Green Tea Side Effects: What You Need to Know Before Your Next Cup

Green tea is often touted as a super drink. High in antioxidants, it has been shown to aid weight loss, improve brain functionality, and even lower the risk of certain illnesses. However, let's take a step back and ask an important question: What are the side effects of green tea? 

The answer is yes! Many people tolerate green tea well, but it is not for everyone! It's worth knowing that drinking it every day (or thinking about it), what could go wrong? 

8 Common Side Effects of Green Tea

Generally, the consumption of green tea is safe. Here are the top eight green tea disadvantages that might take you by surprise: 

1. Green Tea Caffeine Effects: It's Not as Mild as You Think

One of the popular myths is that green tea has "a little" caffeine. It is somewhat true, as it contains around 30–50 mg of caffeine per cup, which is far less than coffee. It is still enough to affect sensitive individuals.

3 Potential Issues Associated with Drinking Green Tea

Drinking green tea can cause: 

• Insomnia: Drinking green tea later in the day may hinder sleep.
• Jitters or anxiety: You may feel jittery or have a racing heart.
• Headaches: The caffeine and tannins can cause headaches. 

Pro Tip:

If you are caffeine-sensitive, consider decaf green tea or opt for herbal and caffeine-free options, such as rooibos or chamomile, later in the day.

2. Irritation of the Stomach: Not Ideal On An Empty Stomach

Green tea contains tannins, which will elevate stomach acid. This can cause: 

• Nausea
• Heart burn
• Stomach ache. 

If you have ever become queasy after drinking green tea in the morning on an empty stomach, it was likely the problem. 

How to avoid it: Drink green tea after meals. Try using low-tannin varieties, such as some Japanese sencha or matcha. Don't make the tea too strong.

3. Iron Absorption Problems: A Secret Problem for Some People 

Green tea can inhibit or interfere with the absorption of iron from food. Green tea's tannins bind to non-heme iron (a type of iron available from foods from plant sources) and make it difficult for your body to absorb iron. 

This is especially important if

• You are a vegan or a vegetarian. 
• If you have anemia 
• If you are pregnant 

What You Can Do: Avoid drinking green tea with meals. Add a source of vitamin C (like lemon) with your meals to improve iron absorption. Take iron supplements either a few hours before or after drinking tea.

4. Liver Health Concerns (In High Doses)

Yeah, Too Much of a Good Thing Could Be Bad.

This is rare, but serious. There have been reports of liver damage from high doses of green tea extract, particularly supplements. According to the European Food Safety Authority, consuming over 800 mg of green tea extract per day may be harmful.

Symptoms include:

• Yellowing of the skin and/or eyes
• Dark urine
• Fatigue or nausea 

Bottom line: Stick to the normal amount of brewed green tea instead of concentrated supplements or high doses, unless recommended by a healthcare expert. 

5. Concerns Related to Pregnancy and Breastfeeding

Balance is key. Green tea is generally considered safe during pregnancy, but it should be consumed with caution. Otherwise, a high intake can: 

• Reduce folic acid absorption. This is essential for fetal growth and development. 
• Total caffeine consumption should be limited to 200 mg or less per day. 

Recommendations: Limit to 1-2 cups per day when pregnant or breastfeeding. Avoid green tea supplements while pregnant.

6. Bone Health And Calcium Loss: A Lesser-Known Risk

Studies show that high caffeine consumption can increase calcium excretion in urine, potentially affecting bone density in the long term. Although the effect is minor, if you have osteoporosis or a high risk of bone density loss, you should be aware of it. 

What to do?  

These tips will help prevent bone and calcium loss: 

• Drink 2-3 cups a day at most. 
• Increase the intake of calcium and vitamin D in your diet. 
• Caffeine from tea can also be balanced with dairy or fortified plant-based milks.

7. Possible Drug Interactions

Green tea is not always "naturally" good. It may affect the action of certain drugs. Therefore, you should discuss it with your doctor if you take:

• Blood thinners (e.g., warfarin): Vitamin K in green tea may interact with these medications, potentially causing side effects. 
• Beta-blockers: These may affect heart rate and blood pressure 
• Stimulants. Their intake may overload your nervous system and increase your anxiety. 

When to contact a doctor?

Seek medical assistance immediately if

• You are taking prescription medications. 
• Plan to drink multiple cups of green tea daily. 
• You are using green tea extracts or matcha supplements. 

8. Issues related to Heart and Blood Pressure

Green tea disadvantages also include heart and blood pressure issues. In rare instances, green tea may make you palpitate or give you an irregular heartbeat, especially if you are suffering from cardiac problems. 

Additionally, green tea may help lower blood pressure or increase caffeine levels, which can elevate blood pressure. This problem is most likely to occur if you do not frequently consume caffeinated beverages.

Green Tea Side Effects: The Untold Truth! 

There are no official or published statistics for 2025 that specifically state the number of Indians who are unaware of the side effects of drinking green tea. However, current sources of information and market trends indicate that urban and health-conscious consumers are becoming more aware of its health benefits, but that knowledge about side effects remains limited, especially among consumers in rural and semi-urban segments.

Are You Drinking Too Much Green Tea? 

Drinking 2-3 cups of green tea daily is safe for most healthy adults and unlikely to cause side effects. 

Drinking 4-5 cups of green tea daily may cause side effects, especially in sensitive individuals. Consuming more than 8 cups per day is unsafe. 

Caution: Be cautious with supplements, which are highly concentrated and have been associated with rare cases of liver damage. 

What are the different ways to reduce green tea side effects?

Below are five practical tips to minimize the side effects of green tea: 

• Do not drink green tea on an empty stomach.
• Brew at a temperature below boiling (160–180°F) to limit the extraction of tannins.
• Limit the intake of green tea if you are pregnant, breastfeeding, or suffer from any of the above health conditions.
• Be aware of how your body feels and talk to your doctor if you experience discomfort or adverse effects. 
• Ensure adequate calcium and iron intake if you regularly drink green tea.

Quick Summary: Green Tea Side Effects

Here is a brief overview of the benefits and side effects of green tea. Additionally, the solution is also provided to minimize the harmful effects associated with its consumption. 

Causes	Side Effects	Solution
Insomnia & Gitters	Caffeine	Limit Intake, avoid at night
Stomach Upset	Tannins	Drink with food
Iron Deficiency	Tannins	Avoid with meals, add lemon
Liver Issues	High-dose supplement	Stick to brewed tea
Pregnancy Concerns	Folate & Caffeine	Limit to 1-2 cups per day
Bone Health	Calcium loss from Caffeine	Ensure enough calcium intake
Drug Interaction	epigallocatechin-3-gallate (EGCG) & Vitamin K	Consult your doctor
Tooth sensitivity	Acidity	Rinse mouth, use a straw

Conclusion

Green tea is more than just a trendy drink; it is a powerhouse of health benefits. Understanding the potential side effects of green tea will help you maximize its benefits and minimize its drawbacks.

If green tea is proper for you, particularly if you have an existing health condition or are taking medication, consult a healthcare professional immediately. You can enjoy the green tea, but like most of life's best things, enjoy it in moderation. 

FAQs: Green Tea Side Effects

1. Is green tea safe every day?

Yes, for most people, consuming 2–3 cups of coffee daily is considered safe. Too much consumption can increase the risk of side effects.

2. Can green tea cause liver damage?

Although rare, high-dose supplements can cause liver damage. Sticking to brewed green tea in moderation is generally safe.

3. Does green tea interact with medications?

Yes. It can interact with blood thinners, blood pressure medications, and others. Talk to your doctor if you're on medication.

4. Is green tea safe for children?

Green tea is generally not recommended for children, especially in regular or large amounts. Possible side effects include insomnia, hyperactivity, irritability, and headaches.