Cognitive Enhancement

Cognitive peptides modulate neurotrophic factors — the proteins responsible for neuron growth, survival, and synaptic plasticity. The two most important neurotrophic factors in this context are BDNF (Brain-Derived Neurotrophic Factor), which supports learning, memory formation, and neuronal resilience, and NGF (Nerve Growth Factor), which is critical for the maintenance and survival of cholinergic neurons. By upregulating these factors, cognitive peptides aim to enhance the brain's capacity for forming new connections and protecting existing neural circuits against damage and age-related decline.

Semax and Selank are the most established compounds in this category, both developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. Semax is a synthetic analog of ACTH(4-10) — a fragment of adrenocorticotropic hormone — that has been approved in Russia and Ukraine since the 1990s as a nootropic and neuroprotective agent. It upregulates BDNF expression and modulates serotonergic and dopaminergic systems. Selank is a synthetic analog of the immunomodulatory peptide tuftsin, primarily researched for its anxiolytic (anti-anxiety) effects alongside cognitive benefits, acting through GABAergic modulation and neurotrophic factor expression. Both are administered intranasally, which provides relatively direct access to the central nervous system.

On the more experimental end, Dihexa is a potent hepatocyte growth factor (HGF) modulator that has demonstrated extraordinary potency in animal models of cognitive enhancement — active at picomolar concentrations, orders of magnitude below most peptides. PE-22-28 is a newer compound that acts as a positive allosteric modulator of the 5-HT1A receptor while also increasing BDNF levels. Cerebrolysin is a unique multi-peptide preparation derived from porcine brain tissue, containing a mixture of neurotrophic peptides and free amino acids. It has been used clinically in Europe and Asia for stroke recovery and Alzheimer's disease, with a substantial (if debated) body of clinical trial data. DSIP (Delta Sleep-Inducing Peptide) rounds out the category with its effects on sleep architecture, which is increasingly recognized as foundational to cognitive performance.

The regulatory landscape in this category is distinctly split. Semax and Selank are approved medications in Russia but have no regulatory status in the United States or Europe. Cerebrolysin is approved in many countries but not by the FDA. Dihexa and PE-22-28 remain purely experimental research compounds with no human clinical trials. This gradient from clinically deployed to early-stage experimental is important context for evaluating each compound.