SUPPLEMENTS·LIFE EXTENSION
Life Extension Neuro-Mag Magnesium L-Threonate
4.4 · 12,000 reviews
Editor score8.1/10
Best for: Racing-mind sleeplessness, cognitive-focused users
Active
Magnesium L-threonate (Magtein) 144mg elemental
Form
Capsule (3/serving)
Mechanism
Brain-barrier crossing form
The brain-first magnesium — L-threonate is the form studied for crossing into the brain, aimed at racing-mind nights and cognitive support.
Most magnesium forms serve the body; L-threonate (Magtein) is the one developed to raise brain magnesium levels, which is why it's the optimizer crowd's pick for the mind-won't-stop kind of sleeplessness. Life Extension is a four-decade lab-grade brand with published CoAs. The catch: three capsules per serving and a genuine price premium over glycinate.
Price across 3 retailers
Prices checked 2026-07-03amazon
AmazonBest price✓ Fast delivery · easy returns
Magnesium L-threonate (Magtein) 144mg elemental
$30.38
2026-07-03
Prices shown were last checked on 2026-07-03and can change at any time — the price on the retailer's site at checkout is the one that applies. As an Amazon Associate and affiliate we may earn a commission on purchases made through these links, at no extra cost to you.
How our prices work
We show the lowest price we found at our last check (2026-07-03) and the manufacturer's list price for comparison. Retail prices — Amazon's especially — move constantly, so treat these as a guide: the price shown on the retailer's own page at checkout is the one that applies. Tap through to see each retailer's current price.
Should you buy it?
What we like
- The only magnesium form targeting brain levels
- Lab-grade brand with published certificates
- Strong pick for racing-mind insomnia
- Stacks safely with glycinate or theanine
What to know before buying
- 3 capsules per serving
- 2-3x the price of glycinate
- Effects build slowly — patience required
At a glance
ActiveMagnesium L-threonate (Magtein) 144mg elemental
FormCapsule (3/serving)
MechanismBrain-barrier crossing form
EvidenceCognition + sleep-quality studies
Count90 capsules (30 servings)
CertificationNon-GMO, CoA published
OnsetBuilds over 2-4 weeks
Best timeEvening
Best forThe neuro-magnesium
How it scores
How our 8.1/10 breaks down — rated on the dimensions that matter most for supplements, from hands-on testing and verified specs, not the marketing.
Evidence
7/10
Dosing
8/10
Purity
9/10
Gentleness
9/10
Value
6.5/10
Compare with alternatives
Quick verdicts for the supplements most often considered alongside the Life Extension Neuro-Mag Magnesium L-Threonate.
VS·HEAD-TO-HEAD
Life Extension Neuro-Mag Magnesium L-Threonate vs Doctor's Best High Absorption Magnesium Glycinate 200mg (240ct)
The highest-rated magnesium on Amazon for sleep — glycinate form is chelated for maximum absorption without laxative effects.
→ Restless legs, muscle tension, anxiety-driven insomnia, athletes
VS·HEAD-TO-HEAD
Life Extension Neuro-Mag Magnesium L-Threonate vs NOW Magnesium Citrate 200mg
The budget workhorse — well-absorbed citrate form from a GMP-certified 50-year brand, at the lowest cost per mg in our lineup.
→ Budget magnesium, constipation-prone users
VS·HEAD-TO-HEAD
Life Extension Neuro-Mag Magnesium L-Threonate vs NOW Foods L-Theanine 200mg (120ct)
The best-value pure L-theanine — 200mg per capsule, GMP-certified, and $17 for 120 servings.
→ Anxiety-driven insomnia, ruminating minds, stackers with melatonin
Decision support · what no other comparison site has
Take the quiz · 60 secNot sure which one is right for you?
Our 60-second sleep score quiz asks 8 questions and recommends the right sleep gear for your goals. Built by sleep engineers. Free, no signup.
Frequently asked questions
L-threonate vs glycinate — real difference?
Glycinate is the relaxation workhorse at a fair price; L-threonate is the only form shown to meaningfully raise BRAIN magnesium in studies. For racing thoughts specifically, threonate is the targeted bet.
Why three capsules?
Magtein's effective studied dose (~2g compound) doesn't fit one capsule. Annoying but honest dosing.
Is the premium worth it?
Try glycinate first at a third of the price. Step up if the mind-racing component persists — that's threonate's lane.
When do effects show?
This is a build-over-weeks mineral, not a knockout pill. Give it 3-4 weeks of nightly use before judging.
Affiliate disclosure: SleepyHero earns a small commission when you buy through these links. It doesn't cost you extra. Reviews and rankings are editorial — we don't accept payment for placement.