Safety and Efficacy of Gamma-Aminobutyric Acid from Fermented Rice Germ in Patients with Insomnia Symptoms: A Randomized, Double-Blind Trial

This study aimed to determine the subjective and objective improvements in sleep quality after treatment with gamma-aminobutyric acid (GABA; 300 mg daily) extracted from unpolished rice germ. This study was a prospective, randomized, double-blind, and placebo-controlled trial. In total, 40 patients who complained of insomnia symptoms were enrolled and randomly assigned to the GABA treatment group (n=30) or the placebo group (n=10). Polysomnography was performed, and sleep questionnaires were administered before treatment and after 4 weeks of treatment. After 4 weeks of treatment the sleep latency had decreased [13.4±15.7 min at pretreatment vs. 5.7±6.2 min at posttreatment (mean±SD), p=0.001] and the sleep efficacy had increased (79.4±12.9% vs. 86.1±10.5%, p=0.018) only in the GABA treatment group. Adverse events occurred in four subjects (10%). This study shows that treatment with unpolished-rice-germ-derived GABA improved not only the subjective sleep quality but also the objective sleep efficacy without severe adverse events.