Is There Caffeine in Green Tea?

caffeine in green tea

What is the caffeine content of green tea?

Answering the question is there caffeine in green tea is quite simple.

However we want you to get your money’s worth from the article so we’ve thrown in some more comprehensive content, so you don’t feel short-changed.

Green tea is one of the most popular, widely consumed tea types worldwide. 

That is thanks in part to the wide range and availability of green tea and because of its numerous health benefits.

This type of tea has a long history of use in folk medicine to control bleeding, improve digestion, boost heart health, regulate body temperature, and more. 

Several clinical trials and preliminary studies show that green tea may be highly effective in reducing the risk of chronic diseases due to its high levels of polyphenols (potent antioxidants). 

Green tea is considered a true tea because it is made from the Camellia Sinensis plant. 

All true teas, including black, oolong, and white tea varieties, are made from the leaves of this plant, and all contain the stimulant caffeine. 

Now at this point you may be starting to get concerns about the caffeine in green tea? 

Don’t worry, this article covers everything you need to know about caffeine and green tea consumption

What Is Caffeine and What Does It Do to The Body?

Caffeine is one of the most widely used natural stimulants worldwide. 

Billions of people rely on caffeine to start their day, alleviate daytime fatigue, or make it through a night shift. 

This natural stimulant is so widely available that the U.S Food and Drug Administration (FDA) states that nearly 80% of Americans consume some type of caffeine daily. 

Caffeine works by stimulating our brain and central nervous system, its most noticeable effect being alertness.

Because it makes you feel more awake and prevents the onset of tiredness, caffeine has become a popular ingredient in medicines, energy drinks, soft drinks, dessert foods, etc.

caffeine in green tea

It works by blocking the effects of a chemical compound called adenosine, which relaxes your brain and makes you feel tired/sleepy. 

But caffeine does so much more than just providing a boost of energy and keeping you awake. 

It can promote a state of arousal and focus by increasing blood adrenaline levels. 

Caffeine is also a diuretic, meaning that it can help your body flush out extra salt and water naturally by urinating more. 

The effects of caffeine often vary from one person to another, depending on their sensitivity and unique biochemistry.

caffeine in green tea

As such, some people may be more sensitive to the effects of caffeine than others. 

In addition, caffeine sensitivity tends to increase with age. 

So, you might find yourself experiencing a more intense adrenaline rush after a highly caffeinated drink as you get older. 

Potential side effects of too much caffeine include: 

  • Insomnia and restlessness
  • Headaches and dizziness
  • Dehydration and anxiety
  • Fast heart rate and increased blood pressure

How Much Caffeine Is in Green Tea?

Caffeine occurs naturally in tea plants

As such, many factors like the type of plant, its growing conditions, the way it is processed, and how it is brewed often contribute to the variation in the amount of caffeine in a cup of green tea

Generally, an 8-ounce (230ml) serving of green tea provides about 35mg of caffeine. 

However, these amounts can vary between 30-50mg of caffeine per 8-oz serving, depending on the aforementioned factors. 

For instance, tea made from older leaves contains small amounts of caffeine, while tea made from younger tea leaves contain higher amounts of caffeine. 

Caffeine can promote a state of arousal and focus by increasing blood adrenaline levels.

The type of green tea you use and how you prepare it will also determine the exact amount of caffeine in your beverage. 

For example, bagged leaves or tea bags tend to contain a higher caffeine content than loose leaf teas

This is perhaps because bagged tea leaves are crushed, so they extract and infuse more caffeine into the drink than whole tea leaves

Matcha, a powdered tea made from stone-ground green tea leaves, offers a more concentrated dose of caffeine than green tea bags and loose leaf green tea. 

But because portion sizes of powdered green tea tend to be small, i.e., 1 gram or half a teaspoon per serving, the caffeine content infused in the drink may be similar to that of bagged tea.

Other factors that determine the caffeine content of green tea include:

  • Brew time: The longer you brew or steep your tea, the more caffeine will be infused into the drink. Black tea tends to be brewed for a much longer amount of time than other types of tea. Hence it has a higher caffeine content. Green tea and white tea have a much lower caffeine content because of the shorter steep time (1-2 minutes). 


  • Water temperature: Water temperature also determines how much caffeine is in a cup of tea. Hotter water tends to result in a high caffeine level. Black tea and Pu-erh tea are brewed with very hot water and have a higher caffeine level than green tea, which is brewed with cooler water. 


  • Amount of tea leaves: The more the tea leaves added to a cup of water, the more caffeine will be present in the tea. If you are looking for a highly caffeinated drink, you can add more tea leaves into the infuser.

Why Does Green Tea Contain Caffeine?

People commonly ask whether tea contains caffeine. 

The simple answer is yes. 

The tea plant (Camellia Sinensis) produces 5-6% caffeine, which is responsible for the stimulating effect of all true teas.  

Unlike animals, plants like Camellia Sinensis are capable of producing caffeine. 

Although the science behind caffeine production by plants is complicated, scientists have studied its role in plants. 

caffeine in green tea

Firstly, caffeine acts as a pesticide by deterring critters from damaging the plant. 

The flowers of tea plants also contain some levels of caffeine. 

Experts believe that this can help insects have some memories of the flowers and may promote pollination by ensuring repeat visits. 

In addition, caffeine seems to increase the biological processes in plants, helping them grow faster and spread quickly. 

Generally, the amount of caffeine in green tea plants depends on several factors like where it was grown, the soil quality, and how much sunlight it received. 

L-Theanine and Caffeine in Green Tea

Theanine, an amino acid found naturally in tea leaves, especially green tea, has been shown to offer a number of health benefits.

These include easing anxiety, alleviating stress, and reducing insomnia. 

In contrast, caffeinated drinks like coffee do not contain l-theanine. 

While the caffeine in tea acts as a central nervous system stimulant, the L-theanine compound promotes calm and relaxation while reducing stress.

Caffeine in green tea

Green tea drinkers generally describe the effects of caffeine combined with l-theanine as more energized with reduced jitters and helping you focus. 

While all true teas contain both l-theanine and caffeine, shade-grown teas and matcha powder are perfect choices for those looking for teas with high l-theanine levels.

Comparing Green Tea to Other Caffeinated Drinks

Unlike herbal teas, all true teas are made from camellia Sinensis plant and they contain some caffeine levels

However, green tea has much less caffeine than other caffeinated drinks like a morning cup of coffee, black tea, and energy drinks

Black tea and Pu-erh tea contain the highest levels of caffeine. 

Green tea, white tea, oolong tea, and purple tea contain low levels of caffeine

But because the amount of caffeine in your brewed cup of tea typically depends on the factors discussed above, even teas in these categories may have varying caffeine levels.

Below is the amount of caffeine in an 8-oz (237ml) serving of some popular caffeinated drinks in comparison to green tea: 

  • Green tea: 30–50mg
  • Black tea: 25–110mg
  • Espresso: 240–720mg
  • Instant coffee: 27–173mg
  • Plain, brewed coffee: 102–200mg
  • Yerba mate: 65–120mg
  • Energy drinks: 50–80mg
  • Soft drinks: 2–40mg

Is Caffeine in Green Tea Good or Bad for You?

Caffeine is an extremely popular natural stimulant that is considered safe when consumed in the recommended amounts. 

The caffeine in regular green tea has been shown to offer positive effects like increasing mental alertness. 

However, drinking too much caffeine may raise some concerns. 

Large caffeine doses have been associated with negative side effects like restlessness, anxiety, jitters, headaches, and difficulty falling asleep. 

Some studies have also found that regular caffeine consumption (even moderate amounts of caffeine) may result in severe headaches and chronic migraines. 

Additionally, caffeine may be mildly addictive, and its users may be at risk of developing a dependence.

The safe limit for adults of 19 years and above is generally considered to be about 400 milligrams of caffeine per day or around 2.7 mg per pound of body weight. 

To prevent the adverse effects of caffeine, experts recommend that you space out your caffeine intake and limit the amount to about 200mg at a time. 

One 8-ounce cup of green tea offers around 50mg of caffeine. 

Therefore, 200mg of caffeine should be around four eight-ounce cups of green tea. 

Consuming the recommended caffeine limit in green tea shouldn’t lead to any adverse effects.

How Long Does the Caffeine in Green Tea Last?

Caffeine effects are noticeable after about 10 minutes, but the peak or maximum effectiveness is felt after one hour. 

For most people, the effects will gradually wear away after this. 

Please note that some people may feel the effects of caffeine for up to six hours after consumption, and this is especially true for the caffeine in green tea.

Caffeine in green tea

According to experts, caffeine levels in the body have a half-life of 5-6 hours. 

This means that 50% of the caffeine from your cup of tea may remain in your system for up to ten hours. 

However, it’s worth noting that how long caffeine remains in your system may be influenced by multiple factors like age, pregnancy, and medications.

Caffeine in Green Tea - The Bottom Line

All true teas made from the camellia Sinensis plants contain some levels of the stimulant caffeine. 

However, these levels vary significantly, with black tea having the highest caffeine content, followed by white tea, green tea, and oolong tea. 

But because the amount of caffeine in a cup of tea typically depends on many factors like how it is processed and the brewing time, caffeine levels may vary even in teas within the same category.

caffeine in green tea

Additionally, there are some Japanese green teas like matcha and covered tea which are covered before harvesting to increase the levels of caffeine than other types of green tea

The recommended safe amount of caffeine for healthy adults of 19 years is 400mg per day, which is about eight, an 8-oz serving of green tea. 

To prevent the potential side effects of caffeine and experience the full health benefits of green tea, it’s a good idea that you don’t consume the 8 cups of green tea at once.

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