Caffeine Content Green Tea; What is its effect on us?


Caffeine has various effects on the body. The caffeine content green tea brings to the table is negligible however.

Why write a page on it then? Well, that’s because drinking LARGE quantities of caffeine, during an extensive period of time can cause side effects .

We already know coffee is the most popular source of caffeine and we know it can also be found in tea……

But did you also know that, in general, tea contains more caffeine than coffee? Well, by dry weight that is. Luckily, a typical serving contains much less because it’s brewed weaker than coffee.

Are you sure you want to buy decaffeinated green tea? Find out why you might want to stick with the regular green tea.


Caffeine content green tea

On average, when we look at the amount of caffeine in green tea we see there’s between 9-50 mg of caffeine in each cup, depending on the strength of the brew and whether it’s the first serving or not.

In comparison, black tea contains 40-70 mg of caffeine per cup, about half of a freshly brewed cup of coffee (90 mg) and instant coffee has about 60 mg of caffeine.

Why does the caffeine content green tea has, differ from black tea and other teas? Well, that’s because they all follow a different processing technique where green tea is the least processed of all teas.

All tea originates from the same plant Camellia sinensis but the various processing techniques of its leaves, create a great diversity in teas and consequently of the caffeine content.

Read more about this on what is green tea.

Green tea has a light color and has less caffeine and coffee is dark, just as the black tea (what’s in a name….) and they contain more caffeine. Nevertheless, color is a poor indicator of caffeine content.

It’s the strength of the brew,
growing conditions,
processing techniques and other variables*
that influence the amount of caffeine.

* For example even the decision to brew a cup of tea by using loose green tea or green tea in a tea bag can influence the amount of caffeine you will find in your cup of tea.

Effects on the body

Due to the limited caffeine content green tea has, it mainly provides advantages such as boosting alertness, raising your blood pressure, stimulating digestion and it can even help in your fight to lose weight!

It also has some drawbacks though, mainly when taken in large doses over extended periods of time, such as nervousness, irritability, anxiety, tremulousness, muscle twitching, insomnia (sleeping disorder) and headaches.

Especially when pregnant it’s wise to limit your caffeine intake to less than 200 mg a day.

I’ll explain why….<br

Caffeine during pregnancy

According to two independent studies caffeine may have negative effects on a pregnancy as large caffeine consumption may result in infertility, low birth weight, miscarriages and still birth.

The first study held in Denmark on 88,482 pregnant women found that relative to non-consumers of coffee, the risk of fetal death was increased by 3% for women who drank 0.5 to 3 cups a day, by 33% for those who drank 4 to 7 cups and by almost 60% for women who drank 8 or more cups a day. Therefore, they recommended drinking no more than three cups of coffee per day during pregnancy. In comparison, the lower caffeine content in green tea would allow up to 18 cups of green tea.

The Yale University research team of the second study found that drinking about 600 mg of caffeine a day, which is about 6 cups of coffee, would reduce birth weight to levels that were clinically significant. The rate at which birth weight was reduced was established at being 28 grams per 100 mg, or 1 cup of coffee per day (or 7 cups of green tea). But they emphasized that this would not be significant for moderate caffeine consumption.

If you are a mum and breastfeeding your newborn, drinking green tea is also not a good idea.

The caffeine content green tea has, will become part of the breast milk which may be harmful for the baby.

The UK’s food agency, recommends that in pregnancy women should limit caffeine consumption to no more than 300 mg a day, translated as three cups of brewed coffee, or six cups of tea a day.

So before throwing away your favorite tea mug keep in mind that the caffeine content in green tea is significantly less than in black tea or coffee and that it’s safe to drink green tea in moderate amounts where it won’t harm the (unborn) baby and you can still benefit from the green tea antioxidants.

Another green tea ingredient EGCG may also influence a pregnancy.

Read about all the (possible) SIDE EFFECTS of green tea
(mainly caused by caffeine)!

Return from caffeine content green tea to green tea home page.



Bech, B.H., Nohr E.A., Vaeth M., Brink Henriksen T., Olsen J. 2005. Coffee and Fetal Death: A Cohort Study with Prospective Data. American Journal of Epidemiology: 162:983–990.

Martin T.R., Bracken M.B. 1986. The association between low birth weight and caffeine consumption during pregnancy. American Journal of Epidemiology: 126(5):813-821.