Betaine, also known as trimethylglycine, is a modified amino acid that serves as a cofactor in essential reactions for maintaining normal cell function. These include the production of creatine, carnitine, and epinephrine, as well as the detoxification of homocysteine. Additionally, betaine aids in maintaining cell volume and function during intense exercise, as shown in clinical studies which suggest that it can enhance endurance and optimize muscle output and performance. When incorporated into a healthy diet and exercise routine, betaine may also promote a healthy body composition.