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Gte9.0
Green Tea Extract Research
Likely helpsModerate safety
54 peer-reviewed studies
What the evidence says
Likely helps
Green Tea Extract appears to help in 7 of 9 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 2006–2026 with a typical study size of 371 participants.
Based on 54 studies · 18 meta-analyses · 8 RCTs · 79,807 total participants
Confidence
High
What the studies found
7helped2unclear· 45 more without graded effect data
By outcome
Therapeutic & clinical
Likely helps27 studies
Weight managementModest fat oxidation and thermogenesis · 4-12 weeks
Mostly mechanism / observational11 studies
Cognitive function
Mostly mechanism / observational9 studies
Cholesterol & lipidsCatechins improve lipid profiles and endothelial function · 8-12 weeks
Mostly mechanism / observational7 studies
Safety profile
Mostly mechanism / observational6 studies
Heart & blood pressureCatechins improve lipid profiles and endothelial function · 8-12 weeks
Mostly mechanism / observational4 studies
InflammationIncreased fat oxidation and metabolic rate · 4-8 weeks
Longevity & agingAntioxidant protection and cardiovascular support · Ongoing
Too few graded studies2 studies
Immune support
Too few graded studies1 study
By the numbers
Pulled from 38 studies with measurable effects
Likely real effects
88%
across studies
People studied
80k
typical study: 371 people
Strongest designs
26
18 pooled, 8 randomised
Showed benefit
78%
7/9 studies
How long studies ran
1–3 months
5
3+ months
3
Populations Studied
Adults4
General population3
Diverse populations1
Adults with obesity markers1
Active research area
37 studies in the last 5 years · Latest meta-analysis: 2025
200620162026
1Office systolic blood pressureMeta-AnalysisCited 6×n=5,205 · very large study2025
Flavan-3-ol-rich foods considerably reduce elevated BP and improve endothelial function independent of blood pressure supporting their use for cardiovascular prevention.
Lagou V et al. · European journal of preventive cardiology (2025)
Noticeable benefit
← WorseNo effectBetter →
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.
5Influenza preventionMeta-AnalysisCited 9×n=5,048 · very large study2021
To confirm the findings before implementation, longitudinal clinical trials with specific doses of green tea consumption are warranted.
Rawangkan A et al. · Molecules (Basel, Switzerland) (2021)
Large benefit
← WorseNo effectBetter →
Likely real
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)).
6Clinical signs and symptoms of preeclampsiaMeta-AnalysisCited 3×n=349 · medium study2025
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.
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.
7Cancer incidenceMeta-AnalysisCited 109×n=1,795 · large study2020
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.
Filippini T et al. · The Cochrane database of systematic reviews (2020)
No clear effect
← WorseNo effectBetter →
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).
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.
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.
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.
However, given the heterogeneity of the included studies, our findings still need to be validated by conducting higher-quality studies.
Zhang Y et al. · The American journal of Chinese medicine (2025)
Barely noticeable benefit
← WorseNo effectBetter →
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.
Findings suggest that well-designed interventions - tailored to the right individuals, implemented at the optimal time - may effectively improve cognition.
Bereczki E et al. · The journal of prevention of Alzheimer's disease (2025)
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.
13Oncological treatment supportSystematic ReviewCited 7×n=371 · medium study2023
Due to limitations, further studies with higher methodological quality and larger sample sizes are needed.
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)
Likely real
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.
14Body weight reductionMeta-AnalysisCited 11×n=169 · medium study2022
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...
Colonetti L et al. · Nutrition research (New York, N.Y.) (2022)
Noticeable benefit
← WorseNo effectBetter →
Likely real
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.
Still, the inconsistent results across the included RCTs require further clinical research to establish optimal dosage and duration.
Ranneh Y et al. · Nutrients (2024)
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.
In healthy individuals, green tea supplementation reduced systolic blood pressure by 2.99 mmHg and diastolic blood pressure by 0.95 mmHg.
Yıldırım Ayaz E et al. · Alternative therapies in health and medicine (2023)
Noticeable benefit
← WorseNo effectBetter →
Likely real
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.
18Antioxidant and anti-inflammatory effects in endometriosisSystematic ReviewCited 121×2021
Medicinal Research Reviews
Hung SW et al. · Medicinal research reviews (2021)
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.
19Systematic ReviewCited 19×n=84 · small study2013
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.
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.
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.
20Lipid profile improvement in type 2 diabetesMeta-AnalysisCited 26×2020
In conclusion, present systematic review and meta-analysis revealed that the supplementary intake of GTE may improve lipid profile by reducing serum concentrations of TG in patients with T2DM.
Asbaghi O et al. · Diabetes & metabolic syndrome (2020)
Furthermore, intervention longer than 8 weeks with doses lower than 800 mg/day resulted in a significant reduction in serum TC concentrations.
In conclusion, present systematic review and meta-analysis revealed that the supplementary intake of GTE may improve lipid profile by reducing serum concentrations of TG in patients with T2DM.
Furthermore, the results of our stratified analyses suggested that long-term GTE intervention may reduce serum concentrations of TG and TC.