How is aspartame handled by the body?
Aspartame is made from aspartic acid and phenylalanine, as the methyl ester.
Upon digestion, aspartame breaks down into its components - the amino acids, aspartic acid and phenylalanine, and methanol - which are then absorbed into the blood. These components are used in the body in exactly the same ways as when they are also obtained from common foods and beverages. Neither aspartame nor its components accumulate in the body over time.
As can be seen in the charts below, the amount of aspartic acid, phenylalanine, and methanol produced during the digestion of aspartame is small compared to that which is obtained from common, everyday foods. In fact, a glass of tomato juice provides 6 times as much methanol as an equal amount of beverage sweetened with aspartame. A serving of skim milk provides about 6 times more phenylalanine and 13 times more aspartic acid than the same amount of beverage sweetened with aspartame.