# L-Theanine |  | Theanine, commonly known as **L-Theanine** and sometimes L-gamma-glutamylethylamide or N5-ethyl-L-glutamine, is an amino acid analogue of the proteinogenic amino acids L-glutamate and L-glutamine and is found primarily in particular plant and fungal species. It was discovered as a constituent of green tea in 1949 and isolated from gyokuro leaves in 1950, thus rendering it a natural product. It constitutes about 1–2% of the dry weight of green tea leaves. | |-|-| | | wikipedia:: [Theanine](https://en.wikipedia.org/wiki/Theanine) |