Benefits
Cognitive performance and working memory in adults
In 100 adults aged 18 to 45, 2 g a day for 6 weeks beat placebo on the NIH Toolbox total cognition score (p = 0.043), a working memory task (p = 0.033) and reaction time (p = 0.031), but not on the fluid or crystallised composites or a reasoning test. The quoted 7.5-year cognitive age figure is an estimate from a 2.24-point group difference. Threotech funded the trial.
Brain magnesium: raised in rats, not measured in people
In a rat study, magnesium L-threonate raised brain magnesium and improved learning and memory. No human study has measured brain or spinal fluid magnesium after taking it, and a later rat comparison reported that magnesium acetyl-taurate raised tissue magnesium more than magnesium L-threonate, so the claim that it is the only form reaching the brain is untested in people.
Sleep: one questionnaire improved, tracked sleep did not
In the 6-week trial, sleep-related impairment improved against placebo (p = 0.043), but sleep disturbance, restorative sleep and all ring-tracked sleep measures did not. In a 21-day trial in 80 adults aged 35 to 55, 1 g a day gave better ring-tracked deep and REM sleep scores, with the supplement group holding steady while placebo declined. AIDP funded that trial and employs three of its six authors.
Stress and anxiety: not demonstrated in these trials
In the 6-week trial, self-reported general wellbeing did not differ from placebo (p = 0.436); resting heart rate fell and heart rate variability rose, which are body readings rather than mood scores. In a 12-week trial of a different magnesium L-threonate product in older adults, the placebo group improved so much that effects on anxiety could not be determined.
Mechanism of action
Brain magnesium and synapses (rodent evidence)
In rats, magnesium L-threonate raised brain magnesium, increased synapse density in the hippocampus, enhanced NMDA receptor signaling linked to learning, and improved short- and long-term memory. Whether any of this happens in a person taking 2 g a day has not been measured, and a 2026 rat comparison found another magnesium salt raised tissue magnesium more.
Clinical trials
Randomised, double-blind, placebo-controlled parallel-arm trial of Magtein® 2 g/day for 6 weeks; outcomes were the NIH Toolbox cognition battery, Raven's Progressive Matrices 2, PROMIS sleep questionnaires, a reaction time task and Oura ring data (Lopresti et al. 2025, Front Nutr).
100 adults aged 18 to 45 with self-reported poor sleep; they were not selected for cognitive complaints.
Magtein® beat placebo on the NIH Toolbox total cognition composite (p = 0.043), the list sorting working memory task (p = 0.033) and reaction time (p = 0.031). The fluid composite (p = 0.277), crystallised composite (p = 0.111) and Raven's matrices (p = 0.953) did not differ. The 7.5-year cognitive age figure converts a 2.24-point group difference at week 6 using an assumed decline of 0.3 points a year. Of the sleep measures, only PROMIS sleep-related impairment improved (p = 0.043); no Oura ring sleep reading differed. Resting heart rate fell and heart rate variability rose. Funded by Threotech Inc., which supplied the product and helped design the study.
12-week randomised, double-blind, placebo-controlled trial of MMFS-01, a magnesium L-threonate product sold as ClariMem® by Neurocentria, not Magtein® (Liu et al. 2016, J Alzheimers Dis).
Adults aged 50 to 70 with self-reported memory and concentration complaints plus anxiety and sleep difficulty; 51 randomised, 44 analysed (23 on treatment, 21 on placebo).
Overall cognitive ability improved against placebo (p = 0.003, Cohen's d = 0.91) in the 44 people who completed 12 weeks. Estimated brain age in the treated group fell 9.4 years by week 12 against 0.8 years on placebo; this is a derived figure. Effects on sleep and anxiety could not be determined because the placebo group improved as much. Funded by Neurocentria Inc. and designed jointly with the study site.
Randomized, double-blind, placebo-controlled parallel-arm trial of 1 g/day magnesium L-threonate (Magtein®, supplied by Threotech) or placebo for 21 days (Hausenblas et al. 2024, Sleep Med X).
80 adults aged 35 to 55 with self-reported sleep problems.
Oura ring deep sleep score, REM sleep score, light sleep time and several activity and readiness scores favored the supplement (p < 0.05), as did self-rated behavior on waking, energy, mood and alertness. The authors describe the supplement group as maintaining good sleep while the placebo group declined. Funded by AIDP Inc., and three of the six authors are AIDP employees; a corrigendum was published in 2025.