Aspartame is the commonly used name for the artificial sweetener N-(L-α-aspartyl)-L-phenylalanine, 1-methyl ester. It was discovered when a chemist working in the Searle labs in 1965 accidentally ingested some and realized it tasted sweet. The chemist at the time was working on drugs to control ulcers! It is formed by making the dipeptide of two amino acids and then producing the methyl ester of that molecule.
It is about 200 times sweeter than sugar and so can sweeten foods without adding a lot of calories, since little is required. Aspartame is very widely used today for numerous foods and beverages, although not without controversy. For decades, there have been concerns and even conspiracy theories associated with the use of aspartame, and it has been claimed to cause numerous health problems ranging from simple headaches to cancer. Many studies over several decades, however, have consistently shown that aspartame is safe at normal levels of ingestion and it continues to be approved for use by the FDA, the EU and other worldwide regulatory agencies.