Comparison
Magnesium Glycinate vs Magnesium L-Threonate
Side-by-side of Magnesium Glycinate and Magnesium L-Threonate. Every row below is pulled from the compound schema and will update as our data grows. For deeper reads, follow through to each compound page.
Magnesium Glycinate
Magnesium glycinate supplement guide: chelated bisglycinate form, 200 to 400 mg dosage, sleep architecture benefits, low GI side effects, glycine co-effect.
Magnesium L-Threonate
Magnesium l-threonate (Magtein) crosses the blood-brain barrier. Typical dose 1,500-2,000 mg. Sleep and cognitive trial data, side effects.
Effects at a glance
Magnesium Glycinate
- •Shortens sleep onset latency in older adults and in deficient populations supplementing 200 to 400 mg elemental Mg
- •Improves subjective sleep quality scores (PSQI, ISI) modestly versus placebo over 4 to 8 weeks
- •Reduces nocturnal leg cramps and exercise-induced muscle cramping in some controlled trials
- •Lowers self-reported anxiety in mild-to-moderate cases, with smaller effect than first-line pharmacotherapy
- •Glycinate form delivers fewer GI side effects than oxide or citrate at equivalent elemental doses
- •Insufficient as a stand-alone hypertension treatment; small adjunctive blood-pressure reductions only
Magnesium L-Threonate
- •Distinct magnesium salt designed for blood-brain barrier penetration; not a higher-quality systemic magnesium
- •Liu 2010 rodent study: elevated CSF magnesium ~15% and increased hippocampal synaptic density
- •Trial portfolio in humans is small and mostly Magtein-funded; cognitive effects are modest where reported
- •Typical dose 1500 to 2000 mg/day delivers only ~108 to 144 mg of elemental magnesium
- •GI tolerability comparable to other magnesium forms; loose stools in a minority at 2000 mg/day
- •Distinct from magnesium glycinate, which is the conventional sleep/anxiety/repletion form
Side-by-side
| Attribute | Magnesium Glycinate | Magnesium L-Threonate |
|---|---|---|
| Category | supplement | supplement |
| Also known as | magnesium bisglycinate | Mg-T, MgT, Magtein, magnesium threonate |
| Half-life (hr) ↗ | 5 | 4 |
| Typical dose (mg) ↗ | 300 | 2000 |
| Dosing frequency | daily (often evening) | 1 to 3 times daily |
| Routes | oral | oral |
| Onset (hr) | 1 | 1 |
| Peak (hr) | - | 2 |
| Molecular weight | - | 294.5 |
| Molecular formula | - | C8H14MgO10 |
| Mechanism | Magnesium acts as a cofactor for 300+ enzymes and as a voltage-dependent antagonist at NMDA receptors; glycine serves as an inhibitory neurotransmitter and co-agonist at glycine receptors. | Proposed to deliver magnesium across the blood-brain barrier more effectively than other oral salts via threonate-related transporters, raising CNS magnesium and modulating NMDA receptor function and synaptic plasticity. |
| Legal status | Dietary supplement | OTC dietary supplement |
| WADA status | allowed | allowed |
| DEA / Rx | OTC supplement | OTC supplement (not scheduled) |
| Pregnancy | Generally considered acceptable at RDA doses; consult clinician | Standard magnesium safety; Mg-T-specific data limited |
| CAS | 14783-68-7 | 778571-57-6 |
| PubChem CID | 84645 | 10691810 |
| Wikidata | - | Q27151568 |
Safety profile
Magnesium Glycinate
Common side effects
- mild GI upset at high doses
- loose stools (dose-dependent, less than with oxide/citrate forms)
Contraindications
- severe renal impairment
- myasthenia gravis
- heart block
Interactions
- tetracycline and fluoroquinolone antibiotics: magnesium chelates antibiotic, reducing absorption; separate by 2+ hours(moderate)
- bisphosphonates: reduced absorption of bisphosphonate(moderate)
- potassium-sparing diuretics: possible hypermagnesemia in renal impairment(moderate)
Magnesium L-Threonate
Common side effects
- loose stools
- mild GI upset
- headache (rare)
- fatigue (rare)
Contraindications
- severe renal impairment (eGFR below 30)
- hypermagnesemia
- myasthenia gravis (high doses)
- concurrent IV magnesium therapy
Interactions
- tetracyclines and fluoroquinolones: magnesium chelation reduces antibiotic absorption; separate by 2 to 4 hours(moderate)
- bisphosphonates: reduced absorption; separate by 2 hours minimum(moderate)
- muscle relaxants and aminoglycosides: potentiated neuromuscular blockade at high doses(moderate)
- antihypertensives: additive blood pressure reduction at high doses(minor)
Which Should You Take?
Magnesium Glycinate comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC dietary supplement, oral dosing, with a Tier-A outcome catalogued. Magnesium L-Threonate is the right call when one of the conditionals below applies.
- → If your priority is post-training recovery, pick Magnesium Glycinate.
- → If your priority is stress and HPA-axis regulation, pick Magnesium Glycinate.
- → If your priority is focus or working memory, pick Magnesium L-Threonate.
Default choice: Magnesium Glycinate. Lower friction to source, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for Magnesium L-Threonate only if your priority sits squarely in the goals it owns above.
This verdict is generated from each compound's schema (goals, legal status, evidence outcomes, dosing route). It updates automatically as our compound data evolves; the deeper read sits on each individual compound page.
Common questions
What is the difference between Magnesium Glycinate and Magnesium L-Threonate?
Magnesium Glycinate and Magnesium L-Threonate differ in category (supplement vs supplement), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Magnesium Glycinate or Magnesium L-Threonate?
Magnesium Glycinate half-life is 5 hours; Magnesium L-Threonate half-life is 4 hours.
Can you stack Magnesium Glycinate with Magnesium L-Threonate?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
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