Glycinate, for almost everyone. Magnesium's blood-pressure and sleep evidence is a mineral effect, and glycinate delivers real elemental magnesium at a lower price. L-threonate is a cognition bet built on small, short, industry-funded trials with no independent replication, and it supplies only about 144 mg of elemental magnesium per 2 g. If your dietary intake is low, food fixes that first.
| Compared on | Magnesium glycinate | Magnesium L-threonate |
|---|---|---|
| Evidence grade | Moderate evidence | Emerging evidence |
| What it is | Magnesium is an essential dietary mineral and the second most abundant intracellular cation, serving as a cofactor in hundreds of enzymatic reactions involved in energy metabolism, protein synthesis, and nerve and muscle function. | Magnesium L-threonate (also called L-threonic acid magnesium salt, L-TAMS, or the branded ingredient Magtein) is the magnesium salt of threonic acid, developed around 2010 as a form of magnesium intended to raise brain levels. |
| Best human evidence | “Magnesium intake resulted in a reduction in systolic blood pressure” Hypertension 2025 · PMID 41000008 | “With MMFS-01 treatment, overall cognitive ability improved significantly relative to placebo (p = 0.003; Cohen's d = 0.91). Cognitive fluctuation was also reduced.” J Alzheimers Dis 2016 · PMID 26519439 |
| Dose / protocol studied | 250–500 mg elemental magnesium/day (sleep trials used 250 mg as bisglycinate or 500 mg; BP analyses center near ~370 mg/day) | 1-2 g/day in trials (about 144 mg elemental magnesium per 2 g) |
| Typical listed price | $26.00 | $30.78 |
| Who it suits | Someone correcting a likely-low magnesium intake, or wanting the sleep and blood-pressure effects, with a form that is gentle on the gut. | Someone specifically chasing the brain-magnesium hypothesis who accepts they are funding an unreplicated bet. |
| Who should skip it | Anyone with normal blood pressure expecting a big drop — pooled trials show about 2 mmHg, and generally no significant effect in normotensive people. | Anyone trying to correct magnesium deficiency — it provides only about 7–8% elemental magnesium — or anyone who wants independent replication before paying a premium. |
| Key caveat | Effect sizes are small — about 2 mmHg for blood pressure and a modest improvement in insomnia scores — and benefits look greatest in people with low baseline magnesium intake. Most evidence comes from other salt forms (oxide, citrate), so glycinate-specific superiority claims outrun the data. | A few small, short, industry-funded randomized trials report cognitive and sleep benefits consistent with rodent mechanism data, but there is no independent replication and human brain-magnesium elevation has not been directly confirmed. It provides little elemental magnesium, so it is a cognitive-support candidate, not a way to correct magnesium deficiency. |
Magnesium L-threonate lists at about 1.2× the price of Magnesium glycinate. Prices are the typical listed prices in our catalog, not live Amazon prices, and a true cost-per-studied-dose is not shown because our catalog does not record servings per container — we would have to guess, so we don't.
Both are magnesium salts. The question is whether you are buying the mineral or the delivery story.
Glycinate. Most people in Western countries under-consume magnesium, and the benefits in trials look largest in people who are hypertensive, magnesium-deficient or insulin-resistant. Glycinate gives you meaningfully more elemental magnesium per capsule than threonate does.
Glycinate. A placebo-controlled trial in older adults with primary insomnia improved sleep scores and efficiency, and a 2025 trial of magnesium bisglycinate itself modestly improved insomnia severity in poor sleepers — especially those with low dietary magnesium intake.
L-threonate, with expectations set low. Small randomized trials report improved composite cognition in older adults with cognitive impairment. The key trials are small, short and manufacturer-funded — one sleep trial later required a funding-disclosure corrigendum — and human brain-magnesium elevation has never been directly confirmed.
Either — the evidence is for magnesium, not the salt. A systematic review gives Grade C (possibly effective) evidence for magnesium in migraine prophylaxis, and that literature is not form-specific. Buy on price and gut tolerance.
Magnesium is abundant in plant foods. Spinach, pumpkin seeds, almonds and beans each contribute roughly 70–150 mg of elemental magnesium, and swapping refined grains for unrefined ones moves intake meaningfully.
Most magnesium trials used oxide, citrate or other salts, which means claims that glycinate or threonate is superior outrun the evidence. If you already eat well, the honest expected effect of either capsule is small.
Each quote below is taken verbatim from the cited paper. Null and negative results are included on purpose — they are the reason a grade means anything.
“Magnesium intake resulted in a reduction in systolic blood pressure”
“The findings of the present umbrella meta-analysis showed an overall decrease of SBP and DBP with magnesium supplementation, particularly at doses of ≥400 mg/day for ≥12 weeks.”
“magnesium significantly reduced systolic and diastolic blood pressure”
“With MMFS-01 treatment, overall cognitive ability improved significantly relative to placebo (p = 0.003; Cohen's d = 0.91). Cognitive fluctuation was also reduced.”
“L-TAMS restoring global cognitive abilities of older adults; increased functional synapse density”
“The purpose of this two-arm, 6-week, parallel-group, randomised, double-blind, placebo-controlled trial was to examine the effects of magnesium L-threonate (Magtein) supplementation on cognitive performance, cognitive age, sleep quality, and selected physiological indicators in adults.”
Links go to an Amazon search for the product name, not to a specific listing, so you can compare sellers, price and third-party testing yourself.
Only if you are specifically buying the brain-magnesium hypothesis. It delivers about 7–8% elemental magnesium — roughly 144 mg per 2 g dose — and its cognitive trials are small, short and manufacturer-funded with no independent replication.
The trial evidence that exists for sleep used magnesium generally, and a 2025 trial specifically tested magnesium bisglycinate in poor sleepers with a modest improvement in insomnia severity. Glycinate is the better-supported and cheaper option.
Analyses centre near 370 mg/day, and an umbrella meta-analysis found reductions particularly at 400 mg/day or more for 12 weeks or longer. The overall effect is small — about 2 mmHg.
For most people, yes — leafy greens, nuts, seeds, legumes and whole grains are rich sources. Western diets frequently fall below recommended intake, which is why supplementation helps some people and does very little for others.
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