https://pubmed.ncbi.nlm.nih.gov/31623400/
Hidese S, Ogawa S, Ota M, Ishida I, Yasukawa Z, Ozeki M, Kunugi
H. Effects of L-Theanine Administration on Stress-Related Symptoms
and Cognitive Functions in Healthy Adults: A Randomized Controlled
Trial. Nutrients 2019;11(10):.