A 2012, double-blind randomized clinical trial aimed to determine the efficacy of Mg supplementation to improve insomnia in the elderly. In this study, 46 elderly subjects were randomly allocated into the Mg or the placebo group and received 500 mg magnesium or placebo daily for eight weeks. Supplementation of Mg appears to improve subjective measures of insomnia such as ISI score, sleep efficiency, sleep time and sleep onset latency, and early morning awakening in elderly people.
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;17(12):1161-1169. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3703169/