What are the side effects of Earl Grey bergamot tea?

October 25, 2025 •

4 min read

According to a case study published in The Lancet, excessive consumption of Earl Grey tea can lead to severe muscle cramps. While generally safe in moderation, it is important to understand the specific side effects associated with both the black tea base and the bergamot oil, which is the signature flavoring in Earl Grey tea.

Quick Summary

Excessive intake of Earl Grey tea may cause muscle cramps due to bergamot oil affecting potassium channels. Other potential issues include caffeine sensitivity, nausea from tannins, and reduced iron absorption.

Key Points

Muscle Cramps: Excessive bergamot can interfere with potassium absorption, potentially causing severe muscle cramps.
Caffeine Sensitivity: The black tea base can cause insomnia, jitters, or anxiety in caffeine-sensitive individuals.
Reduced Iron Absorption: Tannins in black tea can inhibit the absorption of non-heme iron, especially if consumed with meals.
Digestive Upset: Drinking Earl Grey on an empty stomach or in large quantities may cause nausea, heartburn, or stomach irritation.
Medication Interactions: Bergamot can lower blood sugar, interacting with diabetes medication, and may affect the absorption of other drugs.
Photosensitivity: The furocoumarins in bergamot oil can increase skin's sensitivity to sunlight, though this is a greater risk with topical use.
Moderate Intake is Key: Most side effects occur with excessive consumption; sticking to a few cups daily is recommended for most people.

Introduction to Earl Grey Tea and Bergamot

Earl Grey is a popular black tea blend flavored with bergamot oil, derived from a citrus fruit called Citrus bergamia. While the tea offers numerous health benefits in moderation, such as antioxidant properties and improved heart health, excessive consumption can lead to notable side effects. The side effects are primarily a result of high caffeine levels from the black tea base and the bergamot oil itself. This article explores the potential adverse effects and how to enjoy Earl Grey tea safely.

Potential Side Effects from Bergamot Oil

The unique flavor of Earl Grey tea comes from bergamot oil, which contains compounds that can lead to health issues if consumed in high quantities.

1. Muscle Cramps and Fasciculations

The most documented side effect of excessive bergamot oil consumption is its impact on muscle function.

How it happens: Bergamot contains a compound called bergapten, which can act as a potassium channel blocker. Potassium is essential for normal nerve and muscle function, and blocking these channels can disrupt the body's ability to process it properly.
The evidence: A notable case report in The Lancet described a 44-year-old man who developed severe muscle cramps and vision problems after drinking approximately four liters (17 cups) of Earl Grey tea daily. His symptoms resolved after he stopped drinking the tea.
What to watch for: Symptoms include muscle cramps, spasms, and involuntary muscle twitching (fasciculations).

2. Photosensitivity

Bergamot oil contains furocoumarins, such as bergapten, which can increase the skin's sensitivity to sunlight (photosensitivity).

Increased risk: This can increase the risk of sunburn, blistering, or rashes upon sun exposure, particularly for those using bergamot essential oil on their skin. While less common from tea consumption, it is a known effect of the compound.

3. Medication Interactions

Certain compounds in bergamot can interact with medications.

Diabetes medication: Bergamot can lower blood sugar levels, so those taking diabetes medications should exercise caution and monitor their blood sugar closely.
Absorption interference: Bergamot may also affect how certain medications are absorbed, potentially making them less effective.

Potential Side Effects from the Black Tea Base

Beyond the bergamot, the black tea base of Earl Grey also contributes to potential side effects, primarily due to its caffeine and tannin content.

1. Caffeine Sensitivity

The caffeine in Earl Grey can cause adverse effects, especially for those who are sensitive or consume large amounts.

Symptoms: Common symptoms of excessive caffeine intake include insomnia, jitters, anxiety, restlessness, and an increased heart rate.
Dependence: Regular, high-volume consumption can also lead to caffeine dependence, with withdrawal symptoms like headaches and irritability.

2. Reduced Iron Absorption

Black tea contains tannins, which are compounds that can bind with minerals like iron.

Interference: Tannins can interfere with the absorption of non-heme iron (from plant-based sources).
At-risk groups: Individuals with iron deficiencies, such as those with anemia, should be mindful of their intake. To mitigate this, it is recommended to drink Earl Grey tea between meals rather than with them.

3. Digestive Issues

High tannin levels can also irritate the digestive system, especially when tea is consumed on an empty stomach or brewed for too long.

Symptoms: This can lead to stomach upset, nausea, heartburn, or acid reflux.

Comparison of Side Effects: Moderate vs. Excessive Intake


Side Effect	Moderate Intake (1-4 cups daily)	Excessive Intake (5+ cups daily)
Muscle Cramps	Rare or non-existent.	Significant risk due to bergamot's effect on potassium channels.
Caffeine Jitters/Insomnia	Minimal risk for most people.	High risk, especially for sensitive individuals.
Reduced Iron Absorption	Low impact for most people, especially when not consumed with meals.	Higher risk, particularly for those with iron deficiency.
Photosensitivity	Rare risk, primarily associated with topical application of bergamot essential oil.	Increased risk with high oral intake, especially combined with sun exposure.
Medication Interactions	Potential for cautious use with blood sugar and certain other drugs.	Higher risk of significant drug interactions.
Digestive Upset	Less likely, may be avoided by consuming with food.	More likely to cause nausea, heartburn, and stomach irritation.

How to Minimize Risks and Enjoy Earl Grey Tea Safely

To enjoy the flavorful and potentially beneficial aspects of Earl Grey tea while minimizing potential side effects, consider the following strategies:

Moderate Consumption: Stick to a moderate intake of 2 to 4 cups per day. This is generally considered a safe amount for most healthy individuals.
Use High-Quality Tea: Choosing high-quality loose-leaf tea from reputable brands can reduce the risk of contaminants like microplastics and heavy metals.
Time Your Intake: To avoid interfering with iron absorption, consume Earl Grey tea at least one hour before or after an iron-rich meal. Avoid drinking it too close to bedtime if you are sensitive to caffeine.
Try Decaffeinated Versions: If you are sensitive to caffeine but still want the bergamot flavor, opt for a decaf Earl Grey tea.
Listen to Your Body: If you experience any adverse effects like muscle cramps or anxiety, consider reducing your intake or stopping altogether.

Conclusion

Earl Grey bergamot tea is a delicious and popular beverage, but it is not without potential side effects, particularly with high consumption. While bergamot can cause muscle cramps by interfering with potassium channels and increase sun sensitivity, the black tea base adds risks related to caffeine sensitivity, reduced iron absorption, and digestive issues. By consuming it in moderation and being mindful of your body's reactions, you can safely enjoy the distinct flavor of Earl Grey tea. If you have pre-existing health conditions or are taking medication, it is advisable to consult a healthcare professional before making it a regular part of your diet.

Here is a link for more information about the effects of black tea on health.

Frequently Asked Questions

Yes, excessive consumption of Earl Grey tea can be harmful. High intake is linked to side effects such as muscle cramps due to bergamot oil, and symptoms like jitters and insomnia from caffeine.

Earl Grey tea intoxication refers to adverse effects from drinking extremely large amounts of the tea over time. A notable case involved a man who developed severe muscle cramps and twitching from blocking potassium channels, which stopped when he ceased his high-volume intake.

Bergamot contains a compound called bergapten that can block potassium channels in the body. Since potassium is essential for proper muscle function, disrupting this process can lead to muscle cramps and spasms.

Yes, the tannins in black tea can bind to non-heme iron (found in plant-based foods), reducing its absorption. To minimize this effect, drink Earl Grey tea between meals rather than with them.

Due to its caffeine content, pregnant individuals should limit their intake. It's generally recommended to keep caffeine consumption below 200 mg per day, which typically amounts to two to three cups of Earl Grey tea.

Yes, bergamot has been shown to lower blood sugar levels. Individuals with diabetes, especially those on medication, should monitor their blood sugar carefully if they regularly consume Earl Grey tea.

To prevent nausea, especially if you have a sensitive stomach, try to avoid drinking Earl Grey tea on an empty stomach. Consuming it with milk or a meal can help reduce irritation from the tannins.