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Magnesium L-threonate

Supplement mineral chelate brain & moodsleep
Aka: Magtein, Neuro-Mag
Brands seen in Singapore: California Gold Nutrition, NOW Foods, Doctor's Best, Life Extension, Thorne
Third-party tested: Thorne certifies other products with NSF Certified for Sport, but nothing for magnesium l-threonate.Certification is granted per product, so check the tub you actually own. Not being listed is not the same as failing.
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Limited human evidence — two small trials on memory
When to take
Timing not addressed
Take with
Water · labels give elemental magnesium, not compound
Studied for
Trials ran 6 and 12 weeks daily
Pros & cons
Pros
  • 6-week RCT: better overall cognition score vs placebo
  • 12-week RCT in adults 50–70: composite score up
  • Well tolerated, no significant adverse reactions
Cons
  • Two small trials (n=100 and n=44), branded ingredient
  • No group difference on objective sleep measures
  • NIH ODS does not mention l-threonate at all
Sources
  1. NIH ODS — Magnesium (Health Professional), updated January 6, 2026; read via web.archive.org capture 25 Aug 2026 — Table 1 RDAs · read 2026-08-27
    what it says
    “Table 1: Recommended Dietary Allowances (RDAs) for Magnesium in Milligrams (mg) … 19–30 years | 400 mg | 310 mg … 31–50 years | 420 mg | 320 mg … 51+ years | 420 mg | 320 mg”
  2. NIH ODS — Magnesium (Health Professional), updated January 6, 2026; read via web.archive.org capture 25 Aug 2026 — Health Risks from Excessive Magnesium (UL) · read 2026-08-27
    what it says
    “The Tolerable Upper Intake Level for supplemental magnesium is 350 mg for adults … The ULs only include magnesium from dietary supplements and medications; they do not include magnesium found naturally in food and beverages”
  3. NIH ODS — Magnesium (Health Professional), updated January 6, 2026; read via web.archive.org capture 25 Aug 2026 — Dietary Supplements (absorption by form) · read 2026-08-27
    what it says
    “Small studies have found that magnesium in the aspartate, citrate, lactate, and chloride forms is absorbed more completely and is more bioavailable than magnesium oxide and magnesium sulfate”
  4. NIH ODS — Magnesium (Health Professional), updated January 6, 2026; read via web.archive.org capture 25 Aug 2026 — Health Risks from Excessive Magnesium (renal function) · read 2026-08-27
    what it says
    “The risk of magnesium toxicity increases with impaired renal function or kidney failure because the ability to remove excess magnesium is reduced or lost”
  5. NIH ODS — Magnesium (Health Professional), updated January 6, 2026; read via web.archive.org capture 25 Aug 2026 — Interactions with Medications (bisphosphonates, antibiotics) · read 2026-08-27
    what it says
    “Taking magnesium-rich supplements or medications at least 2 hours before or after oral bisphosphonates can minimize this interaction … These antibiotics should be taken at least 2 hours before or 4 to 6 hours after a magnesium-containing supplement”
  6. NIH ODS — Magnesium (Health Professional), updated January 6, 2026; read via web.archive.org capture 25 Aug 2026 — Interactions with Medications (proton pump inhibitors) · read 2026-08-27
    what it says
    “Prescription proton pump inhibitor (PPI) drugs … can cause hypomagnesemia when taken for prolonged periods (typically more than a year)”
  7. NIH ODS — Magnesium (Health Professional), updated January 6, 2026; read via web.archive.org capture 25 Aug 2026 — Interactions with Medications (diuretics) · read 2026-08-27
    what it says
    “Chronic treatment with loop diuretics … and thiazide diuretics … can increase the loss of magnesium in urine and lead to magnesium depletion … potassium-sparing diuretics … reduce magnesium excretion”
  8. NIH ODS — Magnesium (Health Professional), updated January 6, 2026; read via web.archive.org capture 25 Aug 2026 — Dietary Supplements (elemental magnesium on labels) · read 2026-08-27
    what it says
    “The Supplement Facts panel on a dietary supplement label declares the amount of elemental magnesium in the product, not the weight of the entire magnesium-containing compound”
  9. NIH ODS — Magnesium (Health Professional), updated January 6, 2026; read via web.archive.org capture 25 Aug 2026 — Sources of Magnesium: Food (Daily Value note) · read 2026-08-27
    what it says
    “The DV for magnesium is 420 mg for adults and children age 4 years and older”
  10. The effects of magnesium L-threonate (Magtein®) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial (Lopresti & Smith, Front Nutr 2025) — Results: cognition · read 2026-08-27
    what it says
    “Compared to the placebo, Magtein® was associated with greater improvements in overall cognitive performance as measured by the NIH Total Cognition Composite (p = 0.043), with larger treatment effects on working and episodic memory”
  11. The effects of magnesium L-threonate (Magtein®) on cognitive performance and sleep quality in adults (Lopresti & Smith, Front Nutr 2025) — Methods · read 2026-08-27
    what it says
    “One hundred adults aged 18 to 45 with self-reported dissatisfied sleep were supplemented with 2 g daily of Magtein® or a placebo … two-arm, 6-week, parallel-group, randomised, double-blind, placebo-controlled trial”
  12. The effects of magnesium L-threonate (Magtein®) on cognitive performance and sleep quality in adults (Lopresti & Smith, Front Nutr 2025) — Results: sleep · read 2026-08-27
    what it says
    “there was a greater improvement in sleep-related impairment (p = 0.043), but no group differences in changes in sleep disturbances … Based on data from the sleep tracking ring, there were no group differences in sleep outcomes”
  13. The effects of magnesium L-threonate (Magtein®) on cognitive performance and sleep quality in adults (Lopresti & Smith, Front Nutr 2025) — Tolerability · read 2026-08-27
    what it says
    “Magtein® was well-tolerated, and there were no reports of significant adverse reactions”
  14. 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 et al., J Alzheimers Dis 2016) · read 2026-08-27
    what it says
    “Subjects were treated with MMFS-01 (n = 23) or placebo (n = 21) for 12 weeks … overall cognitive ability improved significantly relative to placebo (p = 0.003; Cohen's d = 0.91) … age 50-70”
  15. Efficacy and Safety of MMFS-01 … (Liu et al., J Alzheimers Dis 2016) — sleep and anxiety outcomes · read 2026-08-27
    what it says
    “Due to the strong placebo effects on sleep and anxiety, the effects of MMFS-01 on sleep and anxiety could not be determined”
  16. HSA — Health Supplements Guidelines GL-CHPB-3-001 (January 2026), clause 4.8 and Table 5 Minerals Limits · read 2026-08-27
    what it says
    “HS for use by the general adult population should not contain vitamins and minerals exceeding the stipulated limits stated in Tables 4 and 5 … Table 5: Minerals Limits … Magnesium 350 mg”
  17. HSA — Guidelines on Prohibited and Restricted Ingredients in HS and TM (October 2025), clause 1.3 and Annex B row 65 (Magnesium) · read 2026-08-27
    what it says
    “The objective of this guideline is to highlight the substances of concern … 65. Magnesium — Restricted use in HS and TM … the maximum recommended daily dose should not provide more than 350mg”
  18. iHerb Singapore — 'Magnesium' category page, default order, 817 results · read 2026-08-27
    what it says
    “California Gold Nutrition, Magnesium Bisglycinate Chelate, Albion TRAACS® … NOW Foods, Magnesium Glycinate … Doctor's Best, High Absorption Magnesium Lysinate Glycinate … Life Extension, Neuro-Mag®, Magnesium L-Threonate … Thorne, Magnesium Glycinate”

Updated 2026-08-30. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.