Herb Profile
Green Tea
Camellia sinensis
Green Tea (Camellia sinensis) carries a Grade A rating — strong evidence.
Last reviewed: •3 sources citedReport a correctionProfile-wide ·A Strong
Use extra caution — Liver risk at high dose extracts Details
- Evidence
- Strong Evidence
- Typical onset
- Varies by prep
- Safety rating
- Moderate caution
- Best for
- Antioxidant, Metabolic, Cardiovascular, Stress resilience
- Avoid / review if
- Stimulants, Hepatotoxic Drugs
Safety
Safety & Cautions
Liver risk at high dose extracts
Elevated caution
Caution level: Elevated. One caution category applies — read it before use.
- Liver-SensitiveLiver-related caution language appears in the profile.
Detailed safety fields
Pregnancy, breastfeeding, and contraindications
- Stimulants
- Hepatotoxic Drugs
Safety classifications
- Liver-Sensitive: Liver-related caution language appears in the profile.
Full safety note
- Liver risk at high dose extracts
Safety labels
- Liver-Sensitive
Evidence
Evidence Summary
Evidence lens
Most useful for practical interpretation when safety context also fits.
StrongStrong Evidence
Human clinical evidence: Present in source signals
Mechanistic / preclinical: Mechanism mapped — Oxidative Stress Modulation · Metabolic Regulation · Vascular Function Support
Research maturity: Established research — Long Term Human Evidence May Be Limited.
Safety boundary: Safety note available — Liver risk at high dose extracts
This profile cites 3 human studies.
Study design details
Evidence Grade
Grade A: Strong Evidence
Evaluation of methodological rigor, population reach, and evidence alignment.
- Design Match
- Meta-analysis
- Risk of Bias
- Low
- Consistency
- Consistent
Strongest recorded design is a meta-analysis, drawn from 8 recorded studies, 6 in people. No disagreement is recorded across them.
How evidence grades work
Each grade reflects the strength and consistency of published human evidence — not marketing claims. Grades are based on study count, design quality, effect size, consistency, and recency.
- Strong
- Multiple RCTs, consistent direction, adequate effect size
- Moderate
- Some RCTs or consistent observational data in humans
- Preliminary / Mixed
- Animal or in-vitro only, or conflicting human data
- Traditional / Theoretical
- Traditional use only; no controlled human trials
Clinical Study Summaries (8)6 human evidence sources · 0 human trials · Participant totals not consistently reported · Consistency not yet classifiable
Filter by study class
Showing 8 of 8 studies.
What the evidence actually shows
This table contains 8 structured sources, including 6 human evidence sources; 0 are human trials.
| Study | Design | N | Dose | Duration | Population | Outcome | Result & magnitude | Source |
|---|---|---|---|---|---|---|---|---|
Background | Meta-analysis Statistically combines results from multiple eligible studies; confidence still depends on the quality, consistency, and directness of those studies. | — | — | — | — | — | Some oxidative-stress and antioxidant markers improved, while CRP, IL-6, and TNF-alpha did not clearly improve. | PubMed → |
Background | Meta-analysis Statistically combines results from multiple eligible studies; confidence still depends on the quality, consistency, and directness of those studies. | — | — | — | — | — | Overall pooled effects were not significant for fasting glucose, HbA1c, blood pressure, or major lipid markers, although selected subgroups showed benefit. | PubMed → |
Background | Meta-analysis Statistically combines results from multiple eligible studies; confidence still depends on the quality, consistency, and directness of those studies. | — | — | — | — | — | Green tea extract increased fat oxidation during and after exercise in pooled analyses, with some dose-response signal. | PubMed → |
Background | Meta-analysis Statistically combines results from multiple eligible studies; confidence still depends on the quality, consistency, and directness of those studies. | — | — | — | — | — | Green tea supplementation produced modest pooled reductions in weight, BMI, waist circumference, and body-fat percentage; adiponectin was not clearly improved. | PubMed → |
Background | Meta-analysis Statistically combines results from multiple eligible studies; confidence still depends on the quality, consistency, and directness of those studies. | — | — | — | — | — | Pooled systolic and diastolic blood pressure reductions were about 1 mmHg, with larger subgroup effects in some higher-risk populations. | PubMed → |
Warfarin and food, herbal or dietary supplement interactions: A systematic review Tan CSS et al. · Br J Clin Pharmacol · 2021 Background | Systematic review Uses a predefined method to find and evaluate relevant studies, but may or may not pool their results statistically. | — | — | — | — | — | — | PubMed → |
Show 2 more studies
Green Tea (Camellia sinensis): A Review of Its Phytochemistry, Pharmacology, and Toxicology Zhao T et al. · Molecules · 2022 Background | Narrative review Summarizes selected literature without the full prespecified search and selection methods of a systematic review. | — | — | — | — | — | — | PubMed → |
Common Herbal Dietary Supplement-Drug Interactions Asher GN et al. · Am Fam Physician · 2017 Background | Narrative review Summarizes selected literature without the full prespecified search and selection methods of a systematic review. | — | — | — | — | — | — | PubMed → |
Dosing & Timing
- Dose guidance
- 300 800 mg EGCG/day
How Green Tea works
Simplified mechanism pathway based on preclinical and pharmacological evidence. Does not confirm clinical efficacy.
Mechanism Pathway — How Green Tea Works
CompoundTarget / ReceptorMechanismEffect / Outcome
Mechanisms & biological pathways (preclinical)
- Oxidative Stress Modulation
- Metabolic Regulation
- Vascular Function Support
- Endothelial Function Support
Active Compounds
Key constituents studied in Green Tea, with full pharmacology and safety profiles.
Compare related active botanicals
Explore botanicals with similar chemistry, effects, or safety considerations in the Botanical Activity Atlas.
Compare & Sourcing
Compare side-by-side tradeoffs or verify active marker guidelines.
Review available sources for Green Tea
Independent database mapping — evaluated separately from safety and efficacy scores.
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Safety first · Harm reduction
This information is educational and not medical advice. Start low, avoid risky combinations, and consult a licensed clinician before making health decisions—especially if you use medications, have diagnosed conditions, or are pregnant/breastfeeding.
Learn how we evaluate confidence, safety, and intensity on the methodology page.
Founder & Head Researcher · Oak Ridge, TN · Last reviewed August 2026
Editorial Review
Checked against primary sources, cited evidence, and contraindication language before publication. Evidence claims, safety language, and affiliate modules are reviewed independently. Not personal medical advice.
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