Selank

What Selank is and how it works

Selank is the heptapeptide Thr-Lys-Pro-Arg-Pro-Gly-Pro, also carried in the literature under the code TP-7. Its first four residues are tuftsin, a fragment cut out of the heavy chain of immunoglobulin G that stimulates phagocytic white blood cells. Tuftsin was described in 1970 by Najjar and Nishioka, and named after Tufts University. On its own it is cleared quickly, so the developers at the Institute of Molecular Genetics in Moscow added the Pro-Gly-Pro tail, the same stabilising trick used in Semax.

What emerged is described as an anxiolytic rather than an immune drug, and two mechanisms are proposed. The first runs through GABA, the main inhibitory messenger in the brain and the system benzodiazepines act on. Rat studies report that Selank shifts the expression of genes involved in GABA signalling in a pattern resembling the effect of GABA itself, and its developers suggest it works allosterically, changing how strongly the receptor responds rather than binding where GABA binds.

The second involves the enkephalins, the short opioid peptides the body makes itself and clears within minutes. In test-tube work with human blood, Selank slowed the enzymes responsible for that clearance, which led to the proposal that part of its effect comes from leaving the body with its own opioid signalling for longer. Rat studies have also reported changes in BDNF, and animal work on stress has measured cytokines. None of these threads has been tied to a demonstrated effect in patients.

What the research on Selank shows

The enzyme work is the oldest mechanistic thread. In a 2001 study (Bulletin of Experimental Biology and Medicine), Selank inhibited the breakdown of enkephalin in human plasma in a concentration-dependent way, with half-maximal inhibition at 15 µM, more strongly than the reference inhibitors tested alongside it. That is a test-tube result in plasma, not a measurement in a brain.

Rat studies carry the GABA thread. Volkova and colleagues (Frontiers in Pharmacology, 2016) measured 84 genes involved in neurotransmission in the rat frontal cortex after a single 300 µg/kg dose of Selank or of GABA. Selank changed the expression of 45 genes at one hour and 22 at three hours, and the pattern correlated with the one produced by GABA. Gene expression is an indirect readout: consistent with an action on GABA signalling, but not proof that Selank binds the receptor in a living brain.

The clinical evidence is one small Russian study. Zozulia and colleagues (2008) treated 62 patients with generalised anxiety disorder or neurasthenia, 30 with Selank and 32 with medazepam, a benzodiazepine. The anxiolytic effects were similar, and Selank was also reported to have anti-asthenic and psychostimulant effects. The same paper found a shortened half-life of leu-enkephalin in these patients, which lengthened during treatment. The study is small, its abstract describes no blinding, and it appeared in Russian.

What remains unproven

We have found no placebo-controlled trial of Selank in the international literature, and neither the European Medicines Agency nor the US Food and Drug Administration has assessed it. The suggestion that it reduces anxiety without the sedation and dependence associated with benzodiazepines rests on small Russian studies, and has not been tested over the periods that matter for an anxiety treatment.

Selank doses used in published research

The Russian medicine is a nasal solution, and the clinical dosing behind it is published mainly in Russian; we do not reproduce figures we cannot verify in the original. The rat dose is given per kilogram of body weight and does not translate into an amount for a person. These entries describe published study designs, and nothing here is guidance for human use.

Selank safety and side effects

Safety information comes from Russian clinical experience and a handful of small studies, which is a narrow base for any conclusion.

• Reported tolerability. Russian studies describe Selank as well tolerated over short courses. They were small, so uncommon effects would not have appeared in them.
• Central effects. A peptide proposed to modulate GABA-A receptors and raise enkephalin levels could in principle add to the effects of alcohol, benzodiazepines and opioids. That is unstudied.
• Immune activity. Tuftsin acts on phagocytic cells, and animal work reports effects on cytokines under stress. What repeated exposure does to immune function is uncharacterised.
• Long-term use. Anxiety treatment implies months rather than days, and no study has followed Selank that long, so tolerance and cumulative effects are unknown.
• Research-grade material. Powder sold for laboratory work is not the Russian medicine and has no medicinal status in Europe.

Regulatory status of Selank in Europe

Selank is registered in Russia as an intranasal anxiolytic. It holds no EU marketing authorisation: the European Medicines Agency has not authorised it, and we are not aware of any national authorisation in a member state. Inside the EU it is a research chemical, and presenting it as a treatment for anxiety would make it a medicinal product under EU law, which may not be marketed without authorisation. Rules on possession and personal import differ between member states; our primer on research peptides sets out the difference between an authorised medicine and a laboratory compound.

In sport, Selank is not named on the WADA Prohibited List, but the S0 section catches substances lacking approval for human therapeutic use, and a registration held only in Russia makes that a question for an anti-doping organisation rather than a supplier.

Sourcing and quality of Selank

King Peptides stocks Selank 10 mg as a lyophilised research powder. The certificate for the lot should show HPLC purity of at least 99% and a mass spectrum consistent with 751.9 Da, with the lot number matching the vial in hand. There is a practical reason to check the mass rather than trust the label: Selank and Semax share their last three residues and are often stocked side by side, yet they differ by 62 Da. The mass spectrum separates them in seconds, and our guide to reading a certificate of analysis explains what else the document should contain.

Orders leave from the Netherlands, with a shop estimate of 1–2 business days within the Netherlands and 3–5 business days elsewhere in the EU, and shipments inside the union pass without customs formalities; parcels to the UK, Switzerland and Norway can be subject to import rules and duties. Packaging is neutral and tracked, and buyers confirm at checkout that they are 18 or older and ordering for research. Our storage guide covers the vial once it arrives, including the −20 °C the panel specifies.

Selank: frequently asked questions

How is Selank different from Semax? The shared Pro-Gly-Pro tail is where the resemblance ends. Selank starts from tuftsin, an immune peptide, and is studied for anxiety; Semax starts from an ACTH fragment and is studied mainly for BDNF and stroke.

Is Selank an alternative to benzodiazepines? It was compared with one, medazepam, in a single small Russian study. That is not enough to call it an alternative, and it is authorised for anxiety nowhere in the EU.

What is the enkephalinase angle? Enkephalins are the body's own short opioid peptides, and enzymes in blood destroy them quickly. Selank slowed those enzymes in test-tube experiments, which led its developers to propose that some of its effect runs through endogenous opioid signalling. That has not been shown in patients.