FIELD REVIEW · TP-7 · TUFTSIN ANALOG · 2026
Selank: anxiolytic peptide studied in Russia, sold elsewhere only for research.
A heptapeptide registered as a pharmacopoeia anxiolytic in the Russian Federation and nowhere else. One published controlled human trial. A substantial rodent record. Read the literature, set in billboard type.
Studied since 1971. + Comparable to medazepam in one 62-patient trial. + Not FDA approved.
What Is Selank?
Selank is a synthetic heptapeptide developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. Sequence: Thr-Lys-Pro-Arg-Pro-Gly-Pro. The first four residues are tuftsin — a tetrapeptide cleaved from the heavy chain of immunoglobulin G — and the trailing Pro-Gly-Pro tripeptide was bolted on for one specific reason: to slow plasma carboxypeptidases and keep the molecule alive long enough to act centrally [1].
The registration story is short and unusual. Selank entered Russian pharmacopoeia as an anxiolytic. No FDA approval. No EMA approval. No MHRA approval. No TGA approval. Outside the Russian Federation it is a research chemical, not a drug.
The evidence base mirrors that geography. The largest controlled human study (62 patients, generalized anxiety and neurasthenia) compared a 14-day intranasal Selank course to oral medazepam and reported comparable anxiolytic efficacy plus additional antiasthenic and psychostimulant effects [1]. The preclinical record is broader — twenty-plus rodent and in-vitro studies covering enkephalinase inhibition, GABAA modulation, BDNF up-regulation, monoamine metabolism, and cytokine balance — but the literature is dominated by three Russian-language venues: Bulletin of Experimental Biology and Medicine, Eksperimental'naia i Klinicheskaia Farmakologiia, and Zhurnal Nevrologii i Psikhiatrii [1][2][3]. Independent non-Russian replication is thin. We say so plainly throughout.
MECHANISM
Mechanism
Three pathways carry most of the explanatory weight.
Enkephalin stabilization. Selank inhibits plasma enkephalin-degrading enzymes (carboxypeptidases, dipeptidylcarboxypeptidases) with an IC50 of roughly 20 microM, extending the half-life of endogenous leu-enkephalin [2]. In BALB/c mice with high baseline enkephalinase activity, 100 microg/kg produced an anxiolytic effect in the open field; in C57Bl/6 mice with low baseline enkephalinase, the same dose did nothing [3]. The behavior tracked the enzymology.
GABAA allosteric modulation. In IMR-32 neuroblastoma cells, Selank alone did not change mRNA of 84 GABA-related genes — supporting an allosteric receptor mechanism rather than transcriptional regulation [6]. In rats exposed to unpredictable chronic mild stress, Selank potentiated diazepam's anxiolytic effect, consistent with functional coupling at benzodiazepine-sensitive GABAA sites [7].
BDNF up-regulation. Intranasal Selank (250 and 500 microg/kg) raised hippocampal BDNF mRNA at three hours and BDNF protein at twenty-four hours in rats [4] — a downstream substrate that persists long after intact peptide has cleared plasma.
What the trials show
One published controlled human trial carries most of the clinical weight. Zozulia et al. (2008) randomized 62 patients with generalized anxiety disorder and neurasthenia to intranasal Selank or oral medazepam over fourteen days [1]. Hamilton, Zung, and CGI scores improved comparably across arms. Selank additionally produced antiasthenic and psychostimulant effects — a profile medazepam did not match — and serum leu-enkephalin half-life lengthened in the Selank arm, consistent with the enzyme-inhibition mechanism reported elsewhere [2].
A second human report, also intranasal and also fourteen days, documented Th1/Th2 cytokine balance shifts in patients with anxiety-asthenic disorders [10]. That is the entire English-PubMed-indexed human record. Beyond those two papers, human evidence consists of Russian-language clinical observations the international literature has not independently replicated.
DOSAGE IN STUDIES
Dosage in studies
Reported in the literature, never as a recommendation. Russian clinical protocols cluster around 300-900 microg/day intranasal in adults, divided across two or three administrations, typically as a 7-14 day course [1][11]. Rodent anxiolytic studies use 100-300 microg/kg single intraperitoneal injection [3][17]. Rodent BDNF studies use 250-500 microg/kg intranasal or 0.3 mg/kg/day IP for seven days [4][5].
The plasma half-life of intact peptide is short — minutes-scale in rodents, reported around two to three minutes — but downstream BDNF and gene-expression effects persist for hours to days, which is why dosing frequency in trials is not anchored to plasma kinetics. See the Selank dosage for anxiety page for the full protocol breakdown and the Selank half-life section for the pharmacokinetic detail.
REGULATORY
Regulatory
Russian Federation registration. No FDA approval. No EMA approval. No MHRA approval. No TGA approval. Not currently named on the WADA Prohibited List as of recent annual lists, though status can change and athletes should consult the current list directly.
For a structural comparison to the other Russian-institute peptide of this era, see our Selank vs Semax page. For the discontinuation literature — including the published claim of absent rebound anxiety after short courses — see Selank withdrawal. For the frequently asked questions about Selank, including hair-loss, sleep, and storage queries, see the FAQ index.