In brief: Green tea contains caffeine. The amount in a cup depends on tea type, leaf quantity, water, temperature and steeping time.
What affects caffeine content?
| Factor | Effect |
|---|---|
| Leaf amount | More leaf can mean more caffeine |
| Steeping time | Longer extraction can increase the amount |
| Serving size | Larger cups increase total intake |
| Product | Varieties and harvests differ |
Analyses of commercial teas show wide variation in caffeine per serving.[1]
Caffeine and sleep
EFSA notes that around 100 mg of caffeine close to bedtime can affect sleep in some adults.[2]
Tea is not the same as green-tea extract
Concentrated extracts can deliver much higher catechin amounts and require different safety consideration.
FAQ
Is theine different from caffeine?
No.
Does mild-tasting tea automatically contain little caffeine?
No.
Can green tea disturb sleep?
Yes, especially in sensitive people.
Is matcha low in caffeine?
Not automatically; the whole powder is consumed.
Conclusion
Actual serving size and preparation matter most. Caffeine-sensitive people should pay attention to amount and timing rather than tea colour.
