Comparison
Magnesium L-Threonate vs Omega-3 (EPA/DHA)
Side-by-side of Magnesium L-Threonate and Omega-3 (EPA/DHA). 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 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.
Omega-3 (EPA/DHA)
Omega 3 fish oil profile: EPA/DHA marine fatty acids, 2-4 g/day cuts triglycerides 20-30%, REDUCE-IT showed 25% cardiovascular risk reduction on icosapent eth.
Effects at a glance
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
Omega-3 (EPA/DHA)
- •Reduces fasting triglycerides 20-50% at 2-4 g/day in hypertriglyceridemic patients
- •REDUCE-IT showed 25% relative risk reduction in major CV events at 4 g/day icosapent ethyl
- •Modest antidepressant effect (SMD ~0.40) for EPA-dominant formulations at 1-2 g/day
- •Atrial fibrillation incidence rises ~30-50% at 4 g/day; relevant for older patients with pre-existing CV disease
- •Tissue omega-3 index (RBC EPA + DHA) target ~8%; Western baseline typically 4-5%
- •Triglyceride and re-esterified triglyceride forms absorb ~70% better than ethyl esters in fasted state
Side-by-side
| Attribute | Magnesium L-Threonate | Omega-3 (EPA/DHA) |
|---|---|---|
| Category | supplement | supplement |
| Also known as | Mg-T, MgT, Magtein, magnesium threonate | fish oil, EPA, DHA, marine omega-3 |
| Half-life (hr) ↗ | 4 | 48 |
| Typical dose (mg) ↗ | 2000 | 2000 |
| Dosing frequency | 1 to 3 times daily | 1 to 2 times daily with food |
| Routes | oral | oral |
| Onset (hr) | 1 | 4 |
| Peak (hr) | 2 | 12 |
| Molecular weight | 294.5 | 302.45 |
| Molecular formula | C8H14MgO10 | C20H30O2 (EPA); C22H32O2 (DHA) |
| Mechanism | 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. | Substitutes arachidonic acid in membrane phospholipids, shifting eicosanoid production toward less-inflammatory 3-series prostaglandins and 5-series leukotrienes. Activates PPAR-alpha to lower hepatic VLDL/triglyceride synthesis. DHA modulates synaptic membrane fluidity and neuronal function. |
| Legal status | OTC dietary supplement | Dietary supplement; prescription forms (icosapent ethyl, omega-3 acid ethyl esters) for severe hypertriglyceridemia |
| WADA status | allowed | allowed |
| DEA / Rx | OTC supplement (not scheduled) | Not scheduled |
| Pregnancy | Standard magnesium safety; Mg-T-specific data limited | Recommended at 200 to 600 mg DHA/day for fetal development |
| CAS | 778571-57-6 | 10417-94-4 |
| PubChem CID | 10691810 | 446284 |
| Wikidata | Q27151568 | Q207688 |
Safety profile
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)
Omega-3 (EPA/DHA)
Common side effects
- fishy aftertaste
- eructation (fish burps)
- mild dyspepsia
- loose stools at high doses
Contraindications
- fish allergy (use algal omega-3 alternative)
- active bleeding disorders
- scheduled surgery (discontinue 5-7 days prior)
Interactions
- warfarin and DOACs: additive antiplatelet effect at 2+ g/day; meaningful bleeding risk(moderate)
- aspirin and antiplatelet agents: additive bleeding risk at high doses(moderate)
- statins: complementary cardiovascular effects; no pharmacokinetic interaction(minor)
- antiarrhythmics: high-dose omega-3 increases AF risk; relevant in pre-existing arrhythmia(moderate)
Which Should You Take?
Omega-3 (EPA/DHA) 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 sleep onset or sleep quality, pick Magnesium L-Threonate.
- → If your priority is cardiovascular health, pick Omega-3 (EPA/DHA).
- → If your priority is healthspan extension, pick Omega-3 (EPA/DHA).
Edge case: Half-lives differ materially (Magnesium L-Threonate ~4 hr vs Omega-3 (EPA/DHA) ~48 hr). Omega-3 (EPA/DHA) reaches steady state faster; Magnesium L-Threonate is easier to dial in if tolerability is uncertain.
Default choice: Omega-3 (EPA/DHA). 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 L-Threonate and Omega-3 (EPA/DHA)?
Magnesium L-Threonate and Omega-3 (EPA/DHA) 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 L-Threonate or Omega-3 (EPA/DHA)?
Magnesium L-Threonate half-life is 4 hours; Omega-3 (EPA/DHA) half-life is 48 hours.
Can you stack Magnesium L-Threonate with Omega-3 (EPA/DHA)?
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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