Independent reference & toolkit 100 compounds graded · Last reviewed June 2026

Compare · Nootropic peptide

Dihexa vs Semax

Both are nootropic peptide compounds. Here's how they line up on the evidence — graded the same way.

DihexaSemax
Evidence 3/10 6/10
ClassNootropic peptideNootropic peptide
SummaryAn angiotensin IV-derived oligopeptide studied in animals for synaptogenesis and cognition; it has never been tested in humans, and its foundational mechanism paper was retracted in 2025.A Russian-approved nootropic/neuroprotective peptide whose human evidence is real but small, mostly Russian-language, and methodologically thin.
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Dihexa

Dihexa is a small peptide (a short chain of amino acids, the building blocks of proteins) made from a natural molecule called angiotensin IV. It got attention because of animal studies showing it could help neurons grow new connections and improve learning, along with a striking claim that it is…

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Semax

Semax is a lab-made peptide (a short chain of amino acids, the building blocks of proteins) that was developed in Russia in the late 1980s. Doctors there prescribe it for stroke and for problems with thinking and memory. It is not approved anywhere in the West, and most of the research on it is…

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