Dr. Grey AI

Green Tea Extract

Green tea extract is obtained from green tea leaves and contains high levels of flavonoids, catechins like EGCG, and often caffeine. It might reduce oxidative stress biomarkers and cardiovascular disease risk factors and improve cognitive function. However, the quality of evidence is low to moderate, and high doses can cause liver damage.

Quick Answer

What it is

Green tea extract is obtained from green tea leaves and contains high levels of flavonoids, catechins like EGCG, and often caffeine. It might reduce oxidative stress biomarkers and cardiovascular disease risk factors and improve cognitive function.

Key findings

  • Grade B: Blood Pressure
  • Grade B: Fat Oxidation (General Athletic Performance)
  • Grade C: Adiponectin (Obesity)

Safety

  • It might reduce oxidative stress biomarkers and cardiovascular disease risk factors and improve cognitive function.
ℹ️ Quick Facts: Green Tea Extract

Quick Facts: Green Tea Extract

  • Best Evidence:Grade B
  • Conditions Studied:21
  • Research Outcomes:110
  • Grade B Findings:3
  • Key Effect:General Athletic Performance
Outcomes by grade:
A0
B3
C8
D8
21 conditions · 110 outcomes

Detailed Outcomes

Grade:
Effect:
Size:
Sort:
|
B
Blood Pressure
Small Improvement
small↓Improves
?
C-Reactive Protein (CRP)
↓Improves
?
Interleukin 6
2 studies
↓Improves
?
Oxidative Stress Biomarkers
2 studies
↓Improves
?
TNF-Alpha
2 studies
↓Improves
?
Total Antioxidant Capacity (TAC)
↑Improves
?
Cerebral Blood Flow
1 study
↑Improves
?
Cognition
↑Improves
?
Heart Rate
↓Improves
?
Interleukin 1-beta
1 study
↓Improves
B
Fat Oxidation
Mixed effect
?
Oxygen Uptake
2 studies
↑Improves
?
Heart Rate
↓Improves
?
Muscle Soreness
↓Improves
B
Fat Oxidation
Mixed effect
?
Oxygen Uptake
2 studies
↑Improves
?
Heart Rate
↓Improves
C
Adiponectin
Small Increase
1 study
small↑Improves
C
Blood Pressure
Small Improvement
small↓Improves
?
Body Mass Index (BMI)
46 studies
↓Improves
?
Waist circumference
26 studies
↓Improves
?
Weight
↓Improves
?
Body Fat
↓Improves
?
Leptin
↑Improves
?
Ghrelin
7 studies
↑Improves
?
Fat Oxidation
↑Improves
?
Low-density lipoprotein (LDL)
↓Improves
?
Glycemic Control
1 study
↑Improves
?
High-density lipoprotein (HDL)
↑Improves
?
Metabolic Rate
↑Improves
?
Oxidative Stress Biomarkers
1 study
↓Improves
?
Thermic effect of food (TEF)
1 study
↑Improves
C
Adiponectin
Small Increase
1 study
small↑Improves
?
Weight
↓Improves
?
Leptin
↑Improves
?
Ghrelin
7 studies
↑Improves
?
Body Mass Index (BMI)
3 studies
↓Improves
?
Waist-Hip Ratio
3 studies
↑Improves
?
Body Fat
↓Improves
?
Food Intake
2 studies
↑Worsens
?
High-density lipoprotein (HDL)
↑Improves
?
Waist circumference
2 studies
↓Improves
?
Fat Oxidation
↑Improves
?
Low-density lipoprotein (LDL)
↓Improves
C
Exercise-Induced Oxidation
Small Decrease
small↓Improves
?
Muscle Soreness
↓Improves
C
Cerebral Blood Flow
Small Decrease
1 study
small↓Worsens
?
Cognition
↑Improves
C
Oxidative Stress Biomarkers
Small Decrease
1 study
small↓Improves
?
Weight
↓Improves
C
Cerebral Blood Flow
Small Decrease
1 study
small↓Worsens
?
Cognition
↑Improves
?
Heart Rate
↓Improves
C
Photoprotection
Small Improvement
small↑Improves
?
Skin Quality
1 study
↑Improves
D
Blood glucose
No effect
31 studies
none
?
Insulin
↑Worsens
?
Insulin Resistance
14 studies
↓Improves
?
HbA1c
10 studies
↓Improves
?
C-Reactive Protein (CRP)
↓Improves
?
Fat Oxidation
↑Improves
?
Interleukin 6
2 studies
↓Improves
?
Metabolic Rate
↑Improves
?
Estrogen
1 study
↑Worsens
?
Glycemic Control
1 study
↑Improves
?
Iron Absorption
↑Improves
?
Low-density lipoprotein (LDL)
↓Improves
?
Testosterone
1 study
↑Improves
D
High-density lipoprotein (HDL)
No effect
none
?
Total cholesterol
↓Improves
?
Low-density lipoprotein (LDL)
↓Improves
?
Triglycerides
1 study
↓Improves
D
Blood glucose
No effect
17 studies
none
?
Insulin
↑Worsens
?
Body Mass Index (BMI)
11 studies
↓Improves
?
Weight
↓Improves
?
HbA1c
7 studies
↓Improves
?
Waist circumference
6 studies
↓Improves
?
Insulin Resistance
5 studies
↓Improves
?
Body Fat
↓Improves
?
Glycemic Control
3 studies
↑Improves
D
Blood glucose
No effect
17 studies
none
?
Insulin
↑Worsens
?
HbA1c
7 studies
↓Improves
?
Insulin Resistance
5 studies
↓Improves
?
Glycemic Control
3 studies
↑Improves
D
Blood glucose
No effect
10 studies
none
?
Blood Pressure
↓Improves
?
Total cholesterol
↓Improves
?
Body Mass Index (BMI)
10 studies
↓Improves
?
Low-density lipoprotein (LDL)
↓Improves
?
High-density lipoprotein (HDL)
↑Improves
?
Triglycerides
9 studies
↓Improves
D
Ghrelin
No effect
7 studies
none
?
Leptin
↑Improves
D
Body Fat
No effect
none
?
Fat Oxidation
↑Improves
?
Low-density lipoprotein (LDL)
↓Improves
?
Metabolic Rate
↑Improves
?
Thermic effect of food (TEF)
1 study
↑Improves
D
Body Fat
No effect
none
?
Weight
↓Improves
?
Body Mass Index (BMI)
3 studies
↓Improves
?
Waist-Hip Ratio
3 studies
↑Improves
?
Food Intake
2 studies
↑Worsens
?
Waist circumference
2 studies
↓Improves
?
Body Fat
↓Improves
?
Fat Oxidation
↑Improves
?
Carbohydrate Absorption
↑Improves
?
Cognition
↑Improves

Evidence by Condition

Best grade per condition (each condition may have multiple outcomes)

BGeneral Athletic Performance
1
Fat Oxidation↑Oxygen UptakeImproves↓Heart RateImproves
BAerobic Exercise Performance
1
Fat Oxidation↑Oxygen UptakeImproves↓Heart RateImproves
CObesity
1
↑AdiponectinImproves↓Blood PressureImproves↓Body Mass Index (BMI)Improves
CWeight Loss & Maintenance
1
↑AdiponectinImproves↓WeightImproves↑LeptinImproves
CMuscle Recovery
1
↓Exercise-Induced OxidationImproves↓Muscle SorenessImproves
CCognitive Improvement
1
↓Cerebral Blood FlowWorsens↑CognitionImproves
CMetabolic Syndrome
1
↓Oxidative Stress BiomarkersImproves↓WeightImproves
CMood Improvement
1
↓Cerebral Blood FlowWorsens↑CognitionImproves↓Heart RateImproves
CSkin Health
1
↑PhotoprotectionImproves↑Skin QualityImproves
DMetabolic Health
1
Blood glucose↑InsulinWorsens↓Insulin ResistanceImproves
DType 2 Diabetes
1
Blood glucose↑InsulinWorsens↓Body Mass Index (BMI)Improves
DHigh Blood Pressure
1
Blood glucose↓Blood PressureImproves↓Total cholesterolImproves
DOverweight
1
Body Fat↑Fat OxidationImproves↓Low-density lipoprotein (LDL)Improves
DDyslipidemia
1
High-density lipoprotein (HDL)↓Total cholesterolImproves↓Low-density lipoprotein (LDL)Improves
DPrediabetes
1
Blood glucose↑InsulinWorsens↓HbA1cImproves
DPolycystic Ovary Syndrome (PCOS)
1
Body Fat↓WeightImproves↓Body Mass Index (BMI)Improves
DAppetite Regulation
1
Ghrelin↑LeptinImproves

Research Citations (44)

Effect of Green Tea Supplementation on Inflammatory Markers among Patients with Metabolic Syndrome and Related Disorders: A Systematic Review and Meta-Analysis.
PMID: 38974590
Epigallocatechin-3-gallate and postprandial fat oxidation in overweight/obese male volunteers: a pilot study
PMID: 20372175
The effects of epigallocatechin-3-gallate on thermogenesis and fat oxidation in obese men: a pilot study
PMID: 17906192
Green tea for weight loss and weight maintenance in overweight or obese adults
PMID: 23235664
Effect of green tea extract on obese women: a randomized, double-blind, placebo-controlled clinical trial
PMID: 18468736
Green tea supplementation affects body weight, lipids, and lipid peroxidation in obese subjects with metabolic syndrome
PMID: 20595643
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.
PMID: 38031409
Effects of dietary supplementation with the green tea polyphenol epigallocatechin-3-gallate on insulin resistance and associated metabolic risk factors: randomized controlled trial
PMID: 18710606
Catechin safely improved higher levels of fatness, blood pressure, and cholesterol in children
PMID: 18356827
Green tea catechin consumption enhances exercise-induced abdominal fat loss in overweight and obese adults
PMID: 19074207

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