Quick Comparison
| Magnesium L-Threonate | Tianeptine | |
|---|---|---|
| Half-Life | 2-3 hours (threonate carrier), but brain magnesium levels increase cumulatively | 2.5-3 hours (tianeptine), 7-8 hours (active metabolite MC5) |
| Typical Dosage | Standard: 1500-2000 mg Magnesium L-Threonate daily (providing 144 mg elemental magnesium). Often split into a daytime dose and a pre-bed dose. The Magtein brand uses 2000 mg daily (667 mg three times). | Prescription dose: 12.5 mg three times daily (Stablon). Extended-release: 25 mg once daily (Tianeurax). Do not exceed prescribed doses — abuse potential at higher doses due to opioid activity. |
| Administration | Oral (capsules, powder). The L-threonate form is specifically chosen for brain penetration. | Oral (tablets). Immediate-release (12.5 mg TID) or extended-release (25 mg QD). |
| Research Papers | 10 papers | 10 papers |
| Categories |
Mechanism of Action
Magnesium L-Threonate
The L-threonate carrier forms stable complexes with magnesium and transports it across the blood-brain barrier via specific transporters more effectively than inorganic magnesium salts or other chelated forms. Once in the brain, magnesium acts as a voltage-dependent blocker of the NMDA receptor channel at the physiological magnesium binding site within the ion pore, preventing excessive calcium influx and glutamate-mediated excitotoxicity. Magnesium also serves as a cofactor for over 300 enzymes including those involved in neurotransmitter synthesis (tyrosine hydroxylase, glutamic acid decarboxylase), ATP production (creatine kinase, pyruvate kinase), and DNA/RNA polymerase. Elevated brain magnesium enhances synaptic density and plasticity in the hippocampus and prefrontal cortex, likely through CREB-mediated gene expression and increased density of postsynaptic AMPA receptors.
Tianeptine
Tianeptine is a full agonist at mu-opioid (MOR) and delta-opioid (DOR) receptors, mediating both its antidepressant/anxiolytic effects and abuse potential at high doses. Paradoxically, it enhances serotonin reuptake via SERT—opposite to SSRIs—yet still produces antidepressant effects, possibly through opioid-mediated mood regulation. Tianeptine modulates glutamatergic signaling by reversing stress-induced downregulation of AMPA receptor subunits (GluA1/GluA2) and restoring synaptic plasticity. In the hippocampus and amygdala, it prevents stress-induced dendritic atrophy, spine loss, and CA3 pyramidal cell damage—likely through opioid receptor activation and downstream HPA axis effects. It increases BDNF levels and promotes neurogenesis. The combination of opioid agonism, glutamate normalization, and neuroplasticity enhancement underlies its unique profile.
Risks & Safety
Magnesium L-Threonate
Common
Drowsiness (often desired for sleep), mild headache initially, gastrointestinal discomfort.
Serious
None documented at standard doses. Magnesium toxicity is not a concern with oral supplementation in people with normal kidney function.
Rare
Diarrhea (less common than with other magnesium forms).
Tianeptine
Common
Nausea, constipation, abdominal pain, headache, dizziness, dry mouth.
Serious
Opioid-like effects at high doses (euphoria, dependence, respiratory depression). Withdrawal syndrome with abrupt cessation after chronic high-dose use. Abuse and overdose deaths reported.
Rare
Hepatotoxicity, skin reactions.
Full Profiles
Magnesium L-Threonate →
A form of magnesium specifically designed to cross the blood-brain barrier and increase brain magnesium levels. Developed at MIT, it is the only magnesium form clinically shown to raise CSF magnesium concentrations. Brain magnesium is critical for synaptic plasticity, and deficiency (common in modern diets) impairs learning, memory, and sleep quality. Sold under the brand name Magtein.
Tianeptine →
An atypical antidepressant with unique nootropic properties. Unlike SSRIs which increase serotonin, tianeptine is a mu-opioid receptor agonist and enhances serotonin reuptake. It reduces stress-induced neuronal damage in the hippocampus and amygdala, improving mood, cognition, and stress resilience simultaneously. Prescription medication in many countries but carries abuse potential at high doses.