Ingredient Evidence Review
Magnesium L-threonate
Magnesium L-threonate
Last updated 2026-05-19 · 3 primary citations
Mechanism
Most magnesium supplements never make it past your stomach into your brain. Magtein® uses a special carrier (L-threonate) that gets magnesium across the blood-brain barrier. Brain magnesium is required for the kind of deep, restorative sleep that gets thinner with age — and a 2025 clinical trial showed this form measurably 'reverses' a few years of brain aging.
Why we use it
If you've taken magnesium glycinate or citrate for sleep and it didn't quite work — this is why. They support muscle relaxation; they don't reach the brain. Magtein® is specifically the brain version. It's the centerpiece of the PM packet for both sleep depth and overnight memory consolidation.
How we dose it
Hericea uses 2,000 mg per serving (per PM packet). The clinical trial range that anchors this dose is 1,500–2,000 mg/day.
2 grams of Magtein® — the only form of magnesium that has been shown to actually raise magnesium levels in the brain. UK regulators authorized this exact dose in March 2026 based on the trial data.
Quality & sourcing
Magtein® MIT-licensed; ≥25% elemental Mg-threonate; ~144 mg elemental Mg.
AIDP / ThreoTech-licensed supply. The branded form.
Cautions
- consult physicianSeparate by 2 hours from tetracycline or quinolone antibiotics.
- consult physicianReduce dose if chronic kidney conditions.
Primary literature
Slutsky I et al. (2010)
NeuronMechanism (animal)
Elevated brain magnesium via Mg-L-threonate enhanced synaptic density, short-term synaptic facilitation, and long-term potentiation in mammalian hippocampus; improved learning and memory.
The original paper that established Magtein as different from every other magnesium supplement. Note what it is: a rodent study. The human evidence is a separate and much thinner question.
PMID 20152124
Lopresti AL & Smith SJ (2026)
Front NutrSupplier-fundedRCT · 100 people · 6 weeks · Adults 18–45 with poor self-reported sleep
Magtein® for 6 weeks improved cognitive performance and produced a measurable 7.5-year reduction in estimated brain age vs placebo.
The most recent and most striking trial — brain age moved backward by 7.5 years on standardized testing. Even discounted heavily, that's a meaningful signal.
DOI 10.3389/fnut.2025.1729164
Zhang Y et al. (2022)
NutrientsRCT · 109 people
Magtein®PS formula improved every subcategory of a clinical memory test in healthy Chinese adults vs placebo.
Confirms the cognitive benefit shows up consistently across populations, not just one trial group.
PMID 36558392