Magnesium L-Threonate
Commonly used for
FocusHealthy AgingBrain Fog
Where to Buy
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The cheapest product is usually low quality, but more expensive doesn’t always mean better.
What is it? / Overview
Magnesium L-threonate was developed specifically because animal research found it raises brain magnesium levels more effectively than other magnesium forms, which in that research was linked to improved synaptic plasticity and learning. Human cognitive-outcome evidence is still preliminary and smaller in scale than the animal data — this is a reasonable option for someone specifically interested in the cognitive angle, not a better general-purpose magnesium source than glycinate for sleep, cramps, or overall intake.
How is it used? / Administration
Form: Magnesium L-threonate (branded as Magtein)
Typical dose studied: 1,500–2,000 mg magnesium L-threonate/day (providing roughly 144 mg elemental magnesium)
Timing: Any time; some take it in the evening given proposed cognitive/sleep-supportive effects, though timing-specific evidence is limited
Marketed primarily for its cognitive/brain-health rationale, not as a superior general magnesium source. For sleep, muscle cramps, or general magnesium repletion, Magnesium Glycinate (already in database) is equally or better supported and typically less expensive per elemental mg.
How well does it work? / Evidence
? Emerging / limited evidence
Who should avoid it?
Avoid with: Chronic kidney disease (Stage 3, 4, or 5) — NOT on dialysis; Dialysis (Hemodialysis or Peritoneal Dialysis)
Interacts with: Separate from levothyroxine, tetracyclines, fluoroquinolones, and bisphosphonates by 2–4 hrs
Already taking it? Check total elemental magnesium across all sources — L-threonate provides meaningfully less elemental magnesium per gram than glycinate or oxide, so switching forms without adjusting for this can under- or over-shoot total intake.
Research & references
Slutsky I et al. (2010). Enhancement of Learning and Memory by Elevating Brain Magnesium. Neuron. Liu G et al. (2016). Efficacy and Safety of MMFS-01, a Synapse Density Enhancer, for Treating Cognitive Impairment in Older Adults. Journal of Alzheimer's Disease. NIH Office of Dietary Supplements: Magnesium Fact Sheet.
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