Adrafinil vs NSI-189

Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.

AdrafinilNSI-189
CategoryNootropicsNootropics
Standard Dose300-600 mg once daily (for educational context — unregulated prodrug of a prescription medication)40 mg once daily (for educational context — investigational compound, not approved for any indication)
TimingEarly morning on an empty stomach for faster hepatic conversion. Onset delayed 60-90 minutes. Avoid afternoon/evening dosing due to long effective duration.Once daily, time of day not definitively established from clinical data. With or without food.
Cycle DurationShort-term or intermittent use strongly preferred. Avoid continuous daily use exceeding 3 months without liver function monitoring.Phase 2 trial used 12-week treatment duration. Long-term safety data unavailable.
Evidence Levelmoderate_humanmoderate_human
A

Adrafinil

Nootropics

Mechanism

Inactive prodrug that is hepatically metabolized to modafinil (via hepatic amidase enzymes) and its inactive acid metabolite modafinilic acid. The active metabolite modafinil then exerts its effects as a DAT inhibitor with downstream orexinergic, histaminergic, and noradrenergic activation. Conversion is incomplete — approximately 33-50% of adrafinil is converted to modafinil, with the remainder forming inactive metabolites. The hepatic first-pass metabolism means onset is delayed (60-90 minutes vs. 30-60 minutes for modafinil).

Standard Dosing

300-600 mg once daily (for educational context — unregulated prodrug of a prescription medication)

Timing

Early morning on an empty stomach for faster hepatic conversion. Onset delayed 60-90 minutes. Avoid afternoon/evening dosing due to long effective duration.

Cycle Duration

Short-term or intermittent use strongly preferred. Avoid continuous daily use exceeding 3 months without liver function monitoring.

Side Effects

  • All modafinil side effects apply
  • Elevated liver enzymes (ALT/AST)
  • Potential hepatotoxicity with chronic use
  • Skin reactions
  • GI distress (more common than with modafinil due to hepatic metabolism)

Contraindications

  • Hepatic impairment of any severity
  • Concurrent hepatotoxic medication
  • All contraindications for modafinil apply (cardiac conditions, anxiety disorders, pregnancy)
  • History of liver disease or elevated liver enzymes

Best Stacking Partners

L-TheanineAlpha-GPCMilk Thistle (hepatoprotective adjunct)
B

NSI-189

Nootropics

Mechanism

Benzylpiperizine-aminopyridine compound that stimulates neurogenesis of human hippocampus-derived neural stem cells in vitro and increases hippocampal volume in vivo. Mechanism is independent of serotonin or norepinephrine reuptake inhibition — fundamentally distinct from traditional antidepressants. Activates the TrkB receptor (BDNF receptor) and downstream Akt/PI3K signaling pathways to promote synaptic plasticity, long-term potentiation, and neuronal survival. Enhances BDNF expression in hippocampal subregions critical for memory consolidation and mood regulation. Originally developed as ALTO-100 (Alto Neuroscience) for treatment-resistant depression with cognitive impairment.

Standard Dosing

40 mg once daily (for educational context — investigational compound, not approved for any indication)

Timing

Once daily, time of day not definitively established from clinical data. With or without food.

Cycle Duration

Phase 2 trial used 12-week treatment duration. Long-term safety data unavailable.

Side Effects

  • Headache
  • GI discomfort
  • Dizziness
  • Somnolence
  • Dry mouth
  • Generally well-tolerated in Phase 1b and Phase 2 trials

Contraindications

  • Pregnancy and lactation (no safety data; neurogenic compounds carry theoretical teratogenic risk)
  • History of brain tumors (neurogenic stimulation could theoretically promote growth — speculative)
  • No regulatory approval for any indication — investigational use only

Best Stacking Partners

Lion's Mane (synergistic neurogenesis)Omega-3 (DHA)Magnesium L-Threonate

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