Double Wood Magnesium L-Threonate (Magtein)
Magnesium L-threonate product; check the label for serving details.
Best for: matching the trial's form and dose (2 g/day)
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A 100-person randomized trial of magnesium L-threonate found better memory, reaction time and HRV, but no change in tracked sleep. Here is what it means.
A magnesium study is trending on X: 100 adults took magnesium L-threonate for six weeks and scored better on memory tests, reacted faster, and showed an estimated “brain age” 7.5 years younger than the placebo group. Their wearables showed a lower sleeping heart rate and higher HRV. It is a real randomized, double-blind trial, which is more than most supplement claims can say. But the headline leaves out an important detail: tracked sleep did not improve. Here is what the study found, what it did not, and how to choose between threonate and glycinate.
Researchers randomized 100 healthy adults aged 18–45 who were unhappy with their sleep to 2 g/day of Magtein (magnesium L-threonate) or placebo for six weeks (Frontiers in Nutrition, 2026). They measured cognition with the NIH Toolbox and Raven's matrices, reaction time, sleep and wellbeing questionnaires, and sleep data from an Oura Ring.
Strengths include randomization, placebo control, double blinding, prespecified outcomes and a reasonable size for a supplement trial. Limits include a single six-week trial in young, healthy adults, several p-values close to 0.05, a patented branded ingredient, and a “brain age” measure derived from cognitive test performance. The findings need replication in older adults before the supplement can be called brain anti-aging. That is why the evidence grade is C, not B.
Earlier work includes a 2016 pilot trial in older adults with cognitive complaints using MMFS-01, which also reported cognitive-score improvements, and rodent work from MIT showing that threonate raises brain magnesium. These findings are promising, not proof of a clinical benefit.
| Goal | Form | Evidence grade |
|---|---|---|
| Memory, focus or stress resilience (HRV) | Magnesium L-threonate | C |
| Falling asleep faster or low dietary magnesium | Magnesium glycinate | C |
| Constipation | Magnesium citrate | B for constipation |
| Meeting magnesium intake | Food first: pumpkin seeds, leafy greens, beans and nuts | A for meeting intake |
Threonate delivers relatively little elemental magnesium: 2 g Magtein is about 140–150 mg elemental magnesium. It is not the most efficient way to correct low magnesium intake. Glycinate generally provides more magnesium per dollar. Some people use glycinate for intake and sleep, and consider threonate if cognition is their goal.
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Magnesium L-threonate product; check the label for serving details.
Best for: matching the trial's form and dose (2 g/day)
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Magnesium glycinate supplement; check the label for elemental magnesium per serving.
Best for: correcting low intake and an evening routine
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Some people combine magnesium glycinate with ashwagandha. Several small trials report modest improvements in stress or sleep scores, but evidence is limited. Ashwagandha can affect thyroid hormones, is not recommended during pregnancy, and has rare reports of liver injury. Some European countries have restricted its use. If considering it, discuss safety with a clinician and avoid treating a supplement stack as a substitute for care.
Search results for KSM-66 ashwagandha; check the label and discuss safety with a clinician.
Best for: short-term stress-related sleep trouble
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This article is not medical advice.
The trial is a genuine positive signal for magnesium L-threonate and memory, and a reminder that “better sleep” headlines can describe how people feel rather than what a tracker measures. If your goal is sleep, improve the room first (see our evidence-graded sleepmaxxing guide), then consider whether magnesium glycinate fits your needs. If your goal is focus and memory, threonate has early data, but the result needs replication.
Related: Best Magnesium for Longevity 2026 · Magnesium: the underrated mineral · Sleep architecture optimization · Magnesium supplementation
Does magnesium L-threonate improve sleep? In this trial it improved daytime sleep-related impairment and HRV, but not sleep measured by a ring.
What is “brain age”? An estimate based on cognitive test scores compared with age norms. It is not a brain scan.
Can I take threonate and glycinate together? Some people use both, but keep total supplemental elemental magnesium within the recommended limit unless a clinician advises otherwise.