Quantity of L-theanine included in one bottle of Coffiest: 75 mg
When L-theanine is combined with caffeine it enhances concentration and improves reaction times while producing a calming effect.
How it works in the body
First isolated in 1950, L-theanine is an amino acid found in the leaves of the tea plant (camellia sinensis) which has been shown to temporarily enhance concentration and improve reaction time in users. Although theanine has a negligible effect when consumed on its own, it shares space in the tea leaf with caffeine, the presence of which amplifies theanine’s cognition-boosting properties. In addition, theanine seems to have a calming effect which may help mitigate the less desirable side effects of caffeine consumption.
Theanine, as an analog of glutamate, can be converted into the latter in the liver or intestine. Theanine can bypass digestion and enter the brain directly, where its structural similarity allows it to bind with and act on glutamate receptors.
L-theanine is the more frequently occurring of the theanine molecule’s two forms and as such its properties have been more thoroughly researched. Only L-theanine is produced by tea plants, but its mirror-image version D-theanine can be synthesized as well. Although D-theanine is also in use as a theanine supplement, it has been the subject of far less study and its effects may differ from those of L-theanine.