What Are the Cons of Matcha Tea? The Potential Risks and Side Effects

November 19, 2025 •

4 min read

According to numerous studies, while matcha tea is packed with antioxidants, it is crucial to consume it in moderation, as overconsumption can lead to negative side effects. Understanding the full spectrum of what are the cons of matcha tea is essential for informed and healthy consumption.

Quick Summary

The drawbacks of matcha tea include potential heavy metal contamination, high caffeine content leading to anxiety and insomnia, and digestive problems such as stomach upset, especially on an empty stomach.

Key Points

Caffeine Sensitivity: High caffeine levels in matcha can lead to anxiety, insomnia, headaches, and an increased heart rate, especially for sensitive individuals.
Contamination Risks: Lower-quality matcha may contain heavy metals like lead and arsenic, absorbed from the soil, a risk magnified by consuming the whole tea leaf.
Digestive Upset: The tannins and fiber in matcha can cause digestive issues such as stomach upset, nausea, and changes in bowel habits, especially when consumed on an empty stomach.
Medication Interactions: Matcha can interfere with certain medications, including blood thinners, stimulants, and some mental health drugs, by altering their metabolism or effects.
Iron Absorption: Specific compounds in green tea can inhibit the absorption of iron, a concern for individuals with or at risk of anemia.
High Cost: Quality matcha, particularly ceremonial grade, is expensive, and opting for cheaper alternatives increases the risk of lower quality and higher contamination.
Liver Strain: While rare with moderate consumption of the whole leaf, very high intakes of concentrated green tea extracts have been associated with potential liver strain.

The Double-Edged Sword of Caffeine

Matcha is derived from the same plant as other green teas, but because you consume the entire tea leaf, its caffeine concentration is significantly higher. While many appreciate the sustained energy boost, this high caffeine content is one of the most prominent cons of matcha tea and can lead to a range of unpleasant side effects, especially in individuals with a high sensitivity to stimulants. The L-theanine in matcha does help moderate the effects, creating a state of alert calmness, but it doesn't completely neutralize the caffeine's impact.

Potential Caffeine-Related Side Effects:

Anxiety and jitters: Overdoing it can trigger nervousness and anxious feelings, similar to a strong coffee buzz.
Insomnia: Drinking matcha too late in the day can disrupt sleep patterns, as caffeine can remain in your system for hours.
Heart palpitations: Excessive caffeine intake can increase heart rate and cause heart palpitations in some people.
Headaches: For caffeine-sensitive individuals, a high dose can sometimes lead to headaches.

The Heavy Metal Contamination Concern

Because matcha involves ingesting the whole tea leaf, it also means you consume any contaminants the plant has absorbed from the soil and environment. This is a serious concern, as tea plants are known to absorb heavy metals like lead and arsenic.

Why Source Matters:

Lower-quality or conventionally-grown matcha, particularly that sourced from regions with lax environmental regulations like some parts of China, has been shown to contain high levels of lead. Higher-quality, organically-certified matcha from reputable Japanese sources typically has far less risk of contamination, but it is not entirely zero. Regular testing by third-party labs is the best way to ensure a product's safety.

Digestive Distress and Iron Absorption

For some individuals, matcha can be tough on the digestive system. The tannins present in green tea can irritate the stomach lining, especially when consumed on an empty stomach. This can cause discomfort, stomach aches, and nausea. Additionally, for some, the combination of caffeine and fiber can have a laxative effect, while others may experience constipation if not properly hydrated.

The Issue with Iron

Compounds found in green tea, including catechins, can interfere with the body's absorption of nonheme iron. While this is a minor issue for most, it can be a significant concern for individuals with iron-deficiency anemia. It is recommended that those concerned with iron levels wait at least an hour or two between drinking matcha and taking iron supplements or eating iron-rich foods.

Medication Interactions and Other Risks

Matcha can interact with certain medications, making it a critical con to consider for those on a daily regimen. The caffeine in matcha can affect the metabolism of several drugs, and the vitamin K content in green tea can impact the effectiveness of blood thinners like warfarin.

List of medications that may interact with green tea compounds:

Blood Thinners: The vitamin K content can interfere with anticoagulants.
Stimulants: The additive caffeine effect can worsen side effects of ADHD medications.
Certain Mental-Health Meds: Matcha may affect the metabolism of some antipsychotics and antidepressants.
Blood Pressure Medications: In sensitive individuals, matcha may slightly raise blood pressure.
Iron Supplements: Compounds can inhibit absorption.

Comparing Matcha Grades: A Table of Differences

The quality of matcha greatly influences its taste, potential health benefits, and risk of contaminants. The high price tag associated with ceremonial-grade matcha is often a reflection of the rigorous quality control and careful processing that minimizes the cons of matcha tea.


Feature	Ceremonial Grade Matcha	Culinary Grade Matcha (and lower quality)
Source Quality	Premium, young tea leaves; grown in Japan, often organic	Older, coarser leaves; can be sourced from various, less regulated regions
Taste	Smooth, sweet, with complex umami notes	More bitter and astringent due to higher tannin content
Contaminant Risk	Very low, with frequent third-party heavy metal testing	Higher risk of lead, pesticides, and other contaminants
Best For	Drinking straight, traditional preparation	Lattes, cooking, baking, and blending into smoothies
Cost	Significantly more expensive	More affordable and widely available

The High Cost of Quality

One of the most immediate cons of matcha tea is its price. High-quality ceremonial grade matcha, which is harvested from the youngest leaves and processed with the greatest care, is a premium product. Its price reflects the intensive cultivation and preparation processes. Cheaper, culinary-grade options are widely available but often come with a compromise on taste and a higher potential for contamination.

Conclusion: Moderation, Quality, and Awareness Are Key

While matcha offers a wide array of health benefits, including high antioxidant content, the list of potential cons is not insignificant. The risk of heavy metal contamination in low-quality products, high caffeine levels causing anxiety and sleep issues, and digestive problems are all valid concerns. For those with pre-existing conditions or on specific medications, interactions are also a factor. The key takeaways are to prioritize quality, opt for a certified organic product from a trusted source, and consume it in moderation. Being aware of your own sensitivities and listening to your body's response will help you enjoy matcha's benefits while minimizing its drawbacks. As with any dietary change or supplement, consulting with a healthcare provider is recommended, especially for those with existing health issues or on medication. To understand potential drug interactions more fully, an authoritative source like Drugs.com is a valuable resource for cross-referencing information regarding medications and green tea interactions.

Frequently Asked Questions

Yes, excessive consumption of matcha can lead to side effects primarily due to its high caffeine content. Moderation is key, with some experts recommending no more than 1-2 cups per day to avoid adverse effects like headaches, insomnia, and digestive issues.

Matcha can cause an upset stomach or acid reflux, especially when consumed on an empty stomach. This is often caused by the tannins, which can increase stomach acid, and the high fiber content that can affect digestion.

Low-quality or non-organic matcha from unregulated regions has a higher risk of heavy metal contamination, especially lead, which tea plants can absorb from the soil. Consuming a contaminated powder means you ingest these metals directly.

Yes, matcha can interact with several medications, including blood thinners (like Warfarin), stimulants (like those for ADHD), and certain antidepressants. It is important to consult a doctor if you are on medication.

Yes, matcha contains caffeine, which is a stimulant. If consumed too close to bedtime, it can disrupt your sleep cycle and cause insomnia. It is generally best to have your last cup several hours before sleeping, though individual tolerance varies.

Compounds in green tea, including catechins, have been shown to interfere with the body's absorption of nonheme iron. For those with anemia, it is recommended to separate matcha consumption from iron supplements and iron-rich foods.

To avoid low-quality matcha, look for brands that specify their origin (ideally Japan) and provide certified organic labels. Reputable brands often conduct third-party heavy metal testing, which provides reassurance of quality and safety.