Green Tea Extract

Last Updated: May 24, 2023

Green Tea extract contains phytochemicals, especially catechins like epigallocatechin gallate(EGCG) and caffeine. EGCG and caffeine have been shown to synergistically influence health indices, including body composition, but the contents within green tea extracts vary among brands. Notably, adverse effects have also been reported upon consuming green tea extract.

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Green Tea Extract is most often used for

Summary

Green tea extract (GTE) is derived from the Camellia sinensis plant and is added to dietary supplements such as fat burners. Phytochemicals from this plant, especially epigallocatechin gallate (EGCG) and caffeine, can be found in GTE but in higher concentrations. How, when, and where the Camellia sinensis plant is grown, as well as processing practices, influence the constituents of GTE. Therefore, GTE and its contents vary among products. GTE and its benefits have been investigated in diseases such as obesity, cardiovascular disease, cancer, and type 2 diabetes. A meta-analysis of 11 randomized controlled trials (10 that used GTE and one that used whole green tea) found a statistically significant reduction in body weight, BMI, and body fat in participants with type 2 diabetes.[1] Because the participants all had type 2 diabetes, it’s unclear whether this benefit is also found in people with overweight or obesity but without type 2 diabetes. Other studies also suggest that GTE may benefit cardiovascular health[2] and may have anticancer properties.[3] On the other hand, studies of the effects of GTE on glucose metabolism have reported inconsistent results.[4] Caution should be exercised when taking GTE, as adverse effects have been reported.[5] Such adverse effects include gastrointestinal and liver distress but are considered extremely rare.

What else is Green Tea Extract known as?
Note that Green Tea Extract is also known as:
  • Camellia Sinensis
  • Green Tea Extract
  • GTE
  • Green Tea Catechins
Green Tea Extract should not be confused with:
Dosage information

Most doses are standardized against EGCG. Although the amount of EGCG-equivalent varies from one cup of tea to another, depending on many factors (species of tea, length of steeping, time spent oxidizing), one cup of camellia sinensis green tea contains approximately 50mg of EGCG-equivalent.

The benefits of green tea catechins on lipid oxidation and related fat-burning pathways are achieved in a dose dependent manner. Significant effects in humans are noted only at high doses, such as 400-500mg EGCG equivalent per day (most Green Tea Extract supplements are roughly 50% EGCG). Fat burning effects are highly synergistic, almost dependent, on not consuming caffeine habitually.

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Research Breakdown

References
  1. ^Asbaghi O, Fouladvand F, Gonzalez MJ, Aghamohammadi V, Choghakhori R, Abbasnezhad AEffect of Green Tea on Anthropometric Indices and Body Composition in Patients with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis.Complement Med Res.(2021)
  2. ^Raman G, Avendano EE, Chen S, Wang J, Matson J, Gayer B, Novotny JA, Cassidy ADietary intakes of flavan-3-ols and cardiometabolic health: systematic review and meta-analysis of randomized trials and prospective cohort studies.Am J Clin Nutr.(2019-11-01)
  3. ^Tommaso Filippini, Marcella Malavolti, Francesca Borrelli, Angelo A Izzo, Susan J Fairweather-Tait, Markus Horneber, Marco VincetiGreen Tea (Camellia Sinensis) for the Prevention of CancerCochrane Database Syst Rev.(2020 Mar 2)
  4. ^Wang X, Tian J, Jiang J, Li L, Ying X, Tian H, Nie MEffects 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.J Hum Nutr Diet.(2014-Oct)
  5. ^Oketch-Rabah HA, Roe AL, Rider CV, Bonkovsky HL, Giancaspro GI, Navarro V, Paine MF, Betz JM, Marles RJ, Casper S, Gurley B, Jordan SA, He K, Kapoor MP, Rao TP, Sherker AH, Fontana RJ, Rossi S, Vuppalanchi R, Seeff LB, Stolz A, Ahmad J, Koh C, Serrano J, Low Dog T, Ko RUnited States Pharmacopeia (USP) comprehensive review of the hepatotoxicity of green tea extracts.Toxicol Rep.(2020)
Examine Database References
  1. Fat Oxidation - Thielecke F, Rahn G, Böhnke J, Adams F, Birkenfeld AL, Jordan J, Boschmann MEpigallocatechin-3-gallate and postprandial fat oxidation in overweight/obese male volunteers: a pilot studyEur J Clin Nutr.(2010 Jul)
  2. Fat Oxidation - Boschmann M, Thielecke FThe effects of epigallocatechin-3-gallate on thermogenesis and fat oxidation in obese men: a pilot studyJ Am Coll Nutr.(2007 Aug)
  3. Weight - Hsu CH, Tsai TH, Kao YH, Hwang KC, Tseng TY, Chou PEffect of green tea extract on obese women: a randomized, double-blind, placebo-controlled clinical trialClin Nutr.(2008 Jun)
  4. Weight - Arpita Basu, Karah Sanchez, Misti J Leyva, Mingyuan Wu, Nancy M Betts, Christopher E Aston, Timothy J LyonsGreen tea supplementation affects body weight, lipids, and lipid peroxidation in obese subjects with metabolic syndromeJ Am Coll Nutr.(2010 Feb)
  5. Blood Pressure - Brown AL, Lane J, Coverly J, Stocks J, Jackson S, Stephen A, Bluck L, Coward A, Hendrickx HEffects of dietary supplementation with the green tea polyphenol epigallocatechin-3-gallate on insulin resistance and associated metabolic risk factors: randomized controlled trialBr J Nutr.(2009 Mar)
  6. Low-density lipoprotein (LDL) - Matsuyama T, Tanaka Y, Kamimaki I, Nagao T, Tokimitsu ICatechin safely improved higher levels of fatness, blood pressure, and cholesterol in childrenObesity (Silver Spring).(2008 Jun)
  7. Body Fat - Maki KC, Reeves MS, Farmer M, Yasunaga K, Matsuo N, Katsuragi Y, Komikado M, Tokimitsu I, Wilder D, Jones F, Blumberg JB, Cartwright YGreen tea catechin consumption enhances exercise-induced abdominal fat loss in overweight and obese adultsJ Nutr.(2009 Feb)
  8. Heart Rate - Richards JC, Lonac MC, Johnson TK, Schweder MM, Bell CEpigallocatechin-3-gallate increases maximal oxygen uptake in adult humansMed Sci Sports Exerc.(2010 Apr)
  9. Fat Oxidation - Ichinose T, Nomura S, Someya Y, Akimoto S, Tachiyashiki K, Imaizumi KEffect of endurance training supplemented with green tea extract on substrate metabolism during exercise in humansScand J Med Sci Sports.(2011 Aug)
  10. Muscle Soreness - Kerksick CM, Kreider RB, Willoughby DSIntramuscular adaptations to eccentric exercise and antioxidant supplementationAmino Acids.(2010 Jun)
  11. Body Fat - Hursel R, Viechtbauer W, Dulloo AG, Tremblay A, Tappy L, Rumpler W, Westerterp-Plantenga MSThe effects of catechin rich teas and caffeine on energy expenditure and fat oxidation: a meta-analysisObes Rev.(2011 Jul)
  12. Body Fat - Wang H, Wen Y, Du Y, Yan X, Guo H, Rycroft JA, Boon N, Kovacs EM, Mela DJEffects of catechin enriched green tea on body compositionObesity (Silver Spring).(2010 Apr)
  13. Body Fat - Stendell-Hollis NR, Thomson CA, Thompson PA, Bea JW, Cussler EC, Hakim IAGreen tea improves metabolic biomarkers, not weight or body composition: a pilot study in overweight breast cancer survivorsJ Hum Nutr Diet.(2010 Dec)
  14. Body Fat - Hursel R, Viechtbauer W, Westerterp-Plantenga MSThe effects of green tea on weight loss and weight maintenance: a meta-analysisInt J Obes (Lond).(2009 Sep)
  15. Insulin - Hsu CH, Liao YL, Lin SC, Tsai TH, Huang CJ, Chou PDoes supplementation with green tea extract improve insulin resistance in obese type 2 diabetics? A randomized, double-blind, and placebo-controlled clinical trialAltern Med Rev.(2011 Jun)
  16. Cognition - Wightman EL, Haskell CF, Forster JS, Veasey RC, Kennedy DOEpigallocatechin gallate, cerebral blood flow parameters, cognitive performance and mood in healthy humans: a double-blind, placebo-controlled, crossover investigationHum Psychopharmacol.(2012 Mar)
  17. Blood Flow - Ras RT, Zock PL, Draijer RTea consumption enhances endothelial-dependent vasodilation; a meta-analysisPLoS One.(2011 Mar 4)
  18. Fat Oxidation - Dean S, Braakhuis A, Paton CThe effects of EGCG on fat oxidation and endurance performance in male cyclistsInt J Sport Nutr Exerc Metab.(2009 Dec)
  19. Total cholesterol - Batista Gde A, Cunha CL, Scartezini M, von der Heyde R, Bitencourt MG, Melo SFProspective double-blind crossover study of Camellia sinensis (green tea) in dyslipidemiasArq Bras Cardiol.(2009 Aug)
  20. Estrogen - Wu AH, Spicer D, Stanczyk FZ, Tseng CC, Yang CS, Pike MCEffect of 2-month controlled green tea intervention on lipoprotein cholesterol, glucose, and hormone levels in healthy postmenopausal womenCancer Prev Res (Phila).(2012 Mar)
  21. Insulin - Venables MC, Hulston CJ, Cox HR, Jeukendrup AEGreen tea extract ingestion, fat oxidation, and glucose tolerance in healthy humansAm J Clin Nutr.(2008 Mar)
  22. Fat Oxidation - Gregersen NT, Bitz C, Krog-Mikkelsen I, Hels O, Kovacs EM, Rycroft JA, Frandsen E, Mela DJ, Astrup AEffect of moderate intakes of different tea catechins and caffeine on acute measures of energy metabolism under sedentary conditionsBr J Nutr.(2009 Oct)
  23. Metabolic Rate - Lonac MC, Richards JC, Schweder MM, Johnson TK, Bell CInfluence of short-term consumption of the caffeine-free, epigallocatechin-3-gallate supplement, Teavigo, on resting metabolism and the thermic effect of feedingObesity (Silver Spring).(2011 Feb)
  24. Iron Absorption - Ullmann U, Haller J, Bakker GC, Brink EJ, Weber PEpigallocatechin gallate (EGCG) (TEAVIGO) does not impair nonhaem-iron absorption in manPhytomedicine.(2005 Jun)
  25. Photoprotection - Heinrich U, Moore CE, De Spirt S, Tronnier H, Stahl WGreen tea polyphenols provide photoprotection, increase microcirculation, and modulate skin properties of womenJ Nutr.(2011 Jun)
  26. Cognition - Park SK, Jung IC, Lee WK, Lee YS, Park HK, Go HJ, Kim K, Lim NK, Hong JT, Ly SY, Rho SSA combination of green tea extract and l-theanine improves memory and attention in subjects with mild cognitive impairment: a double-blind placebo-controlled studyJ Med Food.(2011 Apr)
  27. Carbohydrate Absorption - Lochocka K, Bajerska J, Glapa A, Fidler-Witon E, Nowak JK, Szczapa T, Grebowiec P, Lisowska A, Walkowiak JGreen tea extract decreases starch digestion and absorption from a test meal in humans: a randomized, placebo-controlled crossover studySci Rep.(2015 Jul 30)
  28. Exercise-Induced Oxidation - Jówko E, Sacharuk J, Balasińska B, Ostaszewski P, Charmas M, Charmas RGreen tea extract supplementation gives protection against exercise-induced oxidative damage in healthy menNutr Res.(2011 Nov)