Magnesium L-Threonate vs. Glycinate vs. Citrate vs. Oxide: Which Form Should You Take?
Threonate crosses the blood-brain barrier. Glycinate is gentle and calming. Citrate is cheap and effective. Here's when to use each.
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Magnesium is one of those supplements where the form matters as much as the dose. There are at least a dozen different magnesium compounds on the market, and they behave differently in your body. The DoNotAge sachet uses Magnesium L-Threonate. Most standalone magnesium products use glycinate, citrate, or oxide. They're not interchangeable.
The elemental magnesium problem most people miss
When a label says "Magnesium L-Threonate 250 mg," that's 250 mg of the total compound. The actual elemental magnesium (the part your body uses) is only about 7% of that weight. So 250 mg of L-Threonate delivers roughly 48 mg of elemental magnesium.
The male RDA for magnesium is 420 mg elemental. The female RDA is 320 mg. Almost no single magnesium supplement delivers the full RDA in one capsule, but some forms get much closer than others.
Magnesium oxide contains about 60% elemental magnesium. A 500 mg capsule delivers 300 mg elemental. But oxide has the worst absorption rate of all forms. Maybe 4% of what you swallow gets absorbed. It's mostly a laxative at that point.
Magnesium citrate is about 16% elemental with decent absorption. Magnesium glycinate is about 14% elemental with good absorption and a calming effect. L-Threonate is the lowest in elemental content at roughly 7%, but its absorption and tissue distribution properties are unique.
Why the DoNotAge sachet uses magnesium L-Threonate
L-Threonate is the only magnesium form with published research showing it crosses the blood-brain barrier and increases brain magnesium levels. A 2010 study at MIT demonstrated that magnesium threonate enhanced learning, working memory, and both short and long-term memory in rats. It's the form used in cognitive and neuroprotection research.
For a longevity product targeting brain health alongside other aging pathways, threonate makes sense. Your brain needs magnesium for synaptic plasticity, and most other forms don't get there efficiently.
The tradeoff: you're getting almost nothing in terms of whole-body magnesium status. 48 mg elemental when you need 420 mg is 11% of the RDA. Your muscles, heart, and bones aren't being meaningfully served by threonate at this dose.
See also: DoNotAge sachet: what's underdosed and what to stack alongside it
Which magnesium form to use for what
Brain health and cognition: L-Threonate. If you're supplementing specifically for cognitive function, memory, or neuroprotection, threonate is the form with evidence behind it. Dose: 1,000 to 2,000 mg of the threonate compound (delivering 72 to 144 mg elemental).
Sleep and relaxation: Glycinate. Magnesium glycinate is bonded to the amino acid glycine, which has its own calming properties. Well-absorbed, gentle on the stomach, widely recommended for evening use. Dose: 200 to 400 mg elemental.
General supplementation on a budget: Citrate. Good absorption, decent elemental content, cheap. Can have a mild laxative effect at higher doses, which some people consider a feature. Dose: 200 to 400 mg elemental.
Constipation: Oxide or citrate at higher doses. Not joking. Magnesium oxide is a legitimate over-the-counter laxative. If you need that function, it's the cheapest option.
Muscle cramps and recovery: Glycinate or citrate. Both absorb well enough to raise intracellular magnesium levels that affect muscle function. Malate is another option here with some evidence for energy metabolism.
My magnesium stack with the DoNotAge sachet
I get threonate from the DoNotAge sachet (small dose, targeted at the brain). I add 300 mg of magnesium glycinate in the evening for sleep, relaxation, and whole-body magnesium status. Total supplemental elemental magnesium: about 90 mg from the sachet's threonate plus roughly 42 mg from glycinate, around 130 mg elemental total. Still below the RDA, but combined with dietary magnesium from food (dark chocolate, nuts, leafy greens, avocado), I'm probably in a workable range.
If your diet is low in magnesium-rich foods, bump the glycinate to 400 to 600 mg of the compound or add citrate during the day.
See also: DoNotAge sachet review: all 15 ingredients
Frequently asked questions
What is the best form of magnesium to take?
It depends on your goal. L-Threonate for brain health, glycinate for sleep and general supplementation, citrate for budget general use. Most people benefit from glycinate as their primary magnesium supplement.
How much elemental magnesium is in Magnesium L-Threonate?
About 7%. A 250 mg dose of L-Threonate delivers approximately 48 mg of elemental magnesium. The male RDA is 420 mg.
Can I take multiple forms of magnesium?
Yes. Many longevity protocols combine L-Threonate (for cognitive benefits) with glycinate or citrate (for whole-body magnesium status). There's no interaction risk between forms.
Why is the magnesium in the DoNotAge sachet not enough?
The sachet uses L-Threonate, which yields only ~7% elemental magnesium. Even the standalone DoNotAge magnesium product delivers just 48 mg elemental, roughly 11% of the male RDA. You need a separate magnesium supplement for adequate whole-body levels.