Does Green Tea Have Caffeine?

Medically reviewed by Aviv Joshua, MS

Green tea is not naturally caffeine-free. Green tea contains an average of 29 milligrams (mg) of caffeine in an 8-ounce cup, but the amount can vary. Black tea typically has more caffeine at 47 mg per 8 ounces.

Green tea and black tea are the most common caffeinated teas. Both are produced from Camellia sinensis leaves. Black and green tea leaves differ in the degree of oxidation (a chemical reaction) they are exposed to before drying. In addition, black tea is fermented (sugar molecules are broken down through natural processes), and green tea is not.

Research supports various health benefits of green tea, including weight loss, improved cognition, and cancer prevention.

This article covers green tea's caffeine content, decaffeinated tea, green tea's health benefits, and more.

How Much Caffeine Is in Green Tea?

Caffeine is the most widely consumed stimulant. It is naturally found in tea and coffee. Coffee contains up to 3 times more caffeine than green tea.

One 8-ounce cup of brewed green tea contains 20 to 44 mg of caffeine. Bagged teas often have more caffeine than loose teas, but the amount of caffeine will vary depending on the tea plant and other factors, such as growing conditions, processing, and brewing.

Caffeine is found naturally in the plants used to make coffee, tea, and chocolate. It is available in various plants and trees used to make beverages and flavorings, such as:

• Cola acuminate, the cola tree

• Theobroma cacao, the cacao tree

• Paullinia cupana, the guarana plant

• Ilex paraguariensis, the source of yerba mate

Caffeine may also be added as an ingredient to various foods and beverages. Caffeine is also available in dietary supplements.

What Affects How Much Caffeine Is in Green Tea?

The caffeine content in green tea varies depending on the type, processing, quality, and how long you steep the tea bag or tea leaves (soak in boiling water), as follows:

• Type: The variety of green tea can influence its caffeine content. For example, powdered matcha tea tends to have more caffeine than other types of green tea.

• Brewing time: The longer the tea is brewed and steeped, the more caffeine will be extracted from the tea bags or leaves.

• Leaf age/processing: Younger, smaller tea leaves will have more caffeine than older ones. The length of processing may also influence caffeine amounts.

• Tea quality: Higher quality green tea brands will have more caffeine because younger, smaller tea leaves are used to make them.

Is There Decaffeinated Green Tea?

Decaffeinated green tea might be an alternative if you want to enjoy the benefits of green without caffeine.

Most decaffeinated green tea is labeled as “naturally decaffeinated.” Decaffeinating involves removing most of the caffeine from the leaves while trying to maintain its flavor and health benefits. Decaffeination is done using a chemical process.

Even after being decaffeinated, green tea and other decaffeinated teas will still contain small amounts of caffeine. If you react strongly to caffeine, you may want to avoid decaffeinated teas altogether.

You might consider the following alternative non-caffeinated beverages if you are trying to avoid caffeine:

• Herbal teas: Ginseng, ginger, rosemary, sage, etc.

• Plain water: Bottled or tap

• Carbonated water

• Milk: Dairy, soy, almond, oat, rice, etc.

• Fruit and vegetable juices

• Lemonade

• Root beer (most brands, but check the label as some contain added caffeine)

• Caffeine-free homemade sodas

• Apple cider: Cold or hot

Does Green Tea Have Health Benefits?

Green tea has been touted for its health benefits—many of which are backed by research.

Such health benefits of green tea include:

• Weight loss: Green tea contains a catechin (a type of plant compound) called epigallocatechin gallate, which research suggests may help reduce body weight. Catechins may promote small changes in metabolism that may aid with weight loss.

• Cognition benefits: Green tea has ingredients that may improve brain function, cognition, and brain function. These ingredients include l-theanine and caffeine.

• Reduced cancer risk: Some evidence suggests drinking green tea may reduce the risk for some types of cancer, including lung cancer and ovarian cancer.

• Improved oral health: Some evidence suggests that drinking tea or using green tea extract could be linked to better oral health.

• Heart health protection: The catechins in green tea have anti-inflammatory properties, which researchers believe target free radicals (destructive unstable molecules) while inhibiting enzymes (substances that cause certain chemical reactions) that promote oxidation and inducing antioxidant enzymes (that reduce harm from free radicals) to protect heart health.

• Lowers cholesterol: Green tea consumption may help lower total cholesterol and low-density lipoprotein (LDL) cholesterol ("bad cholesterol").

• May help you live longer: Green tea may contain protective active substances that help reduce the risk of death from all causes.
  

How Can Caffeine Affect You?

Caffeine has a wide variety of health benefits, but it also has adverse side effects.

Positive effects of caffeine consumption include:

• Alertness: Caffeine can help improve alertness by blocking neurotransmitters (chemicals that communicate between nerve cells) that make you feel tired.

• Improved blood sugar levels: Some evidence suggests caffeine consumption may regulate sugar levels.

• Improved metabolism: Caffeine affects how fats are generated and broken down in the body.

• Enhanced exercise performance: Research has shown that caffeine can enhance exercise performance, especially for aerobic exercise.
  

Related: Everything You Need to Know About Caffeine

Caffeine is associated with several health issues, including:

• Sleep issues: Caffeine can block the effects of the neurotransmitter adenosine, which regulates sleep. This can affect sleep quality, especially when consumed close to bedtime.

• Anxiety: In people sensitive to caffeine, doses of 400 mg of caffeine per day can cause nervousness and speed up heart rate. People who have an underlying anxiety or panic disorder have a higher risk of this effect from caffeine.

• Increased blood pressure and blood flow: Caffeine can stimulate the heart and increase blood pressure and blood flow, especially for people who do not typically consume it. It may cause palpitations (sensations that your heart is racing or pounding) or extra beats from the heart, shakiness, dizziness, nervousness, or irritability. Fortunately, most of these effects are temporary. However, if symptoms last a half hour or longer or worsen, you should seek immediate medical attention.

• Pregnancy troubles: Caffeine consumption in pregnancy can lead to high caffeine levels in the fetus. The American College of Obstetricians and Gynecologists (ACOG) recommends moderate levels of caffeine during pregnancy—no more than 200 mg or about 2 cups of coffee—as anything higher has been linked to the risk of miscarriage or preterm birth.

• Digestive problems: Some people find that caffeine can lead to stomach troubles, including stomachache and diarrhea.

• May lead to dependence: Regular intake of caffeine may lead to dependence. If you abruptly stop consuming caffeine, you may experience withdrawal symptoms, such as fatigue, irritability, and headaches.

• Drug interactions: Caffeine may interact with some medicines. Medications that may interact negatively with caffeine include some cardiac drugs, anti-seizure medicines, levothyroxine (thyroid hormone), and blood thinners. Discuss your caffeine intake with a healthcare provider when being prescribed medications.

Related: Does Tea Lower Blood Pressure?

How Much Is Too Much?

A daily intake of 400 mg of caffeine or less is usually considered safe for most healthy adults. That is equal to about 14 cups of green tea. The limits for teens and children are much longer at 100 and 2.5 mg, respectively.

Caffeine toxicity can occur if someone consumes 1 gram (g), equal to 1,000 milligrams, or more of caffeine in one dose. Consuming 2 g or more at one time is believed to be dangerous and requires hospitalization. Doses of 5 g or more could be lethal.

Toxicity is rare with the consumption of caffeinated drinks. Higher levels are typically seen with caffeine supplements.

Related: Are You Allergic to Green Tea?

Summary

Green tea is made from Camellia sinensis leaves. The amount of caffeine in green tea varies between blends and averages about 29 mg per cup. This is considered smaller than black tea and other caffeinated beverages. The caffeine content in green tea varies based on brand and type, processing quality, and steeping time.

If you want to enjoy the benefits of green tea but want to avoid caffeine, you might consider its decaffeinated version. However, it should be noted that decaffeinated tea may still contain small amounts of caffeine.

Scientific research supports the belief that green tea has many health benefits. These benefits include boosting alertness, improving cognition and heart health, reducing cancer risk, and promoting weight loss.

A daily intake of 400 mg of caffeine is considered safe for most adults. The limits for children and teenagers are much lower.

While caffeine toxicity is rare, some people should avoid caffeine. This includes people who are caffeine-sensitive, pregnant people, people with anxiety and sleep troubles, and those taking medications that may interact negatively with caffeine.

Read the original article on Verywell Health.