L-Theanine was found to improve relaxation, modulate neurotransmitters, and inhibit excitatory neurons by improving the quality of sleep-in men, women, and children. The improvement in the quality of sleep was further reflected in the recovery from exhaustion and refreshed awakening. L-theanine can simulate improvement in sleep quality.

Supplementation of magnesium appears to improve subjective measures of insomnia such as ISI score, sleep efficiency, sleep time and sleep onset latency, early morning awakening, and likewise, insomnia objective measures such as concentration of serum renin, melatonin, and serum cortisol, in elderly people. Magnesium is important for over 300 different enzymatic reactions either as a structural cofactor. Mg intake was associated with both sleep outcomes in this longitudinal analysis Magnesium may play a role in regulating GABA, which could help promote calm and act as a sedative, to promote sleep.

Abbasi B, Kimiagar M, Sadeghniiat K, Shirazi MM, Hedayati M, Rashidkhani B. The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial. J Res Med Sci. 2012 Dec;17(12):1161-9. PMID: 23853635; PMCID: PMC3703169.