deep cognitive repair

why it works

This is the stack most likely to attract a claim the evidence cannot carry, so the house rule applies hardest here: say what is not known rather than letting silence imply it is settled.

NSI-189 is a benzylpiperizine-aminopyridine investigated for major depressive disorder, associated with hippocampal neurogenesis and increased hippocampal volume in preclinical work. ⚠️ Its human trial history matters and is not a success story: it showed signal in an early phase II study and then did not meet its primary endpoint in the larger follow-up. It is the item here with the most human data and the most disappointing human data, and both of those facts belong on the page.

⚠️ DIHEXA'S CAVEAT IS NOT OPTIONAL AND IS THE MOST IMPORTANT THING ON THIS PAGE. Its HGF and c-Met synaptogenesis story rests on work retracted in 2025, alongside a second retraction and an expression of concern that remains in force; its own entry carries all three notices. That does not make Dihexa a fraud and it does not make the compound inert; it means the specific evidence people cite for its mechanism is no longer citable. It is in this roster by the owner's explicit instruction and it is deliberately absent from the neuroprotection stack, which is consistent: the compound is not banned here, it was simply not the pick when the goal was protection.

Cerebrolysin is a peptide preparation from porcine brain tissue with a substantial but contested clinical literature in stroke, vascular dementia and traumatic brain injury; several meta-analyses reach different conclusions depending on which trials they include. ⚠️ It is given parenterally, usually by intramuscular or intravenous injection over a course of days, which is a real practical barrier and not a footnote.

how they work together

These three converge on neurotrophic support and arrive at it from completely different directions, which is the honest description rather than a shared pathway.

NSI-189 is a small molecule associated with hippocampal neurogenesis in preclinical work, and the hippocampus is specifically where adult neurogenesis occurs in humans. Cerebrolysin is not a molecule at all but a mixture of low-molecular-weight peptides and amino acids derived from porcine brain tissue, with neurotrophic activity attributed to fragments resembling endogenous factors; its mechanism is a family of effects rather than a target. Dihexa was designed as an angiotensin IV analogue acting through hepatocyte growth factor and its receptor c-Met, which would place it upstream of synaptogenesis.

Where they genuinely meet is that all three propose to add structure rather than to modulate signalling in existing structure. That is what makes it a repair stack rather than a performance one, and it is also why nothing here should be expected to work quickly.

what it feels like

Slow, and honestly reported as inconsistent. Cerebrolysin is usually run in courses over weeks and its reported effects build across a course rather than within a day.

NSI-189's human trial reports include mood and cognitive measures that did not consistently separate from placebo, which is worth holding alongside any anecdote.

The most useful thing to say is that a repair stack aimed at damage already done has no reliable early signal, and that a strong first-week effect from any of these is more likely to be expectation than mechanism.