The Research Peptide
Resource

Overview

Selank and Semax are two of the most extensively studied synthetic nootropic peptides in the scientific literature, with the majority of foundational research conducted at Russian academic institutions. Both have achieved regulatory approval in Russia and Ukraine for clinical indications — Semax as a nasal spray for cognitive and cerebrovascular conditions, and Selank for anxiety disorders — providing a clinical data backdrop that is rare among research peptides.

Semax: ACTH Analog and BDNF Upregulator

Semax is a synthetic analog of the ACTH(4-7) fragment, with the addition of a Pro-Gly-Pro sequence at the C-terminus that prolongs activity. Unlike full ACTH, it lacks adrenocortical activity — meaning it doesn't elevate cortisol — while retaining the neurotrophic properties of the ACTH sequence. Its primary mechanism involves upregulation of BDNF (Brain-Derived Neurotrophic Factor) and NGF in the hippocampus and cortex. Research has documented improvements in memory consolidation, learning speed, and attention span in rodent models, as well as neuroprotective effects in ischemia and hypoxia models.

Selank: Anxiolytic Without Sedation

Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is a synthetic analog of the immunomodulatory tetrapeptide Tuftsin. Its anxiolytic mechanism involves modulation of the GABA-A receptor system and stabilization of enkephalin metabolism — inhibiting the enzymes that degrade endogenous enkephalins. This produces anxiolytic effects comparable to benzodiazepines in animal models without the sedation, dependence, or cognitive impairment associated with that drug class. Its immunomodulatory component — inherited from Tuftsin — adds a dimension relevant to stress-immunity research.

• BDNF upregulation and neuroprotection in ischemia models (Semax)
• Cognitive enhancement: learning, memory, and attention research (Semax)
• GABA-A modulation and anxiolytic activity (Selank)
• Enkephalin stabilization and mood regulation research (Selank)
• Immunomodulatory effects — NK cell activity, cytokine balance (Selank)

Background

Dihexa (N-hexanoic-Tyr-Ile-(6) aminohexanoic amide) is a small molecule derived from Angiotensin IV research at Washington State University. The research group of Joseph Wright discovered that Angiotensin IV fragments could potentiate HGF/c-Met signaling in the brain — a pathway involved in synaptic growth, dendritic arborization, and hippocampal neuroplasticity. Dihexa was designed as a stable, CNS-penetrant version of these compounds.

Cognitive Research Profile

Dihexa's most striking preclinical finding is its apparent potency in cognitive enhancement models. Studies in aged rodents with cognitive impairment showed significant improvement in spatial learning and memory tasks (Morris Water Maze, Radial Arm Maze) at doses far below those needed for other cognitive enhancement compounds. The proposed mechanism — HGF/c-Met-driven synaptogenesis and dendritic spine growth — distinguishes it from BDNF-based approaches and makes it of significant interest for neurodegeneration research.

• Reversal of cognitive deficits in aged and scopolamine-impaired rodent models
• HGF/c-Met signaling and synaptogenesis in hippocampal tissue
• Dendritic spine density increases in hippocampal cultures
• Alzheimer's and neurodegeneration model research