What is theanine?

Theanine is also known as L-γ-glutamylethylamide and N5-ethyl-L-glutamine. It is unique amino acid present almost exclusively in the tea plant (Camellia sinensis), where typically occurs in amounts estimated from 1 to 2% by dry weight.

It is thought that theanine makes a significant contribution of the flavor of the tea beverage which is dominated by the bitter taste of the polyphenols and caffeine. L-Theanine is absorbed through the intestinal tract and is hydrolyzed to glutamic acid and ethylamine in the kidney.

L-Theanine may have mood-modulating activity and is able to cross the blood brain-barrier and improve human brain’s reaction to stress. This amino acid actually acts antagonistically against the stimulatory effects of caffeine on the nervous system.

It may also play a role in the formation of GABA, a neurotransmitter that is important for sleep, and memory. L-Theanine also affects the balance of dopamine and serotonin in the brain to create a relaxation effect.
What is theanine?

Theanine in tea

Theanine is a unique free amino acid found only in tea leaves. It is the analogue of glutamine.

Theanine is found in every part of the tea except for the fruit and contributes the major part of amino acids in tea.

Theanine is present in highest concentration in the roots of tea plants, but is absent from tea seeds in which the principal amino acid is pipecolic acid.

Theanine naturally occurs in tea nearly exclusively as L-theanine. The other one is D-theanine but present in lower concentration in tea leaves.

There are many published studies measuring these psycho-stimulant effects of caffeine, and a clear result is that caffeine compared with placebo increases alertness, reduce fatigue and sleepiness and improves performance especially ion vigilance and psychomotor.

It has been a common view that drinking green tea imparts a sense do well being and relaxation.

This may be related to the fact that after administration of L-theanine, the intracerebral gamma-amino butyric acid level, which has antioxidant activity, significantly increases in as little as 30 min.
Theanine in tea