Abstract
PURPOSE: To assess the effects of magnesium bisglycinate supplementation on insomnia symptoms in healthy adults reporting poor sleep quality. PATIENTS AND METHODS: This randomized, double-blind, placebo-controlled trial enrolled 155 adults aged 18-65 years with self-reported poor sleep quality. Participants were randomly assigned to either magnesium bisglycinate supplementation (250 mg elemental magnesium, daily) or placebo capsules. Sleep quality was assessed using the Insomnia Severity Index (ISI) and additional psychological questionnaires at baseline and multiple time points throughout the study. Generalized linear mixed models (GLMM) adjusted for baseline ISI scores, age, sex, body mass index, and occupation were applied. RESULTS: The magnesium bisglycinate group showed a significantly greater reduction in ISI scores compared to the placebo group from baseline to Week 4 (-3.9 [95% CI: -5.8 to -2.0] vs -2.3 [95% CI: -4.1 to -0.4], respectively; p = 0.049). The effect size was small (Cohen's d = 0.2), indicating a modest benefit. Exploratory analyses suggested notably greater improvements among participants reporting lower baseline dietary magnesium intake, potentially indicating a subgroup of high responders. No significant differences were observed in other psychological outcomes. CONCLUSION: Magnesium bisglycinate supplementation modestly improved insomnia severity in adults reporting poor sleep quality. Future research should include objective sleep assessments, longer intervention periods, and better characterization of potential high responders by systematically assessing baseline dietary magnesium intake and status. CLINICAL TRIAL REGISTRATION NAME: Effect of magnesium bisglycinate supplementation on sleep and fatigue parameters in healthy adults reporting poor sleep quality; https://drks.de/search/en/trial/DRKS00031494 DRKS-ID: DRKS00031494.