Whether you drink green tea for health benefit, caffeine alternative, or simply for the taste, green tea does the wonder.
If we caught to the chase, there are about 20~50mg caffeine in 8.5oz (250ml) of green tea. But its effect may be different from the coffee.
Personally, after we switched from coffee (2-3 cups a day) to green tea, we certainly can feel the difference!
In this post, we will explore the caffeine content in green tea along with other caffeinated drinks, the recommended amount for you, and why it effects you differently.
Effect of Caffeine in Your Body
Feeling anxious, jittery, or sleepless? They're common symptom of taking too much caffeine (1). When you take caffeine, it blocks the neurotransmitter called adenosine in your body and prevent it from building up, which makes you feel less tired (2).
When you take caffeine through tea, you're also taking L-theanine. L-theanine helps you feel more calm and collected (3, 4), which makes it different from drinking coffee.
Your Recommended Amount of Caffeine
According to studies, for a healthy adult, the safe level of caffeine is 400mg/day. This may varies on individual's weight and metabolism.
Use 6mg x body weight (kg) to find your caffeine level (5). For example, if you weight 110lb, your recommended amount is 300mg/day.
50kg x 6mg/(kg*day) = 300mg/day
How Much Caffeine in Other Drinks?
Other caffeinated drink like coffee has higher caffeine content. A cup of americano has about two shots of espresso, which is about 80mg of caffeine in total (6).
Caffeine content can vary depending on a few variables like brewing duration, type of leaves, and how it is prepared. If you brew the tea for longer time or in higher temperature, you will extract more caffeine from the tea (7).
In Short
An 8.5oz (250ml) cups of green tea has 20~50mg of caffeine.
Recommended amount of caffeine for an adult is 400mg/day. Calculate your recommended amount using 6mg x body weight (kg).
Caffeine can cause jitter, anxiety, and sleeplessness. Zana Tea has free caffeine chart for each tea with easy steeping method to help you monitor your caffeine intakes.
L-theanine in tea helps you feel calm and collected from caffeine, comparing to spike of energy from coffee.
Overall, green tea has low caffeine and may give additional benefits to your health.