L-theanine is an amino acid isolated from green tea (Camilla sinensis) and some mushroom varieties. It has a neuroprotective effect which is important in today’s world of ever-increasing Alzheimer/dementia patients. With stress being so high, L-theanine also supports a more balanced mood to face life’s many challenges.
Studies have shown L-theanine can help improve cognitive function including decision making and verbal fluency. Additionally, it can help you fall asleep faster. L-theanine also helps reduce overall stress and can increase attentiveness and supports a healthy mood by lowering anxiety and depression scores in a healthy adult population when compared to a placebo.
According to human and animal toxicity studies, L-theanine is well-tolerated. L-theanine is found in single supplements or in formula blends supportive of overall mood, mental health, or improved sleep. Green tea also contains L-theanine. Gyokuro and matcha green teas have been shown to contain more L-theanine than sencha, so if you are looking to add green tea to your diet you may find more benefit from choosing one with more L-theanine.
Baba, Yoshitake, et al. 2021. “Effects of l-Theanine on Cognitive Function in Middle-Aged and Older Subjects: A Randomized Placebo-Controlled Study.” Journal of Medicinal Food, 24(4); 333-341. doi:10.1089/jmf.2020.4803.
Hidese, Shinsuke, et al. 2019. “Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial.” Nutrients, Oct. 3, 2019, 11(10); 2362. doi:10.3390/nu11102362.
Williams, Jackson, et al. 2016. “L-Theanine as a Functional Food Additive: Its Role in Disease Prevention and Health Promotion.” Beverages, 2(2); 13. https://doi.org/10.3390/beverages2020013.