Green tea extract – liver risk or underestimated potential?

Green tea extract has been a source of controversy for years—sometimes celebrated as a natural plant substance with valuable properties, while others are viewed critically due to potential risks if used incorrectly. Public perception fluctuates between superfood status and warnings. However, these extremes help neither consumers nor objective information.

The fact is: In Asia, green tea has been a part of everyday life for thousands of years. The tea plant ( Camellia sinensis ) is valued there not as a trend, but as part of the diet and culture. What makes it special is that it contains a complex mixture of secondary plant substances – most notably the so-called catechins , especially epigallocatechin-3-gallate (EGCG) .

EGCG is the most abundant plant substance in Green tea extract, which is now contained in many high-quality dietary supplements, is a popular choice. But how safe is this form of intake? What dosage is considered safe? And what should you really look for when choosing a product?

In this article, we explore these questions in depth—without hype or trivialization. We reveal what green tea extract really is, how risks can be avoided, and why dosage, quality, and composition are more important than catchy headlines. Because, as is so often the case, the truth doesn't lie in extremes. Green tea extract is neither a miracle cure nor a risk per se—but rather a plant substance that needs to be understood and used correctly.

What is green tea extract – and how does it differ from classic tea?

Green tea is one of the oldest cultivated beverages in the world. It is obtained from the leaves of the tea plant Camellia sinensis – the same plant from which black and white tea are made. The difference lies in the processing: Green tea is not fermented, which means its natural plant compounds are almost completely preserved. It is precisely this unadulterated plant chemistry that makes it attractive for extract production.

Green tea extract is not a simple powdered tea, but a highly concentrated extract of the bioactive components of tea leaves , particularly the so-called catechins . The most important of these are epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), and, above all , epigallocatechin-3-gallate (EGCG) —the most studied component in the extract.

While a cup of green tea provides approximately 20–45 mg of EGCG, depending on the variety and preparation, a single capsule of a high-quality green tea extract can contain several hundred milligrams – precisely dosed and independent of brewing time or water temperature. This standardized form offers the advantage of precisely controlling daily intake – a significant difference from traditional tea consumption, where the EGCG content fluctuates greatly.

In addition, green tea extract is usually formulated to supplement certain accompanying substances – such as vitamin C, which can improve the stability of catechins, or piperine, a black pepper extract that increases their bioavailability.

The aim is not to replace tea, but to supply its most valuable ingredient – ​​EGCG – in a targeted and responsible manner , within the framework of legal requirements and scientifically sound recommendations.

EGCG in Focus: What Research Really Says – and What It Doesn’t

The key ingredient in green tea extract is epigallocatechin-3-gallate , or EGCG for short. It belongs to the catechin family, a subgroup of flavonoids, which in turn belong to the secondary plant compounds. EGCG isn't just any compound—it's the most widely studied component of green tea, both in basic research and in clinical contexts.

It's important to note that EGCG is not a medicinal product. According to the EU Health Claims Regulation, food supplements are not permitted to communicate disease-related effects or claims of healing. Therefore, Tigogreen places particular emphasis on objective, transparent communication based on verifiable facts – without impermissible health claims.

In short : EGCG is exciting and has many benefits . EGCG is undoubtedly a remarkable compound from nature. But as with all high-quality plant substances, the decisive factor is the context – not the hype. Those who pay attention to quality, dosage, and responsibility can integrate EGCG meaningfully into their daily routine. without excessive expectations.

Side effects and safety: What does the EFSA say about green tea extract?

In the discussion surrounding green tea extract, one topic repeatedly arises: potential side effects, especially those related to the liver. In internet forums and media, the search term " liver damage from green tea " is often encountered – but what is behind this concern?

First of all, green tea is considered safe as a beverage when consumed normally. The potential risks only concern highly concentrated extracts, especially when consumed improperly, such as:

·       Consumption on an empty stomach

·       extremely high doses (over 800 mg EGCG daily)

·       Products of unclear origin without laboratory testing or EGCG declaration

The European Food Safety Authority (EFSA) published a comprehensive safety assessment of green tea catechins in 2018. It states:

“Doses of up to 800 mg EGCG per day from food supplements are considered safe for adults when taken for a period of up to 12 months.” (EFSA Journal 2018;16(4):5239)

In the few documented cases in which liver damage actually occurred due to green tea extract, the products almost always involved extremely high EGCG levels, without transparent labeling, and often from non-European sources. Studies such as those by Grajecki et al. (2022) and Fletcher et al. (2024) also show that the exact cause remains unclear in many cases – usually due to overdose or ingestion without medical advice.

On a positive note, the EFSA points out that taking it with or after a meal significantly reduces the risk because it slows down absorption and relieves the strain on the liver.

Conclusion: The term "liver damage from green tea" is often used in a blanket manner, but it only applies if the concentration, origin, or application is incorrect. With a high-quality, transparently labeled product, the risk can be significantly minimized.

The right application makes the difference

Even the highest-quality active ingredient only unfolds its full potential when used correctly. This also applies—or especially—to green tea extract. It's not the substance itself that's problematic, but the method of application.

Anyone who wants to integrate green tea extract meaningfully into their daily routine should pay attention to three key aspects: dosage, timing of intake, and combination with other substances.

The European Food Safety Authority (EFSA) recommends no more than 800 mg of EGCG per day through dietary supplements. This upper limit has been deemed safe based on numerous studies – provided the intake is not on an empty stomach .

Why is this so important? Studies show that EGCG absorption on an empty stomach is not only significantly more intense, but can also place greater strain on the liver. Taking it with or immediately after a meal is better, as this slows absorption and reduces potential side effects.

The combination with other substances—such as those for improved bioavailability—should also be carefully considered. Piperine, for example, can significantly increase the absorption of EGCG. This isn't necessarily a bad thing, but it must be controlled and carefully dosed to stay within safe limits.

Conclusion: Paying attention to dosage, timing of intake, and interactions lays the foundation for safe, everyday use of green tea extract – and avoids unnecessary risks.

Green tea extract: quality, origin and formulation – what really matters

Not all green tea extracts are the same. And this is often overlooked in many discussions about potential side effects. Whether a product is well tolerated depends not only on the amount of EGCG it contains—but primarily on the quality of the raw materials , the manufacturing process , and the composition .

A high-quality green tea extract begins with the plant: Camellia sinensis grows worldwide – but not every variety, every soil, and every cultivation method delivers the same concentration of valuable catechins. Selecting the right variety, the optimal harvest time, and gentle processing are crucial for a natural, plant-rich extract.

Equally crucial is the question: How is the extract processed and formulated?
Only if a product is manufactured under clearly defined standards, regularly tested in the laboratory and transparently declared can it be used safely in the long term.

Tigovit was developed precisely with this in mind: with green tea from controlled cultivation, 170 mg of EGCG per capsule , supplemented with vitamin C and Bioperine® – a patented black pepper extract in a precisely calibrated dosage. The daily dose of 510 mg EGCG deliberately remains below the legally established upper limit and is formulated to be well-tolerated and suitable for everyday use. For a short-term course of treatment, up to 4 tigovit capsules can be taken, corresponding to 680 mg EGCG .

Made in Germany, laboratory-tested, free from unnecessary additives – and packaged in a sustainable glass bottle with a copper beechwood lid, refillable with refill bags.

Anyone who chooses green tea extract should pay attention to verified origins, clear labeling, and well-thought-out formulations – because quality is the key to safety and effectiveness.

Conclusion: Green tea extract – useful if you understand it

Green tea extract isn't a trendy product—nor is it a source of danger per se. It contains highly concentrated plant substances like EGCG and stems from a millennia-old tradition that can now be used specifically with the help of modern science.

The debate surrounding terms like "liver damage from green tea" demonstrates one thing above all: there's often a lack of differentiation. There's a world of difference between safe use and improper application. Anyone who consumes more than 800 mg of EGCG per day, especially on an empty stomach and perhaps from a dubious source, is risking unnecessary side effects. However, anyone who pays attention to tested quality, moderate dosage, and good tolerability can safely integrate green tea extract into their daily routine.

We trust in the power of nature when used consciously and responsibly. In a world increasingly relying on artificial solutions, green tea extract remains a natural option for people who live mindfully and want to supplement their health in a targeted manner.

Not as a substitute for a healthy diet. Not as a miracle cure. But as part of a well-thought-out lifestyle.

What is important is not the material itself, but how responsibly we use it.

Sources:

EFSA Journal (2018): Safety of green tea catechins
https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2018.5239
Kumar N, Chattopadhyay D (2021): Catechins and EGCG – Review

https://pubmed.ncbi.nlm.nih.gov/31131658/
Zhao T et al. (2022): Green Tea – Phytochemistry, Pharmacology, Toxicology

https://www.mdpi.com/1420-3049/27/12/3909
Grajecki D et al. (2022): Green tea extract-associated acute liver injury

https://aasldpubs.onlinelibrary.wiley.com/doi/10.1002/cld.1213
Fletcher C et al. (2024): Acute liver failure secondary to green tea extract

https://www.pathologyjournal.rcpa.edu.au/article/S0031-3025(24)00062-1/fulltextBfR – Federal Institute for Risk Assessment (2023): Statement on EGCG

https://www.bfr.bund.de/cm/343/risikobewertung-von-epigallocatechingallat-egcg-in-nahrungsergaenzungsmitteln.pdf

EU Regulation (EU) 2022/2340
https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32022R2340
Implementing Regulation (EU) 2017/2470 – Novel Foods Union List

https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32017R2470