Comparison
L-Theanine vs Magnesium Glycinate
Side-by-side of L-Theanine and Magnesium Glycinate. 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 Glycinate
Magnesium glycinate supplement guide: chelated bisglycinate form, 200 to 400 mg dosage, sleep architecture benefits, low GI side effects, glycine co-effect.
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 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
Side-by-side
| Attribute | L-Theanine | Magnesium Glycinate |
|---|---|---|
| Category | supplement | supplement |
| Also known as | theanine, gamma-glutamylethylamide | magnesium bisglycinate |
| Half-life (hr) ↗ | 1.5 | 5 |
| Typical dose (mg) ↗ | 200 | 300 |
| Dosing frequency | as needed (with caffeine) or daily | daily (often evening) |
| Routes | oral | oral |
| Onset (hr) | 0.5 | 1 |
| Peak (hr) | 1 | - |
| Molecular weight | 174.2 | - |
| Molecular formula | C7H14N2O3 | - |
| Mechanism | Crosses BBB; modulates GABA/dopamine/serotonin (modest); increases alpha-wave EEG activity; dampens stress-induced sympathetic response without sedation. | 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. |
| Legal status | OTC dietary supplement | Dietary supplement |
| WADA status | allowed | allowed |
| DEA / Rx | OTC supplement | OTC supplement |
| Pregnancy | Insufficient supplement-dose data; tea-source intake safe | Generally considered acceptable at RDA doses; consult clinician |
| CAS | 3081-61-6 | 14783-68-7 |
| PubChem CID | 439378 | 84645 |
| Wikidata | Q909931 | - |
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 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)
Which Should You Take?
L-Theanine and Magnesium Glycinate score evenly on the criteria we weight (goal breadth, legal accessibility, evidence depth). The conditionals below should drive the decision more than any aggregate score.
- → If your priority is focus or working memory, pick L-Theanine.
- → If your priority is post-training recovery, pick Magnesium Glycinate.
- → If your priority is stress and HPA-axis regulation, pick L-Theanine.
Edge case: Half-lives differ materially (L-Theanine ~1.5 hr vs Magnesium Glycinate ~5 hr). Magnesium Glycinate reaches steady state faster; L-Theanine is easier to dial in if tolerability is uncertain.
Default choice: either is defensible. L-Theanine edges out on goal breadth + legal accessibility; Magnesium Glycinate is the right call if your priority sits in the goals listed 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 Glycinate?
L-Theanine and Magnesium Glycinate 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 Glycinate?
L-Theanine half-life is 1.5 hours; Magnesium Glycinate half-life is 5 hours.
Can you stack L-Theanine with Magnesium Glycinate?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
Go deeper