Selank is a synthetic 7-amino-acid peptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) derived from the immune peptide tuftsin. It is studied as an anti-anxiety substance that, unlike benzodiazepines, should neither sedate nor cause dependence. In Russia it has been registered since 2009 as nasal drops for anxiety; it is not approved in the EU.[4]
Selank at a glance
- Basis: tuftsin (Thr-Lys-Pro-Arg), a natural antibody fragment, extended by Pro-Gly-Pro.
- Main mechanisms: influence on the GABA system and slower breakdown of enkephalins.
- Clinical data: Russian studies in generalised anxiety disorder and neurasthenia.
- Administration in studies: intranasal.
What is Selank and how was it developed?
Tuftsin is a short peptide produced by cleaving antibodies, and it activates immune cells. Scientists at the Institute of Molecular Genetics of the Russian Academy of Sciences noticed that it also has effects in the brain but breaks down quickly. As with Semax, they therefore attached the stabilising tripeptide Pro-Gly-Pro. The result was Selank, which kept the immune effects and added anti-anxiety effects.
How does Selank work?
The GABA system
GABA is the brain’s main inhibitory neurotransmitter, and benzodiazepines also act on its receptors. Selank, however, does not bind directly to GABA receptors as benzodiazepines do. A rat study showed that it changes the activity of genes related to the GABA system – in other words, it acts indirectly, more like “tuning” the system.[2]
Enkephalins
Enkephalins are the body’s own opioid peptides, which dampen stress and pain. In the blood they are quickly broken down by enzymes. In a study Selank slowed these enzymes, so the enkephalins lasted longer. The authors consider this one of the mechanisms of its anti-anxiety effect.[1]
Immunity
From tuftsin, Selank inherited an effect on the immune system. In patients with anxiety-asthenic disorders, levels of some cytokines – the immune system’s signalling molecules – changed after treatment.[5]
What have animal studies shown?
In rats exposed to long-term unpredictable stress, Selank reduced anxious behaviour and enhanced the effect of diazepam, so that a lower dose of diazepam produced a similar effect.[3] Other rodent studies looked at memory, learning and effects on BDNF levels.
What have studies in humans shown?
A 2008 clinical study compared Selank with the benzodiazepine medazepam in patients with generalised anxiety disorder and neurasthenia. The authors described a comparable anti-anxiety effect; with Selank, the drowsiness and muscle weakness typical of benzodiazepines were also absent.[4] The study was carried out in Russia and does not meet the requirements European authorities set for clinical trials. That is why Selank is not approved as a medicine in the EU.
| Property | Selank | Benzodiazepines |
|---|---|---|
| Main target | Indirectly the GABA system, enkephalins | Directly the GABA-A receptor |
| Sedation and drowsiness | Not described in studies | Common |
| Risk of dependence | Not described; long-term data are lacking | Proven |
| Approval in the EU | No | Yes |
What are the side effects of Selank?
In the available studies Selank was well tolerated. Mild irritation of the nasal mucosa and occasional tiredness are described. However, large long-term studies are lacking, so rarer side effects and interactions with other medicines are not known.
How does Selank differ from Semax?
Selank and Semax are “siblings” from the same institute with the same stabilising Pro-Gly-Pro tail. Semax is based on the hormone ACTH and is studied for memory, attention and brain protection; Selank is based on tuftsin and is studied for anxiety and stress. Both are given intranasally in studies.
What is tuftsin?
Tuftsin is the tetrapeptide Thr-Lys-Pro-Arg, which is cleaved from the heavy chain of IgG antibodies. It was described in the 1970s by the American immunologist Victor Najjar and named after Tufts University. Tuftsin activates phagocytes – white blood cells that engulf bacteria – and supports their ability to destroy microorganisms. People with an inherited defect in tuftsin production or without a spleen are more susceptible to certain infections.
Selank kept the beginning of tuftsin’s sequence, which is why its immune effects are studied too. The stabilising Pro-Gly-Pro extension prolonged its action enough for an effect on the brain to appear as well.
What is generalised anxiety disorder?
Generalised anxiety disorder is a condition in which a person experiences excessive, hard-to-control worry for at least six months, accompanied by tension, fatigue, and sleep and concentration problems. It is treated with psychotherapy and medication, most often SSRI antidepressants; benzodiazepines are recommended only short term because of the risk of dependence. That is exactly why substances are sought that could dampen anxiety without sedation or addiction – and it is in this context that Selank is studied.
What is N-acetyl Selank amidate?
As with Semax, there is a modified version of Selank with acetyl and amide end groups. The modifications are meant to increase stability, but no peer-reviewed studies comparable to those on the original Selank have been published for it.
Does Selank affect memory?
Rodent studies described Selank improving memory and learning, especially under stressful conditions. The explanation is sought in its effect on neurotrophic factors such as BDNF and in dampening the stress response, which impairs memory. These effects have not been studied separately in humans; clinical studies focused on anxiety and fatigue.[4]
What effect does Selank have on immunity?
From tuftsin, Selank inherited an effect on immune cells. In patients with anxiety-asthenic disorders, levels of some cytokines – signalling molecules linked to both inflammation and anxiety – normalised after treatment.[5] This dual effect – on the brain and on immunity – is unusual for anti-anxiety substances and is one of the reasons for the interest in Selank.
Summary
- Selank is a heptapeptide derived from the immune peptide tuftsin, stabilised by the tripeptide Pro-Gly-Pro.
- It acts indirectly on the GABA system and slows the breakdown of enkephalins, the body’s own opioid peptides.[1][2]
- In a Russian clinical study it dampened anxiety much like a benzodiazepine, but without drowsiness.[4]
- It has also kept tuftsin’s immune effects.
- In Russia it is registered as nasal drops; it is not approved in the EU, and long-term data are lacking.
Frequently asked questions
Is Selank addictive?
Dependence and withdrawal symptoms were not described in the available studies. Long-term studies that would reliably rule this out are lacking, however.
Can Selank be combined with Semax?
In research the two peptides are sometimes studied in parallel, because their focus is complementary. Studies directly with their combination have not been published, however.
Why is Selank given intranasally?
The peptide would be broken down in the digestive tract. The nasal mucosa allows rapid absorption and a direct route to the brain, which is why the registered Russian product comes as nasal drops.
Is Selank legal in the Czech Republic?
Selank is not a registered medicine in the Czech Republic. It may be sold only as a research chemical, not as a medicine for use in humans.
How long does Selank act?
The peptide itself breaks down quickly in the blood, within minutes. The effects described in studies lasted longer, however, which is explained by changes in gene activity and in the balance of neurotransmitters that persist after it has been broken down.[2]
What is Selank made of?
Seven amino acids: Thr-Lys-Pro-Arg-Pro-Gly-Pro. The first four form tuftsin, the last three the stabilising tripeptide it shares with Semax.
Sources
- Zozulya AA, et al. The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity. Bulletin of Experimental Biology and Medicine. 2001;131(4):315–317. PubMed ↗
- Volkova A, et al. Selank administration affects the expression of some genes involved in GABAergic neurotransmission. Frontiers in Pharmacology. 2016;7:31. PubMed ↗
- Kasian A, et al. Peptide Selank enhances the effect of diazepam in reducing anxiety in unpredictable chronic mild stress conditions in rats. Behavioural Neurology. 2017;2017:5091027. PubMed ↗
- Zozulia AA, et al. Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. 2008. PubMed ↗
- Uchakina ON, et al. Immunomodulatory effects of selank in patients with anxiety-asthenic disorders. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. 2008;108(5):71–75. PubMed ↗
The information in this article is for educational purposes only and does not replace medical advice. The substances described are not approved medicines, and Jolt Peptides products are intended solely for laboratory research, not for use in humans or animals.