Green tea side effects

20 Damaging Side Effects of Green Tea on Your Body

According to reports, tea is the second most-consumed drink in the world. Green tea is the least processed type of tea and is a powerhouse of important anti-oxidants and other beneficial compounds.

This makes it one of the healthiest drinks in the world. Every day green tea is used for many ailments, relieving periods pain and achieving goals like weight loss.

But can this propitious beverage pose any health risks?

Let’s see in detail, how green tea can cause side effects to your body that you never knew.

20 Side Effects of Drinking Green Tea

The are many side effects associated with drinking green tea especially when it is taken in excess every day. We have gathered all the possible side effects that green tea can pose to your health. These are as follows:

1) Iron deficiency

Drinking excessive green tea causes low blood count and lead to anemia.

Anemia is the cause of iron deficiency in the body, many people especially children are affected by it around the world. It causes low levels of hemoglobin in the blood.

The EGCG on green tea interferes with iron absorption in the body.

Drs recommend the best times to drink green tea for better iron absorption. Green tea should be avoided to drink with food or meals.

Also, never take your iron supplements with green tea.

2) Medicine Interaction

Green tea caffeine interferes with drugs like birth control pills, antidepressants, antibiotics, etc. When you consume too much green tea and are also on pills, it may cause side effects.

Usually, when you drink green tea or any drink with caffeine, the caffeine is absorbed in the body and flushed out when you pee.

Pills that cause side effects

This is why green tea also makes your pee more. However, when you are on certain medications, they do not let caffeine to a breakdown into your system.

Thus, as caffeine stays in the body it causes effects like palpitations, jitters, etc.

3) Pregnancy Risks

According to studies if you consume more than 300 mg of caffeine a day, it will increase the risk of hypertension during pregnancy. Too much green tea negatively affects the baby and the mother.

Folic acid is essential during pregnancy for the development of the baby’s organs. The caffeine and tannins in green tea can decrease the levels of folic acid in the mother’s body. Thus, this can cause birth defects.

Therefore, you need to be careful while consuming large cups of green tea in this period. One cup of green tea is a safe option for pregnant mothers.

4) Cause Hypokalemia and Seizures

Potassium is a key vitamin in the body. People with potassium deficiencies have muscle pains and weakness. When you consume too much green tea it causes potassium levels to decrease.

This leads to hypokalemia and weakness of the muscles.

In a research patients with low potassium levels decreased their green tea consumption, this caused the potassium levels to go back to normal after a few weeks.

However, they were taking other medications along with green tea.

When green tea consumption is increase, the condition of people with seizure worsens.

Hence, caffeine in green tea is the main cause of increased seizures and may lead to hypokalemia.

5) Problems Sleeping

It is a common fact that caffeine makes you more alert and active. Green tea contains caffeine and minimal amounts of it do relaxes you and helps you with good quality sleep.

On the other hand, higher doses of caffeine will interrupt your sleeping patterns.

People with sleeping trouble and caffeine sensitivity should avoid green tea especially later in the evenings.

6) Dizziness and Convulsions

When you drink green tea it may make you feel dizzy. Caffeine reduces the blood flow to the brain which results in sickness.

However, keep in mind that if you smoke green tea it will make the caffeine absorb more quickly this can lead to confusion and convulsions.

A girl feeling dizzy as a side effect of green tea

These side effects are rare and depend upon the individual to individual.

7) Green Tea Extract May Be Toxic for The Liver

The effects of high amounts of green tea extracts on liver damage are alarming. EGCG in green tea is responsible for many health benefits but high amounts of it can cause hepato-toxicity.

It is also observed that people with no history of liver damage or alcohol use when they started taking green tea extract supplements it increased inflammation in their bodies and cells.

Especially those women who took weight loss supplements for a longer period. The main ingredient was green tea extracts, these ladies faced liver problems.

8) Headache And Vomiting

Green tea itself is not the cause of these side effects. Consuming a large amount of caffeine causes toxicity in the body.

Especially when you drink green tea on an empty stomach it may lead to nausea, vomits, chills, and headache.

People with caffeine sensitivity can have blood pressure issues.

Do not take caffeine pills along with stimulant drugs. They may be a fatal combination.

9) May Impair Thyroid Function

The catechins provide many benefits including the prevention of cancer.

However large amounts of catechins may increase the risk of thyroid cancer and create problems in thyroid functions.

Green tea catechins in high doses may cause abnormal thyroid function and women at stage of the postmenopausal phase are at high risk.

10) Caffeine May Cause Bone Weakness

Studies show that green tea extracts weaken the bones, increase the risk of fracture, and decrease the none accumulation rate.

National Osteoporosis Foundation warns about excessive caffeine that prevents calcium absorption in the body. It may even cause bone loss in the elderly and osteoporosis in women.

Moreover, don’t take calcium supplements along with green tea. It will affect the absorption of calcium.

11) Causes Dehydration

Green tea is a natural diuretic and it causes the body to lose water.

When you drink green tea it causes your kidneys to function quickly and this leads to excessive urination which can lead to dehydration.

Dehydration causes electrolyte imbalance, headaches, and fatigue.

12) Cause Anxiety and Insomnia

The benefits and side effects of green tea depends upon the way you intake or the quantity of green tea you drink. Most of the times lower amount is beneficial and relaxes you.

On the other hand, the higher amount will lead to anxiety, palpitations, and even insomnia.

You should take 300mg of caffeine in a day. More than this will make you irritable, anxious and affect your sleep quality.

13) Prevent Actions of Drugs Used for Treating Clotting

If you are on drugs that are treating blood clotting and are anticoagulant you should stay away from green tea and any other drink that contains caffeine.

The caffeine in green tea can interfere with these drugs. These drugs like Warfarin are essential for reducing the risk of stroke and heart attack.

Thus, when you take green tea Vitamin K and caffeine inhibits Warfarin and its effects on the body.

14) Bleeding Disorders

Although rarely, green tea may cause bleeding disorders. Fibrinogen is a protein that helps in blood clotting. Too much green tea can decrease the levels of this protein in the body.

Green tea also interferes with the oxidation of fatty acids.

So, if you have a heavy mensuration problem or blood clotting disorder, then avoid drinking green tea.

15) Irregular Heartbeat and Blood Pressure

As we read earlier green tea may be the cause of anxiety. When you face anxiety, irregular heartbeat and blood pressure issues also arise.

This, however, depends on different individuals. It may affect some and may not pose any risk to others.

People who are taking blood pressure medicines and have anxiety issues should not drink green tea. This may cause palpitations and BP issues.

16) Heartburn

Green tea is generally not acidic. But the lifestyle we follow and eating unhealthy foods every day along with excessive caffeine can cause GERD.

This is caused by acidity caused by foods and drinks that in return lead to heartburn.

Hence, people with acidity issues can have acid reflux after drinking green tea, especially at bedtime.

17) Stomach Upset and Pain

Most people brew a cup of green tea after meals for digestive issues. It has laxative properties.

But most people suffer from diarrhea and upset stomach if they exceed 3 cups per day.

Dry green tea

So, green tea extract contains caffeine which may cause jaundice, abdominal pain, and change in the color of urine when consumed excessively.

18) Frequent Urination

Green tea may make you pee more than usual. It is a natural diuretic and the more green tea you drink, the more urine it produces.

The caffeine creates an effect that makes the bladder function more.

Thus, Excessive doses of green tea caffeine may increase urination frequency.

19) Cause Infertility in Men

The unrestricted use of green tea damage sperm DNA and is not good for the male reproductive system.

The polyphenols in green tea usually have therapeutic effects but excessive use will damage reproduction which can lead to infertility.

Thus, men with infertility issues should avoid green tea.

20) Drinking Green Tea May Stain Teeth 

Does green tea stain teeth? Well not like regular teas and coffee which decays your teet hand turns them yellow.

But regular long-term green tea drinkers do stain their teeth from it. Green tea turns your teeth to greyish color.

Furthermore, after a whitening treatment, avoid green tea or use it carefully with a straw and in minimum amounts.

Who Should Not Drink Green Tea?

These people should avoid green tea:

  • Pregnant ladies or lactating mothers.
  • People with insomnia, sleeping disorders
  • If you have regular spells of headaches and anxiety.
  • People with blood pressure issues and palpitations.
  • If you face urinary tract infections or have bladder control conditions.
  • Green tea before bed should be avoided.
  • If you are on medications for blood clotting, BP, etc.
  • If you have osteoporosis or liver disease.

Is Green Tea Safe?

Green tea is considered safe by FDA for most healthy individuals. It does have several side effects but we need to know that all these adverse effects are caused when green tea is not taken in moderation.

The negative side effects are caused by an overdose of caffeine.

A cup of green tea

Another thing to consider is the time of taking green tea. Know what time is best to drink green tea.

It is not a good idea to drink it on an empty stomach or just before bed. Drink it between meals so it doesn’t become acidic and cause negative effects.

Frequently Asked Questions

People ask these questions about green tea side effects and we answered them for you below.

Does Green Tea Have Any Side Effects on Skin or Hair?

Green tea does not have any adverse side effects on hair or skin. Green tea extract is likely safe when an FDA-approved ointment is used, short-term. Other green tea products are possibly safe when used appropriately.

What Happens If I Drink Green Tea Every Day?

Green tea is a safe drink for daily use. However, people with certain conditions should avoid green tea. Drink 2-4 cups of green tea every day to gain maximum benefits without overdoing it.

Does Green Tea Have Any Side Effects on Periods?

Green tea is mostly brewed by women to ease period pains and to relax the muscles that stiffen during menstruation. Excessive green tea may cause more bleeding and stomach pain. Moderation is the key.


In conclusion, green tea is a healthy drink and it only becomes harmful when it is taken in large amounts. The overdose of caffeine causes most of the side effects of green tea.

Most of the side effects of green tea can be avoided by consuming green tea in moderation.

Also, you can keep yourself safe from green tea effects by checking with your doctor when to take green tea and how much green tea to take in a day according to your health and condition.

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