What's on the label is the measured result — net peptide mass, not gross powder weight, plus RP-HPLC purity, on a lot-numbered COA for every batch.
Net peptide mass and RP-HPLC purity — a lot-numbered COA for every batch.
Net peptide mass + HPLC purity, per lot.
PCAC will review 7 peptides for the 503A bulks list, BPC-157, KPV, TB-500, MOTS-c, Emideltide, Semax, Epitalon. Read our briefing →
PCAC will review 7 peptides for the 503A bulks list. Read →
FDA PCAC reviews 7 peptides in July. Read →
Tuftsin analog · anxiolytic research peptide
PeptideXpo buyer fit
This PeptideXpo page is intentionally positioned for distributors, OEM buyers, and procurement teams comparing Selank inside a wider peptide catalog. It is not trying to be the deepest single-molecule monograph; the differentiated intent is assortment planning, export-ready documentation, fill-size comparison, and whether this SKU belongs in a broader buyer program.
Overview
Selank is a synthetic heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) derived from the immunomodulatory tetrapeptide Tuftsin, with a C-terminal Pro-Gly-Pro extension for protease resistance. Developed in parallel with Semax at the Institute of Molecular Genetics in Moscow, Selank is approved in Russia for the treatment of generalized anxiety disorder and is studied in research contexts for anxiolytic, cognitive, and mood-related effects. The molecule's pharmacology is thought to involve modulation of GABAergic transmission and enkephalin metabolism without the sedation or dependence profile of benzodiazepines, which is the mechanistic basis for the anxiolytic research interest. PeptideXpo supplies Selank acetate as a lyophilized powder at ≥99.0% HPLC purity. As with Semax, the dominant administration route in published research is intranasal, Selank is not meaningfully blood-brain-barrier permeable when delivered systemically. Buyers preparing intranasal formulations should use isotonic carrier vehicles and avoid preservatives that interact with short peptides. Standard 5 mg and 10 mg fill sizes cover most research workflows; LAL endotoxin and microbial limits are available as add-on testing for in vivo workflows.
Who buys this, and why
Cognitive and neuropeptide buyers are predominantly research labs running in vivo rodent studies. The dominant administration route in the literature is intranasal, these peptides are not meaningfully blood-brain-barrier permeable when delivered systemically. For in vivo workflows, endotoxin and microbial-limit testing is recommended at the COA stage so the bioassay readout is not confounded by contamination unrelated to the test article.
Primary buyer fit: academic and contract research laboratories.
Specifications
Documentation available on request
Regulatory note
Approved as a prescription medication in Russia for generalized anxiety disorder; unapproved in US and EU. Sold for research use only in jurisdictions outside Russia.
Frequently asked questions
Both are synthetic heptapeptides with the same C-terminal Pro-Gly-Pro stabilization motif, but the N-terminal tetrapeptide differs: Semax is derived from ACTH 4-10 and engages neurotrophin-pathway (BDNF) signaling, while Selank is derived from Tuftsin and engages GABAergic and enkephalin-pathway signaling. The downstream behavioral readouts differ accordingly, Semax research focuses on cognitive enhancement, BDNF expression, and neuroprotection, while Selank research focuses on anxiolytic and mood-stabilizing effects. The two peptides are sometimes used in combination in research workflows targeting both cognitive and anxiolytic axes.
Benzodiazepines act as positive allosteric modulators of the GABA-A receptor, which produces both the anxiolytic effects and the dose-limiting side-effect profile (sedation, motor impairment, dependence, withdrawal). Selank's hypothesized GABAergic modulation occurs through a different mechanism that does not appear to produce the same sedation or dependence signal in the available research and clinical data from Russia. This is the mechanistic basis for the research interest in Selank as a non-benzodiazepine anxiolytic lead, though the comparative pharmacology data outside Russia remains limited.
Selank reconstitutes cleanly in either bacteriostatic water for injection (for multi-use research stocks) or sterile saline (for intranasal formulation work). The reconstituted solution should be split into single-use aliquots and held at -20 °C; as with other short peptides, freeze-thaw cycling is the dominant source of measured-potency loss. For intranasal formulations, brands and research labs should use isotonic vehicles at near-neutral pH and avoid benzalkonium-chloride preservatives that interact with short peptide sequences.
