L-theanine (γ-glutamylethylamide) is a water-soluble, for glutamic similar amino acid.
It occurs almost exclusively in the tea plant (Camellia sinensis) and partly determines the taste of tea. Dried green tea, enriched with L-theanine than black tea contains about 1-2% L-theanine.
L-theanine is a free amino acid (which is not incorporated into body proteins) with a beneficial effect on the health. In order to exploit the beneficial effects of this unique amino acid optimally is L-theanine as a dietary supplement available.
Not everyone is drinking large amounts of green tea daily, needed to get within a relevant amount of L-theanine.
Do not use L-theanine supplement during pregnancy or lactation