What Are the Side Effects of Drinking Matcha Green Tea?

Matcha side effects – Enjoy Green Tea

Matcha is a finely ground powder of specially processed leaves from the plant Camellia sinensis, the same as green tea. Matcha tea is generally safe and offers ample health benefits for most adults. But there are a few common side effects linked to matcha. They include:

•          Upset stomach

•          Diarrhea

•          Exposure to lead and other toxic elements

•          Irritability

•          Anxiousness and insomnia

•          Anemia and iron deficiency

But don’t worry about your daily cup of matcha tea yet. These side effects occur mostly in more sensitive people or when consuming matcha in high amounts. Different people might experience different side effects. And in most cases, these are similar to and less than what you’d get with coffee.

Most side effects are mild, rare, and can be prevented if you’re informed about them.

What are the main sources of matcha side effects?

Matcha contains nutrients like vitamins, amino acids, polyphenols (like catechins and tannins), and is a natural source of caffeine. Some of these compounds also can cause side effects. These are generally quite minor and simply a matter of drinking a bit less matcha or drinking it with food.

Caffeine, tannins, catechins, and contaminants like heavy metals are the main source of side effects. But regardless of what side effects you suffer, you can learn to avoid them. Sometimes it’s a simple matter of preparation and timing.

Upset stomach

Upset stomach, or indigestion, is discomfort in the upper abdomen. It may produce symptoms like fullness, bloating, nausea, vomiting, and belching. Indigestion is often related to personal lifestyle and intake of some foods, drinks, or medication.

Matcha contains tannins, a bitter substance. Tannins cause a dry feeling in the mouth when you drink red wine or tea. Matcha, for the most part actually promotes gut health. But on an empty stomach or in people with higher sensitivity to certain things, tannins also may cause indigestion.

Indigestion because of matcha or green tea is unusual. Yet, it can be annoying or aggravate an underlying condition. To prevent this, try to always drink your matcha with or after a meal. Especially foods high in protein are helpful because studies show protein can bind tannins.


Matcha can in fact help you poop. In a small percentage, though, it can help a bit too much. Diarrhea is a well-known state in which you have loose or even liquid poop. Along with that, abdominal cramps and frequent bowel movements are their main symptoms. Usually, this is short-term when it’s not caused by a condition such as an infection. But even when it’s not severe, it can make you feel uneasy.

Caffeine from matcha can help boost your digestion. But this effect also can increase absorption of indigestible foods. In some people that can trigger an acute episode of diarrhea. This episode could last just a few hours or a couple of days at worst, and that’s highly unlikely.

If you’re often having diarrhea incidents, consider looking at your nutrition habits. Changing some foods in your diet can help you to improve your digestion. You might increase the amount of fiber in your diet. You also can cut down your matcha or overall caffeine intake.

Exposure to lead and other toxic elements

This side effect comes from the environment where the plant grows. Heavy metals like arsenic, lead, and fluoride can be present in the soil or pesticides and be absorbed by the plants. These toxic elements are hazardous when are accumulated in the body over time. Most of the time, the level of these metals in foods is not reported.

Symptoms vary depending on the toxic metal and personal traits (like age and sex). Younger children are most prone to suffer intoxications. With low exposures, most adults may not have any evident symptoms. But larger or chronic exposures may cause mild symptoms like nausea, vomiting, and skin problems, up to more serious illnesses like organ failure and cancer.

Because matcha is a finely grounded powder, its compounds are more concentrated than in green tea. That means the amount of healthy substances is higher, but so is the amount of toxic elements. You can avoid this by choosing an organic or certified brand with a lower amount of these metals. But research shows that you’ll be safe if you drink a couple of cups a day.

Organic matcha also may be inferior in taste to non-organic. It really doesn’t make much difference in most cases other than with low-quality matcha from countries with looser environmental standards than Japan or the United States.


Irritability is a mood of unruly agitation. You become upset or frustrated quite easily. This state can make more difficult your daily activities. Sometimes is accompanied by other symptoms like racing heart and fast breathing.

Tea is considered a relaxing beverage, and usually, it helps to calm you down. But matcha caffeine content may actually cause irritability. Excess caffeine intake sparks the brain to intensify alertness. This effect can make a person feel like everything is a hassle.

A small boost in our alertness is helpful. But like coffee, excessive matcha intake can overstimulate you and make you feel bad. If you often feel like this, consider reducing your matcha or caffeine intake. But as experts suggest, to avoid withdrawal syndrome don’t fully stop drinking matcha.

Anxiousness and insomnia

Insomnia is a common sleep disorder where you’re unable to fall or stay asleep. You feel anxious because of that, making it harder to get to sleep, so it’s an ugly circle.

Some conditions like poor sleep habits and stress can cause insomnia. But also some substances like nicotine, alcohol, and caffeine can trigger insomnia.

Caffeinated drinks, like matcha, have energy-boosting effects. This is good in the morning to help us start fresh our day. But too much caffeine can make us feel anxious and restless. And when that happens at night, we may suffer from insomnia.

The caffeine content in a cup of matcha is similar to a cup of coffee. Heavy matcha consumption or drinking it a few hours before sleep (ditto for coffee, sodas, etc.) may cause insomnia. The best way to prevent insomnia is to limit your overall caffeine consumption. Also, drinking all your matcha in the morning or early afternoon can help you to avoid sleep issues.

Anemia and iron deficiency

Anemia is a health condition where your red blood cells are malfunctioning. They cannot carry enough oxygen to your body’s tissues. Hemoglobin transports oxygen, but without adequate iron, your body can’t produce enough of it. Having anemia can make you feel weak and short of breath.

Iron deficiency anemia is common in pregnant women and people with poor diets. It’s easily treated with iron supplements. But it can appear in healthy people as a side effect of some drugs or foods containing antinutrients. Antinutrients, like tannins or catechins, can impair the absorption of minerals like iron.

Catechins and tannins from matcha can bind dietary iron, preventing its absorption. Drinking matcha in high amounts and for long periods of time may lead to anemia. You can keep low your matcha intake or increase your iron consumption to prevent anemia. Research shows you can drink your matcha 1 hour after a meal to avoid this side effect.