8 Side Effects Of Green Tea You Should Be Aware Of November 4, 2015

Did you know that green tea has side effects? As shocking as it might seem, it is actually true. Seriously.

I don’t remember how many times I have seen people worshipping green tea. Well, worshipping is probably the apt word – because that’s how beneficial this miracle drink is. It has been found to lower the risk of cardiovascular diseases and cancer.

But then, just like any other ingredient out there, green tea too has side effects. Find that hard to believe? Then you must read on.

[ Read: Side Effects Of Cranberry Tea ]

Green Tea Side Effects

  1. Caffeine-Related Health Problems
  2. Risky During Pregnancy And Lactation
  3. Interference With Medication
  4. Toxicity
  5. Iron Deficiency
  6. Osteoporosis
  7. Lower Testosterone Levels
  8. Harmful For The Liver

1. Caffeine-Related Health Problems:

A steaming hot cup of coffee is the only image that is conjured up in anyone’s mind on hearing the word ‘caffeine’. But, did you know that green tea also contains caffeine? Its caffeine content might be lower than that of its counterparts, but overconsumption of green tea (more than three to five times a day) can lead to several ailments. These include insomnia, upset stomach, nausea, diarrhea, and frequent urination in some people (1).

So, the next time you experience any of these symptoms, and you happen to be swigging too much of green tea, you know whom to blame.

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2. Risky During Pregnancy And Lactation:

For any woman, pregnancy and lactation are sweet, yet delicate times. A high level of consumption of green tea during pregnancy has been linked to an increased risk of miscarriages and a number of other negative effects. Not more than two cups of green tea should be consumed during these times. Completely avoiding green tea would be the best option. For lactating women, the caffeine in green tea can pass into breast milk and affect the nursing infant (2).

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3. Interference With Medication:

This is one of nature’s biggest ironies, if you ask me. Green tea has been marketed and used since ages for its anticancer properties. It has been named the ‘Miracle Herb’ and has been lauded for its other healing abilities. But, on the other hand, the polyphenols in green tea, which are known for their healing properties, were also found to block the anticancer properties of a drug named bortezomib (3).

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[ Read: Side Effects Of Lemon Tea ]

4. Toxicity:

There is a misconception that consuming green tea while fasting would compensate for the nutritional deficiency created by skipping meals. It has been found that green tea, when taken during fasting, leads to toxicity (4). This also includes gastrointestinal, renal, and liver toxicities. Though the tests have been performed only on animals, there is a possibility  that humans would exhibit the same symptoms if they consume green tea while fasting. One should be aware of this common side effect of green tea.

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5. Iron Deficiency:

This might sound unbelievable, but it’s true. Too much of green tea consumption might increase the chances of iron deficiency (5). Green tea contains tannins that block the absorption of iron from food and supplements.

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[ Read: Black Tea Side Effects ]

6. Osteoporosis:

This may not make sense in the beginning. What’s the link between green tea and osteoporosis? This is how they are linked.

Drinking too much of green tea can increase the amount of calcium that is flushed out in the urine (6). And, we know that the deficiency of calcium leads to osteoporosis. It is advisable not to take more than 300 mg on any given day. The possible loss of calcium can be compensated by taking calcium supplements.

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7. Lower Testosterone Levels:

You wouldn’t have come across this one before – but it’s true. Excessive consumption of green tea can lower testosterone levels. In a Brazilian study, it was found that excessive green tea intake lowered the amount of testosterone hormone in rodents. The study also found that the effect could be reversed by reducing the consumption of green tea (7).

Another study conducted on albino rats, at University College of Science and Technology, Kolkata, India, revealed that high doses of green tea extract may cause impairment of the functional status of the testis in rodents, thereby raising concerns of its effects on the male reproductive functionality (8).

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8. Harmful For The Liver:

I had to read this twice to actually believe it.

The culprits are a type of polyphenols called catechins. Though they are antioxidants, catechins can prove to be harmful if taken in excess. They target the mitochondria, which are the powerhouses of the cells in your body, and disrupt the metabolic processes. They prevent your body from metabolizing food and turning it into energy, thereby leading to severe health conditions like jaundice, hepatitis, or in some extreme cases, even liver failure (9).

Catechins can also deplete the protective molecules (like glutathione) in the cells that guard us from injury. This might eventually lead to fatal liver injury in susceptible individuals. The results of an American study linked the role of catechins to liver damage (10).

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Special Precautions/Warnings

In addition to the side effects, there are certain other precautions one must keep in mind before going for green tea.

  • Green tea can make anxiety worse. So, people with anxiety disorders must stay away from it.
  • The caffeine in green tea has been found to meddle with blood sugar control. Hence, diabetics must be cautious while consuming it.
  • The caffeine in green tea can even cause irregular heartbeats.
  • If you are on blood thinning medication (like warfarin), it’s better not to take green tea. This is because of the presence of vitamin K in green tea, which can nullify the effects of warfarin (11). Also, refrain from consuming green tea if you are taking aspirin as using the two together might increase your risk of bleeding.

These are some of the possible side effects of green tea. As the saying goes, all that glitters is not gold. I don’t mean to say green tea is bad. Of course, when taken in limited and required amounts, green tea is one of the best sources of vitality on the planet.

Unable to digest the fact that green tea has side effects? Take a cup of green tea; it’s good for digestion (12).


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  • http://www.stylecraze.com/members/chahna/ Chahna

    basically i hate tea i even i dont know about this green tea!! as you mentioned here green tea cons i never drink for next time yup!! thanks aparajita :)

  • http://www.stylecraze.com/members/gargisinha/ GARGI SINHA

    i never drink any tea or coffee..thank god

  • http://www.stylecraze.com/members/nimratachowan/ Nimrata

    Very informative one aparajitha:) Didnt know green tea has side effects:O

  • anonymous

    Wow, ya’ll even read the article?

  • mon

    Everything in moderation is mostly good . . anything in excess no matter how good may always have some undesirable side effects. . .

  • Jimit Shah

    Thanks for sharing.

  • JOE


  • Akhlesh Narayan Shukla

    Must read..

  • Akhlesh Narayan Shukla

    may be use full informatio..must read and share…

  • maheen

    last 15 years daily i drink grean tea no side effect nothing…goma happnd…its talkin about only caffeine side effects…The green tea helps from 1000 disease ….

  • Praveen

    decaffinated green tea is worthless…please investgate and update this article…good prporties of green tea are lost in the decaffination process

  • Tg Padmanabhan

    we all have been brought up on mother`s milk. Cow is our mother; so drink only cow`s milk and keep away from tea, coffee !!

  • sangeeta

    Its just been 2 days since self has started with Organic TULSI tea but feels good. What do you advice? ?

  • Anonymous

    Hai, recently I started drinking green tea, now. I stop it ….! Fine information. My age is 56 / male . With 74 kg wt. 5’9″ ht..

  • Sudhir Kumar Kalra

    Hello Aparajita, thanks for sharing information relating to side effects of Green Tea. I suffer from hyper acidity, therefore I switched to Green Tea. In a day, I took only three cups maximum. After few months once or twice I found acide reflux acting up. I think your information would help me to remain cautious while taking tea.

  • Nasir

    It’s very useful article informing the possible side affects of excess usage. I had been taking 4-5 cups of green tea a day for the last 7 to 8 years and during past year, I increased its consumption considerably in place of water – and the caffeine in it ((the presence of which in green tea is not known to many of us) has taken its toll and my problem of PBH got worsened recently leading to blockage and consequent UTI.

  • Kandie

    I have been taking green tea twice a day and I started having irregular heartbeats, feeling dizzy and feverish, like I started having symptoms of low iron. I know these symptoms because I was once on iron supplements and I had no idea it might be green tea until today. I thought it was because of sleeping less hours due to my studies and I continued consuming green tea since 2008 until now. My daughter heard on radio yesterday from an invited specialist that taking too much green tea is harmful and asked me to do the research since she realized the side effects of it match what I have been going through. I really am thankful that now I will start consuming the right amount and be aware of the side effects. Indeed too much of everything is not good.

    • http://www.stylecraze.com/ StyleCraze

      Hi Kandie, indeed, too much of anything isn’t good. Thank you for your valuable comment.