Too Much Green Tea
Why It Is Harmful

Drinking too much green tea or consuming too much green tea supplement can be harmful. Here's why. How much to take to prevent overdose.

Drinking green tea is one of the safest thing you can ever do. After all, it has been consumed by Asians for thousands of years - what can possibly go wrong?

Clever marketers also claim that the Chinese and Japanese people drink 10 to 20 cups of green tea a day - you need to drink this much or take a green tea capsule to benefit fully from its numeous health benefits!

Common Complaints

Well, the reality is actually quite different. I grow up in Malaysia and my wife come from China. I also have a couple of Japanese friends.

I can tell you - not everyone drinks green tea. Furthermore, many people - even if they do drink green tea - they will only do so in certain times of the day and at the tiniest amount (say 1 gram).

The most common complaints are stomach upset and caffeine sensitivity.

Part of the reason is because in Asia we drink spring harvested green tea buds, which are highly potent. However, these side effects are present even if you are drinking the highest grade in the smallest amount.

The rules of thumb is to only drink green tea in between meals and never on an empty stomach. If you are concerned about insomniia, never drink green tea in the late afternoon or early evening.

Green tea is unbelievable. The caffeine it contains is extraordinarily powerful. Acting together iwth antioxidants and theanine, drinking even a small amount can have a powerful energizing effect that can last up 6 hours or longer.

I have always advised my customer who are sensititve to caffeine to drink 1 gram a day and it works for quite a few of them. I am always very pleased for them because that way their money goes a long way as well!

For further guidance, please read

Green Tea and Stomach Gastric Irritation

Best Time for Drinking Green Tea

Quality Issue

Drinking green tea is very safe if you are drinking only the highest grade. These tend to be the youngest tea buds found on top of the tea bush and harvested in the first three days of spring. Also, the tea farm has to be located in high altitude away from road traffic.

However, issues can emerge when you start consuming mature leaves and tea farm that is located in the low alttiude. There are issues such as pesticides and heavymetals to deal with.

Also, tea plants accumulate nutritions such as aluminium, manganese and fluoride from soil and water. These minerals can be harmful when consumed in large amounts over many years.

Cheap branded tea has been found to be at fault. For example, a 2005 study conducted by Dr. Michael Whyte from Washington University raised concerns about the high fluoride content in Lipton instant iced tea.

University of Derby also reported on a study that found that economy tea bags from supermarket brands can contain dangerous concentration fluoride, making UK people susceptible to fluorosis.

How Many Cups?

If you are drinking a quality green tea at the right time of the day and avoiding insomnia, congratulation! You should be avoiding 80% of any side effects of drinking green tea.

As for how many cups a day to avoid overdose, let me say the following.

If you are drinking highly potent green tea that is made from spring harvested tea buds, you only need to drink three grams a day to get the health benefits.

Infused over three times, they will give you approximately 300 milligrams of catechins.

That should be sufficient and you can easily double this if you think you need it i.e. 3 to 6 cups a day. Many population studies conducted in Asia has found significant health benefits based on this dosage.

The following article discusses this topic at length:

How Much Green Tea Should You Drink Per Day?

Green Tea Supplement

Finally, we come to this much misunderstood topic of green tea supplement.

The golden rule here is to following the manufacturer's instructions and take great care not to overdose.

Taking green tea supplement is not exactly the same as drinking green tea, it depends on which method was used to extract the tea. This is explained in the Green Tea Supplement Side Effects article, where three studies have found green tea extract to be toxic at high doses.

On the other hand, you don't want to consume too little or else you will lose out on the health benefits.

In the Green Tea Extract Weight Loss article, we examine four scientific studies, which found that you need to consume somewhere between 300 to 700 milligrams of catechins or EGCG a day to have any weight loss effect.

New! Comments: Like This Story? Leave A Comment!


Imai K, Suga K, Nakachi K. Cancer-preventive effects of drinking green tea among a Japanese population. Prev Med 1997;26:769–75.

Imai K, Nakachi K. Cross sectional study of effects of drinking green tea on cardiovascular and liver diseases. BMJ 1995;310:693–6.

Back to Top of Drinking Too Much Green Tea

Back to Green Tea Side Effects Main Page

Back to Amazing Green Tea Home

rss  Subscribe via RSS

twitter  Twitter Julian

bug Spot a bug? Suggest an improvement and win a prize!

Amazing Green Tea

The definitive guide to Gourmet Tea and healthy drinks
Want to drink tea buds that look good, taste good and feel good? Check out my top three recommendations!