What are the disadvantages of drinking green tea every day?

October 8, 2025 •

3 min read

While green tea is often lauded for its antioxidant benefits, excessive intake is not without risks. The disadvantages of drinking green tea every day can range from mild side effects like jitteriness to more serious concerns like liver damage in susceptible individuals.

Quick Summary

Excessive daily green tea consumption can lead to caffeine-related issues like anxiety and sleep problems. It may also inhibit iron absorption, cause digestive distress, and interact negatively with certain medications. High-dose green tea extracts pose a rare but serious risk of liver injury.

Key Points

Caffeine Sensitivity: High daily green tea intake can cause anxiety, insomnia, and increased heart rate in sensitive individuals.
Iron Absorption Interference: The tannins in green tea can significantly inhibit the absorption of non-heme iron, which can lead to anemia, especially in at-risk populations.
Digestive Distress: Drinking green tea on an empty stomach can lead to stomach upset, nausea, and acid reflux due to increased stomach acid.
Medication Interactions: Green tea can interfere with several medications, including blood thinners, stimulants, and heart medications, affecting their efficacy.
Liver Health Risk: High doses of green tea extract, often found in supplements, have been linked to rare but serious cases of liver damage.
Moderation is Key: To avoid the potential negative effects, moderate daily consumption (around 2-3 cups) is recommended, while high intake should be avoided.

Green tea is known for its health benefits, including antioxidants that may support heart health and metabolism. However, moderation is key, and drinking it daily in large amounts can have disadvantages. It's important to understand the potential downsides, from caffeine effects to concerns about nutrient absorption and liver health.

Caffeine Overload and Sensitivity

Despite having less caffeine than coffee, frequent, high daily intake of green tea can cause side effects, especially in caffeine-sensitive individuals. This can manifest as anxiety, restlessness, insomnia, increased heart rate, headaches, and dizziness.

Comparing Caffeine in Coffee and Green Tea

Here's how the caffeine content compares in an 8 oz (240 mL) serving:


Beverage (8 oz / 240 mL)	Approximate Caffeine Content (mg)	Potential Impact of Excessive Intake
Brewed Coffee	95-165	Stronger stimulant effect, higher risk of overload.
Green Tea	25-50	Milder energy boost; overload risk with high volume.
Green Tea Extract	Highly Variable	Much higher concentration, significantly increased risk of adverse effects.

Digestive Issues

The tannins in green tea can raise stomach acid levels, potentially causing digestive problems, particularly when consumed on an empty stomach. These issues can include stomach upset, nausea, diarrhea, and aggravated acid reflux.

Reduced Iron Absorption

Compounds in green tea like catechins and tannins can hinder the absorption of non-heme iron. This effect increases with the amount of green tea consumed. While typically not a major concern for healthy individuals, those at risk of iron deficiency, such as pregnant women or those with low iron intake, should be cautious. Drinking green tea between meals can help minimize this issue.

Potential Liver Complications

While brewed green tea in moderation is usually safe for the liver, concentrated extracts in supplements have rarely been linked to liver damage. Excessive intake of these extracts, which are not regulated by the FDA, has been associated with liver injury, including acute liver failure in some cases. High levels of EGCG in extracts can be difficult for some individuals to process. Symptoms of liver issues may include dark urine, abdominal pain, or jaundice.

Interactions with Medications

Daily green tea can interact with certain medications. Its vitamin K content can affect blood thinners like warfarin. When combined with stimulants, green tea's caffeine can dangerously raise heart rate and blood pressure. It may also reduce the effectiveness of some heart and blood pressure drugs and certain antibiotics.

Considerations for Specific Populations

Some individuals may be more susceptible to green tea's side effects:

Pregnant and breastfeeding women due to caffeine risks.
Those with iron deficiency or anemia because of hindered iron absorption.
People with osteoporosis, as high intake might increase calcium loss.
Individuals with liver disease, as concentrated extracts could worsen their condition.

How to Safely Consume Green Tea

Enjoying 2-3 cups of green tea per day is generally considered safe for most people. To minimize risks:

Avoid drinking on an empty stomach.
Consume between meals.
Consider decaffeinated options if sensitive to caffeine.
Consult a healthcare provider if you have health conditions or take medications.

Conclusion

While beneficial, daily and excessive green tea consumption can have disadvantages, including caffeine sensitivity, digestive issues, reduced iron absorption, and potential interactions with medications and, in rare cases with extracts, liver complications. Moderate consumption is recommended. Consult a healthcare professional to determine the right amount for your health. For further information, refer to resources like the National Center for Complementary and Integrative Health (NCCIH).

Frequently Asked Questions

Yes, if you are sensitive to caffeine, drinking green tea every day, especially in large amounts, can cause symptoms like anxiety, irritability, and restlessness.

Yes, green tea contains tannins that can inhibit the absorption of non-heme iron. It is best to avoid drinking it with meals to minimize this effect.

Pregnant women should limit their caffeine intake. While some moderate consumption may be safe (typically up to 2-3 cups), high intake should be avoided, and consulting a healthcare provider is recommended.

In rare cases, excessive intake of high-dose green tea extracts, often found in supplements, has been linked to liver damage. However, moderate consumption of brewed green tea is generally considered safe.

Green tea can interact with blood thinners (like warfarin), stimulants, certain antibiotics, and some heart and blood pressure medications. Always consult a doctor if you are on medication and drink green tea regularly.

Yes, the tannins in green tea can increase stomach acid, potentially causing stomach upset, nausea, diarrhea, and acid reflux, especially if consumed on an empty stomach.

While the amount varies by individual, drinking more than 8 cups per day is often considered excessive. Moderation, typically 2-3 cups daily, is recommended to avoid adverse effects.