Magnesium L-Threonate: Evidence, Limits and Safety
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[Supplement · Compound guide]

Magnesium L-Threonate: half-life, strengths and approval status

Amounts studied · Approval status · Half-life notes

What is Magnesium L-Threonate?

Magnesium L-threonate is the mineral magnesium bound to L-threonate. It is sold, often under the brand name Magtein, as a form of magnesium for memory and brain health.

Also known as: magnesium threonate, Magtein, MgT, Mg L-threonate.

Amounts studied

The European Food Safety Authority (EFSA) assessed magnesium L-threonate at up to 3,000 mg a day for adults, which supplies about 250 mg of magnesium and 2,730 mg of L-threonate (EFSA 2024). The one memory trial used 2 g a day of a blend of magnesium L-threonate, phosphatidylserine and vitamins C and D (Zhang 2022). In the US, the Tolerable Upper Intake Level for magnesium from supplements is 350 mg a day for adults (ODS). These are study protocols, not a recommendation.

Approval status and how it is used

It is sold in the US as a dietary supplement. Under the 1994 dietary supplement law (DSHEA), FDA does not approve dietary supplements before they are marketed, and the maker, not FDA, is responsible for safety and labeling.

What studies show: in a placebo-controlled trial of 109 healthy Chinese adults aged 18 to 65, 30 days of a blend of magnesium L-threonate, phosphatidylserine and vitamins C and D (2 g a day) improved scores on a standard memory test, more so in older people (Zhang 2022). Because the blend had several ingredients, the trial cannot show what magnesium L-threonate did on its own. The trial was funded by Wu-xi Magtein Bioscience, the maker. We found no other placebo-controlled trials of magnesium L-threonate for memory in people. The evidence is very small and industry-funded.

Safety: in 2024 EFSA concluded that magnesium L-threonate is safe as a new food ingredient at up to 3,000 mg a day for adults (it was not assessed for pregnancy or breastfeeding), that the magnesium in it is absorbed, and that the up to 1% oxalic acid it may contain is not a safety concern (EFSA 2024). The NIH Office of Dietary Supplements (ODS) says too much supplemental magnesium can cause diarrhea, nausea and cramps, and that magnesium can interact with oral bisphosphonates and tetracycline and quinolone antibiotics; some diuretics and other medicines change magnesium levels.

Magnesium L-Threonate half-life and time to peak

  • Half-lifeNot listed
  • Time to peak (Tmax)Not listed

We could not find a single published half-life or time to peak for magnesium L-threonate that applies to a supplement dose, so we do not list one. Blood magnesium is tightly regulated, so a supplement dose does not show up as a clear curve.

How to track Magnesium L-Threonate in Dose Track

  1. Add Magnesium L-Threonate as a custom compound. Start typing its name and Dose Track fills in the details from its research library for you to check, and it sits next to everything else you take.
  2. Log each dose when you take it so your history shows exactly what you took and when.
  3. Set reminders on your own schedule, whether that is daily, weekly or every few days.
  4. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

How Dose Track handles peptides · Reconstitution calculator · Half-life calculator

Magnesium Bisglycinatemagnesium glycinate, magnesium diglycinate PhosphatidylserinePS, soy phosphatidylserine Citicoline (CDP-Choline)CDP-choline, cytidine diphosphate choline

Frequently asked questions

What is the half-life of Magnesium L-Threonate?+
We could not find a single published half-life or time to peak for magnesium L-threonate that applies to a supplement dose, so we do not list one. Blood magnesium is tightly regulated, so a supplement dose does not show up as a clear curve.
Does magnesium L-threonate improve memory?+
There is very little evidence. One 30-day trial in 109 healthy adults, funded by the maker, found better memory test scores, but it tested a blend that also contained phosphatidylserine and vitamins C and D, so it cannot show what the magnesium L-threonate did on its own.
How much magnesium is in magnesium L-threonate?+
Not much by weight. EFSA says 3,000 mg of magnesium L-threonate supplies about 250 mg of magnesium; the rest is L-threonate. The US upper limit for magnesium from supplements is 350 mg a day for adults.
Can I track Magnesium L-Threonate in Dose Track?+
Yes. Magnesium L-Threonate is in Dose Track's research library, so when you add it as a custom compound its details are filled in for you to check. You can then log each dose next to your other compounds, set reminders on your own schedule, and see your history next to your lab results. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

Sources

  1. Zhang C, et al. A Magtein, magnesium L-threonate, -based formula improves brain cognitive functions in healthy Chinese adults. Nutrients. 2022;14(24):5235.
  2. EFSA Panel on Nutrition, Novel Foods and Food Allergens. Safety of magnesium L-threonate as a novel food pursuant to Regulation (EU) 2015/2283 and bioavailability of magnesium from this source. EFSA J. 2024;22(3):e8656.
  3. NIH Office of Dietary Supplements. Magnesium fact sheet for health professionals (updated January 6, 2026).
  4. FDA. Questions and answers on dietary supplements.

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