L-theanine is a free (non-protein) amino acid found almost exclusively in tea plants. It is the predominant amino acid in green tea leaves. The calming effect of green tea can be explained by the action of L-theanine. This amino acid actually acts antagonistically against the stimulatory effects of caffeine on the nervous system. Research has demonstrated that L-theanine creates a sense of mental and physical relaxation.
Clinical studies have shown that L-theanine is able to mitigate many of the harmful effects of stress without sedating in the process. L-theanine doesn’t promote sleep or drowsiness because this amino acid does not produce theta waves in the brain. L-Theanine has also been shown to improve memory and learning ability.
Additionally, studies have shown that L-theanine has a regulatory effect on blood pressure and it exhibits some antioxidant activity.


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