Magnesium L-Threonate — The Brain-Penetrant Magnesium
Magnesium L-threonate is a patented form of magnesium (MgT) developed at MIT specifically to cross the blood-brain barrier. It is the only magnesium form shown to increase brain magnesium levels and improve synaptic density, making it the preferred form for cognitive and neuroprotective applications.
Mechanism of Action
The threonate carrier enables MgT to cross the blood-brain barrier more efficiently than other magnesium salts. In the brain, magnesium acts as an NMDA receptor gatekeeper, preventing excitotoxicity and enabling synaptic plasticity (LTP). Elevated brain magnesium increases synapse density in the prefrontal cortex and hippocampus, improving working memory and executive function.
Human Trial Evidence
A 2016 Journal of Alzheimer's Disease RCT showed MgT (2,000 mg/day providing 144 mg elemental Mg) significantly improved cognitive performance in older adults with cognitive decline over 12 weeks. A 2023 Neuron study showed MgT reversed synaptic density loss in aged mice. Human trials for Alzheimer's prevention are ongoing.
Dosing Protocol
1,500–2,000 mg/day of magnesium L-threonate (providing ~144 mg elemental magnesium). Best taken in the evening (promotes relaxation and sleep quality). Andrew Huberman takes 145 mg elemental Mg as MgT nightly. Can be combined with magnesium glycinate for broader coverage.
Safety & Contraindications
Well-tolerated. Same safety profile as other magnesium forms. At high doses: loose stools (less common than magnesium oxide). May cause drowsiness — take in the evening. Avoid in severe renal impairment. No significant drug interactions.