Green tea has gone through various stages of preparation since it was discovered 4,700 years ago.
Some people eat the leaves, others dry them, and most of us just brew it into a cup on a slow morning.
But somewhere along the way, we figured out how to pull out the most potent part and put it in a capsule. That changes things.
The compound responsible is called epigallocatechin gallate, EGCG for short, and honestly most people have never heard of it. Here is why it is worth knowing about.
EGCG and Catechins: What They Are and Why They Get Attention
Green tea contains a large number of compounds, including polyphenols (catechins), alkaloids (caffeine), amino acids, vitamins, and minerals. However, Catechins are found in high concentrations and give green tea its antioxidant properties.
And if you are wondering why catechins have been getting so much attention lately, it mostly comes down to their antioxidant properties and what some research has found about oxidative stress in skin cells. The evidence is still building, but it is genuinely interesting.
Catechins
Green tea contains the catechins, including Epigallocatechin gallate (EGCG), alongside epicatechin (EC), epicatechin gallate (ECG), and epigallocatechin (EGC), which make up 20 to 30 percent of its dry weight.
- Epigallocatechin gallate (EGCG)
Epigallocatechin gallate (EGCG) is a chemical compound found in green tea which gives it specific antioxidant properties. It is a polyphenol compound with two phenol rings and eight hydroxyl groups, which gives it antioxidant properties.
- EGCG in Tea Form Versus Extract
Green tea, when boiled in the form of leaves, includes chlorophyll in its leaves, EGCG, Vitamins, minerals and other trace compounds. So it takes time for your body to absorb EGCG.
The green tea extract is prepared by putting the dried and ground green tea leaves in boiling water or a food-grade solvent, including water and ethanol. Some extraction processes also include active enzymes that break the cell walls of the green tea leaves to separate catechins in their most active form. This extract is then dried and placed in capsules or mixed with a gelling base to form gummies.
According to research by Xin-Qiang Zheng and colleagues conducted in 2024. EGCG is known to interact with skin physiology to protect it against UV rays. (1) The in vivo and clinical studies suggest that green tea extract seeps into the skin. When taken orally, some research has looked at whether it may support skin health through antioxidant pathways, though most of that evidence is still from small studies.
However, the studies were in vivo (within the living) and had a small sample of the human population, and more research is required to confirm these effects on large groups of people.
A 2025 scoping review by Febrinasari and colleagues looked at green tea as a cosmetic agent for skin ageing across both topical and oral use. The results across the studies they reviewed were mixed, and the authors felt that larger, longer-term trials are still needed before anything firm can be said (2).
What the Antioxidant Research Actually Shows
We all know that menopause can be a challenging time for women, with hormones raging inside the body. Your skin takes the brunt of all this hormonal imbalance, leading to various skin conditions. The following research was conducted to measure exactly how green tea extract impacts the skin of women who are going through menopause.
In the sub-study of the Minnesota Green Tea Trial by Feike and colleagues, 40 menopausal women took approximately 843 mg EGCG on a daily basis for a whole year. (3) Researchers found lower urinary excretion of two specific lipid peroxidation biomarkers.
The authors described it as modest in vivo antioxidant activity, measured through lower urinary excretion of two lipid peroxidation biomarkers in the supplement group compared to placebo. It was not a skin-specific finding, and the authors were careful about how far they took the conclusion.
Keep in mind that the women included in the research were not on any dietary restrictions. Moreover, the sample size was small and further research will help us find further benefits of catechins and green tea extract.
How to Read a Green Tea Extract Label
Once you go through the research on green tea extract yourself, you realize that there is so much more to a label than a flashy design.
- Catechin standardization percentage
The percentage of catechin is a marker of its effectiveness. Most commercially sourced green tea extracts available in Canada are standardized from 20% to 90% catechins. In this regard, Nutravea’s green tea extract is standardized to 80% catechins.
- EGCG percentage
The EGCG percentage shows how much Epigallocatechin gallate is present per mg of each capsule. Nutravea contains 50% EGCG, which means that you get 250mg EGCG per 500mg capsule
- Total extract amount per capsule
Look for the total extract weight of each capsule because the weight of extract is different from the standardized percentage of catechins and other chemical compounds. The standard extract amount per capsule ranges from 250 mg to 560 mg
- NPN number
The NPN means Health Canada reviewed the formulation before it went on shelves. It confirms regulatory review, not that the product is guaranteed to work for you.
- Caffeine content
It is worth checking if you are sensitive to caffeine or tend to take supplements in the evening. The Nutravea product has about 5mg per capsule, which is quite low, but still good to know.
- Serving size
Serving size should be clearly displayed on the bottle. A high-potency green tea extract should be taken once a day to reduce the risk of nausea on an empty stomach.
For those looking for a highly standardized Canadian option, a green tea extract with 80% catechins and 50% EGCG per capsule, such as the one from Nutravea, is one of the higher-potency formulas available with a confirmed Canadian NPN (80144682, verifiable on the Health Canada database).
Green tea extract is a plant that has been studied extensively for its antioxidant properties. However, the research is not conclusive and requires further exploration of the impact of its chemical compounds on the body. So it is always better to look for a standardized extract with a clear label mentioning the licensing facility as well as the NPN number.
References
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Zheng, X. Q., Zhang, X. H., Gao, H. Q., Huang, L. Y., Ye, J. J., Ye, J. H., Lu, J. L., Ma, S. C., & Liang, Y. R. (2024). Green Tea Catechins and Skin Health. Antioxidants (Basel, Switzerland), 13(12), 1506. https://doi.org/10.3390/antiox13121506
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Febrinasari, R. P., Benedictus, B., Tan, K., Mardhiati, Y., Putri, S. K., Choiri, S., & Wahyuni, D. S. C. (2025). Green tea as a cosmetic agent for skin aging: A scoping review. Avicenna journal of phytomedicine, 15(5), 1393–1407. https://doi.org/10.22038/ajp.2025.25449
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Fiecke, C., Kurzer, M., Chen, C., & Csallany, A. S. (2019). The in Vivo Antioxidant Effects of (-)-Epigallocatechin-3-Gallate Consumption in Healthy Postmenopausal Women Measured by Urinary Excretion of Secondary Lipid Peroxidation Products. Food and Nutrition Sciences, 10(1), 15–27. https://doi.org/10.4236/fns.2019.101002
