Magnesium L-Threonate
Also known as: Magtein, MgT, magnesium threonate, L-threonic acid magnesium salt
A magnesium salt of L-threonic acid, a vitamin C metabolite, developed at MIT as a form that raises brain magnesium in animal models. It is the magnesium of choice in nootropic and memory formulas and has been studied in randomized trials in older adults with cognitive complaints and in healthy adults. Elemental content is low, about 7.2%, so a full 2,000 mg serving of compound provides roughly 144 mg of magnesium.
Research summary
Supplies magnesium with a proposed advantage in crossing into cerebrospinal fluid; magnesium modulates NMDA receptor activity and synaptic density in preclinical work.
Dosage
Daily amounts, elemental (7% of the compound is the element).
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 72 mg | 100–144 mg | 144 mg | 350 mg |
NIH ODS — UL of 350 mg applies to supplemental magnesium only, not magnesium from food
Doses are elemental magnesium; the trial dose is usually expressed as compound. 2,000 mg of magnesium L-threonate ≈ 144 mg Mg (7.2%). Liu 2016 dosed about 1,500–2,000 mg/day of compound split morning and evening for 12 weeks; Lopresti 2025 used 1,000 mg of Magtein per day. Well below the 350 mg supplemental UL at labeled doses. Often stacked with a denser magnesium form to reach a meaningful total.
Source material: synthetic (L-threonic acid magnesium salt)
As supplied: ≈ 7.2% Mg; 2,000 mg compound ≈ 144 mg Mg
Forms of Magnesium
| Form | Typical dose | Element % | Formats | Price |
|---|---|---|---|---|
| Magnesium L-Threonate | 100–144 mg | 7% | Capsule, Powder, Tablet | high |
| Magnesium Glycinate | 200–350 mg | 14% | Capsule, Powder, Tablet | low |
| Magnesium Citrate | 150–350 mg | 16% | Capsule, Powder, Tablet, Gummy, Liquid | low |
| Magnesium Oxide | 200–350 mg | 60% | Capsule, Powder, Tablet, Gummy | low |
| Magnesium Malate | 100–350 mg | 16% | Capsule, Powder, Tablet | low |
| Magnesium Chloride | 100–300 mg | 12% | Capsule, Powder, Tablet, Liquid | low |
| Magnesium Taurate | 100–300 mg | 9% | Capsule, Powder, Tablet | mid |
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Bulky and low-potency: a 2,000 mg serving fills about three size-00 capsules. Neutral taste, dissolves well in powders.
Formulation notes
Usually paired with other cognitive ingredients; no notable formulation conflicts. Separate from bisphosphonates and some antibiotics.
- Has an upper limit
Sources
- Magnesium — Health Professional Fact SheetNIH ODS
- Efficacy and Safety of MMFS-01, a Synapse Density Enhancer, for Treating Cognitive Impairment in Older Adults: A Randomized, Double-Blind, Placebo-Controlled Trial (Liu 2016)PubMed
- The effects of magnesium L-threonate (Magtein®) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial (Lopresti 2025)PubMed
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