NOW Foods Magtein Magnesium L-Threonate is the 'grab it off the shelf' pick in the Magtein category — the easiest licensed-Magtein bottle to find in stock, online or in a US health store, from a brand whose entire reputation is value and consistency at scale. NOW is a 50+ year family-owned manufacturer that runs its own in-house analytical and microbiology labs (a real, documented QC operation, not outsourced paperwork) on top of GMP-certified manufacturing. The Magtein inside is the same patent-verified L-threonate form as Life Extension's Neuro-Mag, delivered at the exact Liu 2016 trial dose: 2000 mg Magtein, 144 mg elemental magnesium, 3 capsules. The one honest catch is price — at ~$32/month (~$1.07 per serving) it runs slightly above Neuro-Mag and Jarrow, because the licensed-Magtein raw material dominates the cost and compresses NOW's usual value edge on this particular SKU.
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Read the complete Magnesium Glycinate guide →Licensed, patent-verified Magtein L-threonate — the specific stereoisomer the published RCTs (Slutsky 2010, Liu 2016) actually measured. NOW sources it from Magceutics, the patent holder, the same supplier behind Life Extension's Neuro-Mag. The molecule does the same thing in the body regardless of which trusted brand puts it in the capsule.
144 mg elemental magnesium per 3-cap serving (2000 mg Magtein). The same trial dose as Neuro-Mag and the rest of the licensed-Magtein field. Low elemental yield is the threonate trade-off for blood-brain-barrier crossing — threonate is only ~7% magnesium by weight. Right for cognition; wrong form for peripheral magnesium needs, where you'd stack a bisglycinate.
This is where NOW earns its trusted-value reputation: the company runs its OWN in-house analytical and microbiology labs, testing raw materials and finished products in addition to GMP-certified manufacturing — unusually deep QC infrastructure for the price tier, from a 50+ year family-owned operation. It stops just short of Life Extension's published per-batch assays, but NOW's testing rigor is well-documented and a genuine strength.
$32/month at 3 caps/day = ~$1.07 per 144 mg elemental serving. NOW's whole identity is value-per-mg, and on most substances it's the category-low price — but on this threonate SKU the licensed-Magtein raw-material cost dominates and lands it slightly above Neuro-Mag (~$0.93) and Jarrow (~$1.00), and well above Double Wood (~$0.77). Fair, not a bargain. The value strength is the brand and its QC, not this SKU's sticker.
Same licensed Magtein form means the same trial-validated cognitive-response profile. Liu 2016's ~9% executive-function improvement at 12 weeks applies identically, and subjective effects (sharper recall, less brain fog) land in the same 4-6 week window. NOW's lot-to-lot consistency, backed by in-house testing, is a reliable floor for getting that effect batch after batch.
“Patented Magtein magnesium L-threonate.”
NOW licenses Magtein from Magceutics, the patent holder — the same source as the premium picks. The patent form is on-label and verifiable via Magtein's brand registry; it's the stereoisomer the RCTs measured.
“Supports cognitive health, memory, and learning.”
Liu 2016 (Journal of Alzheimer's Disease) measured ~9% improvement on executive-function tests after 12 weeks at this exact 2000 mg Magtein dose. NOW's bottle delivers the trial-protocol dose accurately, so the cognitive claim is trial-backed.
“Crosses the blood-brain barrier to raise brain magnesium.”
Slutsky 2010 (Neuron) showed brain-magnesium levels rise only with L-threonate, not other magnesium forms. This BBB-crossing property is the foundational, evidence-based differentiator of the threonate category.
“Manufactured in NOW's GMP-certified facility with in-house testing.”
NOW operates GMP-certified manufacturing and runs its own in-house analytical and microbiology labs — a real, documented QC operation. Verifiable via FDA registration and NOW's published quality program.
“Provides a high-potency form of magnesium.”
True for Magtein potency (2000 mg compound, the full trial dose), but 'high-potency magnesium' can mislead on ELEMENTAL magnesium — this delivers only 144 mg elemental per serving. Accurate as a threonate-compound claim; potentially confusing if read as elemental Mg content.
The Magtein inside NOW's capsule is chemically identical to the Magtein inside Life Extension's Neuro-Mag and Jarrow's MagMind: same Magceutics patent, same stereoisomer, same 2000 mg trial dose. What you're choosing with NOW is the trusted-value brand and the easiest in-stock availability, not a superior or inferior molecule. Match the decision to what you actually value — a name you already trust and can find anywhere, versus squeezing the lowest per-serving price.
NOW's reputation isn't built on the cheapest possible sourcing — it's built on testing. The company runs its own analytical chemistry and microbiology labs, screening raw materials and finished products on top of GMP manufacturing, which is unusually deep QC for a value-tier price and a big part of why it's one of the most trusted shelf brands in the US. On a form whose entire value proposition is brain delivery, buying from a manufacturer that verifies its own raw materials is worth real weight.
On most substances NOW is the category-low price — value-per-mg is its identity. On threonate specifically, the licensed-Magtein raw material dominates the cost of any bottle, which compresses that edge and pushes NOW's SKU to ~$1.07 per serving — slightly above Neuro-Mag (~$0.93) and Jarrow (~$1.00), and clearly above Double Wood (~$0.77). It's still fairly priced for verified Magtein with NOW's QC behind it; just don't assume NOW automatically means cheapest here the way it usually does.
3 caps AM, or split 2 AM + 1 mid-afternoon. Don't dose at night — Magtein's brain-magnesium signal can be mildly activating and can interfere with sleep onset in sensitive users (the opposite of bisglycinate, which is sedating PM). If you're running both forms, the clean protocol is NOW Magtein AM for cognition through the day + a magnesium glycinate PM for sleep, cramps, and general magnesium status that threonate's low elemental yield can't cover.
If you want the cognition form of magnesium, prefer a household-trusted value brand, and value being able to grab it in stock at most US health stores when the boutique picks sell out, NOW is the right call. If your single deciding factor is the lowest cost-per-serving, step to Double Wood (cheaper verified Magtein). If you're drug-tested, you need an NSF Certified for Sport option. And if your real goal is sleep or a deficiency rather than cognition, the honest answer is a magnesium glycinate, not any threonate.
NOW Foods Magtein Magnesium L-Threonate is the 'grab it off the shelf' pick in a niche category where the active is identical across brands and the real decision is trust, availability, and price. The Magtein inside is the same Magceutics-patented, trial-validated form as Life Extension's Neuro-Mag and Jarrow's MagMind, delivered at the exact Liu 2016 dose — 2000 mg Magtein, 144 mg elemental, 3 capsules. There's no compromise on the molecule. What NOW adds is a 50+ year reputation as a trusted value brand, built on its own in-house analytical and microbiology labs that test raw materials and finished products — genuinely deep QC for the price tier. For buyers who want verified Magtein from a name they already trust and can find in stock at most US health stores, that combination is exactly the value, even though NOW's usual category-low pricing doesn't fully carry over to this licensed-Magtein SKU. The 'consider' verdict (not 'buy') reflects one honest knock: at ~$1.07 per serving it runs slightly above Neuro-Mag (~$0.93) and Jarrow (~$1.00), and clearly above Double Wood (~$0.77), because the licensed-Magtein raw-material cost compresses NOW's value edge here. If lowest cost-per-serving is your deciding factor, Double Wood is the cheaper verified Magtein. If availability and a trusted value brand with its own QC labs matter more — and especially when the boutique picks are out of stock — NOW is a dependable, fairly priced buy. Run it AM, give it 4-12 weeks, and pair a magnesium glycinate at night for the peripheral magnesium threonate can't reach.
Check NOW Foods · licensed Magtein · 90 vegetarian capsules on AmazonThe category-benchmark Magtein at ~$0.93/serving — same licensed form with published per-batch testing. The default cognition pick if you want the leaders' QC at a lower per-serving price.
See it on the list →The value pick at ~$0.77/serving — same licensed Magtein, NSF Certified, the cheapest verified threonate on the list. The call if lowest cost-per-serving is your deciding factor (4 caps/day).
See it on the list →Another long-trusted household brand at ~$1.00/serving — one of the original Magtein products, licensed form at the standard 3-cap trial dose. A close substitute when NOW is out of stock.
See it on the list →The foundational MIT paper for the L-threonate category: brain-magnesium levels rose only with L-threonate (not other magnesium forms), with downstream increases in NMDA-receptor density and synaptic plasticity. The basis for the BBB-crossing claim.
The human RCT anchoring the cognitive evidence: 2000 mg Magtein/day for 12 weeks improved executive function by ~9% on standardized tests vs placebo in older adults. The exact trial dose NOW's 3-cap serving matches.
Follow-up to Slutsky 2010: L-threonate-driven brain-magnesium elevation enhanced fear extinction and prefrontal synaptic plasticity, extending the mechanistic case beyond memory toward emotional regulation.
Reference trial for peripheral magnesium sleep effects — frames why a bisglycinate is the right form for sleep and the right co-stack with Magtein, which is a different category.
Population-level evidence that a large share of US adults fall below the magnesium RDA. Context for why threonate users should still ensure peripheral magnesium adequacy via diet or a glycinate co-supplement.
Magnesium is the obligate cofactor for vitamin D activation. Relevant context for Magtein users — peripheral magnesium from diet or a co-supplement is still needed to support D3 utilization.
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