Tea cup with loose leaf green tea

Most Common Antioxidants in Green Tea (Antiox Part 8)

Posted by Stephany Morgan

Welcome to part 8 of my Antioxidant Series! By now you are practically an expert, and if you are joining me for the first time, welcome! In this article I will explore the marvelous antioxidants in your cup of green tea. I will discuss:


  • The polyphenol family: What are polyphenols anyway?
  • EGCG, the most famous of the green tea antioxidants
  • EGC, a metabolite of EGCG (and what the heck that means)
  • Theanine - a natural wonder and one of my favorite antioxidants
  • And how to supercharge your tea


If this list sounds overly sciencey and intimidating, don’t worry, I have made it accessible to science lovers and laypeople alike! If you are wondering what antioxidants are, it may be helpful to check out some of our past discussions, All About Antioxidants or How are Antioxidants Measured or start from the top and read the whole series. Let's get started!


 Green tea in a handheld mug


What are the Polyphenols in Tea?

So you may be wondering, what antioxidants are actually in green tea? And, why does it matter? The amount of antioxidants in your cup of tea vary depending on their fermentation process, which is why it is interesting to see how different types of tea benefit you.

Green tea mainly contains polyphenols: Polyphenols are a group of antioxidants that include flavonoids, phenolic acids, catechins, and flavonols (Po1). 

EGCG and ECG make up about 80% of green tea’s catechins. (EC is also notable even though it is less common (Pr1).) Polyphenols act by inhibiting redox sensitive factors, inducing the action of antioxidant enzymes, and inhibiting enzymes that have pro-oxidant activity.

Redox is a short way of referring to a chemical reaction where one molecule is reduced (the molecule gains electrons, which have a negative charge so hence the word “reduce”) and the other is oxidized (loses electrons making it become more positive). While our bodies produce oxidants, we also have endogenous or natural antioxidants, too.

The simplest way of explaining that is via enzymatic reactions: Enzymes catalyze and/or speed up a response within a cell and are necessary for changes to take place. Enzymes usually facilitate the redox reactions (originally it was thought these reactions always involved oxygen but that was later discovered to not be true).

Anyway, the loss and gaining of electrons is constantly taking place in our cells to maintain balance of electrical charge. It is maintained by our natural (endogenous) antioxidants reacting with Reactive oxygen species, which generally occur as byproducts of metabolism. Systems can be overwhelmed, consuming antioxidant foods can support these processes (theoretically - we haven’t actually proven it, it’s just a strong likelihood) (Ya1).

So, polyphenols actually help by increasing the number of our natural antioxidants, which are also enzymes. (For example, polyphenols increase the amount of glutathione peroxidase. The “-ase” suffix generally indicates the substance is an enzyme). Polyphenols also inhibit oxidative enzymes, so they are essentially regulators of the sensitive redox reaction processes that must occur to keep the cells healthy and balanced (Er1). 

Basically, polyphenols act to maintain cellular homeostasis as they can both increase or decrease the oxidative state. The easiest way to say this is that that the polyphenols activate the signaling factors in the cell, which support its adaptation and survival. They are sensitive to what is occurring in the cell at a given time (Kn1).

Whew, that was a mouthful!


Loose Leaf Tea Steeping in a mug


Epigallocatechin-3-gallate: What are EGCG's health benefits in green tea? 

Our first antioxidant is EGCG. This catechin is abundant in green tea and has powerful health benefits that make it the most famous antioxidant in green tea. So what does EGCG do?


Anticancer Properties of EGCG

According to recent scientific literature, green tea may have cancer preventive properties (Ka1). The academic research examining the molecules has shown that EGCG may in fact prevent the multiplication of cancer cells, and even cause them to self-destruct (Ya1, Va1).

Of course it is important to note that green tea is not a treatment for cancer, but a complement to a healthy lifestyle.


Health Benefits of EGCG

There’s more! EGCG is antimicrobial (Hep C bacteria for example) (Cu1, Ca1) and even has liver-protective properties (Zh1). A rather unique trait, EGCG can cross the blood-brain barrier giving it neuroprotective effects (Sc1), and the ability to help with Alzheimers. How? It limits the accumulation of amyloid plaques typical of Alzheimers by reducing inflammation and neurotoxicity (Am1). As you may have heard these amyloid plaques are one of the chief suspects in the causes of Alzheimer's disease.



To Summarize, EGCG has...

  • Antimicrobial properties
  • Cancer preventive properties
  • Liver protective properties
  • Neuroprotective effects (ex. helps with Alzheimers)
  • Important Note: No tea is a treatment, just because particular papers and journals have researched these properties does not mean it can be used as a medicine in itself. Here at MatchaAlternatives.com we do not support false claims, pseudoscience or over-simplified health claims!


Mug of tea and milk pitcher


Epigallocatechin (EGC) in Green Tea: What does it do?

Next up, EGC! EGC is a catechin formed from EGCG through the process of metabolism. There are several forms of EGC (they are called M1, M4, M9, etc) but I won’t get into these specific variations today.


Health Benefits of EGC

While slightly less studied than its famous big sister, EGC has anti-inflammatory and anticancer effects, and helps to prevent breast cancer cell invasion (Bi1). EGC is also known for its antidiabetic, neuritogenic, blood pressure reducing effects and ability to modulate your immune system (Pe1). Last but not least, it exhibits the famous antioxidant quality of being a free radical scavenger (Py1).

Neuritogenic is when something causes the development or growth of new nervous system tissue. There are nerve growth factors that can be administered (medically) in high doses to help repair axons (nerve fibers), and also improve the potential of our naturally occurring nerve growth factors. It's been found those that green tea polyphenols do the same thing but at much lower doses than are needed from isolated nerve growth factors (Gu1).

EGCG specifically does this, but the activity is increased by the synergistic action of the other polyphenols. In short, green tea polyphenols help enhance the action of the body’s naturally occurring nerve growth factors, which are useful for healing damaged nerve fibers and other neurological injuries (Gu1).

But I must emphasize: I am not suggesting green tea can be used as a treatment for nerve damage - the above is the possibility that may arise from green tea's use after observing that “neuritogenic” action in studies. 


EGC Heart Support

The four M catechins mentioned above act together harmoniously to increase human plasma’s antioxidant capacity. What does this mean? The resulting effect is beneficial for heart conditions such as thrombosis, cardiovascular disease and inflammation (Ep1).

I guess that makes Camellia sinensis a heart-y tea! Eh? No? Moving on...


To Summarize, EGC is...

  • Anti-inflammatory
  • Anticancer (it helps prevent breast cancer cells)
  • Antidiabetic
  • Neuritogenic
  • Able to reduce blood pressure
  • Beneficial for heart conditions
  • Important note: no tea is a treatment, just because particular papers and journals have researched these properties does not mean it can be used as a medicine in itself. Here at MatchaAlternatives.com we are not into false claims or pseudoscience.


Steaming mug of tea with loose leaf tea


L-Theanine & Green Tea: How does it help?

Last but not least: theanine! More commonly known as L-theanine this is a non-proteinogenic amino acid. It has been simultaneously reported to cause relaxation, stress relief, and improved focus and concentration (He1).


Theanine: The Caffeine Agonist

This sounds like the title of a surreal poem! But no, it's a fantastic scientific term. So, what does it mean when I say theanine is a caffeine agonist? This means it can help prevent some of the less desirable effects of caffeine, such as the jitters (He1). For lots more about how caffeine works, check out my previous post about caffeine here

Does black tea or green tea have more theanine? Well, a cup of black tea contains 20-30 mg of theanine while a cup of green tea contains 4-12mg. Two to three cups of green tea may provide about 50 mg of theanine, which is the lower end of doses tested in studies (Bn1). These results are based on tested samples with brew time being the largest factor influencing the amount of theanine (Ke1).

Despite the smaller amount in green tea, the effects are not lost! It was green tea that first led to the exploration of it, afterall! Seeing as tea created a state of calm alertness, it is not surprising that the varying components within tea were explored.

But the synergistic effects of herbs should never be ignored. While drinking a caffeinated beverage prior to bedtime is not recommended, enjoying a cup in the late afternoon to stave off drowsiness and increase alertness is certainly a perk. :-)


Woman sleeping in bed


Health Benefits of Theanine

Interestingly, using theanine as an additive (not in tea, but on its own) has been seen to improve sleep and anxiety with mg levels upwards of 250mg (Wi1). Theanine is thought to increase GABA production in the brain and modulate serotonin and dopamine (Bn1). (GABA is a chemical that binds to the neurons in the brain, and helps reduce fear and anxiety responses, Mc1.)

Further, it helps to produce cell-protective glutathione (an important antioxidant) by maintaining appropriate levels of it in cells, and it is this glutathione which exhibits antioxidant action. In mouse studies, it has preserved antioxidant action within the liver via the hepatocyte (that is, liver cell) antioxidant capabilities (Th1). Again if you want a reminder of why you would want ‘antioxidant action’ read my primer: All about Antioxidants. Basically, *yes* you do want this!

Different studies have observed anti-inflammatory, reduced blood sugar, reduced blood pressure (antihypertensive) and mood-modulating effects. It may also improve learning and memory, according to rat studies (Th1). Pretty neat!


To summarize, Theanine...

  • Prevents negative effects of caffeine (like the jitters)
  • Improves sleep and anxiety
  • Increases GABA production in the brain
  • Modulates serotonin and dopamine
  • Makes glutathione that protects your cells
  • Preserves antioxidant action in the liver (mouse studies)
  • Has anti-inflammatory properties
  • Reduces blood sugar
  • Reduces blood pressure
  • Modulates your mood
  • Improves learning and memory (rat studies)
  • Important note: no tea is a treatment, just because particular papers and journals have researched these properties does not mean it can be used as a medicine in itself. Here at MatchaAlternatives.com we are not into false claims or pseudoscience.


Lemon in a glass with bowl of citrus


How to supercharge your tea with citrus

Did you know that adding lemon to your tea has real scientific benefits?! It turns out that while sprucing up your tea with lovely notes, this fruit is also working hard to help you. One benefit is ascorbic acid antioxidant action. 

Citrus also helps the catechins in your green tea (like EGCG and EGC) to survive digestion (Pu1). Only around 20% of catechins can survive the non-acidic environment of your intestines, but by adding Vitamin C, you cultivate a more acidic space, and support their bioavailability. The result? EGC and EGCG are increased by 6 and 13 times respectively (Pu1, Gr1). I mean, WOW!

Go citrus!



Stephany Morgan

A Note From The Herbalist...

Antioxidants are no small feat to explain, so thank you for taking the time to learn with me!

Green tea contains some antioxidants that are unique from other foods in their compositions and quantity, giving it special health benefits. With thousands of years of use as a traditional health food and use in traditional medicine systems this tea has had plenty of time to earn its dazzling reputation.

Speaking of health benefits, I wanted to mention the anticancer/cancer-preventive properties of green tea. To say one a final time, as we are always seeing silly claims online: I want to stress that green tea (and perhaps other kinds of botanical medicines) should not be employed alone as a medicine for the purpose of treating cancer.

While research has been conducted into the action against cancer, herbs like tea are meant to be given as a system of medicine under the direction of a qualified healthcare professional. Otherwise, the best way to utilize green tea and other medicinal herbs is as a complementary supplement to healthy lifestyles.

Questions? Thoughts? Are the health benefits of Green Tea one of the reasons you drink it? Or perhaps not at all? I'm curious to know! Let me know in the comments below or on our IG @MatchaAlternatives

Now, time to drink some green tea! Here are some of my favorites: 


Delicate Fuji Sencha Organic Green Tea

Delicate Fuji Sencha Organic Green Tea
This tea has a round slightly floral, salty, and grassy liquor taste.

Gentle Red Raspberry Green Tea
This gentle fruity tea is lovely with creamy desserts or as an iced tea
Sleep Easy Hojicha Roasted Green Tea
This tea has a lovely toasted barely flavor with lots of antioxidants!
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All of the information regarding the herbs, botanicals, minerals, vitamins, etc., is information drawn from traditional use data or academic research and should be regarded as such. If you, the reader, has a health or medical concern, please consult your healthcare professional. The information found here is not meant to diagnose, treat, prescribe or cure and has not been evaluated by the FDA. This information is for educational purposes only. 


Antioxidants in Green Tea: References & Further Reading

Internal References

MatchaAlternatives.com. The Health Benefits of Teas and Tisanes

MatchaAlternatives.com. What Are Antioxidants and How Do They Work? Part 1.


External Research and References

(Po1) Healthline, What Are Polyphenols? Types, Benefits, and Food Sources. https://www.healthline.com/nutrition/polyphenols#what-they-are. Accessed 10/20/2020.

(Pr1): Prasanth, et al (2019). A Review of the role of green tea (camellia sinensis) in Antiphotoaging, stress resistance, neuroprotection, and autophagy. doi:10.3390/nu11020474. Accessed 10/20/2020.

(Ya1) Yang, C., Du, W., & Yang, D. (2016). Inhibition of green tea polyphenol EGCG((-)-epigallocatechin-3-gallate) on the proliferation of gastric cancer cells by suppressing canonical wnt/β-catenin signalling pathway. International journal of food sciences and nutrition, 67(7), 818–827. https://doi.org/10.1080/09637486.2016.1198892. Accessed 10/20/2020.

(Ya1) Yan, Z., Zhong, Y., Duan, Y., Chen, Q., & Li, F. (2020). Antioxidant mechanism of tea polyphenols and its impact on health benefits. Animal nutrition (Zhongguo xu mu shou yi xue hui)6(2), 115–123. https://doi.org/10.1016/j.aninu.2020.01.001 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7283370/ . Accessed 10/29/2020.

(Er1) Erik A. Fraunberger, Gustavo Scola, Victoria L. M. Laliberté, Angela Duong, Ana C. Andreazza, "Redox Modulations, Antioxidants, and Neuropsychiatric Disorders", Oxidative Medicine and Cellular Longevity, vol. 2016, Article ID 4729192, 14 pages, 2016. https://doi.org/10.1155/2016/4729192 https://www.hindawi.com/journals/omcl/2016/4729192/ . Accessed 10/29/2020.

(Kn1) Kanner, J. Polyphenols by Generating H2O2, Affect Cell Redox Signaling, Inhibit PTPs and Activate Nrf2 Axis for Adaptation and Cell Surviving: In Vitro, In Vivo and Human Health. Antioxidants 2020, 9, 797. https://www.mdpi.com/2076-3921/9/9/797. Accessed 10/29/2020.

(Ka1) Kazue Imai, Kenji Suga, Kei Nakachi, Cancer-Preventive Effects of Drinking Green Tea among a Japanese Population, Preventive Medicine, Volume 26, Issue 6,1997, Pages 769-775, ISSN 0091-7435, https://doi.org/10.1006/pmed.1997.0242.
(http://www.sciencedirect.com/science/article/pii/S0091743597902425)Accessed 10/20/2020.

(Va1) Van Aller, G. S., Carson, J. D., Tang, W., Peng, H., Zhao, L., Copeland, R. A., Tummino, P. J., & Luo, L. (2011). Epigallocatechin gallate (EGCG), a major component of green tea, is a dual phosphoinositide-3-kinase/mTOR inhibitor. Biochemical and biophysical research communications, 406(2), 194–199. https://doi.org/10.1016/j.bbrc.2011.02.010 . Accessed 10/20/2020.

(Cu1) Cui, Y., Oh, Y. J., Lim, J., Youn, M., Lee, I., Pak, H. K., Park, W., Jo, W., & Park, S. (2012). AFM study of the differential inhibitory effects of the green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) against Gram-positive and Gram-negative bacteria. Food microbiology, 29(1), 80–87. https://doi.org/10.1016/j.fm.2011.08.019 . Accessed 10/20/2020.

(Ca1) Calland, N., Albecka, A., Belouzard, S., Wychowski, C., Duverlie, G., Descamps, V., Hober, D., Dubuisson, J., Rouillé, Y., & Séron, K. (2012). (-)-Epigallocatechin-3-gallate is a new inhibitor of hepatitis C virus entry. Hepatology (Baltimore, Md.), 55(3), 720–729. https://doi.org/10.1002/hep.24803 #Accessed 10/20/2020.

(Zh1) Zhou, J., Farah, B. L., Sinha, R. A., Wu, Y., Singh, B. K., Bay, B. H., Yang, C. S., & Yen, P. M. (2014). Epigallocatechin-3-gallate (EGCG), a green tea polyphenol, stimulates hepatic autophagy and lipid clearance. PloS one, 9(1), e87161. https://doi.org/10.1371/journal.pone.0087161. Accessed 10/20/2020.

(Sc1) ScienceDirect. Catchins. https://www.sciencedirect.com/topics/neuroscience/catechinAccessed 10/20/2020.

(Am1) Cheng-Chung Wei, J., Huang, H. C., Chen, W. J., Huang, C. N., Peng, C. H., & Lin, C. L. (2016). Epigallocatechin gallate attenuates amyloid β-induced inflammation and neurotoxicity in EOC 13.31 microglia. European journal of pharmacology, 770, 16–24. https://doi.org/10.1016/j.ejphar.2015.11.048. Accessed 10/20/2020.

(Bi1) (-)-Epigallocatechin. Biomol. https://www.biomol.com/products/chemicals/biochemicals/epigallocatechin-cay11809-1 . Accessed 10/20/2020.

(Pe1) Pervin, M., Unno, K., Takagaki, A., Isemura, M., & Nakamura, Y. (2019). Function of Green Tea Catechins in the Brain: Epigallocatechin Gallate and its Metabolites. International journal of molecular sciences, 20(15), 3630. https://doi.org/10.3390/ijms20153630 retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6696481/. Accessed 10/20/2020.

(Gu1) Gundimeda U, McNeill TH, Schiffman JE, Hinton DR, Gopalakrishna R. Green tea polyphenols potentiate the action of nerve growth factor to induce neuritogenesis: possible role of reactive oxygen species. J Neurosci Res. 2010 Dec;88(16):3644-55. doi: 10.1002/jnr.22519. Epub 2010 Oct 8. PMID: 20936703; PMCID: PMC2965808. https://pubmed.ncbi.nlm.nih.gov/20936703/. Accessed 10/20/2020.

(Py1) Priyatharini Ambigaipalan, Won Young Oh, Fereidoon Shahidi, Epigallocatechin (EGC) esters as potential sources of antioxidants, Food Chemistry, Volume 309, 2020, 125609, ISSN 0308-8146,
(http://www.sciencedirect.com/science/article/pii/S0308814619317340)Accessed 10/20/2020.

(Ep1) ScienceDirect. Epicatechin Gallate. https://www.sciencedirect.com/topics/neuroscience/epicatechin-gallate . Accessed 10/20/2020.

(He1) Healthline, What You Should Know About L-Theanine. https://www.healthline.com/health/l-theanine. Accessed 10/24/2020.

(Th1) ScienceDirect, Theanine. https://www.sciencedirect.com/topics/medicine-and-dentistry/theanine . Accessed 10/20/2020.

(Bn1) ScienceDirect,Theanine. https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/theanine. Accessed 10/20/2020.

(Mc1) McGill University, The Brain from Top to Bottom: Anxiety Neurotransmitters. https://thebrain.mcgill.ca/flash/d/d_04/d_04_m/d_04_m_peu/d_04_m_peu.html  Accessed 10/30/2020.

(Ke1) Emma K. Keenan, Mike D.A. Finnie, Paul S. Jones, Peter J. Rogers, Caroline M. Priestley, How much theanine in a cup of tea? Effects of tea type and method of preparation, Food Chemistry, Volume 125, Issue 2, 2011, Pages 588-594, ISSN 0308-8146, https://doi.org/10.1016/j.foodchem.2010.08.071.(http://www.sciencedirect.com/science/article/pii/S0308814610011416). Accessed 10/20/2020.

(Wi1) Williams, J.; Kellett, J.; Roach, P.D.; McKune, A.; Mellor, D.; Thomas, J.; Naumovski, N. l-Theanine as a Functional Food Additive: Its Role in Disease Prevention and Health Promotion. Beverages 20162, 13. https://www.mdpi.com/2306-5710/2/2/13

(Pu1) Purdue University, 2007. Citrus juice, vitamin C give staying power to green tea antioxidants https://www.purdue.edu/uns/x/2007b/071113FerruzziTea.html. Accessed 10/20/2020.

(Gr1) Green, R. J., Murphy, A. S., Schulz, B., Watkins, B. A., & Ferruzzi, M. G. (2007). Common tea formulations modulate in vitro digestive recovery of green tea catechins. Molecular nutrition & food research, 51(9), 1152–1162. https://doi.org/10.1002/mnfr.200700086 Retrieved from: https://pubmed.ncbi.nlm.nih.gov/17688297/Accessed 10/20/2020.


External Research Not Referenced

Oregon State University. Tea. https://lpi.oregonstate.edu/mic/food-beverages/tea

A.T. Atanasov1, V. H. Petrova-Tacheva, R. T. Todorova. Biologically active substances with antioxidant activity isolated from the medicinal plant Galega officinalis L. Bulgarian Chemical Communications, Volume 51, Special Issue A (pp. 161-166) 2019. 

Boros, K., Jedlinszki, N., & Csupor, D. (2016). Theanine and Caffeine Content of Infusions Prepared from Commercial Tea Samples. Pharmacognosy magazine, 12(45), 75–79. https://doi.org/10.4103/0973-1296.176061 Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4787341/

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  • Thank you for your comment Trinity! So happy this article was useful, and that you are a fellow green tea lover :-) Happy steeping!

    Elizabeth Taeed, co-founder, MatchaAlternatives.com

  • Loved this blog! Green tea is my favorite (drinking some right now, actually) and it’s wonderful to hear about all the amazing properties that it has :-)

    Trinity Kendrick

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