NSI-189 (also known as Amdiglurax, ALTO-100, ALTO-300)
NSI-189 phosphate (INN: Amdiglurax); synonyms: NSI-189, ALTO-100, ALTO-300; CAS 1270138-40-3 (freebase), CAS 1270138-41-4 (phosphate salt); DrugBank DB16230; UNII YVE9U408ZL
Investigational compound that has undergone Phase 2 clinical trials (Neuralstem). Not FDA-approved. No current compounding pathway.
A small molecule (not actually a peptide) that stimulates growth of new brain cells in the hippocampus (the brain's main memory and learning center) as a potential new approach to treating depression. Clinical trials in 220 patients showed it was safe and well-tolerated, but did not show strong enough improvement in depression symptoms to meet study goals.
This entry is a cited research summary, not an established treatment reference. Dosing language is included as source context, not as medical instruction.
Safety Summary
In clinical trials (Phase 1B: PMID 26643541; Phase 2: PMID 30626911; PMC7303010), NSI-189 phosphate was generally well tolerated at doses of 40-120 mg/day. No treatment-related serious adverse events (SAEs) were reported in any trial. No dose-limiting toxicities were identified. Discontinuation rates in the Phase 2 trial were lower in the NSI-189 groups than placebo. Complete adverse event frequency tables by dose cohort were not published in the publicly available manuscripts. No abuse potential has been reported (DrugBank DB16230; Wikipedia). No anti-drug antibody formation or immunogenicity concerns exist (NSI-189 is a small molecule, not a biologic). Community reports (ANECDOTAL) consistently cite anxiety as the most common adverse effect, along with paresthesia, headaches, and depersonalization, particularly during early dosing or at higher doses. These effects often abate with dose reduction or cycling. No formal drug-drug interaction data (CYP inhibition/induction, transporter effects) has been published (DrugBank DB16230). Long-term safety data beyond 12 weeks is not available from controlled clinical studies; no tolerance, withdrawal, or carcinogenicity signals have been reported in the available data.
Clinical check-in
If real-world use or exposure is being considered, review potential interactions, contraindications, and monitoring needs with a licensed clinician rather than relying on summary copy alone.
Sources: [1-10]