Mixed evidence for magnesium and sleep Original paper

Magnesium is a popular ingredient in sleep aids, despite mixed results in research. Although supplementation may improve sleep quality in older adults with low magnesium status,^[1] the effectiveness of supplementation in other groups has not been established.

This systematic review analyzed data from 9 research publications with 7,582 total participants to determine whether magnesium status is associated with sleep quality and whether supplementation had positive effects in controlled trials.

The observational evidence suggested an association between higher magnesium intake or status and better sleep quality. Among 3,262 adults in Turkey, consumption of magnesium was higher in individuals with better sleep quality. The researchers also found that urinary magnesium was an independent predictor of daytime sleepiness among 98 dialysis patients. Another study indicated that people in the highest quartile of magnesium intake among 1,487 adults had lower rates of falling asleep during the day, compared to the lowest quartile.

The results of controlled trials are inconsistent. A randomized trial with 46 older adult participants who received 500 milligrams of magnesium or a placebo for 8 weeks found that magnesium supplementation increased sleep time and sleep efficiency, with a decrease in latency. Baseline serum magnesium was 0.83 mmol/L in the intervention group, which may be considered low by some standards. The other 4 controlled trials examined in this review — some of which also had older adult cohorts — did not produce statistically significant improvements in sleep metrics.

The authors of this review suggested that larger clinical trials with longer follow-up times are needed to clarify the effect of magnesium supplementation on sleep.