Not medical advice. I am a software engineer, not a physician. This page documents my own protocol and the research I read while building it. Talk to a qualified clinician before changing your supplementation, diet or any treatment. Lab reference ranges quoted here vary by laboratory and by individual.
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Magnesium is involved in over 300 enzymatic reactions in the body, yet roughly 50% of the population is deficient. For brain function specifically, the challenge is that most magnesium forms (oxide, citrate, glycinate) have poor penetration of the blood-brain barrier. Magnesium L-threonate (branded as Magtein) was developed by MIT researchers specifically to solve this problem. It is the only magnesium form with published evidence showing it increases cerebrospinal fluid magnesium levels, directly enhancing synaptic density and cognitive function.
Magtein vs. Mg Glycinate: These are complementary, not competing. Magtein targets the brain (synaptic density, NMDA receptors, memory). Mg Glycinate targets muscles and the peripheral nervous system (muscle relaxation, GABA modulation, sleep). Use both for comprehensive magnesium support.
The L-threonate moiety in Magtein acts as a carrier that facilitates magnesium transport across the blood-brain barrier via specific transporters. Once in the brain, elevated magnesium concentrations produce multiple downstream effects on synaptic function and plasticity.
| Parameter | Detail |
|---|---|
| Product | NOW Foods Magtein (Magnesium L-Threonate) 2,000 mg, 180 Veg Capsules |
| Morning dose | 1 capsule pre-breakfast (66.6 mg elemental Mg) |
| Evening dose | 2 capsules pre-sleep (133.2 mg elemental Mg) |
| Total daily | 3 capsules = 2,000 mg Mg L-threonate (approx. 200 mg elemental Mg) |
| Rationale | Split dosing: morning for daytime cognitive function, larger evening dose for sleep and overnight memory consolidation |
| Duration | 6-8 weeks minimum for measurable cognitive improvements |
Slutsky, I., et al. (2010). Enhancement of learning and memory by elevating brain magnesium. Neuron, 65(2), 165-177. PubMed 20152124
Liu, G., et al. (2016). Efficacy and safety of MMFS-01, a synapse density enhancer, for treating cognitive impairment in older adults. J Alzheimers Dis, 49(4), 971-990. PubMed 24077207
Abumaria, N., et al. (2011). Effects of elevation of brain magnesium on fear conditioning, fear extinction, and synaptic plasticity in the infralimbic prefrontal cortex and lateral amygdala. J Neurosci, 31(42), 14871-14881. PubMed 26519439
A 2025 randomized, double-blind, placebo-controlled trial published in Frontiers in Nutrition found that 6 weeks of Magtein supplementation significantly improved overall cognition, cognitive age (reducing "brain age" by up to 7.5 years), working memory, and reaction time in adults with self-reported sleep dissatisfaction. The study also showed improved heart rate variability (HRV) and lower resting heart rate during sleep, indicating better autonomic recovery. A 2025 Mendelian randomization study across 250,000+ individuals found threonate to be one of the most robust cerebrospinal fluid metabolites with clear causal effects on cognitive function. The L-threonate ligand's mechanism works through glucose transporters, which enhances magnesium bioavailability and enables significant increases in brain magnesium concentrations — a property unique among magnesium forms.
| Test | Why It Matters | Details |
|---|---|---|
| Magnesium RBC (Erythrocyte) | Serum magnesium only reflects 1% of total body Mg and is a poor marker. RBC magnesium measures intracellular levels, which better correlates with tissue and brain Mg status. Optimal range: 5.2-6.5 mg/dL. | Lab Tests |
NOW Foods Magtein, Magnesium L-Threonate 2,000 mg (180 Veg Capsules) — $39.24 (morning) / $72.29 (evening bottle)
Patented Magtein form developed at MIT. Each capsule provides 666 mg Mg L-threonate (66.6 mg elemental Mg). Vegan, non-GMO.
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