The clinical evidence
Selank's anxiety data are not imaginary. Russian teams led by Zozulia and colleagues ran controlled comparisons…
A real clinical record, in the wrong language
Selank's anxiety data are not imaginary. Russian teams led by Zozulia and colleagues ran controlled comparisons against benzodiazepines and reported comparable anxiety relief with a different side-effect profile. The catch is that this evidence lives almost entirely in Russian-language journals, indexed in English only as abstracts.
This unit examines what the trials actually showed, why the language barrier is a real scientific limitation and not a footnote, and how to read this unusual evidence base honestly.
Key terms
The Zozulia comparison
The foundational clinical study compared Selank against the benzodiazepine medazepam in sixty-two patients with generalized anxiety disorder and neurasthenia, 30 on Selank and 32 on medazepam. The anxiolytic effects of both drugs were similar, but Selank added something medazepam lacked. Two details the abstract does not give: the route, and the treatment duration.
The headline is a genuine finding: in this trial, a peptide matched a benzodiazepine for anxiolytic effect while also showing antiasthenic and psychostimulant effects the comparator did not. Plasma enkephalin half-life rose alongside it, tying the clinical result loosely back to the mechanism. A later Russian comparison against the benzodiazepine phenazepam in 60 patients with phobic-anxiety and somatoform disorders reported pronounced anxiolytic and mild nootropic effects, with the anxiolytic effect lasting for a week after the peptide was stopped (Medvedev 2014).
AdvancedWhat the enkephalin correlation does and does not show
A trial that only reports symptom scores can be hard to interpret, so a moving biomarker is welcome. Read this one exactly: the abstract reports that the increase in plasma Leu-enkephalin half-life, and stronger positive correlations with anxiety level, were seen during Selank treatment mostly in the GAD patients. It does not report a correlation with symptom change. So the biomarker moved and tracked how anxious patients were, which is weaker than a mechanism-to-response bridge and should not be described as one.