As matcha has been continuously marketed as healthy, a superfood, and all those sweet words that make you want to try it, or maybe you’re already noticing some negative changes and asking yourself if matcha really has side effects. Yes, I can tell you, sometimes drinking too much of matcha can affect your liver, kidneys, digestion, menstruation, blood pressure, and skin, both positively and negatively.
But I don’t want you to worry too much, because in this matcha side effects guide, I’m going to walk you through exactly how matcha works, its side effects, and everything you can do to make sure you stay healthy while enjoying this trending superfood.
If that sounds good to you, let’s get into it.
Why Matcha Works Differently Than Regular Green Tea
firstly before we get into the matcha side effects, understanding why matcha can affect your body more intensely than you do expect from a cup of tea worth knowing.
When you brew regular green tea, you steep the leaves in water and throw them away. in this case you’re mostly only extracting maybe 20% of what’s in the leaf. But with matcha, you whisk the entire powdered leaf into your drink and consume all of it. Giving you up to 137 times more of its key antioxidant (EGCG) than some many steeped green tea varieties.
With that concentration being a good thing that gives you the health benefits can also means any side effects, and when they happen, they tend to hit harder and faster than regular green tea would.
One or two cups a day? For most people, could be the sweet spot. But three or four and beyond? Your body may start sending signals worth paying attention to. So keep that in mind as you read through what follows.
10 Matcha Side Effects You Should Know About
I love my morning matcha routines. But, even that daily healthy habits can sometimes have hidden surprises. It’s easy to think a natural green drink is perfect. But ignoring side effects can lead to bad surprises.
1. The Caffeine Jitters – Even Though Matcha Shouldn’t Cause Them
Imagine you switched from coffee specifically because you wanted to escape the jittery, heart-racing feeling. You’d heard matcha gives calm, focused energy instead. And for a while, it did. Then one morning, maybe you used a little more powder, maybe you skipped breakfast, and your hands felt shaky or your heart started doing something funny.
Let me tell you exactly what might be happening. Matcha’s “calm energy” reputation comes from L-theanine, an amino acid that’s supposed to smooth out the caffeine rough edges, which it does that most of the time.
But research published in Nutrients found that theanine’s calming effect only works properly when the ratio of caffeine to theanine stays within a certain threshold. Using too much matcha powder, or buying a lower-quality matcha with poor theanine content, and making you feel the regular caffeine buzz, jitters and all.
A cup of matcha contains roughly 38–88mg of caffeine depending on how much powder you use, the caffeine in matcha was less than coffee, but still something, especially if you’re stacking it with other caffeinated drinks during the day.
What actually helps: Stick to 1 to 2 teaspoons of powder per cup. Choose shade-grown ceremonial or premium grade matcha, which naturally has a higher theanine content. And if you’re also drinking coffee, factor that into your total caffeine load for the day.
2. Nausea and Stomach Pain
Most of matcha lovers have been asking “Can matcha be safely drunk on an empty stomach?” Well, your stomach usually gives you the answer pretty quickly.
A lot of matcha drinkers know this feeling well, you fix your beautiful morning cup, take your first few sips, and twenty minutes later your stomach is not happy with you. Cramps, nausea, that unsettled churning feeling, it can range from mildly annoying to genuinely uncomfortable.
What your gut is reacting to are tannins, the plant compounds that give matcha its slightly bitter, astringent quality. Tannins stimulate stomach acid production, and on an empty stomach, that extra acid has nothing to buffer against except your stomach lining, and that’s mostly where the irritation comes from.
The more matcha you drink, the more tannins, and the more your digestive system feels it.
So, this is why the question “Can you drink matcha on an empty stomach?” does not have the same answer for everyone. Some people tolerate one cup just fine, while others feel sick after only a few sips. And usually, the more matcha you drink, the stronger the reaction becomes.
What I will advice for most people is to never drink matcha on a completely empty stomach. Even a small snack first makes a significant difference. If you love matcha lattes, strawberry matcha, or mango matcha latte, the proteins in milk (dairy or plant-based) bind to tannins and reduce the irritation noticeably. This one small change fixes the problem for most people.
3. Disrupted Sleep and Insomnia
You know that frustrating feeling when your body is tired, but your brain absolutely refuses to shut off?
You are lying in bed, scrolling, turning your pillow over for the fifth time, wondering why you still cannot sleep, even though you did not even drink coffee that late.
For a lot of people, matcha is the hidden reason.
The tricky part is that matcha feels very different from coffee. It truly gives a calmer, smoother kind of energy, so people naturally assume it is gentler on sleep too. But even though it feels relaxing, matcha still contains real caffeine, and your body still has to process it.
And here is what many people do not realize, caffeine can stay in your system much longer than you think. A cup of matcha at 2pm can still leave a noticeable amount of caffeine circulating in your body by the evening. So if you naturally process caffeine slowly, which many people do without realizing it, the effects can last even longer.
That is why some people feel perfectly calm after drinking matcha, but then suddenly find themselves wide awake at midnight with a racing mind. The connection is easy to miss because the sleep problem shows up hours later.
What helps is to give yourself a matcha cut-off time. For most people sensitive to caffeine, 1–2pm is a safe boundary, keep a simple sleep note for two weeks, it’s often enough to spot the pattern clearly.
4. Liver Stress – When “More Antioxidants” Becomes Too Much
Matcha contains a powerful antioxidant called EGCG, which is responsible for many of its health benefits. In normal amounts (about 1–2 cups a day), EGCG is generally safe and may even help protect the liver.
However, very large amounts can have the opposite effect and may put stress on the liver. Health authorities have warned that drinking the equivalent of 8 or more cups of matcha per day may increase the risk of liver problems.
Most people won’t drink that much matcha. But problems can arise when people combine matcha drinks with green tea supplements, matcha capsules, or matcha-containing products, since the total amount of EGCG can add up quickly without them realizing it.
What to do:
- Stick to about 1–3 cups of matcha per day.
- If you take green tea extract or matcha supplements, include those in your total intake.
- If you have a liver condition (such as fatty liver, hepatitis, or abnormal liver tests), speak with your doctor before drinking matcha regularly.
It is important to know that matcha can be healthy, but more is not always better. Excessive amounts, especially when you combine matcha drinks with supplements, may increase the risk of liver stress.
5. Teeth Staining
I spend enough time in matcha communities online, and this comes up a lot.
Many people switch from coffee to matcha thinking it will be better for their teeth. While matcha usually stains teeth less than coffee, it can still cause discoloration over time, especially if you drink it every day.
Though to be fair, matcha teeth staining is usually milder than heavy coffee staining. But it can slowly build up, especially if you sip on ordinary matcha for long periods throughout the day. The longer the liquid sits on your teeth, the more opportunity those compounds have to stick to your enamel.
Also, as I have said above matcha contains tannins, that same compounds that cause stomach irritation and block iron absorption, and tannins bind to tooth enamel, causing discoloration over time. It’s the exact same mechanism behind tea, red wine, and coffee staining. Matcha’s effect is generally milder than black coffee, but it’s cumulative.
How you drink matcha matters too. Slowly sipping a matcha drink over a long period gives the tannins more time to contact your teeth, increasing the chance of staining. Drinking it more quickly reduces that exposure.
What to do:
- Rinse your mouth with water after drinking matcha.
- Use a straw when drinking matcha lattes to reduce contact with your teeth.
- Avoid sipping the same drink for hours.
- Consider using a whitening toothpaste a few times per week if you notice light staining.
Matcha is generally less likely to stain teeth than coffee, but regular consumption can still lead to gradual discoloration if you’re not careful.
6. Menstrual Changes
Some women notice their cycle feels “Off” and this is one of those matcha side effects that people rarely talk about openly, but if you spend enough time reading women’s experiences online, you will notice the same question keeps popping up:
“Ever since I started drinking matcha daily… why does my cycle suddenly feel different?”
Some women report shorter periods, spotting between cycles, worse cramps, delayed periods, or changes in PMS symptoms after increasing their matcha intake. Others say they noticed absolutely nothing at all. And interestingly, some people even claim their cycle improved after switching from coffee to matcha.
So, it is important to be careful here, there is currently no strong scientific proof showing that normal matcha consumption directly disrupts menstruation in healthy people.
Most experts believe the bigger issue is likely the caffeine itself, especially in larger amounts is consumed, which can sometimes affect sleep, stress hormones like cortisol, blood flow, and overall hormonal balance, while all these can indirectly influence your cycle in some people.
Another possible factor I noticed could be iron absorption. As mentioned earlier, matcha tannins can reduce how much iron your body absorbs from food. And since low iron levels can already affect energy, fatigue, and menstruation for some women, drinking multiple strong matchas daily without enough nutrition could potentially make things worse.
The important thing to understand is that, everyone’s body reacts differently.
Some people can drink matcha every day with zero issues. Others are simply more sensitive to caffeine, stress, sleep disruption, or hormonal shifts.
What actually helps:
- Avoid drinking several strong matchas every day.
- Pay attention to changes after increasing your intake.
- Try not to drink matcha too close to iron-rich meals.
- If your cycle suddenly changes significantly, consider reducing caffeine for a couple of weeks and see if things improve.
- And if symptoms are severe, persistent, or unusual, it is always best to talk with a healthcare professional.
7. Iron Deficiency Risk
Have you ever felt more tired lately, even though you’re sleeping enough? Maybe you’re feeling colder than usual, getting headaches more often, or finding it harder to focus.
Most people would never suspect their healthy morning matcha.
The reason comes back to something we’ve already talked about several times in this guide: tannins.
Matcha contains tannins and other compounds called catechins that can interfere with your body’s ability to absorb non-heme iron, the type of iron found in foods like beans, lentils, spinach, nuts, seeds, and many vegetables.
This doesn’t mean matcha is “stealing” iron from your body. The issue is that when matcha is consumed with meals, especially iron-rich meals, your body may absorb less of the iron available in that food.
For most healthy adults with a balanced diet, this is usually not a major problem.
But for people who already struggle to maintain healthy iron levels, such as women with heavy periods, vegetarians, vegans, endurance athletes, or anyone with a history of iron deficiency, drinking multiple cups of matcha every day could make it harder to meet their iron needs.
The tricky part is that the effects happen slowly. You don’t wake up one morning with low iron. It can take weeks or months before symptoms like fatigue, weakness, dizziness, brain fog, brittle nails, or feeling unusually cold start showing up.
What actually helps:
- Avoid drinking matcha with iron-rich meals.
- Wait at least 1–2 hours before or after eating when possible.
- Pair iron-rich foods with vitamin C sources like oranges, strawberries, bell peppers, or lemon juice to improve absorption.
- If you have a history of anemia or low iron, speak with your healthcare provider about the best timing for matcha.
For most people, matcha won’t cause iron deficiency by itself. But if you’re already on the edge of low iron, your daily matcha habit could be one piece of the puzzle.
Who Should Be Extra Careful With Matcha
As matcha have become go to drink for many people, it is important for some people to pay closer attention to these matcha side effects than others:
- Pregnant and breastfeeding women: Safe caffeine limits during pregnancy are around 200mg per day. One or two cups of matcha fits within that, but any additional caffeinated drinks push you over. If you are pregnant or breastfeeding, make sure to check with your OB or midwife.
- People with iron deficiency or anemia: The tannin-iron absorption issue matters most for this group. Timing is not optional here.
- Anyone on medications: Matcha’s compounds can interact with how certain medications are absorbed or metabolized. Blood pressure drugs, anti-anxiety medications, blood thinners, and certain antibiotics can all be affected. A quick check with your pharmacist takes two minutes.
- People with anxiety disorders: Matcha is marketed as anxiety-friendly, and for many people it is. But if your specific matcha has a high caffeine-to-theanine ratio, it can still trigger or worsen anxiety in sensitive individuals.
- People with liver conditions: High EGCG intake may add stress to a liver that’s already under pressure. Always consult your doctor first.
- Children under 12: Not recommended due to caffeine content relative to their body weight.
How to Keep Enjoying Matcha Without the Downsides
Even with all these matcha side effects, you absolutely don’t have to give up matcha. Almost every side effect on this list is avoidable, or at least manageable with a few intentional habits:
- Buy quality matcha: Ceremonial grade from reputable Japanese farms with published third-party testing. Not sure which products are worth it? We review them so you don’t have to, our honest breakdown of Matcha Extreme covers exactly what’s inside, how it compares, and whether it’s worth the investment.
- Drink it after food: Even a light snack beforehand makes a significant difference for stomach sensitivity.
- Set a cut-off time: 1–2pm works for most people. Adjust earlier if your sleep is being affected.
- Space it away from iron-rich meals: Wait at least 1–2 hours before or after eating plant-based iron sources.
- Stay at 1–3 cups per day: This is the range where benefits reliably outweigh risks for most healthy adults
If you drink matcha for weight management, which many people do, the timing and quantity advice above matters doubly. Our guide on Easy Matcha Drinks for Weight Loss shows you exactly which recipes to use and when to drink them to get the metabolism benefits without the side effects.
Conclusion – Should You Stop Drinking Matcha?
After reading all these side effects, you might be wondering whether matcha is actually bad for you.
Not at all.
In fact, most of these side effects happen for one simple reason: too much matcha, poor timing, or individual sensitivity.
For the average healthy adult or matcha drinker, one to two cups of quality matcha per day is unlikely to cause problems and may provide benefits such as sustained energy, antioxidants, and improved focus.
The key is understanding that matcha is powerful. You’re consuming the entire tea leaf, not just a brewed infusion. That means the benefits can be stronger, but so can the downsides if you overdo it.
Pay attention to how your body responds. If you’re experiencing jitters, nausea, sleep issues, menstrual changes, or signs of low iron, your body may simply be telling you it’s time to adjust your intake, timing, or preparation method.
The goal is not to fear matcha. The goal is to enjoy it in a way that works for your body.
Frequently Asked Questions
Is it safe to drink matcha every day?
For most healthy adults. Yes, 1–2 cups daily is considered safe and often beneficial, but understand that quality and moderation matter more than frequency. Listen to how your body responds over time.
How much matcha is too much in a day?
Most health experts suggest capping at 3 cups daily to stay within a safe caffeine range and avoid excessive fluoride or EGCG accumulation, and also we saw The European Food Safety Authority has linked 8+ cups daily to liver toxicity risk.
Can matcha cause anxiety?
It can, especially in caffeine-sensitive individuals or when low-quality matcha has a poor caffeine-to-theanine ratio. If matcha makes you feel anxious or wired, reduce the amount of powder per cup and opt for higher-grade matcha.
Why does matcha upset my stomach?
Almost certainly because of tannins irritating your digestive tract, especially on an empty stomach. Drinking matcha after a meal or snack typically resolves this quickly.
Can matcha affect my medications?
Yes. Matcha can interfere with certain drugs including blood pressure medications, blood thinners, and some antibiotics. Always check with your pharmacist if you’re on regular medication.
Why is my poop green after drinking matcha?
Completely normal and harmless. High chlorophyll content in real, high-quality matcha can temporarily change stool color. Nothing to worry about.