Side effects of green tea

10 Shocking Side Effects Of Green Tea

Can I drink green tea all day? Because it contains caffeine, an overdose of green tea can cause insomnia, upset stomach, vomiting, diarrhea, and frequent urination in some people are the side effects of green tea.

Tea contains tannins, so if you drink green tea before eating, you may have abdominal pain, nausea, or constipation.

Catechin in green tea may cause a decrease in the absorption of iron from food.

If you are taking medicines, you should make sure that green tea does not interfere with any medicine.

Read morewhat is green tea

Side Effects of Green Tea

The tendency to drink green tea on the planet is growing at a breakneck pace.

Many people believe green tea is beneficial for health, which can be true to a large extent.

At the same time, due to these benefits, many people excessively start consuming it, which is not suitable for health.

Excessive intake of green tea can call for the loss of green tea. Through this article, we want to tell you how much harm can be caused by excessive consumption of green tea.

Excessive Caffeine –

What happens if I drink green tea every day? Green tea can be beneficial for health, but it should not be forgotten that green tea contains caffeine. There is 12 mg of caffeine per 100 grams of green tea (1). Caffeine is a bitter element found in many other foods and tea naturally (2). Excessive caffeine intake can harm your health. The Common side effects of green tea are dizziness, insomnia, dehydration, nausea, vomiting, and discomfort (3).

Iron deficiency –

According to WHO, anemia affects 1.62 billion people worldwide (4). Iron deficiency is one of the leading causes of anemia, and excessive intake of green can cause iron deficiency in the body. It revealed in related research published on the NCBI (The National Center for Biotechnology Information). The study states that excessive intake of tea may inhibit the absorption of iron in the body, leading to iron deficiency and an increased risk of anemia (5) (6).

Causes of muscle weakness –

Excessive intake of drinking green tea also includes muscle weakness. This information comes from a case study available on the NCBI website, in which a 49-year-old man had muscle weakness for a few days. During the blood test, the person was confirmed to hypokalemia (lack of potassium in the blood), causing muscle pain. However, the supplementation of potassium by the doctor soon saw an improvement in her condition.

During the medical examination, when his dietary information obtained, it was found that he was consuming an overdose of beverages made from extracts of green tea two weeks before muscle weakness. The case study showed that excessive intake of caffeine present in green tea might increase the risk of hypokalemia (7). In such a situation, it is our opinion that green tea should consume in balanced quantities.

Weak bones –

side effects of green tea

Weak bones can cause significant side effects of green tea. As we mentioned above, caffeine is present in green tea. In such a situation, excessive intake of green tea can also affect the bones.

Indeed, according to studies done on the health effects of caffeine, excessive intake of caffeine can inhibit calcium absorption in the body.

This effect can lead to thinning of bones and result in bone disease such as osteoporosis (8).

Not only this, but another research related to this has also shown signs of spinal weakness due to excessive intake of caffeine in postmenopausal women. In such a situation, we would advise that to avoid the problem of bones, green tea should be consumed in a balanced manner (9).

Liver problems –

According to one study, green tea can cause liver damage in some cases. This may be followed by EGCG (a type of catechin), which may exhibit hepatotoxicity (toxic to the liver) effect. At the moment, further research requires on this topic (10), but still, it considered as side effects of green tea.


Gastroesophageal Reflux Disease is a condition in which the elements present in the stomach get into the food pipe. It is a type of digestive problem in which there may also be a problem of heartburn (11). If we talk about the major side effect of green tea, then Japanese scientists found that excessive intake of green tea and a sluggish lifestyle can increase the risk of GERD (12). At the same time, another study conducted on the Asian population found that an ingredient called theophylline in tea may cause fatal acid reflux (14).

disadvantages of green tea - Dehydration

Dehydration –

The common side effects of Green tea also include dehydration. It can act as a natural diuretic (diuretic). Excessive drinking of green tea may be a problem with frequent urination, which can cause dehydration (13). In such a situation, it is better to consume green tea in balanced quantities.

Stomach problem –

Drinking green tea can also cause stomach problems. The caffeine present in green tea may be the reason. Excessive intake of caffeine can cause stomach upset or other stomach problems (14). Is green tea safe to drink?  If more than five cups of green tea drink in a day, then there may be a problem like a stomach ache or stomach upset (15) (16). If someone already has stomach problems, they should take it only after the advice of the doctor.

Dizziness and vomiting –

The loss of green tea includes dizziness and vomiting. The reason for this can also be attributed to the caffeine present in green tea. Excessive caffeine intake can harm the nervous system, causing problems such as dizziness, restlessness, confusion, and insomnia. Along with this, it can also cause trouble like nausea or vomiting (17)

Side effects of green tea in pregnancy –

Medical advice is necessary before the consumption of caffeinated beverages during pregnancy.

side effects of green in pregnancy

Caffeine can get into the placenta in the mother’s blood, which can harm the fetus. Excessive caffeine intake may impede fetal development (18).

Consuming more than 300 mg of caffeine during pregnancy may pose a risk of high blood pressure in the pregnant but may also increase pregnancy duration (19). At the moment, still more research we need.   

Side Effects Of Green Tea On Skin

Truly said that there are no side effects of green on the skin, studies show that drinking green tea and applying both are beneficial for the skin. Green tea and green tea extract helpful in reduce acne and make skin younger.

Side effects Of Green Tea On Hair

Hair loss is a common problem in men and women around the globe. The causes are hormonal changes, stress, diet, and disease. Studies show that green tea is helpful in hair regrowth. Consuming green tea and use hair products reduce the risk of hair loss.

After reviewing the twenty research studies the result found that oral intake of green tea is helpful in cancer prevention, hair loss, skin aging, and scavenging of free radicals plus reduce the harmful effects of psoralen-UV-A therapy. (20)

How Many Cups of Green Tea Should You Consume Per Day?

One teaspoon of green tea can use in one cup (about 236 ml) of warm water (20). At the same time, pregnant women can consume one to two small cups of caffeine-containing beverages.

Pregnant women should take care not to consume more than 200mg of caffeine per day (21).

Also, green tea contains EGCG (a type of catechin). Research related to this on the NCBI website has shown that intake of EGCG up to 338 mg a day can be safe (22).

However, our opinion in this matter is that even though there is scientific evidence, people should consult the doctor once before taking green tea. Every person’s health and body’s needs are not the same in such a situation; it is also necessary to seek medical advice.

Which people should not drink green tea?

People suffering from the following problems should not consume green tea (23) (24) (25) (26).

People who have anemia (anemia problem) do not consume green tea. As we mentioned above, green tea can act to inhibit the absorption of iron in the body.

People suffering from hypokalemia (lack of potassium in the body) should not consume green tea. According to a case study on the NCBI website, green tea can cause hypokalemia, and in such cases, its consumption can make the problem even more complicated.

If a person is taking warfarin (Warfarin – blood clotting drug), then avoid green tea. Green tea contains vitamin-K, which can harm the function of the drug.

Heart disease patients are advised not to consume green.

Conclusion –

Given the properties of green tea, people are drinking it a lot. Although green tea is a boon for humans, drinking too much green tea can increase its harmful effects on the body. The common side effects of green tea are upset stomach, vomiting, insomnia, constipation, nausea, muscle weakness, weak bones, liver problem, dehydration, etc. Considering these ill effects, I would advise you to avoid excessive consumption and use it with a doctor’s advice.

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  1. October 16, 2020

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