Neuro-Mag Magnesium L-Threonate

Neuro-Mag is Life Extension's long-running magnesium L-threonate supplement and one of the best-selling products in its niche on Amazon. Each three-capsule serving provides 2,000 mg of Magtein, the patented form of magnesium L-threonate, which supplies 144 mg of elemental magnesium. Magtein grew out of MIT rat research in which it raised brain magnesium and improved memory, and that is the premise behind its cognitive and sleep marketing.

The human evidence is promising but thin. In a 2024 randomized trial, 80 adults with self-reported sleep problems who took 1 g a day for three weeks scored better than placebo on sleep-tracker deep and REM sleep measures and on daytime functioning. A six-week trial published in 2026, using the same 2 g daily dose as Neuro-Mag, found better cognition and less self-reported sleep-related impairment, but no difference in sleep measured by a wearable ring. Both trials were funded by companies behind Magtein, so independent replication is still needed.

In practice, 144 mg of magnesium sits well under the NIH's 350 mg daily upper limit for supplemental magnesium, and the capsules are an easy fit for most routines. buyers most often credit Neuro-Mag with better sleep, a calmer mind and sharper focus; the recurring complaints are cramps for some users and a price many consider steep. At about $1.05 per serving at list price, it costs several times more than magnesium glycinate. Life Extension makes its products in an NSF GMP-registered facility, says it uses third-party analysis and provides certificates of analysis on request, but Neuro-Mag carries no product-level certification seal.