Green tea comes from the leaves of the Camellia sinesis plant. This plant naturally contains caffeine. Caffeine from natural plants has been proven safe.
If we compare the caffeine content of green tea with other sources of caffeine, we can conclude that green tea has a significantly less amount per cup. However, caffeine content in green tea is stronger than the caffeine content in coffee, when measured in dry form.
Caffeine content in tea metabolizes differently in the body than the caffeine in coffee.
Content of caffeine in green tea varies by the amount of tea used and the length of time the leaves are infused. The size and shape of our brewing vessel also influence caffeine content.
Generally, the caffeine content of green tea depends on the type of tea and the way of preparation. The first and second leaves of the tea plant are believed to contain the largest amount of caffeine (3.4 %).
Smaller leaves extract caffeine into the water faster. Caffeine is water-soluble and the longer it is exposed to water the more caffeine molecules are released. If we want less caffeine, we can infuse the leaves for a shorter time. Also, the high temperature can destroy valuable therapeutic compounds found in green tea.
Green tea also contains two caffeine metabolites the obromine and theophylline, which are present in trace amounts.
Green tea contains large amounts of catechin tannins (10-25%) which are known to decrease the digestibility of proteins. A cup of tea contains lesser amounts of caffeine than coffee, but the tannin content is much higher. Tannins have anticancer and carcinogenic properties.
Check out Green Tea Nutrition Facts to find more details about green tea nutrition.
Green tea contains 15 - 60 mg caffeine per 8 ounce cup, average 30.
It is difficult to provide exact measurements, because many factors are contributing to the caffeine content.
Comparison with other beverages:
Traditional coffee contains more caffeine than green tea. The caffeine content of an average 8 ounce cup of coffee can vary from 80 to 135mg.
An 8-ounce cup of instant coffee contains average about 70mg of caffeine.
Espresso contains about 100mg of caffeine per 2 ounce cup.
Black tea contains 40 to 80mg per 8 ounce cup. Green and black teas undergo different processing and the result is that green teas generally yield less caffeine in the cup than black teas.
Instant tea contains about 12 - 30mg caffeine per 8 ounce cup.
A 12 oz can of Coke contains 34mg.
Decaffeinated green tea contains about 2-5mg per 8 ounce cup.
Decaffeinated tea, which despite its name, does contain some caffeine. The decaffeination process effectively removes about 97% of the caffeine. Teas are decaffeinated with the gentler CO2 method to retain most of the health properties.
Generally, caffeine content of green tea is difficult to define, because different studies have found that the caffeine content of any given cup of green tea varies.
Read more about green tea caffeine content in next article: Green Tea Caffeine Content.
Note: All figures are approximate, this site does not provide medical advice, diagnosis or treatment.