L-Theanine is a free (non-protein) amino acid found in tea plants. It is the most abundant amino acid found in green tea leaves. Research on human volunteers has demonstrated that L-Theanine creates a sense of relaxation in about 30-40 minutes after ingestion via at least two different mechanisms. First, this amino acid directly stimulates the production of alpha brain waves, creating a state of deep relaxation and mental alertness similar to what is achieved through meditation. Second, L-Theanine is involved in the formation of the inhibitory neurotransmitter, gamma amino butyric acid (GABA). GABA influences the levels of two other neurotransmitters, dopamine and serotonin, producing the key relaxation effect.

In a study of mental responses to L-Theanine, brain wave topography showed that alpha waves were observed from the back to the top of a person's head (occipital and parietal regions of the brain) within approximately 40 minutes after the subjects had taken either 50 or 200 mg of L-Theanine. In a separate study, the intensity of alpha waves were determined to be dose dependent (with a 200 mg dose showing a significant increase over controls) and detectable after 30 minutes.

L-Theanine has a significant effect on the release or reduction of neurotransmitters like dopamine and serotonin, resulting in improved memory and learning ability. L-Theanine may also influence emotions due to its effects on the increased release of dopamine. L-Theanine reduces brain serotonin concentration by either curtailing serotonin synthesis or increasing degradation in the brain.

Stress Relief

People under stress can mitigate many of the harmful effects of stress with L-Theanine without becoming sedated in the process. L-Theanine doesn't make you drowsy, nor does it promote sleep because this amino acid does not produce theta waves in the brain. It should be noted that if an individual were already relaxed, taking L-Theanine would not produce further relaxation.

L-Theanine is extremely safe. There are no dietary limits on L-Theanine intake by the Japan Food Additive Association. In 1964, the Japanese Ministry of Health and Welfare approved L-Theanine for unlimited use in all foods, with the exception of infant foods.

L-Theanine is most effective in the range of 50-200 mg, with the effect being felt within 30 minutes and lasting for 8-10 hours. Individuals with high stress levels may increase their dosage of L-Theanine to at least 100 mg, with no more than 600 mg being taken in a six hour period. FDA recommends a maximum dose of 1200 mg daily. There are no known adverse reactions to L-Theanine and no drug interactions have been reported. L-Theanine is not affected by food and may be taken anytime, as needed. Because it has a mild taste, capsules may be opened and dissolved in water. Although it is probably safe for pregnant women and nursing mothers, we discourage its use by them pending conclusive research.