Effects of Oral Supplement L-Theanine on Relaxation Indexed by Alpha Brainwave

Abstract

Background: This study used electroencephalography (EEG) to measure brain wave activity to investigate the physiological impact of L-theanine, an amino acid found naturally in green tea, on a state of relaxation.

Objective: The purpose was to assess whether L-Theanine supplementation enhances relaxation by modulating brain waves in healthy middle-aged adults. This study focused on how L-Theanine affected alpha wave activities in different brain regions.

Materials and Method: Thirty healthy middle-aged participants were randomly assigned to receive either 200 mg of oral L-Theanine or a placebo. EEG recordings were obtained at baseline and 90 minutes after intake.

Results: Even though the results weren’t statistically significant, there was a clear pattern of higher alpha wave power in the L-Theanine group, especially in the left frontal and parietal cortex 90 minutes after consumption, which suggests that they were more relaxed.

Conclusion: Despite the lack of statistical significance, the findings demonstrated that L-Theanine might modulate alpha wave activity. However, this finding may require further investigation with longer usage of L-theanine supplementation and extended observation periods.