This randomized, triple blinded and placebo-controlled study examined the effects of AlphaWave^® L-theanine on stress in healthy, moderately stressed adults. Participants received a single dose of 200 mg of L-theanine or a placebo, with a 7-day washout between the two tests. To induce stress, a mental arithmetic test (MAT) was administered before and after the dose.

The MAT induced stress, highlighted by increases in heart rate, blood pressure and self-reported stress and anxiety. AlphaWave^® L-Theanine led to a greater increase in frontal region and whole-scalp alpha power 3 h post-dose compared to placebo (p < 0.05). The changes in alpha wave activity are supported by greater decreases in salivary cortisol 1 h post-dose (p < 0.001) with AlphaWave^® L-Theanine compared to placebo.

These results show that a single dose of L-theanine is able to reduce stress in healthy adults.

Evans M, McDonald AC, Xiong L, Crowley DC, Guthrie N. A Randomized, Triple-Blind, Placebo-Controlled, Crossover Study to Investigate the Efficacy of a Single Dose of AlphaWave® L-Theanine on Stress in a Healthy Adult Population. Neurol Ther. 2021 Sep 25.

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