L-theanine is a non-proteinic amino acid that influences resting state activity and increases the alpha frequency, which has been associated with a reduced level of anxiety. It has been shown to promote a "Relaxed, yet alert, feeling at rest" (Owen et al., 2008). Evidence-based research has shown a variety of benefits from taking l-theanine. It has been shown to have a calming effect when people are under physical and psychological stress, enhance attentional capacity and mental clarity, and improve overall cognitive performance. It has also been found that l-theanine improves simple reaction time, speed of numeric working memory, word recognition, and accuracy of sentence verification.