Magnesium Glycinate vs L-Threonate: Evidence | Dose Track
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Magnesium glycinate vs magnesium L-threonate: what is the difference?

Forms · Evidence · Upper limit · Interactions

Short answer: Both are magnesium bound to something else: glycine in glycinate, L-threonate in threonate. The NIH magnesium fact sheet does not compare them.1 L-threonate's brain claims rest on one 30-day, maker-funded trial of a blend.2 We found no trial comparing the two. The supplement limit for magnesium is 350 mg a day for adults either way.1

How do magnesium glycinate and L-threonate compare side by side?

From the NIH Office of Dietary Supplements, EFSA and the one published trial.
Magnesium glycinateMagnesium L-threonate
Bound toThe amino acid glycineL-threonate3
Main claimA general magnesium supplementMemory and brain health2
Human outcome trials foundNone comparing it with other forms in the sources checkedOne 30-day trial of a blend with phosphatidylserine and vitamins C and D, 109 adults2
Magnesium per doseCheck the label for elemental magnesium3,000 mg supplies about 250 mg magnesium3
Upper limit (adults)350 mg a day from supplements and medicines1Same 350 mg limit1
Side effects at high dosesDiarrhea, nausea, cramps1Same for magnesium in general1
FDA approvalSupplements are not approved before sale4Same4

Reviewed . Half-life figures are shown only where the value Dose Track uses agrees with the cited source.

What does the evidence show for each?

Magnesium in general: NIH says forms that dissolve well in liquid are absorbed better than others, and that aspartate, citrate, lactate and chloride tend to be absorbed better than oxide and sulfate. The fact sheet does not rank glycinate or L-threonate.1

Magnesium L-threonate: in a 30-day placebo-controlled trial of 109 healthy Chinese adults aged 18 to 65, 2 g a day of a blend of magnesium L-threonate, phosphatidylserine and vitamins C and D improved scores on a standard memory test, more so in older people. Because the blend had several ingredients, the trial cannot show what the magnesium L-threonate did alone.2 In 2024 EFSA judged it safe as a food ingredient at up to 3,000 mg a day for adults, not counting pregnancy and breastfeeding.3

We found no trial that gave people the two forms side by side. These are study protocols, not personalized advice; confirm any dosing with your prescriber.

What safety points apply to both?

  • The adult upper limit of 350 mg a day counts magnesium from supplements and medicines, not food.1
  • Take oral bisphosphonates at least 2 hours apart from magnesium, and tetracycline or quinolone antibiotics at least 2 hours before or 4 to 6 hours after it. Diuretics and proton pump inhibitors can change magnesium levels.1

More detail: the Magnesium Bisglycinate and Magnesium L-Threonate guides.

This page summarizes labels and published studies. It is not personalized medical advice; confirm any dose or change with your prescriber.
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Frequently asked questions

Is magnesium L-threonate better for the brain than glycinate?+
Not shown. The only trial tested a blend that also had phosphatidylserine and vitamins C and D, and it did not include glycinate.2
How much magnesium is in magnesium L-threonate?+
Not much by weight. EFSA says 3,000 mg supplies about 250 mg of magnesium.3
What is the upper limit for magnesium supplements?+
For adults, 350 mg a day from supplements and medicines combined. Food magnesium does not count toward it.1
Can magnesium interact with my medicines?+
Yes. NIH lists oral bisphosphonates and tetracycline and quinolone antibiotics, and says to space them apart from magnesium.1
Can I track magnesium in Dose Track?+
Yes. Log each form with its milligrams and reminders.

Sources

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

All compound comparisons · Magnesium Bisglycinate guide · Magnesium L-Threonate guide · All compound guides · Peptide tracking in Dose Track