Selank: research overview

Selank is reported to act as a positive allosteric modulator of GABA-A receptor binding by Vyunova and colleagues (2018) using radioligand-receptor analysis. Kasian and colleagues (2017) tested selank alongside diazepam in male Wistar rats under unpredictable chronic mild stress and reported that the combination restored anxiety indicator values to pre-stress baseline more completely than either compound alone in the elevated plus maze. This is animal-model data, not a human trial, and the pairing is included to document the GABA-A axis that selank shares with classical benzodiazepines rather than as a clinical recommendation.

Selank has been shown to modulate brain serotonin metabolism. Semenova and colleagues (2009) reported in rats pretreated with p-chlorophenylalanine (a tryptophan hydroxylase inhibitor that depletes 5-HT) that selank restored 5-HT metabolism in the brain stem within 30 minutes of injection, while tuftsin did not. L-tryptophan is the dietary precursor of 5-HT via tryptophan hydroxylase. The pairing is mechanistic: selank acts on a serotonergic axis whose substrate availability is determined by tryptophan. No human co-administration trial has been published; this is animal-model context.

Kozlovskii and colleagues (2012) reported that pretreatment with the opioid antagonist naloxone modulated the anxiolytic profile of selank in BALB/c and C57BL/6 mice, indicating that the enkephalin-opioid system contributes to selank's mechanism. Selank has been characterised as an inhibitor of enkephalin-degrading enzymes, which would prolong the half-life of endogenous enkephalins. This is mechanistic context for why selank's anxiolytic profile differs from classical benzodiazepines; it is not a supplement that can be administered, and it is included here to document the second axis (enkephalinergic) alongside the GABAergic axis.

Inozemtseva and colleagues (2008) reported that intranasal selank at 250 and 500 mcg/kg increased BDNF mRNA in the rat hippocampus within 3 hours and BDNF protein within 24 hours. Kolik and colleagues (2019) extended this to an ethanol-withdrawal model, reporting that selank prevented ethanol-induced changes in hippocampal and prefrontal BDNF and the associated memory and attention disturbances. BDNF is not a directly supplementable cofactor; this entry documents the neurotrophin axis that selank engages, which is the mechanistic ground a future cofactor candidate (e.g. an exercise or omega-3 intervention) would have to be co-studied against. No such human co-administration trial currently exists.