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The amount of caffeine in green tea varies between blends, but is typically between 11-25 mg in a cup (assuming around 2 grams of tea brewed).
Like other drinks from cultivated plants (tea, coffee), there are numerous variables that can alter caffeine content.
The length of brewing time is a major factor - the longer the brew - the higher the caffeine. The Journal of Food Science evaluated different brands of green tea and had extremely varied results using the same amount of tea leaves brewed for 3 minutes.
This table shows the amount of caffeine in an 8 fl oz cup of tea (using 2 grams of tea leaves).
|Green Tea Brand||Caffeine|
|Stash Tea (Exotica Dragonwell)||47.8 mg|
|Peets Coffee||33.4 mg|
|Stash Tea (Premium)||30.2 mg|
|Stash Tea (Organic)||27 mg|
|Herb Enterprise||20.2 mg|
|Midori Tea & Ginseng Co.||17.6 mg|
|Ten Ren Tea||16.4 mg|
|Zen Green & Herbal Fusion||15.6 mg|
|Celestial Seasonings||12 mg|
|Stash Tea (decaffeinated)||7.6 mg|
As you can see from the above data, green tea caffeine can vary greatly among brands and the type of green tea used. Another study compared the content of dry matter from tea leaves and found Green Tea had 10-20 mg per 1 gram dried matter. Research in 2020 found that green tea caffeine was in the range of 11.3–24.67 mg/g.
Black Tea had 22-28 mg per 1 gram dried matter. So as a general rule, Green Tea has less caffeine than Black Tea but can vary depending on which brand/type chosen.
Yet another study (here) showed that Green Tea (in Japan) has 30 mg caffeine per 200ml cup. The figure we have included in our caffeine database is an average amount.
Green tea is also high in the amino acid L-theanine. This has a calming effect and aids with concentration. There's a myth that green tea has more caffeine than coffee, but this isn't true. L-theanine is most likely responsible for this. People will have a different level of alertness when drinking green tea which people mistake for the caffeine's effect when it is really the effect of L-theanine.
Matcha green tea can have more caffeine because of the unique way it is made. You can find the caffeine content of Matcha here.
Caffeine in Other Green Tea Based Products
|Product||Size (fl oz)||Caffeine|
|Zest Green Tea||8||140 mg|
|Lipton Brisk green Tea||12||6 mg|
|Nestea Peach Green Tea||20||42 mg|
|Oi Ocha Green Tea||16.9||60 mg|
|SoBe Green Tea||20||35 mg|
|Caribou Green Tea Smoothie||12||44 mg|
|Mega-T Green Tea Supplement||1 capsule||50 mg|
|Xingtea Flavored Green Tea||23.5||35 mg|
|Arizona Green Teas||23.5||22 mg|
|Bazza Green Tea||16.9||150 mg|
|Snapple Green Tea||16||15 mg|
|Green Tea Ginger Ale||12||9 mg|
|Starbuck's Tazo Green Tea Latte||12||55 mg|
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Ingredients in Tea (Green)Leaves From The camelia Sinensis Plant
Is Green Tea high in caffeine?
Green Tea contains 18 mg of caffeine in a 8 fl oz cup.
This equates to 2.25 mg of caffeine for every fl oz and 7.61 mg for every 100 ml.