Summary: Caffeine is known to inhibit short-wave deep sleep. Rats given L-theanine and caffeine showed a measurable increase in short-wave sleep, counteracting the negative effects of caffeine.
Citation: L-theanine partially counteracts caffeine-induced sleep disturbances in rats, Jang HS, Jung JY, Jang IS, Jang KH, Kim SH, Ha JH, Suk K, Lee MG, Pharmacology Biochemistry and Behavior, 2012. (Abstract)
Summary: Melatonin decreased clock hour of sleep onset by 0.67 hours in adults and children with no change in wake-up time.
Citation: The use of exogenous melatonin in delayed sleep phase disorder: a meta-analysis, van Geijlswijk, Korzilius, Smits, Sleep, 2010. (Abstract)
Summary: A study of magnesium levels in mice demonstrated that sub-optimal magnesium levels decrease sleep quality as measured by EEG brain activity.
Citation: Magnesium involvement in sleep: genetic and nutritional models. Chollet D, Franken P, Raffin Y, Henrotte JG, Widmer J, Malafosse A, Tafti M., Behavior Genetics, 2001. (Abstract)
Summary: In a study of young adults, supplementation of L-theanine improved relaxation as measured by alpha brain activity.
Citation: L-theanine, a natural constituent in tea, and its effect on mental state, Nobre AC, Rao A, Owen GN, Asia Pacific Journal of Clinical Nutrition, 2008. (Abstract)
Summary: A study of 170 insomnia patients age 55 years and older showed a marked improvement in symptoms and increase in morning alertness after taking melatonin, indicating it also improves sleep quality.
Summary: Oral administration of magnesium resulted in a decrease of EEG brain wave activity in a study of 12 elderly adults.
Citation: Oral Mg(2+) supplementation reverses age-related neuroendocrine and sleep EEG changes in humans. Held K1, Antonijevic IA, Künzel H, Uhr M, Wetter TC, Golly IC, Steiger A, Murck H., Pharmacopsychiatry, 2002. (Abstract)