What are the potential side effects of matcha tea?
What do testimonials and scientific studies say?
Summary: Consuming more than 800mg per day of catechins (one of the components of matcha tea) can lead to liver issues, but it would require a significant amount of tea to reach this quantity. More common and easily passing side effects of matcha tea include nausea and gastrointestinal problems.
Happy reading 🙂!
Last update: November 2023
Disclaimer: Affiliate links. Complete disclosure in legal notices.
Written by Nelly Darbois, physical therapist and scientific writer
Summary
What does Matcha tea contain?
Matcha is a powdered form of Japanese green tea (Camellia sinensis) of the Tencha variety.
It is becoming increasingly popular, even in France, and is often considered the highest quality tea.
Here’s what it contains:
- Theanine
- Caffeine
- Chlorophyll
- Various types of catechins.
Green tea contains four main catechins:
- (-)-epicatechin (EC)
- (-)-epicatechin-3-gallate (ECG)
- (-)-epigallocatechin (EGC)
- And (-)-epigallocatechin-3-gallate (EGCG): matcha is the most concentrated source of this.
I provide this information because to understand its side effects, you need to look at the known side effects of the different substances it contains!
Source: Kochman 2021
Whether your Matcha tea is organic or not, it contains the same types of substances, and thus, the same potential side effects.
What are the known side effects of Matcha tea?
Clinical studies on Matcha tea have only been conducted since 2017, as shown in the graph below:
Some studies assess the potential health benefits, both physical and mental, of consuming Matcha tea.
These studies, which include people who drink Matcha tea, mention that those consuming the tea are asked to report potential side effects like a cold or stomach discomfort (Baba 2021). However, the authors of these publications do not further discuss these side effects in their results.
I went on to examine the described side effects of the different substances contained in Matcha tea.
Since we do not have data from scientific studies specifically on Matcha tea, we need to look at the known side effects of the individual components.
Side Effects of Theanine
Theanine is an amino acid naturally found in tea, especially in green tea, and thus in Matcha tea!
This substance is well-tolerated by the body, even at significant daily doses. It has been tested, for example, on rats to whom up to 4 grams per kilogram per day of theanine were administered for several weeks.
Source: Chen 2023
However, discomfort can still occur when consuming a large amount of this substance, depending on an individual’s sensitivity. Known side effects include:
- Decreased blood pressure
- Loss of appetite
- Difficulty concentrating
- Dizziness
- Diarrhea
- Headaches
- Nausea (especially when consumed on an empty stomach in the morning)
- Gastrointestinal discomfort
Source: Saeed 2020
Side Effects of Caffeine
Caffeine is a well-known and studied molecule.
It can be toxic to the body, but only at very high doses. It is important to consider all sources of caffeine that you consume (coffee, tea, energy drinks, etc.).
The recommended maximum doses are precautious at 400 mg per day.
The described side effects of caffeine are:
- Anxiety, restlessness, insomnia
- Facial flushing
- Increased urination
- Muscle twitches or tremors
- Irritability, aggression
- Increased heart rate or irregular heart rhythms
- Gastrointestinal issues
- And more rarely: disorientation, hallucinations, psychosis, seizures, arrhythmias, ischemia, rhabdomyolysis
- Withdrawal syndrome lasting several days after discontinuing caffeine
Source: Evans 2023
How much caffeine is in a cup of Matcha tea?
Matcha tea generally contains more caffeine than ordinary green tea because you consume the entire tea leaf, rather than infusing it. However, the caffeine content can vary depending on the product you consume and how you prepare it.
Most recommendations for preparing Matcha suggest using approximately 1 to 2 grams of Matcha powder per cup, which is roughly 30 to 140 milligrams of caffeine per 250ml cup.
Side Effects of Chlorophyll
Chlorophyll is a green pigment found in plants and algae (you’ve probably heard about it in your biology or life sciences classes in school!).
Many dietary supplements containing chlorophyll have been marketed for decades without significant reported side effects.
The most commonly described side effects are nausea and headaches when consumed in significant quantities.
Source: Martins 2023; Wangcharoen 2016
Side Effects of Catechins
The catechins in green tea extracts can have a different composition from the catechins in traditional green tea infusions.
Consuming more than 800 mg per day of catechins from green tea extract in liquid form is not recommended (as a precaution), as it is believed to cause long-term liver damage. The maximum recommended dose for solid forms of green tea extract (such as capsules) is 338 mg per day.
However, if you consume Matcha tea in the form of traditional infusion, this problem does not seem to arise.
Source: EFSA 2018, Hu 2018
How to know if you might experience side effects from Matcha tea?
It is very difficult to predict in advance if you will be susceptible to potential side effects associated with the consumption of large amounts of Matcha tea.
The recommended maximum dose to avoid liver problems is 800 mg/day (which is a really large, large, large amount of tea!).
However, for the “minor” transient side effects like nausea or stomach discomfort, it is likely that lower doses are sufficient to trigger them.
These are, however, bothersome side effects that disappear within a few hours or days by either discontinuing tea consumption or simply reducing your intake.
Personally, here’s how I interpret this information (I am a heavy tea consumer):
- I don’t particularly monitor my tea consumption as long as I don’t experience side effects.
- When I do experience side effects, I try to see if there is any other factor (such as contracting a virus or eating something unusual) that could explain these symptoms. In my case, it’s mostly nausea, and sometimes even vomiting. I also have some doubts about morning headaches.
- When I can’t identify another cause, I am more cautious in the following days regarding my tea consumption. I try to find the maximum dose that my body can tolerate.
- I try to identify the circumstances in which the side effects occur. In my case, it involves heavy consumption, but mostly a prolonged lack of food intake before drinking tea.
By paying a bit more attention to how you consume Matcha tea, you should be able to better identify if you experience side effects and how to limit their impact.
Are there many negative reviews and testimonials about Matcha tea?
As you’ve noticed, I have relied less on testimonials regarding the side effects of Matcha tea and more on data from scientific publications.
Why?
Because these publications attempt to evaluate the effects on as many people as possible, and most importantly, to identify if other causes might explain these side effects.
I find this more reliable than testimonials, even though the latter can also be useful for providing more concrete examples.
By perusing forums or social media (using keywords or hashtags like #MatchaTea), you will find numerous testimonials from people describing both positive effects and side effects related to Matcha tea consumption.
Here’s an illustrative example of a review on Amazon regarding side effects experienced from Matcha tea consumption (based on my research, morning nausea seems to be the most commonly reported side effect):
***
I hope my article has been helpful to you! Do you have any comments or questions? Your comments are welcome 🙂 !
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📚 SOURCES
Kochman J, Jakubczyk K, Antoniewicz J, Mruk H, Janda K. Health Benefits and Chemical Composition of Matcha Green Tea: A Review. Molecules. 2020 Dec 27;26(1):85. doi: 10.3390/molecules26010085. PMID: 33375458; PMCID: PMC7796401
Baba Y, Inagaki S, Nakagawa S, Kobayashi M, Kaneko T, Takihara T. Effects of Daily Matcha and Caffeine Intake on Mild Acute Psychological Stress-Related Cognitive Function in Middle-Aged and Older Adults: A Randomized Placebo-Controlled Study. Nutrients. 2021 May 17;13(5):1700. doi: 10.3390/nu13051700. PMID: 34067795; PMCID: PMC8156288.
EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS); Younes M, Aggett P, Aguilar F, Crebelli R, Dusemund B, Filipič M, Frutos MJ, Galtier P, Gott D, Gundert-Remy U, Lambré C, Leblanc JC, Lillegaard IT, Moldeus P, Mortensen A, Oskarsson A, Stankovic I, Waalkens-Berendsen I, Woutersen RA, Andrade RJ, Fortes C, Mosesso P, Restani P, Arcella D, Pizzo F, Smeraldi C, Wright M. Scientific opinion on the safety of green tea catechins. EFSA J. 2018 Apr 18;16(4):e05239. doi: 10.2903/j.efsa.2018.5239. PMID: 32625874; PMCID: PMC7009618.
EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS); Younes M, Aggett P, Aguilar F, Crebelli R, Dusemund B, Filipič M, Frutos MJ, Galtier P, Gott D, Gundert-Remy U, Lambré C, Leblanc JC, Lillegaard IT, Moldeus P, Mortensen A, Oskarsson A, Stankovic I, Waalkens-Berendsen I, Woutersen RA, Andrade RJ, Fortes C, Mosesso P, Restani P, Arcella D, Pizzo F, Smeraldi C, Wright M. Scientific opinion on the safety of green tea catechins. EFSA J. 2018 Apr 18;16(4):e05239. doi: 10.2903/j.efsa.2018.5239. PMID: 32625874; PMCID: PMC7009618.
Hu J, Webster D, Cao J, Shao A. The safety of green tea and green tea extract consumption in adults – Results of a systematic review. Regul Toxicol Pharmacol. 2018 Jun;95:412-433. doi: 10.1016/j.yrtph.2018.03.019. Epub 2018 Mar 24. PMID: 29580974.
Chen S, Kang J, Zhu H, Wang K, Han Z, Wang L, Liu J, Wu Y, He P, Tu Y, Li B. L-Theanine and Immunity: A Review. Molecules. 2023 May 1;28(9):3846. doi: 10.3390/molecules28093846. PMID: 37175254; PMCID: PMC10179891.
Saeed M, Khan MS, Kamboh AA, Alagawany M, Khafaga AF, Noreldin AE, Qumar M, Safdar M, Hussain M, Abd El-Hack ME, Chao S. L-theanine: an astounding sui generis amino acid in poultry nutrition. Poult Sci. 2020 Nov;99(11):5625-5636. doi: 10.1016/j.psj.2020.07.016. Epub 2020 Aug 6. PMID: 33142480; PMCID: PMC7647716.
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Written by Nelly Darbois
I love writing articles based on my experience as a physiotherapist (since 2012), scientific writer, and extensive researcher in international scientific literature.
I live in the French Alps 🌞❄️, where I work as a scientific editor for my own website, which is where you are right now.