Does Green Tea Have Caffeine?

This popular drink has a beloved flavor and impressive health benefits, but it might not be best right before bed.

Since ancient times, green tea has been known as a healthy and rejuvenating drink. Green tea originated in China, tracing all the way back to 2737 B.C. when the Chinese emperor mistakenly drank water with a dead tea leaf boiled inside and actually found it quite refreshing. Happy accident, I'd say!

It's common knowledge that green tea is incredibly popular, rich in antioxidants and offers an array of health benefits. However, despite all of the positive aspects of this beloved beverage, many people are still left wondering whether or not green tea contains caffeine. Whether you're craving more caffeine, trying to steer clear of it, or you're nearing bedtime and would rather not lie wide-eyed and awake all night long, let's get to the bottom of what's in the popular tea.

a woman pulling a green tea bag out of a cup
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Does Green Tea Have Caffeine?

In short, yes. Green tea does contain caffeine. However, not all green teas are created and brought to shelves equally, and there are slight differences worth acknowledging. In fact, there are specific factors that can affect the caffeine content in different types of green tea.

For example, the harvest season of tea leaves may impact caffeine content. Earlier harvests of the same exact plant can potentially contain a higher caffeine content. This is because the longer the tea leaves have oxidized, the less caffeine they will contain. In the time that passes between harvests, polyphenols in the tea are produced in a greater quantities. These polyphenols can bind to the caffeine and ultimately make it less available for us to absorb when we drink the tea.

Additionally, the temperature of water at which you brew your tea, as well as your brewing method, can impact caffeine levels. Cold-brewing tea extracts less caffeine than hot-brewing. Brewing time can also play a role. If you steep your green tea in boiled water for 5 minutes versus 15 minutes, the caffeine level will be lower and the taste of the tea will be milder.

So while green tea does contain caffeine, there are several factors that can influence exactly how much caffeine makes it into your cup. Read on to learn how much caffeine that cup of green tea may contain, on average.

How Much Caffeine Does Green Tea Have?

Now that it is confirmed that green tea does, in fact, contain caffeine, it's important to understand how much. Based on the Food and Drug Administration's estimate, an 8-ounce cup of green tea typically contains 30 to 50 milligrams of caffeine. For some context, this FDA estimate also states that an 8-ounce cup of black tea contains 45 to 90 milligrams of caffeine, and an 8-ounce cup of coffee contains 80 to 100 milligrams of caffeine.

How Much Caffeine Should I Consume In a Day?

Many people wake up in the morning yearning, longing, desperate for that morning caffeine kick-start. Similarly, the common "midday slump" may call for an afternoon caffeine boost from the nearest cafe. Caffeine can absolutely be part of a healthy eating pattern for most individuals. However, too much caffeine can potentially pose problems for your health. This depends on factors such as body weight, medications you may be taking, and individual tolerance or sensitivity to caffeine, as this varies from person to person.

The FDA cites 400 milligrams per day—about 5 cups of coffee or 10 cups of green tea—as the maximum amount of caffeine healthy adults should consume each day. According to the FDA, this amount is not generally associated with negative effects. However, as previously stated, different people have different sensitivity levels to caffeine and metabolize it at different rates. Signs that you've consumed too much caffeine include jitters, anxiousness, headache, nausea, insomnia or an increased heart rate. It is important for individuals to determine what works best for them and to be mindful of how they react to different levels of caffeine intake.

Health Benefits of Green Tea

According to a 2019 review published in the journal Medicine, people who habitually consume green tea had a 17% lower risk of developing breast cancer than non-tea drinkers, despite heterogeneity among those studied. This review also noted that green tea is rich with polyphenols, which contribute additional antioxidant and anti-inflammatory properties to the tea. Antioxidants are compounds found in several types of foods, especially fruits and vegetables, that help protect our cells from oxidative damage, a factor that contributes to several chronic illnesses and cancers.

Other research suggests that green tea may help improve blood sugar control and reduce inflammation in the gut. This may help lower the risk of diabetes, digestive problems, high blood pressure and more. Green tea may also support brain function, aid in digestion, reduce heart disease risk and may even offer protection against cancer. Not to mention, it has a deep and earthy flavor and beautiful color that may help calm both the mind and body. What's not to love about this centuries-old beverage?

Frequently Asked Questions

1. Is green tea very high in caffeine?

Compared to its counterparts, like black tea and coffee, green tea is not high in caffeine. If you're limiting your caffeine intake, green tea may be a good option for getting that slight energy boost without reaching the point of jitters.

2. Which has more caffeine: coffee or green tea?

Coffee contains significantly more caffeine than green tea. One 8-ounce cup of green tea typically contains 30 to 50 milligrams of caffeine, whereas coffee contains around 80 to 100 milligrams of caffeine per 8-ounce cup.

3. Does green tea dehydrate you?

Natural diuretics—like beverages containing caffeine—can cause the body to lose water. Therefore, drinking green tea in excess may lead to frequent urination and potentially dehydration. However, according to the British Dietetic Association, studies suggest that dehydration from beverages containing caffeine only occurs when very high doses of caffeine are consumed. Because the amount of caffeine in green tea is relatively low, it is unlikely that green tea will dehydrate you. But always be sure to enjoy water throughout the day as well as tea.

The Bottom Line

Yes, green tea does contain caffeine. However, it contains less caffeine than black tea and much less caffeine than coffee. While green tea can give you a slight caffeine boost, it is milder than a higher-caffeine beverage that may lead to feeling an energy crash later.

That being said, caffeine is a stimulant which may cause you to be more alert, and it typically takes four to six hours for your body to metabolize half of what you've consumed. If caffeine tends to keep you awake at night, it might be wise to reconsider steeping a warm cup of green tea near bedtime and choose a decaffeinated option instead, such as mint or chamomile tea.

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