Doses of green tea vary significantly, but usually range between 1-10 cups daily. The commonly used dose of green tea is based on the amount typically consumed in Asian countries, which is about 3 cups per day, providing 240-320 mg of the active ingredients, polyphenols. To make tea, people typically use 1 teaspoon of tea leaves in 8 ounces boiling water.
For headache or restoring mental alertness:
Tea providing is up to 250 mg of caffeine per day, or approximately 3 cups of tea per day.
For improving thinking:
Tea providing 60 mg of caffeine, or approximately one cup.
For reducing cholesterol:
Drinking 10 or more cups per day has been associated with decreased cholesterol levels. Theaflavin-enriched green tea extract, 375 mg daily for 12 weeks, has also been used for lowering cholesterol.
For human papilloma virus (HPV) infections of the cervix:
Green tea extract, 200 mg daily alone or in combination with topical green tea ointment, for 8-12 weeks.
For preventing Parkinson’s disease:
Men consuming 421-2716 mg total caffeine (approximately 5-33 cups of green tea) daily have the lowest risk of developing Parkinson’s disease. However, a significantly lower risk is also associated with consumption of as little as 124-208 mg of caffeine (approximately 1-3 cups of green tea) daily.
In women: more moderate caffeine consumption seems to be best, equivalent to approximately 1-4 cups of green tea per day.