Human studies have found that supplemental L-theanine can cross the blood-brain barrier and promotes the generation of alpha brain waves, suggesting a state of relaxation.

Controlled clinical trials have shown that L-theanine can support a healthy stress response by improving stress perception and resilience. The stress-buffering mechanisms of L-theanine have been connected to the ability of L-theanine to increase serotonin and dopamine production in the brain. L-theanine has also been shown to significantly increase alpha brain wave activity, which is critical for increasing attention as well as promoting a sense of relaxation.

In a study using 16 healthy volunteers, electroencephalograph (EEG) readings of participants were recorded following the ingestion of 50 mg of L-theanine. The researchers found a greater increase in alpha brain wave activity versus placebo. L-theanine has also been shown to have a protective effect for nerve cells and reduces excitatory glutamate activity in the brain.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.