Comparison
L-Theanine vs Magnesium L-Threonate
Side-by-side of L-Theanine 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.
L-Theanine
L-theanine is a non-protein amino acid found in tea leaves. The most-replicated nootropic; pairs with caffeine at 1:1 (100-200 mg each) for acute focus.
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
L-Theanine
- •Non-protein amino acid in tea; the most-replicated nootropic in the human RCT literature
- •Caffeine + theanine at 1:1 (100-200 mg each) is the gold-standard acute focus stack
- •Solo doses of 200-400 mg reduce subjective stress and improve sleep quality
- •Increases alpha-wave EEG activity within 30-45 minutes of 200 mg oral dose
- •Crosses blood-brain barrier; bioavailability high, half-life 60-90 minutes
- •Clean safety record; minimal interactions at supplement doses
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 | L-Theanine | Magnesium L-Threonate |
|---|---|---|
| Category | supplement | supplement |
| Also known as | theanine, gamma-glutamylethylamide | Mg-T, MgT, Magtein, magnesium threonate |
| Half-life (hr) ↗ | 1.5 | 4 |
| Typical dose (mg) ↗ | 200 | 2000 |
| Dosing frequency | as needed (with caffeine) or daily | 1 to 3 times daily |
| Routes | oral | oral |
| Onset (hr) | 0.5 | 1 |
| Peak (hr) | 1 | 2 |
| Molecular weight | 174.2 | 294.5 |
| Molecular formula | C7H14N2O3 | C8H14MgO10 |
| Mechanism | Crosses BBB; modulates GABA/dopamine/serotonin (modest); increases alpha-wave EEG activity; dampens stress-induced sympathetic response without sedation. | 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 | OTC dietary supplement | OTC dietary supplement |
| WADA status | allowed | allowed |
| DEA / Rx | OTC supplement | OTC supplement (not scheduled) |
| Pregnancy | Insufficient supplement-dose data; tea-source intake safe | Standard magnesium safety; Mg-T-specific data limited |
| CAS | 3081-61-6 | 778571-57-6 |
| PubChem CID | 439378 | 10691810 |
| Wikidata | Q909931 | Q27151568 |
Safety profile
L-Theanine
Common side effects
- mild GI upset (rare)
- headache (rare)
Contraindications
- pregnancy / lactation (insufficient data at supplement doses)
- concurrent strong GABAergics without caution
Interactions
- caffeine: synergistic for acute focus; dampens jitter without blunting alertness(minor)
- benzodiazepines / alcohol: potential additive sedation(minor)
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?
L-Theanine 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 stress and HPA-axis regulation, pick L-Theanine.
- → If your priority is focus or working memory, pick L-Theanine.
- → If your priority is sleep onset or sleep quality, pick L-Theanine.
Default choice: L-Theanine. 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 L-Theanine and Magnesium L-Threonate?
L-Theanine 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, L-Theanine or Magnesium L-Threonate?
L-Theanine half-life is 1.5 hours; Magnesium L-Threonate half-life is 4 hours.
Can you stack L-Theanine 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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