can be accrued from green tea, there is currently insufficient evidence to support green tea as a treatment or preventative agent for lung cancer.
- Green tea should not be used by patients on bortezomib therapy.
- Further research is warranted to explore this natural agent for lung cancer treatment and prevention.