Tests for the caffeine content of green tea show variations from 7 milligrams to 75 milligrams per 8 ounce servings.
Most authorities say the average is 15-40 milligrams of caffeine in green tea per cup.
References: USDA 2006, American Beverage Association 2005, Bowes and Church Food Values 2005, Mayo Clinic 2007, Bunker and McWilliams 1979.
Green tea at 15-40 milligrams per cup is low compared to:
the average cup of black tea at 40-80 milligrams
instant coffee at 50-100 milligrams per cup
drip coffee at 100-200 milligrams per cup
espresso at 100 milligrams for only two ounces (that’s 400 mgs. for the same 8 ounces)
soft drinks currently vary from 0 to 80 mgs. per 8 ounces
new energy/sports drinks average 80 mgs. per 8 ounces
over-the-counter caffeinated pain relief tablets vary from 30 mgs. to 100 mgs.
or caffeine tablets that vary from 100 mgs. to 200 mgs.