Comparison
Magnesium L-Threonate vs Rapamycin
Side-by-side of Magnesium L-Threonate and Rapamycin. 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.
Rapamycin
Rapamycin for longevity: sirolimus, an mTOR inhibitor with ITP mouse lifespan data. Off-label geroprotective dosing remains investigational.
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
Rapamycin
- •Inhibits mTORC1 signaling by binding FKBP12, reducing protein synthesis and relieving autophagy suppression
- •ITP mouse program reproduced lifespan extension of ~10 to 25% across multiple genetic backgrounds and sexes
- •Mannick trials showed improved influenza vaccine response in elderly adults using analogs of rapamycin
- •PEARL human trial reported acceptable safety at 5 to 10 mg weekly with some functional and lean-mass signals
- •Common dose-limiting adverse effects include stomatitis, acne-like rash, and mildly elevated lipid markers
- •CYP3A4 substrate: grapefruit, ketoconazole, and clarithromycin substantially raise rapamycin exposure
Side-by-side
| Attribute | Magnesium L-Threonate | Rapamycin |
|---|---|---|
| Category | supplement | pharmaceutical |
| Also known as | Mg-T, MgT, Magtein, magnesium threonate | Sirolimus, Rapamune |
| Half-life (hr) ↗ | 4 | 62 |
| Typical dose (mg) ↗ | 2000 | 6 |
| Dosing frequency | 1 to 3 times daily | weekly (longevity protocols); daily for transplant indication |
| Routes | oral | oral |
| Onset (hr) | 1 | 1 |
| Peak (hr) | 2 | 2 |
| Molecular weight | 294.5 | 914.17 |
| Molecular formula | C8H14MgO10 | C51H79NO13 |
| 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. | Binds FKBP12, and the resulting complex inhibits mTORC1, reducing protein synthesis and autophagy suppression downstream of nutrient and growth-factor signaling. |
| Legal status | OTC dietary supplement | Prescription only (off-label for longevity) |
| WADA status | allowed | allowed |
| DEA / Rx | OTC supplement (not scheduled) | Rx only (not a controlled substance) |
| Pregnancy | Standard magnesium safety; Mg-T-specific data limited | Not recommended |
| CAS | 778571-57-6 | 53123-88-9 |
| PubChem CID | 10691810 | 5284616 |
| Wikidata | Q27151568 | Q410174 |
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)
Rapamycin
Common side effects
- mouth ulcers (stomatitis)
- acne-like rash
- GI upset
- altered lipid panel
- delayed wound healing
Contraindications
- active infection
- severe hepatic impairment
- planned surgery (delayed wound healing)
- pregnancy
- live vaccines within dosing window
Interactions
- strong CYP3A4 inhibitors (ketoconazole, clarithromycin, grapefruit): substantially raises rapamycin levels, toxicity risk(major)
- strong CYP3A4 inducers (rifampin, St John's wort): lowers rapamycin levels, reduced effect(major)
- ACE inhibitors: increased risk of angioedema(moderate)
- live vaccines: reduced vaccine efficacy due to immunosuppression(major)
Which Should You Take?
Magnesium L-Threonate comes out ahead for most readers on the criteria we weight: 2 catalogued goals, OTC dietary supplement, oral dosing, with a Tier-B outcome catalogued. Rapamycin is the right call when one of the conditionals below applies.
- → If your priority is focus or working memory, pick Magnesium L-Threonate.
- → If your priority is sleep onset or sleep quality, pick Magnesium L-Threonate.
- → If your priority is healthspan extension, pick Rapamycin.
- → If your priority is immune support, pick Rapamycin.
Edge case: If you want to avoid prescription-only, Magnesium L-Threonate is the more accessible choice.
Default choice: Magnesium L-Threonate. Lower friction to source, and broader goal coverage. Reach for Rapamycin 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 Rapamycin?
Magnesium L-Threonate and Rapamycin differ in category (supplement vs pharmaceutical), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Magnesium L-Threonate or Rapamycin?
Magnesium L-Threonate half-life is 4 hours; Rapamycin half-life is 62 hours.
Can you stack Magnesium L-Threonate with Rapamycin?
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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