How does it work?
Selank is a heptapeptide – a short chain of seven amino acids. Researchers believe it may affect the brain's GABA system, which is the body's most important "brake" signal and contributes to calm. In addition, studies have investigated whether Selank affects signalling substances such as serotonin and a growth protein called BDNF, which is linked to memory and nerve cells' ability to adapt. Exactly how it all fits together has still not been fully mapped.
Technical mechanism
Synthetic analogue of the immune peptide tuftsin, stabilised with Pro-Gly-Pro. Modulates GABA and serotonin systems, affects BDNF and enkephalinases in research models.
What is being researched?
- Anxiety and restlessness (anxiolytic effect) – mostly investigated in small Russian studies
- Stress response and mental endurance
- The GABA system and the balance between signalling substances in the brain
- BDNF, memory and nerve cells' ability to adapt (neuroplasticity)
- Immune defence and inflammation-related genes (so far only in animal and cell studies)
About the evidence: Research on Selank is limited. Large parts have been carried out in animals or cells, and the few human studies that exist are small and come mainly from Russia. There are no large, independent clinical studies from the West. The results should therefore be interpreted with caution, and Selank is intended for research purposes only – not for treatment of humans or animals.
Research profile
Studies and sources
The links go to independent research databases (PubMed, PubMed Central, ClinicalTrials.gov). The studies are in English and open in a new tab.
Anxiety, stress and anxiolytic effect
Studies have investigated whether Selank can dampen anxiety and restlessness. One small Russian human study compared Selank with a sedative medicine, while animal studies have explored the effect under chronic stress.
- [Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia] Clinical (human)PubMed· 2008
In this human study, 62 patients with generalised anxiety disorder and neurasthenia were treated, with 30 receiving Selank and 32 receiving a sedative medicine (medazepam). Their condition was assessed using anxiety scales, and a substance in the blood (enkephalin) was measured. The anxiety-reducing effect was similar for both, but Selank also had a stimulating effect against fatigue. The researchers also reported changes in enkephalin levels during treatment with Selank. This is a Russian study.
- Peptide Selank Enhances the Effect of Diazepam in Reducing Anxiety in Unpredictable Chronic Mild Stress Conditions in Rats PreclinicalPubMed· 2017
In this animal study in rats, the researchers investigated whether Selank affects the action of the sedative medicine diazepam under prolonged, unpredictable mild stress. They used a maze test for anxiety. Selank alone was most effective at dampening elevated anxiety, while the combination of diazepam and Selank was most effective under chronic stress. The researchers believe Selank may modify the action of classic sedative medicines. This is an animal study, not a test in humans.
Mechanism of action: GABA and signalling substances
Researchers have explored how Selank affects the brain's GABA system and other signalling substances such as serotonin, to understand how a possible calming effect may arise.
- Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission PreclinicalPubMed· 2016
In this animal study in rats, the researchers investigated how Selank affects genes linked to signal transmission in the brain, particularly the calming GABA system. One hour after Selank or GABA was given, activity had changed in 45 of 84 genes examined, and after three hours in 22 genes. The changes after Selank and GABA were related. The researchers believe Selank has complex effects on nerve cells, possibly by affecting the GABA system indirectly. This is a Russian animal study.
- GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells PreclinicalPubMed· 2017
In this laboratory experiment, the researchers tested Selank on a type of nerve cell (IMR-32) and measured activity in 84 genes linked to the calming GABA system. Selank alone did not change gene activity in these cells. But when Selank was given together with GABA, GABA's effect on the genes was almost cancelled out, and together with the medicine olanzapine, Selank affected more genes than olanzapine alone. The researchers believe this partly supports the idea that Selank can affect the interplay between GABA and its receptors. This is a cell study, not a test in humans.
- Comparison of the effects of selank and tuftsin on the metabolism of serotonin in the brain of rats pretreated with PCPA PreclinicalPubMed· 2009
In this animal study in rats, the researchers compared Selank and the related substance tuftsin. The rats had first been treated with a substance (PCPA) that inhibits production of the signalling substance serotonin. Selank increased serotonin turnover in the brainstem 30 minutes after injection, while tuftsin had no such effect and reduced it in the cerebral cortex. The researchers suggest that Selank may be worth investigating in disorders linked to low serotonin turnover. This is a Russian animal study.
- [Selank-induced normalizing effects on the integrative brain activity and biogenic amine level disorders due to antenatal hypoxia] PreclinicalPubMed· 2006
In this animal study, the researchers investigated Selank in adult rats that had been exposed to oxygen deprivation before birth. Selank increased attention several-fold, improved learning ability, normalised exploratory behaviour and restored the balance between two signalling systems in the brain (serotonin and noradrenaline). The researchers believe the results show that Selank can counteract long-lasting negative effects of oxygen deprivation before birth on brain function. This is a Russian animal study, not a test in humans.
BDNF, memory and neuroplasticity
Several animal studies have looked at whether Selank affects the growth protein BDNF, which is linked to memory and nerve cells' ability to adapt.
- Intranasal administration of the peptide Selank regulates BDNF expression in the rat hippocampus in vivo PreclinicalPubMed· 2008
Based on the title: This appears to be an animal study investigating how Selank given in the nose affects the amount of the nerve growth factor BDNF in the hippocampus of rats.
- Selank, Peptide Analogue of Tuftsin, Protects Against Ethanol-Induced Memory Impairment by Regulating of BDNF Content in the Hippocampus and Prefrontal Cortex in Rats PreclinicalPubMed· 2019
In this animal study in rats that were given alcohol as their only drink for 30 weeks, the researchers investigated Selank and memory. In a recognition test, Selank improved memory in older rats and counteracted memory and attention problems that arose during alcohol withdrawal. Selank also counteracted alcohol-related changes in the nerve growth factor BDNF in the hippocampus and the frontal lobe. The researchers link the effect to BDNF. This is an animal study, not a test in humans.
Immune defence and other effects
Because Selank is derived from the immunoactive substance tuftsin, some studies have investigated effects on inflammation-related genes and immune cells, as well as other areas such as opioid withdrawal in rats.
- Expression of inflammation-related genes in mouse spleen under tuftsin analog Selank PreclinicalPubMed· 2011
In this animal study in mice, the researchers investigated how Selank and two of its fragments affect genes linked to inflammation in the spleen. Of 84 genes examined, 34 changed activity. One gene (Bcl6), which is important for the immune system, changed clearly for all the peptides. The researchers believe the results confirm that Selank helps regulate inflammatory processes in the body. This is a Russian animal study, not a test in humans.
- The temporary dynamics of inflammation-related genes expression under tuftsin analog Selank action PreclinicalPubMed· 2014
In this animal study in mice, the researchers followed over time how Selank and the fragment Gly-Pro affect four inflammation genes in the spleen. They saw a clear decrease in one gene (C3) as early as 30 minutes after injection, and wave-like changes in another (Casp1). Selank and Gly-Pro often produced similar patterns, which the researchers believe may indicate that this fragment contributes to Selank's overall effect. The researchers link this to balance in the immune system. This is a Russian animal study.
- Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats PreclinicalPubMed· 2022
In this animal study in rats, the researchers investigated Selank in morphine withdrawal induced with naloxone. A single injection of Selank at an anxiety-reducing dose reduced the overall withdrawal signs by around 40 per cent, dampened convulsions and postural disturbances, and clearly raised the sensitivity threshold. Selank was slightly weaker than diazepam. The researchers conclude that Selank, like diazepam, dampens the unpleasant signs of morphine withdrawal in rats. This is an animal study, not a test in humans.