“Magnesium supplementation improves sleep”

## The Evidence A 2012 double-blind RCT (Abbasi et al., *Journal of Research in Medical Sciences*) in 46 elderly subjects found 500mg magnesium oxide for 8 weeks significantly improved sleep efficiency, sleep time, sleep onset latency, and morning serum renin and melatonin compared to placebo. A 2022 review in *BMC Psychiatry* (Arab et al.) concluded that magnesium supplementation has a significant positive effect on subjective sleep quality measures (Pittsburgh Sleep Quality Index), but noted that most evidence comes from elderly populations and those with magnesium deficiency. ## Mechanisms Magnesium is a cofactor for GABA receptors (the brain's main inhibitory pathway) and influences melatonin synthesis. It also reduces cortisol and blocks NMDA receptors, promoting neurological calm. Deficiency leads to neurological excitability. ## Practical Note About 50% of Americans consume less than the RDA for magnesium. Food sources (dark leafy greens, nuts, seeds, legumes) are preferable. Supplementing with magnesium glycinate or threonate is better tolerated than oxide for gut-sensitive individuals.