BETAINA is an amino acid – also known as trimethylglycine (TMG). It is a derivative of glycine, the simplest protein amino acid. TMG was first isolated in the 19th century from sugar beets (Beta vulgaris – beta is the Latin generic name for beets). This is where the common name betaine comes from, which over time came to refer to a whole class of compounds of this type, and TMG itself was distinguished as glycine betaine.