Cognitive research has drawn on a range of peptide mechanisms — from stress-response modulation to direct synaptic growth signaling. Below is an overview of what’s being studied in this category, along with an honest look at how strong the evidence is for each.

Compounds commonly studied for brain function research

• Semax — A synthetic heptapeptide derived from a fragment of ACTH, developed and studied extensively in Russia. Research has focused on its neuroprotective effects and its role in upregulating BDNF (brain-derived neurotrophic factor), a protein associated with neuron growth and survival.
• Selank — A synthetic analog of the immunomodulatory peptide tuftsin, also developed in Russia. Studied primarily for anxiolytic (anxiety-modulating) effects without the sedation associated with traditional anti-anxiety compounds, alongside some immune-system research interest.
• Dihexa — A synthetic hexapeptide derived from angiotensin IV, developed at Washington State University. Studied for its potent effect on synaptogenesis (new synapse formation) via the HGF/c-Met signaling pathway — in preclinical hippocampal models, it showed a dramatically larger effect than BDNF itself. Important context: this evidence is entirely preclinical (cell and rodent studies), no human trials exist, and one of the foundational papers behind it carries a 2021 Notice of Concern from its journal over possible image manipulation. We think that’s worth knowing before you research it, not after.
• Cerebrolysin — Distinct from the synthetic peptides above: it’s a mixture of low-molecular-weight neuropeptides and free amino acids derived from purified porcine brain tissue, not a single defined compound. It has one of the largest clinical evidence bases of anything on this page (over 160 trials, approved for prescription use in 50+ countries) but remains unapproved by the FDA, and independent Cochrane reviews have found more mixed results than individual manufacturer-sponsored trials suggest.
• PE-22-28 — A synthetic heptapeptide derived from spadin, engineered for potent, selective blockade of the TREK-1 potassium channel. Rodent studies show antidepressant-like effects and increased hippocampal neurogenesis. Preclinical only — no completed human trials exist.
• FGL (FG Loop) — A synthetic 15-amino acid peptide derived from the neural cell adhesion molecule (NCAM), studied as an FGFR1 agonist. Research has shown it facilitates long-term synaptic plasticity and memory consolidation in animal models via new synapse formation.

What the research generally focuses on

• Neurotrophic factor signaling (BDNF and related pathways) and its relationship to cognitive resilience
• Stress and anxiety modulation via non-sedating mechanisms
• Synaptic plasticity and the growth-factor pathways that drive it

Before you start

New to this category? Start with our What Are Peptides? overview and Peptide Stability & Handling in Research Settings guide.

This content is provided for research and informational purposes only. Agape Compounds products are not intended for human or animal consumption.