Efficacy and possible mechanisms of action of a new peptide anxiolytic Selank in the therapy of generalized anxiety disorders and neurasthenia
Zozulia AA, Neznamov GG, Siuniakov TS, Kost NV, Gabaeva MV, Sokolov OIu, Serebriakova EV, Siranchieva OA, +6 more
Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova (2008) · n=62
Across 62 patients with GAD or neurasthenia, Selank's anxiolytic effect was reported as comparable to medazepam — the only English-indexed clinical trial that puts Selank head-to-head against a benzodiazepine.
This is the comparative clinical trial of Selank that English-language readers most often find when looking for human evidence on the peptide. Conducted at the V.V. Zakusov Research Institute of Pharmacology in Moscow and reported in the Russian Korsakov Journal of Neurology and Psychiatry, the study enrolled 62 patients diagnosed with generalized anxiety disorder or neurasthenia and assigned them to receive Selank (n=30) or medazepam, a benzodiazepine active comparator (n=32). Outcomes were assessed using Hamilton, Zung, and CGI psychometric scales, supplemented by serum measurements of leu-enkephalin enzymatic stability — the latter intended to support a mechanistic story about peptide-mediated modulation of endogenous opioid turnover. The authors report that the anxiolytic magnitude of Selank and medazepam was clinically comparable, with Selank additionally producing antiasthenic and mild psychostimulant effects that the benzodiazepine did not. Selank treatment was associated with an increase in leu-enkephalin half-life that correlated, in GAD patients in particular, with anxiety reduction. The trial is the most-cited human-efficacy data point for Selank and the basis for its 2009 Russian regulatory approval in GAD and neurasthenia.
The published abstract does not specify whether the trial was blinded, which is a significant methodological limitation in psychometric outcome assessment — anxiolytic ratings are particularly susceptible to expectancy effects in unblinded designs. The sample size (n=62) is small; the active-comparator design (rather than placebo-controlled) makes the underlying anxiolytic magnitude harder to estimate independently of medazepam's known effect. The trial was conducted by the institute that developed Selank, which raises a routine conflict-of-interest concern in the same way industry-sponsored trials do. The paper was published in Russian; the English-language abstract is the only translation widely indexed, which limits independent reanalysis. The Western peer-reviewed literature has not produced an independent replication of these results in a comparable population, which is the central reason Selank is positioned on this site as having an evidence-depth gap rather than as a peer-validated anxiolytic.