Does Green Tea Contain Caffeine?
Yes, green tea contains caffeine, typically ranging from 15-50 mg per 8 oz (237 mL) serving, which is lower than coffee but still significant. 1
Caffeine Content in Green Tea
Green tea is a natural source of caffeine, though at lower concentrations than black tea or coffee:
- Brewed green tea contains 15-50 mg of caffeine per 8 oz (237 mL) serving 1
- Research studies have documented green tea caffeine levels ranging from 14-61 mg per serving (6-8 oz), with considerable variability depending on brewing conditions and tea variety 2
- Green tea caffeine content (11-20 mg/g of dry matter) is significantly lower than black tea (22-28 mg/g of dry matter) due to less fermentation 3
- The average caffeine content in green tea is approximately 3% of dry leaf weight 4
Factors Affecting Caffeine Levels
The actual caffeine concentration in your cup of green tea varies based on:
- Steep time: Longer brewing extracts more caffeine from the leaves 2
- Serving size: 6 oz versus 8 oz servings contain proportionally similar caffeine concentrations per ounce 2
- Tea variety and processing: Different cultivars and manufacturing methods produce variable caffeine levels 3
- Leaf age and storage conditions: Agronomic factors and post-harvest handling affect final caffeine content 3
Clinical Context
Green tea contributes approximately 17% of total caffeine intake in the U.S. population (27.9 mg/d on average), making it the third most common caffeine source after coffee and soft drinks 1
For individuals monitoring caffeine intake:
- Decaffeinated green tea contains ≤10 mg caffeine per 8 oz serving 1
- Herbal teas contain no detectable caffeine as they are not derived from the Camellia sinensis plant 2
- Green tea's caffeine provides central nervous system stimulation and mental alertness, similar to other caffeinated beverages 1, 5
Important Distinction
Green tea's health benefits derive primarily from its rich catechin and polyphenol content, not from caffeine. 6 The catechins (including EGCG) constitute up to 30% of dry leaf weight and provide antioxidant, anti-inflammatory, and metabolic benefits that are independent of caffeine's stimulant effects 4, 7