Image of L-Theanine | C7H14N2O3 | Supreme Pharmavet
Chemical FormulaC7H14N2O3
Molecular weight174.2 g/mol
Names and Identifiers
PubChem Link
Traditional NameL-Theanine, L-γ-glutamylethylamide, N5-ethyl-L-glutamine
CAS Registry Number3081-61-6


Theanine, also known as L-γ-glutamylethylamide and 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 in 1950 was isolated from gyokuro leaves. Theanine provides a unique brothy or savory (umami) flavor to green tea infusions.

The name “theanine” without a prefix generally implies the enantiomer L-theanine, which is the form found in tea leaves and as a dietary supplement ingredient. Most studies have used L-theanine. The opposite enantiomer, D-theanine, has been studied less.

The regulatory status of theanine varies by country. In Japan, L-theanine has been approved for use in all foods, including herb teas, soft drinks, desserts, etc. Restrictions apply to infant foods. In the United States, the Food and Drug Administration (FDA) considers it to be generally recognized as safe (GRAS) and allows its sale as a dietary supplement. The German Federal Institute for Risk Assessment, an agency of their Federal Ministry of Food and Agriculture, objects to the addition of L-theanine to beverages. The European Food Safety Authority EFSA advised negatively on health claims related to L-theanine and cognitive function, alleviation of psychological stress, maintenance of normal sleep, and reduction of menstrual discomfort. Therefore, health claims for L-theanine are prohibited in the European Union.

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