Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of ISRIB and Nefiracetam — mechanism, side effects, legal status, and pricing.
ISRIB is a non-peptide small-molecule eIF2B activator (bis-chlorophenoxyacetamide-cyclohexane class) that antagonizes the integrated stress response (ISR) by stabilizing the eIF2B guanine-nucleotide exchange factor complex. It is not an approved drug and has no completed human clinical trials or validated human safety or efficacy data. Chemically distinct eIF2B-activator analogs (DNL343, ABBV-CLS-7262) have reached human trials, but DNL343 missed primary endpoints in a Phase 2/3 ALS trial (January 2025). ISRIB is sold by reagent suppliers for research use only.
Nefiracetam is a non-peptide small molecule in the racetam (pyrrolidinone/2-oxopyrrolidine acetamide) class, investigated as a cognitive enhancer. It was never approved by the FDA, EMA, or Japan's PMDA; Daiichi Seiyaku withdrew its Japanese NDA (Translon) in February 2002 after a repeat Phase III trial in dementia failed to demonstrate efficacy. A US/Canada Phase II trial in poststroke depression (600 mg and 900 mg/day) showed no overall separation from placebo, though a subgroup analysis suggested benefit in the most severely depressed patients at 900 mg. No validated therapeutic dose or approved indication exists; it is sold by research-chemical and laboratory-reagent suppliers for research use only.
ISRIB
Nefiracetam
Category
Legal Status
Mechanism
Side Effects
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ISRIB
Nefiracetam
No pricing data yet.
Check Nefiracetam prices →COA corpus from Disclosed Labs — independently tested batches only.
ISRIB
1
COAs
99.8%
Avg purity
1
Labs
Nefiracetam
2
COAs
99.6%
Avg purity
2
Labs
No completed or published human clinical trials of ISRIB itself exist; it has no validated human pharmacokinetic, safety, or efficacy data. In mice, systemic ISRIB enhanced spatial and fear-associated long-term memory in healthy animals, reversed hippocampus-dependent spatial-learning and working-memory deficits weeks after traumatic brain injury, and reset elevated ISR activity in aged (18–24 month) mice, reversing age-related spatial-memory decline with a brief 3-day dosing course. In prion-disease transgenic mice, ISRIB partially restored protein synthesis and prevented neurodegeneration without the pancreatic exocrine toxicity seen with PERK-inhibitor approaches. In vitro and in a patient-derived xenograft mouse model, ISRIB combined with imatinib attenuated RAS/RAF/MAPK and STAT5 signaling and eliminated therapy-resistant chronic myeloid leukemia cells.
Key references
Human clinical data are limited and largely negative or mixed. Japanese Phase II/III trials in dementia/cognitive sequelae after cerebrovascular disorders showed improvement over placebo in some early trials, but a Ministry of Health-mandated repeat Phase III trial under revised guidelines failed to demonstrate efficacy, and Daiichi Seiyaku withdrew its Japanese NDA (Translon) in February 2002. A US/Canada multicenter randomized double-blind Phase II trial (28 sites, 1999–2001, n=159) tested nefiracetam 600 mg and 900 mg/day vs. placebo for poststroke depression; the drug did not separate from placebo overall (response >70%, remission >40% in both arms) but showed significant benefit in the most-severely-depressed subgroup at 900 mg (Robinson et al., J Neuropsychiatry Clin Neurosci 2008). A related post hoc analysis examined apathy outcomes in the same cohort. Preclinical findings include: rat cortical neurons showed potentiation of native α4β2-type nicotinic acetylcholine receptor currents via a G(s)-protein-dependent pathway; rat dorsal root ganglion neurons showed dual concentration-dependent effects on GABA_A receptor-channel currents mediated via cAMP-dependent protein kinase and Gi/Go proteins; rat neuronal preparations showed enhancement of high-voltage-activated N/L-type Ca²⁺ channel currents and modulation of NMDA receptor function via PKC-dependent phosphorylation; rat passive avoidance models showed reversal of apomorphine-induced amnesia and preservation of hippocampal NCAM-mediated memory consolidation during scopolamine disruption.
ISRIB and Nefiracetam 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
Disclosed Labs