Selank is often grouped with Semax as a Russian-developed research peptide, and the two do share a design philosophy. Their origins are quite different, though, and Selank's starting point is the more unusual of the two.
What Selank is
Selank is a synthetic heptapeptide derived from tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin G heavy chain. Tuftsin itself is an immunomodulatory peptide: it stimulates phagocytosis and has well-documented effects on macrophage activity.
As with Semax, the modification is a proline-glycine-proline extension at the C-terminus, which slows enzymatic degradation. The result is a compound with an immunological parent molecule that is studied predominantly for effects on behaviour, which makes it an unusual case.
The immune-brain connection
That dual character is the most scientifically interesting thing about Selank. Kozlovskaya and colleagues framed the early work in terms of tuftsin-family peptides regulating adaptive behaviour under stress, published in Neuroscience and Behavioral Physiology.[1]
Research on neuroimmune interaction has expanded considerably since, and a compound with a clear immunological lineage and reported central effects sits directly on that boundary. Kolomin and colleagues examined changes in expression of chemokine and cytokine genes in response to Selank, which is the kind of work that connects the two domains rather than treating them separately.
What the published research examines
BDNF and memory models
A 2019 study in the Bulletin of Experimental Biology and Medicine reported that Selank protected against ethanol-induced memory impairment in rats, with the effect associated with regulation of BDNF content in the hippocampus and prefrontal cortex.[2] The BDNF link echoes the Semax literature, suggesting the two peptides may share downstream mechanisms despite different parent molecules.
Withdrawal and dependence models
A 2022 paper from the same journal examined Selank in morphine withdrawal in rats, reporting attenuation of aversive withdrawal signs.[3] Withdrawal paradigms are a demanding test of an anxiolytic-like compound because the behavioural readouts are robust and well-validated.
Genetic models of depression
Sarkisova and colleagues studied Selank in WAG/Rij rats, a genetic model of depressive-like behaviour, alongside Wistar rats and BALB/c mice.[4] Comparing a genetically predisposed strain against controls is a stronger design than a single-strain study, since it tests whether an effect depends on baseline state.
Handling and stability
Selank is supplied as a lyophilised solid, stored at −20°C and protected from light and moisture. Reconstitution uses sterile solvent added slowly down the vial wall with gentle swirling rather than vortexing.
At seven residues Selank is a short peptide, and short peptides at low working concentrations are particularly prone to adsorption onto container surfaces. Where concentration accuracy matters, low-binding plasticware and freshly prepared working dilutions reduce a source of error that is easy to overlook.
What the literature does not establish
Selank's mechanism is not fully characterised. Effects on GABAergic signalling and on serotonin metabolism have both been reported, but a primary molecular target has not been established in the way that would be expected for a well-understood ligand.
As with Semax, much of the literature originates from a small number of research groups and is published in Russian-language journals. Independent replication outside those groups is limited, and the behavioural endpoints used vary enough between studies to make direct comparison difficult.
References
- Kozlovskaya MM. Selank and short peptides of the tuftsin family in the regulation of adaptive behavior in stress. Neuroscience and Behavioral Physiology. 2003. PMID 14969422
- Kolik LG. Selank, Peptide Analogue of Tuftsin, Protects Against Ethanol-Induced Memory Impairment by Regulating of BDNF Content in the Hippocampus and Prefrontal Cortex in Rats. Bulletin of Experimental Biology and Medicine. 2019. PMID 31625062
- Konstantinopolsky MA. Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats. Bulletin of Experimental Biology and Medicine. 2022. PMID 36322304
- Sarkisova KIu. Effects of heptapeptide selank on genetically-based and situation-provoked symptoms of depression in behavior in WAG/Rij and Wistar rats, and in BALB/c mice. Zhurnal Vysshei Nervnoi Deiatelnosti. 2008. PMID 18661785
Research use only
Selank is supplied by MMpeptides strictly for laboratory and in vitro research. It is not approved for human or veterinary use, is not a cosmetic or medicinal product, and nothing in this article should be read as describing use in people. Third-party studies are cited for scientific context only. Researchers are responsible for observing all applicable regulations in their jurisdiction.