A quiet analytical research laboratory at night, racks of glass vials along a dim bench.

Selank and Semax

Selank and Semax are synthetic heptapeptides registered as intranasal medicines in Russia and not approved by the FDA, EMA or Health Canada. This page covers their molecular class, regulatory position and the delivery problem that small neuropeptides share: survival on the nasal mucosa long enough to be absorbed.

Molecular class and size

Both are linear seven-residue peptides built by extending a short bioactive sequence with a Pro-Gly-Pro tail, a motif chosen to slow peptidase cleavage. Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro, about 751 Da) is an analog of tuftsin, a tetrapeptide fragment of immunoglobulin G. Semax (Met-Glu-His-Phe-Pro-Gly-Pro, about 813 Da) is an analog of the ACTH(4-10) fragment without hormonal corticotropic activity. Both were developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. They are hydrophilic, charged at physiological pH, and have short plasma half-lives.

Regulatory status and anti-doping

Semax and Selank are listed in the State Register of Medicinal Products of the Russian Federation as nasal drops. Neither holds marketing authorization from the FDA, the European Medicines Agency or Health Canada, and neither is lawful to sell as a dietary supplement or natural health product in those markets. Products offered online as "research peptides" have no approved human use outside Russia. Neither peptide is named on the WADA Prohibited List; athletes should confirm status with their national anti-doping organization, since classification can change between annual lists. Vegalab does not supply either compound.

Why intranasal delivery matters for small neuropeptides

Peptides of this size are degraded within minutes in plasma and do not cross the blood-brain barrier efficiently. The nasal route offers a partial bypass: the olfactory and trigeminal nerve pathways connect the nasal epithelium to the brain, and a fraction of an applied dose can reach the central nervous system without entering systemic circulation. Two barriers limit it. Mucociliary clearance moves nasal mucus toward the pharynx with a half-time of roughly 15 to 20 minutes, and the nasal mucosa contains aminopeptidases and endopeptidases that cleave unprotected peptides. Absorbed fractions for hydrophilic peptides are typically low single-digit percentages.

How mucoadhesive encapsulation addresses it

Mucoadhesive polymers such as chitosan bind to negatively charged mucin, lengthening residence time on the epithelium and slowing clearance. Chitosan also transiently opens tight junctions, which raises paracellular transport of hydrophilic molecules. An encapsulating shell additionally limits peptidase access to the payload before it contacts the absorptive surface. These principles are established for nasal peptide delivery in general; they are not evidence of any effect of Selank or Semax, and any formulation work in this class would be for a licensed developer within an approved regulatory pathway.

Key facts

Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is a tuftsin analog and Semax (Met-Glu-His-Phe-Pro-Gly-Pro) is an ACTH(4-10) analog, both carrying a Pro-Gly-Pro extension (Deigin et al. 2022, Pharmaceutics 14:716)
Neither compound is approved by the FDA, EMA or Health Canada (FDA Drugs@FDA; EMA medicines database; Health Canada Drug Product Database)
Intranasal delivery can reach the central nervous system through olfactory and trigeminal pathways (Lochhead and Thorne 2012, Adv Drug Deliv Rev)
Mucociliary clearance and nasal peptidases limit residence and absorption; chitosan increases residence time and paracellular transport (Illum 2003, J Control Release)

How our delivery technology applies

For a heptapeptide of about 800 Da, the nasal barriers are residence time and enzymatic cleavage, not size. A multi-layer shell with a cationic mucoadhesive outer layer (chitosan class) can anchor the particle to mucin, and inner layers can restrict peptidase contact until release at the epithelium. This is platform capability described in general terms; Vegalab does not formulate unapproved neuropeptides for human use.

Licensed developers can request a technical call on mucoadhesive nasal carriers.