Quick Answer
Green tea contains less caffeine than black tea, with on average about 35-70 mg per 8 oz cup compared to 50-100 mg in the same serving of black tea. So while green tea is not very high in caffeine compared to other teas, it does contain a moderate amount that some people may want to limit.
Caffeine Content in Green Tea
The amount of caffeine in green tea can vary based on the specific tea leaves, brewing time, and cup size. But on average, an 8 ounce (237 ml) cup of green tea contains around 25-50 mg of caffeine.
For comparison, here are the average amounts of caffeine in other tea varieties and drinks:
| Beverage | Caffeine (mg) |
|---|---|
| Black tea | 50-100 mg per 8 oz |
| Green tea | 25-50 mg per 8 oz |
| White tea | 25-50 mg per 8 oz |
| Oolong tea | 12-55 mg per 8 oz |
| Decaffeinated tea | 2-4 mg per 8 oz |
| Coffee | 95-200 mg per 8 oz |
| Energy drinks | 50-100 mg per 8 oz |
| Cocoa beverage | 3-32 mg per 8 oz |
As you can see, green tea contains less caffeine than black tea and coffee, but more than herbal teas which contain no caffeine.
Factors Affecting Caffeine Levels in Green Tea
Several factors can influence the caffeine content in green tea:
- Tea variety – The cultivar, growing conditions and processing can affect caffeine levels.
- Brewing time – The longer tea steeps, the more caffeine is released from the leaves.
- Water temperature – Hotter water extracts more caffeine from the tea.
- Loose vs bagged – Loose leaf teas tend to be higher in caffeine than bagged.
- Serving size – Drinking a 16 oz cup will have double the caffeine of an 8 oz cup.
So green tea brewed hot for a long time in large servings will be at the higher end of the caffeine range. Cold brewed, weak green tea will be at the lower caffeine end.
Caffeine Sensitivity
While green tea is not extremely high in caffeine, some individuals are more sensitive to the effects of caffeine. Caffeine sensitivity is determined by factors like:
- Natural tolerance – Some people are just more susceptible to caffeine’s effects.
- Weight – Caffeine has a greater effect on people who weigh less.
- Age – Sensitivity may increase with age.
- Medical conditions – Anxiety, high blood pressure, etc can be exacerbated by caffeine.
- Medications – Interactions with certain drugs may increase caffeine sensitivity.
- Genetics – Variations in certain genes can affect caffeine metabolism.
For those with higher caffeine sensitivity, even the moderate amount in green tea may cause unwanted effects like jitters, anxiety, headaches or sleep disruption.
Health Benefits of Green Tea
While green tea contains caffeine, it also provides a range of beneficial plant compounds and antioxidants:
- Flavonoids – Green tea contains catechins like epigallocatechin gallate (EGCG), which have antioxidant and anti-inflammatory properties.
- Theanine – This amino acid promotes relaxation and counters some of the jittery effects of caffeine.
- Vitamin C – Important for immune health, vitamin C is found in green tea leaves.
- Other antioxidants – Green tea contains beta-carotene, lutein, zeaxanthin and more.
Research shows these compounds have positive effects on:
- Brain health and memory
- Metabolic rate and fat burning
- Exercise endurance
- Heart health
- Lifespan
- Cancer risk
So while limiting caffeine intake is wise for some, green tea can be part of a healthy diet for many others due to its unique nutrient profile. Moderating serving sizes is key.
Caffeine Content in Matcha Green Tea
Matcha is a type of powdered, high-grade green tea grown and processed in Japan. Since matcha is made from ground whole tea leaves, matcha contains even more caffeine than regular green tea prepared with steeped leaves.
A 1⁄2 teaspoon serving can contain around 35 mg of caffeine. A single serving of matcha is typically 1-2 teaspoons. So drinking matcha may provide 70+ mg of caffeine compared to about 35mg in regular green tea.
Those sensitive to caffeine may want to avoid drinking multiple servings of matcha per day. But matcha also provides higher doses of antioxidants like EGCG.
Decaffeinated Green Tea
For those monitoring caffeine intake, decaffeinated green tea is an option. Decaf green tea goes through a process to remove nearly all of the caffeine, typically about 97% of it. This leaves only trace amounts, around 2-4 mg per 8 oz cup.
Decaf green tea still provides antioxidants like EGCG, though they may be reduced by around 15% from the decaffeination process. But levels remain high enough to still benefit health.
Green Tea Caffeine During Pregnancy
Green tea caffeine is something pregnant women may need to limit. Health authorities recommend consuming no more than 200 mg of caffeine daily during pregnancy.
Since an 8 oz cup of green tea contains around 35 mg caffeine, 6 cups or less would fall below the recommended 200 mg max. But caffeine sensitivity varies, so some pregnant women opt to further restrict or eliminate all caffeine.
Decaf green tea is the safest bet for pregnant women who want to enjoy the antioxidants of green tea but limit caffeine intake. Consulting a doctor is wise to address any concerns.
Does Green Tea Make You Pee More?
The caffeine in green tea is a stimulant and mild diuretic, meaning it can increase urine output and frequency of urination. So yes, the caffeine in green tea may make you need to pee more often.
However, research suggests the caffeine in green tea does not seem to increase urination as much as an equivalent amount of pure caffeine or coffee. This is likely due to tea flavonoids which counter the mild diuretic effect.
But those who drink large amounts of green tea, have existing bladder issues, or are sensitive to caffeine are still more likely to experience a laxative effect.
Green Tea Caffeine Withdrawal and Tolerance
For regular green tea drinkers, abruptly stopping caffeine intake can sometimes cause withdrawal symptoms for a few days, including:
- Headaches
- Fatigue
- Irritability
- Difficulty concentrating
- Depressed mood
- Muscle pain or stiffness
Gradually decreasing green tea over a week instead of stopping abruptly can minimize symptoms. Tolerance to the effects of caffeine also builds over time with regular use.
Best Time to Drink Green Tea
To avoid disrupting sleep, it is best to avoid drinking green tea in the late afternoon or evening, especially for caffeine-sensitive individuals. Green tea is optimally consumed 1-2 hours after waking up or before early afternoon for the energizing benefits of caffeine without interference on nighttime rest.
However, the L-theanine in green tea balances out some of the jitteriness of caffeine and prolongs the wakefulness effect longer than caffeine alone. So the timing does not need to be as strict as with drinks that contain only caffeine without these moderating compounds.
Is Green Tea Keto-Friendly?
Pure green tea without any sweeteners or additives is keto-friendly. Since green tea contains virtually no carbs, calories, or sugar, it fits into a ketogenic diet limiting carb intake to reach ketosis for weight loss or health benefits.
Adding milk, creamer, or sweeteners like sugar or honey will add carbs and affect ketosis. But a touch of stevia, erythritol, or lemon can provide zero or minimal carbs while adding flavor.
Green tea may even modestly boost ketosis by raising metabolism and fat burning, especially when paired with caffeine and regular exercise.
Conclusion
Green tea contains moderate amounts of caffeine, typically around 25-50 mg per 8 oz cup. While not extremely high in caffeine, green tea exceeds decaf varieties and approaches coffeehouse coffee levels, so individuals sensitive to caffeine may want to limit intake.
However, green tea provides a constellation of plant nutrients, flavonoids, and antioxidants that benefit health. Moderating serving size based on caffeine sensitivity and avoiding drinking it in the late evening are wise precautions for most people to enjoy green tea as part of an overall healthy lifestyle.
