Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of NSI-189 and Oxiracetam — mechanism, side effects, legal status, and pricing.
NSI-189 (INN: amdiglurax; developmental code ALTO-100) is a non-peptide small-molecule benzylpiperazine-aminopyridine derivative investigated as a neurogenic/neuroplasticity-modulating agent for major depressive disorder. It stimulates hippocampal neural progenitor proliferation and differentiation in vitro and neurogenesis in vivo (mouse), acting independently of monoamine reuptake pathways. NSI-189 has never been FDA-approved; Phase 2 monotherapy trials in MDD (220 patients, 2020) and a Phase 2b trial under Alto Neuroscience (~300 patients, 2024) both failed to meet primary MADRS endpoints, and it remains investigational only.
Oxiracetam is a non-peptide racetam-class cognitive enhancer, structurally the 4-hydroxy analog of piracetam. It is approved as a prescription drug for dementia in Italy (since 1984) and China, but is NOT FDA-approved in the United States. The FDA has classified oxiracetam as a 'new drug' requiring approval and determined it does not qualify as a dietary supplement; in the US it is sold only as an unregulated gray-market research chemical.
NSI-189
Oxiracetam
Category
Legal Status
Mechanism
Side Effects
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NSI-189
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NSI-189
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2
COAs
99.4%
Avg purity
2
Labs
Human data exist from three registered trials: a Phase 1 single-dose PK study in healthy volunteers (NCT01310881), a Phase 1B multiple-dose-escalation study in 24 MDD patients (28-day inpatient dosing at 40 mg once/twice/thrice daily; half-life ~17.4–20.5 hours; no serious adverse events; no significant hippocampal volume change at day 28 or 84), and a Phase 2 double-blind, placebo-controlled trial in 220 MDD outpatients (12 weeks at 40 mg or 80 mg daily) that missed its primary MADRS endpoint at both doses (p=0.22 and p=0.34, respectively), with some significant secondary/patient-reported benefits at 40 mg. A Phase 2b trial under the ALTO-100 designation (~300 adults, 34 US sites, 6-week double-blind) also failed to meet its primary MADRS endpoint (topline October 2024). Preclinical findings include improved motor/neurological deficits sustained to 24 weeks in a rat stroke model (oral dosing starting 6 hours post-MCAO; increased hippocampal/cortical MAP2 neurite outgrowth; in vitro OGD/R assays showed reduced cell death and upregulated BDNF/SCF), reversal of motor and cognitive impairments in an Angelman syndrome mouse model (with mild performance enhancement in wild-type mice), improved Barnes maze memory retention in a 5xFAD Alzheimer's mouse model (conference abstract), and prevention of peripheral neuropathy indices with increased hippocampal neurogenesis/synaptic markers/volume and protected long-term memory in mouse and rat models of type 1 and type 2 diabetes, alongside enhanced mitochondrial function in a type 2 diabetic rat model.
Key references
Multiple placebo-controlled human trials exist in dementia, organic brain syndrome, and traumatic brain injury populations, plus human pharmacokinetic studies. One double-blind controlled trial in elderly organic-brain-syndrome patients used doses titrated from 400–2400 mg/day; a separate placebo-controlled trial in senile dementia of Alzheimer type and multi-infarct dementia used 800 mg twice daily and reported improvement on cognitive measures versus placebo. Preclinical findings include AMPA receptor modulation and enhanced neurotransmitter release in rat hippocampal preparations, and identification of the (S)-enantiomer as the active component alleviating cognitive impairment in a rat chronic cerebral hypoperfusion model. Oral bioavailability in humans is ~56% (versus 28–42% in rats, 81–90% in dogs), with predominantly renal excretion of unchanged drug.
NSI-189 and Oxiracetam are both in the Cognitive category and may have overlapping mechanisms. Researchers should review both profiles carefully, understand the mechanisms of action, and monitor the relevant biomarkers when combining compounds in the same class. As always, consult a licensed healthcare provider before making any decisions about combining research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Contraindications
Lab Testing
Key references