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 Phenylpiracetam hydrazide — 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.
Phenylpiracetam hydrazide is a non-peptide racetam-class small molecule — specifically a pyrrolidinone acetohydrazide in which the terminal carboxamide of phenylpiracetam (fonturacetam) is replaced by a carbohydrazide group. First synthesized in 1980 by a Russian medicinal-chemistry group screening 4-phenyl-2-pyrrolidinone derivatives for anticonvulsant activity, it has never been approved as a drug in any jurisdiction and has no human clinical trial data. The parent compound phenylpiracetam is explicitly listed on the WADA Prohibited List under S6.A (Non-Specified Stimulants); the hydrazide analog's own it is not on the WADA Prohibited List (only beta-2 agonists are prohibited, Category S3). It is sold by gray-market research-chemical vendors labeled 'not for human consumption.'
ISRIB
Phenylpiracetam hydrazide
Category
Legal Status
Mechanism
Side Effects
COA-verified vendors · trust score ≥70 required · single-vial price — bulk/bundle deals may be lower
ISRIB
Phenylpiracetam hydrazide
No pricing data yet.
Check Phenylpiracetam hydrazide prices →COA corpus from Disclosed Labs — independently tested batches only.
ISRIB
1
COAs
99.8%
Avg purity
1
Labs
Phenylpiracetam hydrazide
2
COAs
99.4%
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
No human clinical trials have been conducted; no ClinicalTrials.gov record or DrugBank entry exists. The sole preclinical finding is from the 1980 Glozman et al. synthesis paper: an ED<sub>50</sub> of approximately 310 mg/kg for seizure protection in a rodent electroshock assay (species, strain, sex, and route not fully recoverable from accessed sources). No published human toxicology, LD<sub>50</sub>, pharmacokinetics, or adverse-event data were located for this compound.
ISRIB and Phenylpiracetam hydrazide 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