Why do I feel shaky after drinking green tea? Understanding the reasons behind the jitters

October 15, 2025 •

5 min read

While green tea is often celebrated for its calm and focusing properties, it's estimated that a percentage of people experience negative side effects like jitters or shakiness after drinking it. If you've ever wondered why do I feel shaky after drinking green tea?, the answer lies in a combination of chemical compounds and your body's individual response.

Quick Summary

The jitters from green tea are often due to caffeine sensitivity, irritating tannins on an empty stomach, or consuming an excessive amount. The balancing effect of L-theanine helps, but individual factors dictate the final outcome.

Key Points

Caffeine Sensitivity: Your body's genetic ability to process caffeine varies, and if you are a slow metabolizer, even the moderate caffeine in green tea can cause jitters and shakiness.
L-theanine's Balancing Act: Green tea contains L-theanine, which normally provides a calm, focused energy. However, if you are highly sensitive to caffeine or drink a very strong brew, the stimulant effects can still prevail.
Tannins on an Empty Stomach: Tannins, responsible for tea's bitter taste, can irritate the stomach lining and increase stomach acid when consumed on an empty stomach, leading to nausea and a shaky feeling.
Dosage Matters: Excessive consumption increases the total amount of caffeine and other stimulants like theophylline, pushing your body past its comfortable limit and intensifying side effects.
Solutions for Calm Enjoyment: Adjusting your brew time and temperature, drinking with a meal, and choosing lower-caffeine varieties can help reduce the likelihood of experiencing jitters.

The Primary Suspect: Caffeine Sensitivity

Although green tea has a reputation for being a mild source of energy, it still contains caffeine. An 8-ounce cup of green tea can contain anywhere from 30 to 50 milligrams of caffeine, compared to a cup of coffee which can have 80 to 100 milligrams or more. For many, this is a manageable dose, but for individuals with a higher sensitivity to caffeine, even a small amount can trigger a noticeable reaction.

This sensitivity is largely determined by genetic factors that influence how quickly your body metabolizes and clears caffeine from your system. If you are a "slow metabolizer," the stimulating effects of caffeine can linger longer and feel more pronounced, leading to restlessness, an increased heart rate, and, of course, that shaky feeling. This is not a matter of choice but of genetic predisposition.

Theophylline and Nervous System Stimulation

Beyond caffeine, green tea also contains smaller amounts of other methylxanthine stimulants, including theophylline. While caffeine primarily affects the central nervous system, theophylline has a more direct effect on smooth muscle tissue, which can contribute to muscle tremors and restlessness, especially in sensitive individuals. When these stimulants are combined, even in small amounts, their effects can be amplified, resulting in a more potent—and for some, unpleasant—experience.

The Balancing Act of L-theanine

Green tea's unique quality, which often distinguishes its effect from coffee, is the presence of the amino acid L-theanine. This compound promotes relaxation without causing drowsiness by increasing alpha brain wave activity and boosting the production of neurotransmitters like serotonin and dopamine. This creates a state of alert calmness, smoothing out the sharp, jittery edge often associated with caffeine.

However, this balancing act is not foolproof. The ratio of caffeine to L-theanine can vary depending on the type of green tea and its preparation. For highly sensitive individuals or when consuming a strong brew, the caffeine's stimulating effects can overpower the calming influence of L-theanine, leading to the familiar jitters. Matcha, for instance, contains higher levels of both caffeine and L-theanine because you consume the entire powdered leaf, which can produce a different—and sometimes more intense—effect than steeped green tea.

The Impact of Tannins and an Empty Stomach

Another significant contributor to feeling shaky or nauseous is the presence of tannins in green tea. Tannins are naturally occurring compounds that give tea its bitter and astringent taste. When consumed on an empty stomach, tannins can increase stomach acid, irritate the stomach lining, and lead to symptoms like nausea, abdominal discomfort, and a general unsettled feeling that can easily be mistaken for or exacerbate shakiness.

Drinking green tea after a meal can help to counteract this effect, as the tannins can bind to proteins and carbohydrates in food, which reduces their irritating effect on the digestive system.

Comparison of Green Tea vs. Coffee Effects


Feature	Green Tea	Coffee
Caffeine Content (Average 8oz)	30–50 mg	80–100+ mg
L-theanine Presence	Yes, provides calm focus	No
Jittery Potential	Lower due to L-theanine balance	Higher due to higher caffeine dose
Stimulant Experience	Milder, more stable energy	Stronger, more immediate buzz
Tannin Effects (Empty Stomach)	Can cause irritation, nausea	Less irritating; primarily due to caffeine

When is Too Much, Too Much?

Excessive consumption can overwhelm the body and intensify any negative effects. For most healthy adults, a daily caffeine intake of up to 400 mg is considered safe. However, this threshold can be much lower for those with sensitivities. Drinking too many cups of green tea in a short period can quickly accumulate caffeine, pushing you past your personal tolerance and leading to symptoms like:

Increased anxiety and restlessness
Jittery hands and tremors
Disrupted sleep patterns
Irregular heart rate

Strategies to Prevent and Alleviate Shakiness

Fortunately, there are several simple strategies to help mitigate the shaky side effects of green tea and enjoy its benefits. Adjusting your consumption habits can make a significant difference.

Drink with Food: Consuming green tea after a meal can buffer the effects of tannins on your stomach lining, reducing nausea and irritation.
Adjust Brew Time and Temperature: A shorter steeping time (1-2 minutes) and cooler water temperatures (160-180°F) will extract less caffeine and fewer tannins, resulting in a milder brew.
Choose Lower-Caffeine Varieties: Some green teas, like bancha or genmaicha, are naturally lower in caffeine than others due to the maturity of the leaves or the presence of roasted rice.
Reduce Overall Intake: If you regularly experience jitters, try cutting back from multiple cups to just one or two per day to find your personal tolerance level.
Stay Hydrated: Drinking plenty of water alongside your green tea can help flush out the caffeine and combat potential diuretic effects.
Switch to Herbal Tea: If caffeine is the issue, opting for herbal teas like chamomile or peppermint is a great way to enjoy a warm beverage without any stimulant side effects.

Conclusion: Listen to Your Body

Green tea remains a healthy beverage for most, celebrated for its antioxidant properties and other potential health benefits. However, the key to enjoying it without unwanted side effects is understanding your body's unique metabolism and chemical sensitivities. For those who find themselves asking, why do I feel shaky after drinking green tea?, the answer is often tied to caffeine sensitivity, tannins, and dosage. By adjusting your brewing habits and listening to your body's signals, you can find a balance that allows you to reap the benefits of green tea without the jitters.

Read more about caffeine metabolism on PubMed Central.

Citations

Frequently Asked Questions

Yes. While green tea generally has less caffeine than coffee, some individuals are more sensitive to caffeine and other stimulants like theophylline, and your body might react differently to the specific combination of compounds in green tea.

Tannins are compounds that give tea its astringent taste. On an empty stomach, they can increase stomach acid production and irritate the digestive lining, leading to nausea, stomach discomfort, and an overall shaky feeling.

To reduce caffeine, use cooler water (around 160-180°F) and steep for a shorter duration (1-2 minutes). You can also opt for naturally lower-caffeine varieties like bancha or choose decaffeinated green tea.

It is generally recommended to drink green tea with or after a meal, especially if you have a sensitive stomach. This helps buffer the effects of tannins and reduces the likelihood of nausea or shakiness.

The main difference is the presence of L-theanine in green tea. L-theanine works with caffeine to create a state of calm alertness, whereas coffee provides a more direct and often more intense stimulant effect.

While the safe limit varies by individual, consuming more than 4-5 cups a day can increase your risk of experiencing side effects like jitters, anxiety, and sleep issues. Listen to your body and adjust accordingly.

Yes, green tea can interact with certain medications. It contains vitamin K, which can interfere with blood thinners, and its stimulants can interact with other drugs. Consult your healthcare provider if you take any prescription medications.