Green tea contains caffeine, but the amount is not fixed. It varies with the tea variety, growing and processing conditions, leaf quantity, water temperature, steeping time, serving size, and whether you consume the whole leaf as with matcha.
How much caffeine is in green tea?
There is no single number that applies to every cup. Brewed green tea commonly contains less caffeine than brewed coffee, but products and serving sizes vary enough that the label or manufacturer information is the best source when caffeine intake matters to you.
The U.S. Food and Drug Administration notes that for most adults, up to about 400 mg of caffeine per day is not generally associated with negative effects, but individual sensitivity varies substantially.
What changes caffeine content?
- Amount of tea: using more leaf generally increases caffeine in the finished drink.
- Water temperature: hotter water can extract caffeine more quickly.
- Steeping time: longer infusion can increase total extraction.
- Tea style and leaf material: cultivars, harvest timing, shading, processing, and leaf size can all affect caffeine.
- Matcha: because the powdered leaf itself is consumed, caffeine exposure can differ from a strained infusion.
- Serving size: a large café drink may contain more caffeine simply because there is more tea.
Is green-tea caffeine different from coffee caffeine?
Caffeine is the same stimulant molecule regardless of whether it comes from tea or coffee. Green tea also contains other compounds, including L-theanine and catechins, which can affect the drinking experience, but that does not make caffeine itself medically safer or uniquely “better.”
How to reduce caffeine from green tea
- choose a smaller serving;
- use less tea leaf or powder;
- brew for a shorter time when the tea still tastes good to you;
- choose a lower-caffeine or decaffeinated product when available; and
- avoid stacking green tea with coffee, energy drinks, pre-workout products, or other caffeine sources if you are sensitive.
Decaf is not caffeine-free
Decaffeinated tea still contains some caffeine. If you need to avoid caffeine completely for a medical reason, check the product label and discuss suitable beverages with your healthcare professional.
Signs you may be getting too much caffeine
Possible effects include insomnia, restlessness, jitteriness, headache, faster heartbeat, stomach upset, or increased anxiety. People differ greatly in sensitivity, and pregnancy, medications, age, and some medical conditions can change what amount is appropriate.
Green tea extract is not the same as a cup of tea
Concentrated green-tea extracts can deliver much larger amounts of catechins and may also contain caffeine. NCCIH reports uncommon liver injury associated mainly with green-tea extract products. Treat supplements as a separate category from ordinary brewed tea.
Sources
This guide provides general information about caffeine and green tea. Individual caffeine limits can differ.
