Nutricost Magtein Magnesium L-Threonate Review
#7 of 8 · 150 mg Magnesium Printed✓ Label verified · Supplement Facts read Oct 18, 2026Real retailer photo, cut out. Label unedited.
Consider it. A reasonable Magtein buy if you like a plain two-line label and 3 capsules a day. The dose is the trial dose and the magnesium figure is printed clearly. Against that, the testing claim names no lab, the licence could not be confirmed at the source, and the price sits above most of the list.
$32.95 / 90 caps (30-day supply)~$1.10 / 3-cap serving
Why It Scores 8.0 — And The Label Line Behind Each Number
Form / Magtein verification
30% of scoreThe panel names Magtein with the registered mark and prints the licence line: a trademark of, and licensed exclusively by, ThreoTech LLC, protected under a family of US patents. That is the form the cognition trials measured (Slutsky 2010, Liu 2016). We could not match Nutricost to the source: the partner selection on magtein.com lists Double Wood, Jarrow, Life Extension, Momentous, NOW and Source Naturals, which all score 9.5 here, and does not show Nutricost. It is labelled a selection, so we read it as a gap in the paper trail and not as a red flag.
- Form
- Magtein (Magnesium L-Threonate), registered mark printed on the panel; licensed exclusively by ThreoTech LLC and protected under a family of US patents (panel footer)
Elemental Mg + dose honesty
25% of scoreMagnesium 150 mg, 36% DV, is printed on its own line above Magtein 2,000 mg, and the serving is 3 capsules with 30 servings per bottle, so the dose and the supply are easy to read. The 150 mg is a few milligrams above the 144 to 147 mg the other Magtein bottles print, and 2,000 mg of Magtein is the same trial dose. It scores level with Jarrow (8.0) and below Momentous (8.5) because the front of the bottle shows only the 2,000 mg figure, and the magnesium number is on the panel and not on the front.
- Per serving
- Magnesium 150 mg (36% DV) and Magtein 2,000 mg (Daily Value not established), per 3 capsules
- Per capsule
- About 667 mg Magtein and 50 mg magnesium (per-serving amounts divided by 3)
- Servings
- 90 capsules · 30 servings of 3 capsules · 30 days at the label dose
Third-party testing + QC
20% of scoreThe bottle prints made and quality tested in the USA. Third Party Tested is on a gallery tile and the product page says ISO-accredited laboratories, but no lab is named, no certificate of analysis is linked, and no Nutricost product is in the NSF Certified for Sport brand list, the NSF/ANSI 173 listings or Clean Label Project (searched October 18, 2026). A plausible claim with no paper trail. That is above Pure North Naturals (6.5), which has the same kind of claim from a smaller brand, and below Source Naturals (7.5), Jarrow (8.0), Double Wood (8.0, NSF Contents Certified on its label) and NOW (8.5).
- Testing
- Back label: made and quality tested in the USA with globally sourced ingredients. Third Party Tested (gallery tile) and ISO-accredited laboratories (product page), no lab named, no certificate of analysis linked; no Nutricost product in NSF Certified for Sport, NSF/ANSI 173 or Clean Label Project (checked October 18, 2026)
- Certifications
- None verified. Printed seals: Vegetarian, Gluten-Free, Non-GMO (daggered), Nutricost Quality Guaranteed; gallery tile adds GMP Compliant Facility. No NSF, USP or Informed mark.
Cost per elemental mg
15% of score$32.95 for 30 servings on Oct 18, 2026: $1.10 a serving and about $0.73 per 100 mg of magnesium. Per serving that is above NOW (about $1.07) and Jarrow (about $1.00), and below Momentous (about $1.17). Because Nutricost prints 150 mg of magnesium, the cost per milligram is level with NOW, which scores 7.0. Life Extension (about $0.93, 8.0) and Double Wood (about $0.77, 8.5) are cheaper per serving. Threonate costs many times more per milligram of magnesium than a glycinate; you are paying for the form, not the magnesium.
- Price
- $32.95 for 90 capsules = $1.10 per 3-capsule serving (Amazon US, October 18, 2026)
- Cost per 100 mg
- About $0.73 per 100 mg of magnesium
Real-world response + value
10% of scoreSame Magtein at the same 2,000 mg dose, so the expected response matches the other licensed bottles: modest, slow, measured at 12 weeks in Liu 2016. The 3-capsule serving is easy to split as the label suggests. We have no bottle-specific tolerance data, and the label itself warns of sleepiness, drowsiness or headaches. Level with Source Naturals (8.5) and below Jarrow, Momentous and NOW (9.0 each), whose testing gives more confidence that every lot delivers what the panel says.
- Suggested use
- 3 capsules daily: 1 in the morning and 2 two hours before sleeping, with 8-12 oz of water; 2 capsules at night in the first week; do not exceed 4 g Magtein per day (back label)
- Other ingredients
- Hypromellose (cellulose) capsule, calcium laurate, rice extract blend (rice extract, rice hulls, gum arabic, sunflower oil), magnesium stearate (vegetable source), silica
- More Specs
- Manufacturer
- Nutricost, Vineyard, UT (back label)
Label verified. Every figure read from the Supplement Facts photo, Oct 18, 2026.
Marketing Claims Vs. Reality
2,000 mg of Magnesium L-Threonate per serving.
The panel lists Magtein (Magnesium L-Threonate) 2,000 mg per serving, and a serving is 3 capsules. That is the weight of the compound. The magnesium itself is the separate 150 mg line (36% DV).
Made with Magtein.
Magtein is named on the panel with the registered mark, and the footer carries the ThreoTech LLC licence and patent statement. We could not confirm the licence at the source: the partner selection on magtein.com (October 18, 2026) lists six brands we review and does not show Nutricost. The page calls it a selection, so absence is not proof.
Third-party tested by ISO-accredited laboratories.
Stated on Nutricost's product page, and Third Party Tested appears on a gallery tile. No lab is named, no certificate is linked, and we found no Nutricost product in NSF Certified for Sport, NSF/ANSI 173 or Clean Label Project (searched October 18, 2026).
Gluten-free, vegetarian and Non-GMO.
All three seals are printed on the bottle with a dagger, which points to the standard FDA disclaimer, and no certifier mark such as the Non-GMO Project is shown. The capsule is hypromellose, which fits the vegetarian seal.
Manufactured in a GMP-compliant facility.
A GMP Compliant Facility seal appears on a gallery tile and in the Amazon bullets. We did not check an audit or an FDA registration. For a US supplement it is a baseline, not a quality signal on its own.
What Our Test Actually Found
Two lines on the panel: 150 mg of magnesium inside 2,000 mg of Magtein
The front of the bottle says 2,000 mg per serving, which is the Magtein compound. The magnesium is the first line of the panel: 150 mg, 36% of the Daily Value. That is a few milligrams above what the other Magtein bottles print, and it does not change the picture: threonate delivers little magnesium by weight, which is why it is not the form for sleep, cramps or a deficiency. Read the panel, not the front, before you compare it with a glycinate.
The label puts two of the three capsules at night
The directions are 1 capsule in the morning and 2 capsules 2 hours before sleeping, with two capsules at night suggested for the first week and a ceiling of 4 g Magtein a day. The label also warns of sleepiness, drowsiness or headaches. Our list advises morning or early-afternoon dosing because some people find magnesium L-threonate alerting. Both can be true for different people. If you take the label schedule and it keeps you awake, move the doses earlier.
Magtein is named, but we could not match the licence at the source
The panel prints the registered mark and the ThreoTech LLC licence line, which is more than a bare mention. magtein.com shows a selection of partner brands, and Nutricost is not in it, while the six brands we scored 9.5 on this axis are. We read that as a missing paper trail, not as evidence the form is wrong. If the form is your whole reason to buy, ask Nutricost for the supplier's certificate for your lot.
Testing: printed on a tile, not proven
The bottle says made and quality tested in the USA. Third Party Tested and ISO-accredited laboratories appear on a gallery tile and on the product page, with no lab named and no certificate of analysis. We searched NSF Certified for Sport, NSF/ANSI 173 and Clean Label Project on October 18, 2026 and found no Nutricost product; Nutricost does not claim any of them. Absence from a list is not proof of failed testing. It means there is nothing for us to check.
Priced in the upper half of the list
At $1.10 a serving Nutricost costs more than Jarrow, Source Naturals, Life Extension and Double Wood and less than Momentous. Per milligram of magnesium it is level with NOW. Subscribe and Save was $29.65 on the day we checked and is not what we scored. If price is your main filter, Double Wood is cheaper per serving, with a 4-capsule dose and a gelatin capsule.
Full analysis: all pros & cons (8), buy if / skip if
- Magtein named on the panel with the licence line, at the 2,000 mg trial dose
- 150 mg of magnesium printed on its own line with a %DV
- 3 capsules a day, a vegetarian hypromellose capsule, a short list of other ingredients
- A 30-day bottle at $32.95, about $0.73 per 100 mg of magnesium
- Third Party Tested names no lab, and no Nutricost product is in the NSF or Clean Label Project listings
- Nutricost is not in the partner selection on magtein.com, so the licence could not be matched at the source
- $1.10 a serving is above most of the other Magtein bottles
- The label sends two of the three capsules to bedtime, and warns of sleepiness, drowsiness or headaches
- You want Magtein at the 2,000 mg trial dose in 3 capsules, not 4
- You like a short panel: one magnesium line, one Magtein line, a vegetarian capsule
- You want a 30-day bottle: 90 capsules at 3 a day
- You want the testing to be checkable: Life Extension and Double Wood give you more to verify
- You are drug-tested: Momentous is the one with NSF Certified for Sport
- You want magnesium for sleep, cramps or a deficiency: buy a glycinate instead
- You expect a same-day effect: the trial effect is slow and was measured at 12 weeks
2,000 mg of Magtein and 150 mg of magnesium per 3 capsules, printed on two clear lines, for about $1.10 a serving. That is the dose the cognition trials used (Liu 2016), and the panel makes it easy to see what you are getting. What holds the score at 8.0 is what the label cannot show: no lab is named behind Third Party Tested, and the licence could not be matched to the source. Life Extension publishes per-batch results and Double Wood prints an NSF Contents Certified mark on its label, both for less money per serving.
Nutricost Magtein Magnesium L-Threonate has a short Supplement Facts panel. It lists Magnesium 150 mg, 36% of the Daily Value, and Magtein (Magnesium L-Threonate) 2,000 mg, per serving of 3 capsules, with 30 servings in the bottle. The panel footer carries the Magtein patent and licence statement, naming ThreoTech LLC as the licensor. The Amazon offer we checked on October 18, 2026 was $32.95, which is $1.10 a serving and about $0.73 per 100 mg of magnesium. The bottle says made and quality tested in the USA. A Third Party Tested tile in the gallery and Nutricost's product page go further, but neither names a lab, and we found no Nutricost product at NSF or Clean Label Project. This is the trial dose of Magtein at a mid-range price. What to weigh is the testing paper trail, the evening-heavy label directions, and a per-serving price that sits above most of the other bottles.
Magtein at the right dose and a clean label, with less to verify than the better-scored bottles.
Nutricost Magtein gives you what the front says: 2,000 mg of Magtein per serving, with 150 mg of magnesium printed on the line above it. The panel is short, the serving is 3 capsules, and the bottle lasts 30 days. If you want the form the cognition trials used and you like a plain label, it does the job. What holds the score at 8.0 is what the label cannot show. Third Party Tested names no lab and links no certificate, we found no Nutricost product at NSF or Clean Label Project, and magtein.com does not show Nutricost among its partner brands. Life Extension (8.5) publishes per-batch results at about $0.93 a serving, and Double Wood (8.3) prints an NSF Contents Certified mark at about $0.77. Pick Nutricost because you prefer this label and bottle, not because it is a better Magtein. Run it the way the label says or move the doses earlier if it keeps you awake, give it 12 weeks, and buy a glycinate for sleep.
If This Doesn’t Fit — Try These
Life Extension Neuro-Mag Magnesium L-Threonate
Licensed Magtein at about $0.93 a serving, with per-batch test results published.
Double Wood Magnesium L-Threonate (Magtein)
About $0.77 a serving and an NSF Contents Certified mark on the label.
Momentous Magnesium L-Threonate (Magtein)
The same Magtein dose with NSF Certified for Sport testing, at about $1.17 a serving.
Quick Answers
How much magnesium is in Nutricost Magtein?
The Supplement Facts panel prints two lines for a 3-capsule serving: Magnesium 150 mg (36% of the Daily Value) and Magtein (Magnesium L-Threonate) 2,000 mg. The 2,000 mg is the weight of the Magtein compound; the magnesium inside it is the 150 mg line. That is the figure to compare with a glycinate or citrate bottle, and it is why threonate is a brain-magnesium product and not a repletion product. The 90-capsule bottle is 30 servings.
Is Nutricost's Magtein the same as the Magtein in Life Extension or NOW?
The panel names Magtein with the registered mark and carries the licence line: Magtein is a trademark of, and licensed exclusively by, ThreoTech LLC. The dose is the same 2,000 mg of Magtein as the other bottles we review. We could not confirm the licence at the source: the partner selection on magtein.com lists Double Wood, Jarrow, Life Extension, Momentous, NOW and Source Naturals and does not show Nutricost. The page calls it a selection, so that is not proof either way. We scored the form one notch below the six listed brands for that reason.
Should I take the capsules in the morning or at night?
The label directs 1 capsule in the morning and 2 capsules 2 hours before sleeping, with two capsules at night suggested for the first week. It also warns that Magtein may cause sleepiness, drowsiness or headaches and says to reduce the dose or stop if that lasts more than a week. Our list advises morning or early afternoon for people who find magnesium L-threonate alerting. Follow the label if it suits you and move the doses earlier if it keeps you awake.
Is Nutricost Magtein third-party tested?
The bottle itself says made and quality tested in the USA. Third Party Tested appears on a tile in the Amazon gallery, and Nutricost's product page says the product is tested by ISO-accredited laboratories. Neither names a lab, and the page links no certificate of analysis. We searched the NSF Certified for Sport brand list, the NSF/ANSI 173 listings and Clean Label Project on October 18, 2026 and found no Nutricost product. The claim is plausible, but we could not verify it at any certifier.
How long does one bottle last?
30 days at the label dose: 90 capsules at 3 a day. The Amazon title says 30 servings and the panel agrees. Divide the capsule count by 3 before you compare prices with other threonate bottles.
Sources & Further Reading
2 peer-reviewed sources, each linked to PubMed
- [1] Slutsky 2010 PMID 20152124 — Enhancement of learning and memory by elevating brain magnesium. The MIT paper that founded the magnesium L-threonate category. Showed brain-magnesium levels rise only with L-threonate (not other magnesium forms), with downstream increases in NMDA-receptor density, synaptic plasticity, and learning + memory. The foundational evidence for the BBB-crossing claim.
- [2] Liu 2016 PMID 26519439 — Efficacy and safety of MMFS-01, a synapse density enhancer, for treating cognitive impairment in older adults: a randomized, double-blind, placebo-controlled trial. The human RCT (MMFS-01) anchoring the cognitive evidence: 2000 mg Magtein/day for 12 weeks improved executive function by ~9% on standardized tests vs placebo in older adults. Establishes the trial dose used across this list (2000 mg Magtein = 144 mg elemental).
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