A new study published in Pharmacology, Biochemistry and Behavior has once again confirmed that the amino acid L-theanine helps reduce anxiety, which may lead to better sleep.
The single-blind, placebo-controlled study was conducted by researchers at the University of Shizuoka’s School of Pharmaceutical Sciences. Their goal: to investigate the effects of L-theanine on the stress responses of 20 fifth-year pharmacy students who were assigned to practice in a hospital or drug store setting for 11 weeks. “Such a long-term commitment in new environment provides a stressful condition for young students,” noted the researchers.
The students were given either 200 mg. of L-theanine twice daily or a placebo for a total of 17 days: one week prior to establish a baseline plus the first 10 days of their practice program, because those days were assumed to be the most stressful. Suntheanine, a pure form of L-theanine, was used in this study. Researchers then assessed several stress markers, including the amount of the stress enzyme amylase present in their saliva, which is an indicator of psychological stress, and the amount of the students’ sleeping time.
Researchers found that while all participants reported that they felt less stressed toward the end of their 11-week practice, those who initially took Suntheanine were able to get more sleep and experienced less anxiety.
Previous studies have shown that Suntheanine supports alpha brain waves, a state often achieved by meditation where one is deeply relaxed and mentally alert. It does not cause grogginess, and has no known side effects.