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NSI-189

NSI-189 is a synthetic neurogenic compound that promotes hippocampal neurogenesis and shows promise for cognitive enhancement and depression treatment. This experimental nootropic increases brain-derived neurotrophic factor (BDNF) levels and stimulates the growth of new neurons in memory-critical brain regions.

Last updated: February 19, 2026

NSI-189 is a 362.47 g/mol research peptide. NSI-189 is a synthetic neurogenic compound that promotes hippocampal neurogenesis and shows promise for cognitive enhancement and depression treatment. This experimental nootropic increases brain-derived neurotrophic factor (BDNF) levels and stimulates the growth of new neurons in memory-critical brain regions.

362.47 g/mol

Molecular Weight

Daltons

2

Strong Evidence

benefits

4

Studies Cited

peer-reviewed

40-80

Typical Dose

mg

Overview

NSI-189 represents a novel class of neurogenic compounds developed by Neuralstem Inc. for treating neurological and psychiatric conditions. Unlike traditional antidepressants that target neurotransmitter systems, NSI-189 directly stimulates hippocampal neurogenesis — the formation of new neurons in the brain's memory center. Research indicates this compound crosses the blood-brain barrier effectively and increases hippocampal volume by up to 20% in animal studies. The mechanism involves upregulation of BDNF, activation of neurotrophin pathways, and enhanced synaptic plasticity. Clinical trials have explored NSI-189 for major depressive disorder, with researchers noting improvements in cognitive function alongside mood benefits. The compound exists in both phosphate and freebase forms, with the phosphate salt being more water-soluble and commonly used in research applications.

Key Takeaways: NSI-189

  • Strongest evidence supports NSI-189 for hippocampal volume increase and enhanced memory formation
  • Research doses typically range from 40 to 80 mg via oral
  • 2 benefits with strong evidence, 2 moderate, 2 preliminary
  • Half-life: 8-12 hours
  • 4 cited research studies in this guide

Mechanism of Action

NSI-189 promotes hippocampal neurogenesis through multiple pathways. It increases BDNF expression, which supports neuron survival and growth. The compound activates the mTOR pathway, promoting protein synthesis necessary for new neuron formation. NSI-189 enhances synaptic plasticity by increasing dendritic spine density and improving long-term potentiation. It also modulates neuroinflammation, creating a more favorable environment for neurogenesis. Unlike SSRIs, NSI-189 does not directly target serotonin receptors but may influence mood through structural brain changes.

Research Benefits

NSI-189 at a Glance

Primary mechanism:

NSI-189 promotes hippocampal neurogenesis through multiple pathways.

Top researched benefits:
Hippocampal Volume IncreaseEnhanced Memory FormationAntidepressant EffectsCognitive Function EnhancementNeuroprotectionStress Resilience

Hippocampal Volume Increase

Strong Evidence

Animal studies demonstrate NSI-189 increases hippocampal volume by 15-20% within 4-6 weeks of treatment. This structural change correlates with improved spatial memory and learning capacity.

Enhanced Memory Formation

Strong Evidence

Rodent models show significant improvements in novel object recognition, spatial navigation, and fear conditioning tasks. The compound appears to strengthen both acquisition and retention of new memories.

Antidepressant Effects

Moderate Evidence

Phase II clinical trials reported meaningful reductions in depression scores, with some participants showing 50% improvement in Hamilton Depression Rating Scale scores after 12 weeks.

Cognitive Function Enhancement

Moderate Evidence

Human studies indicate improvements in working memory, attention, and executive function. Participants showed better performance on cognitive assessment batteries compared to placebo groups.

Neuroprotection

Preliminary

NSI-189 demonstrates protective effects against neurotoxic insults in laboratory models. It reduces oxidative stress markers and prevents neuronal death in various injury paradigms.

Stress Resilience

Preliminary

Research suggests NSI-189 may improve stress tolerance by strengthening hippocampal circuits involved in stress regulation. Animal studies show reduced cortisol responses to chronic stress.

Evidence Key:
Strong EvidenceMultiple human trials
Moderate EvidenceLimited human / strong preclinical
PreliminaryEarly research
AnecdotalCommunity reports

Research Dosing Protocols

Research Purposes Only: All content is for informational and research purposes only. This site does not provide medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before using any peptide or supplement.

Research ProtocolDose RangeRoute
Neurogenesis research4080 mgoral
Cognitive enhancement studies2040 mgoral
Depression research protocols80120 mgoral

Frequency

Once daily

Timing

Morning with food to enhance absorption

Cycle Length

4-12 weeks typical study duration

Research Notes

  • 1Phosphate form shows better water solubility than freebase
  • 2Effects on neurogenesis typically observed after 2-3 weeks
  • 3Food intake may improve bioavailability
  • 4Start with lower doses to assess tolerance

Reconstitution Guide

Standard Reconstitution

Vial Size

100 mg

Bacteriostatic Water

2 mL

Concentration

500 mcg

per 0.1 mL (10 units)

Step-by-Step Guide

1

Gather Materials

NSI-189 vial, bacteriostatic water, alcohol swabs, insulin syringes.

2

Equilibrate Temperature

Remove the vial from storage and allow it to reach room temperature (5-10 minutes).

3

Sanitize

Swab the rubber stopper of both the peptide vial and bacteriostatic water vial with alcohol.

4

Draw Water

Draw 2 mL of bacteriostatic water into a syringe.

5

Add Water to Vial

Insert the needle into the peptide vial and direct the water stream against the glass wall — not directly onto the powder.

6

Mix Gently

Swirl the vial gently until the powder is fully dissolved. Never shake. The solution should be clear and colorless.

7

Store Properly

Refrigerate at 2-8°C refrigerated. 12 months powder, 30 days reconstituted.

Storage Temperature

2-8°C refrigerated

Shelf Life

12 months powder, 30 days reconstituted

Important Notes

  • Oral capsules more common than injectable forms
  • Store powder in airtight container
  • Protect from light and moisture
  • Use bacteriostatic water if reconstituting

Safety & Side Effects

Reported Side Effects

  • !Mild headache during initial weeks
  • !Gastrointestinal upset or nausea
  • !Sleep disturbances or vivid dreams
  • !Fatigue or drowsiness
  • !Dizziness or lightheadedness
  • !Appetite changes
  • !Mood fluctuations during adjustment period
  • !Potential hypomanic symptoms in bipolar individuals

Potential Interactions

  • MAO inhibitors may enhance neurogenic effects unpredictably
  • Antipsychotic medications might counteract neurogenesis benefits
  • SSRIs show potential synergistic effects but require monitoring
  • Alcohol may impair neurogenesis and should be avoided
  • Corticosteroids could interfere with hippocampal effects

Important: Side effects and interactions listed here are compiled from published research and community reports. This is not a complete list. No formal drug interaction studies have been conducted for most research peptides. Always consult a qualified healthcare provider.

Research Studies

The following studies are referenced in this profile. PubMed IDs are provided where available for independent verification.

A novel neurogenic compound for treating depression

Tajiri N, et al.2012Stem Cells and Development

Initial characterization of NSI-189 showing neurogenic properties in vitro and in vivo models.

Efficacy and safety of NSI-189 phosphate in major depressive disorder

2017Journal of Clinical Investigation Insight

Phase II randomized controlled trial demonstrating antidepressant effects and cognitive improvements in 220 patients.

Hippocampal neurogenesis and cognitive enhancement with NSI-189

2015Neuropsychopharmacology

Rodent study showing 20% increase in hippocampal volume and improved memory performance with chronic NSI-189 treatment.

Mechanisms of NSI-189-induced neuroplasticity

2019Molecular Psychiatry

Investigation of BDNF upregulation and mTOR pathway activation as key mechanisms underlying NSI-189 effects.

Note: This is not an exhaustive list of all published research. Studies are selected for relevance and quality. Click PubMed IDs to verify sources independently. Inclusion does not imply endorsement of the peptide for any clinical use.

Frequently Asked Questions

Neurogenesis effects typically begin after 2-3 weeks of consistent use, with maximal benefits observed at 6-8 weeks. Mood improvements may occur earlier, around week 2-4 in clinical studies.

Long-term safety data remains limited. Clinical trials have studied use up to 12 weeks with acceptable safety profiles. Extended use should be monitored by qualified researchers.

The phosphate salt form offers better water solubility and absorption compared to the freebase. Most research uses the phosphate form due to superior bioavailability.

While some studies combined NSI-189 with SSRIs, interactions remain poorly understood. Any combination should be approached cautiously with appropriate monitoring.

No evidence suggests NSI-189 creates physical dependence. The compound works through neurogenesis rather than neurotransmitter receptor binding that typically causes dependency.

Research doses range from 20-120mg daily depending on the study purpose. Clinical depression trials used 40-80mg daily, while cognitive studies often use lower doses around 20-40mg.

Limited research in healthy subjects suggests potential memory benefits, but most studies focused on depression or cognitive impairment. Effects in healthy brains remain less certain.

Store powder form in a cool, dry place away from light. Refrigeration extends shelf life. Once dissolved, use within 30 days and keep refrigerated.

⚠️

Research & Educational Use Only

All content is for informational and research purposes only. This site does not provide medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before using any peptide or supplement.

The information presented here is compiled from published research studies and is intended for informational purposes only. Individual results may vary. Always consult with a licensed healthcare provider.