Comparison
Magnesium L-Threonate vs Selank
Side-by-side of Magnesium L-Threonate and Selank. 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.
Selank
Selank peptide benefits: tuftsin analog heptapeptide, intranasal anxiolytic and nootropic. Russian clinical data, dosing, half-life, safety.
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
Selank
- •Synthetic heptapeptide analog of tuftsin developed in Russia in the 1990s
- •Approved in Russia for generalized anxiety disorder and asthenic conditions
- •Russian RCTs report anxiolytic effects comparable to medazepam without sedation or dependence
- •Modulates GABAergic and serotonergic signaling and BDNF expression in preclinical models
- •Most commonly administered intranasally; subcutaneous use is anecdotal
- •No Western-validated trials; not FDA approved; research-use-only outside Russia
Side-by-side
| Attribute | Magnesium L-Threonate | Selank |
|---|---|---|
| Category | supplement | peptide |
| Also known as | Mg-T, MgT, Magtein, magnesium threonate | TP-7, Tuftsin analog |
| Half-life (hr) ↗ | 4 | 0.5 |
| Typical dose (mg) ↗ | 2000 | 0.4 |
| Dosing frequency | 1 to 3 times daily | 2-3x daily (intranasal) |
| Routes | oral | intranasal, subcutaneous |
| Onset (hr) | 1 | 0.25 |
| Peak (hr) | 2 | 1 |
| Molecular weight | 294.5 | 751.85 |
| Molecular formula | C8H14MgO10 | C33H57N11O9 |
| 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. | Modulates GABAergic, serotonergic, and dopaminergic signaling. Increases BDNF expression in hippocampal neurons in preclinical models. Modulates enkephalin levels and immune cytokine signaling via tuftsin-like activity. |
| Legal status | OTC dietary supplement | Approved as a prescription anxiolytic in Russia; not FDA approved; research-use-only grey market in most other jurisdictions |
| WADA status | allowed | unknown |
| DEA / Rx | OTC supplement (not scheduled) | Not FDA approved; not scheduled; research-chemical status outside Russia |
| Pregnancy | Standard magnesium safety; Mg-T-specific data limited | Not recommended; insufficient data |
| CAS | 778571-57-6 | 129954-34-3 |
| PubChem CID | 10691810 | 11765600 |
| Wikidata | Q27151568 | Q4416793 |
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)
Selank
Common side effects
- mild nasal irritation (intranasal)
- transient drowsiness (uncommon)
- mild headache
Contraindications
- pregnancy
- lactation
- severe psychiatric disorder (insufficient data)
Interactions
- benzodiazepines: additive anxiolytic effect; potential for over-sedation when stacked(moderate)
- SSRIs: no documented adverse interaction; co-administration described in Russian protocols(minor)
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. Selank 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 anxiety reduction, pick Selank.
- → If your priority is mood, pick Selank.
Edge case: If you want to avoid research-only / gray-market sourcing, Magnesium L-Threonate is the more accessible choice.
Default choice: Magnesium L-Threonate. Lower friction to source, and broader goal coverage. Reach for Selank 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 Selank?
Magnesium L-Threonate and Selank differ in category (supplement vs peptide), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Magnesium L-Threonate or Selank?
Magnesium L-Threonate half-life is 4 hours; Selank half-life is 0.5 hours.
Can you stack Magnesium L-Threonate with Selank?
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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