2004 Volume 9 Issue 4 Pages 143-150
The physiological effect of L-theanine, an amino acid from tealeaves, on sleep was investigated using questionnaire and actigraph. A cross over double blind study with placebo as control was performed. Four tablets containing 200 mg of L-theanine were ingested I hour before bedtime. Recovery from fatigue and an extension in sleep-time was felt during the ingestion of L-theanine in 22 volunteers (p < 0.05). The actigraph data showed a significant improvement in sleep efficiency and (p < 0.05), and decrease of wake after sleep onset (WASO) (p < 0.05) in I O students. However, total-sleep-time was not significantly different between L-theanine and placebo treatments. The physiological effects of L-theanine on sleep was to improve sleep quality.