Researchers from the National Institute of Mental Health in Japan have found that taking Suntheanine®, a pure L-theanine dietary supplement, before bed produces a significant improvement in sleep quality. The results were released at the Society of Physiological Anthropology conference in Tokyo in late 2003 and will be presented at the 17th European Sleep Research Society (ESRS) Congress October 2004 in Prague. The research team’s findings outline the first human study showing that L-theanine, an amino acid found in green tea, can enhance the quality of actual sleep experienced by young subjects. The Japanese research team first had 22 young men (12 daytime workers, average age of 28; 10 students, average age of 26) undergo three-day acclimatization period. They then were asked to take 200 mg of Suntheanine or a placebo one hour before bedtime for six consecutive days. After subjects completed this first blinded supplementation phase they were then crossed over to receive the opposite treatment. Subjects’ sleep performance was assessed by interviews upon awakening, self-reported questionnaires and a wrist actigraph, which records bodily movement during sleep. The entire group reported a statistically significant absence of feeling exhausted and a reduced need for sleep during the Suntheanine administration period, relative to placebo.