as patrick said, it totally depends on the vitamin, but it also depends if an individual is a male or female, and is also dependant on age. if an individual is an athlete (Ie. bodybuilder, soccer player, hockey, etc) certain vitamins are in higher demand by the body, and therefore that individual may consume higher doses than the average person. the labels on the bottles are usually good indications. if you are ever unsure, check with your pharmacist or doctor.