The effects of magnesium L-threonate (Magtein ® ) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial.
Level 2 - randomized trial
Individual randomized double-blind placebo-controlled trial
PubMed 41601871 · doi:10.3389/fnut.2025.1729164
What was done
A two-arm, 6-week, parallel-group, randomised, double-blind, placebo-controlled trial evaluated daily supplementation with 2 g of magnesium L-threonate (Magtein) versus placebo in 100 adults aged 18 to 45 years with self-reported dissatisfied sleep. Cognitive function was measured via the NIH Cognitive Toolbox, Raven's Progressive Matrices Version 2, and a reaction time test. Sleep and wellbeing were evaluated using self-report questionnaires and physiological data (including resting heart rate and heart rate variability) collected via an Oura Ring wearable device.
What was found
Compared to placebo, magnesium L-threonate produced: - Greater improvement in overall cognitive performance on the NIH Total Cognition Composite (p = 0.043), with larger effects on working and episodic memory, and an estimated 7.5-year reduction in brain cognitive age. - Greater improvement in reaction time (p = 0.031), with no group difference on Raven's Progressive Matrices (p = 0.953). - Greater improvement in self-reported sleep-related impairment (p = 0.043), but no group differences in sleep disturbances (p = 0.316), restorative sleep (p = 0.439), or general wellbeing (p = 0.436); a subset with severe sleep problems showed improved sleep disturbances (p = 0.031). - No group differences in wearable-derived sleep outcomes, but a greater reduction in nocturnal resting heart rate (p = 0.030) and an increase in heart rate variability (p = 0.036). - No reports of significant adverse reactions.
Why it matters
This trial suggests magnesium L-threonate supplementation can modestly improve working memory, reaction time, and autonomic balance (HR and HRV) over 6 weeks in adults reporting sleep dissatisfaction, despite minimal changes in objective sleep metrics.
Limits
Modest sample size (n = 100) and short follow-up (6 weeks) restricted to adults aged 18–45. Sleep tracking relied on a consumer wearable ring rather than gold-standard polysomnography. Objective sleep outcomes and several subjective wellbeing scores showed no significant differences, and no adjustments for multiple testing were described in the abstract.
Cited by
- partial Magnesium L-threonate, L-theanine, chamomile extract, and glycine are clinically supported ingredients that can improve sleep latency, sleep maintenance, and morning refreshment.