# Deep Dive Peptides — Cognitive & Nootropic Research Peptides > Deep Dive Peptides is a reference digest for Cognitive & Nootropic research peptides — Semax and Selank — summarized from peer-reviewed literature. A research reading desk, not a vendor or clinic. A thoughtful reading desk for the published science on Semax and Selank — what each was actually studied for, in which species, and how strong the evidence really is. ## The short version Deep Dive Peptides is a reading desk, not a store. It collects what the published research literature actually says about two peptides that keep appearing in conversations about **cognitive enhancement and anxiety**: Semax and Selank. A *peptide* is simply a short chain of amino acids — the same building blocks that proteins are made from, only far fewer of them joined together. Each of these two has been studied because it seems to nudge aspects of the brain's chemistry: boosting the proteins that help nerve cells grow and survive, quieting the signals that generate anxiety, or sharpening the mental processes involved in focused attention. This desk does one job: it tells you, in plain language and with citations, what each peptide was tested on, in which species (mostly rats and mice, with some Russian clinical work), and how far that evidence actually reaches. Neither compound is approved by the FDA or EMA. We do not sell anything, we do not give medical advice, and we never list a human dose. ## What are research peptides? Proteins are long chains of amino acids folded into complex three-dimensional shapes — an enzyme, a hormone, a structural fiber. A *peptide* is a much shorter chain of those same amino acids, sometimes only a handful of links long. Because they are small and structurally specific, peptides can act like keys fitting particular molecular locks — receptors, enzymes, transport proteins — turning certain cellular processes on or off. A *research peptide* is one that has been synthesized and studied in laboratories — in cell cultures, in animal models, occasionally in early human pilots — but has **not** been approved by a regulator as a medicine for a specific indication in most Western countries. Sellers of these compounds describe them as being for laboratory research only, and that framing matters: it means dosing, long-term safety, and real-world effectiveness in healthy humans are usually unestablished for the indications researchers care about. When this site reports a number, it reports it the way the study did — for example, *a single 50 micrograms per kilogram intranasal dose in Wistar rats* — never as a recommendation. Where a peptide derives from a natural molecule, we note that lineage, because it is usually the clue to what the compound does and why. ## How Semax and Selank fit into cognitive research The two peptides on this desk approach brain function from related but genuinely different angles, which is why they sit together. - [**Semax**](/semax) is the lead compound. It is a seven-amino-acid synthetic analog of the ACTH(4-7) fragment of adrenocorticotropic hormone, stabilized with a C-terminal Pro-Gly-Pro tail to slow enzymatic breakdown. In rodent brains it rapidly and region-specifically upregulates the growth factors BDNF and NGF [3][4], and in a cerebral ischemia model its neuroprotective effect is tied to a broad shift in immune- and vascular-gene expression rather than any single receptor [2]. A specific, reversible binding site with a dissociation constant of 2.4 nM has been characterized in rat brain [4]. - [**Selank**](/selank) approaches the brain from the anxiety side. It is a synthetic heptapeptide extending the endogenous immunomodulatory tetrapeptide tuftsin with the same C-terminal Pro-Gly-Pro tail. Its anxiolytic effects are attributed to positive allosteric modulation of GABA receptors [8] and inhibition of the enkephalin-degrading enzymes that normally break down the body's own calming opioid peptides [7]. In rat frontal cortex, a single dose shifted the expression of 45 GABA-pathway genes within one hour [10]. Together they sketch a picture of neuroactive peptide research: one compound tilted toward neuroprotection and cognitive sharpening via neurotrophins, the other toward anxiety reduction via GABAergic and enkephalinase pathways. Use the pages to read each in depth, or [compare these peptides](/compare) side by side. ## A note on how this desk reads the literature Deep Dive Peptides is a cross-referenced literature digest. Each peptide page summarizes the peer-reviewed studies for that compound, cites them by number, and links to a single shared [references list](/references) that aggregates every source across both. Where the evidence is thin, geographically concentrated (most Semax and Selank research originates from a small number of Russian institutions), or preclinical, we say so plainly — that caveat is part of the record, not a disclaimer tacked on at the end. We describe findings as they appear in the cited literature and the community-reported effects that researchers and users have documented — clearly labeled as anecdotal where they are anecdotal. We do not recommend, prescribe, or sell. The aim is an accurate, unhurried map of what is known, so you can read where the science is solid, where it is limited, and where it is still mostly a question. --- Peer-reviewed research, carefully read — a literature digest, not a clinic or a vendor, and never a dose.