What is Selank? What it does, benefits and what the evidence shows

Selank is a synthetic heptapeptide developed at the Institute of Molecular Genetics of the Russian Academy of Sciences in Moscow, built from tuftsin — a naturally occurring immune-signaling fragment of an antibody — with the same stabilizing Pro-Gly-Pro tail used in Semax, its better-known sibling compound from the same lab. It's marketed in the U.S. grey market as an anxiolytic and mild nootropic. Selank is often described online as an approved Russian anxiety drug. A 2022 review of peptide drugs developed in Russia lists Selank, as an anxiolytic, among the 14 peptide products registered in the Russian Federation (Deigin et al., Pharmaceutics, 2022), but it gives no registration date, so we're not asserting one here. What we can verify is thinner and more recent than the marketing suggests: a handful of small Russian clinical studies, a few rat studies, and one small human brain-imaging study — all from Russian research groups.

What Selank is and how it works

The name and structure trace to tuftsin, a four-amino-acid fragment (Thr-Lys-Pro-Arg) cleaved from an antibody's Fc region that's involved in activating immune cells called phagocytes. Selank adds a Pro-Gly-Pro tripeptide to tuftsin's sequence, a modification the same Moscow research group used on Semax specifically to slow enzymatic breakdown and extend the peptide's activity (Kolomin et al., Neuroscience and Medicine, 2013). That review describes Selank and Semax as products of the same design lineage — regulatory peptides re-engineered for stability — with Selank developed specifically as an anxiolytic candidate without the sedation and muscle-relaxant effects associated with benzodiazepines.

Mechanistically, the clearest data is in rats. A gene-expression study gave rats intranasal Selank or GABA itself and measured expression of a panel of neurotransmission-related genes in frontal cortex tissue one and three hours later. At one hour, Selank significantly changed 29 of 77 genes analyzed, and the pattern of change correlated closely with GABA's own effect on the same genes (a correlation of 0.86); by three hours, fewer genes were affected and the correlation with GABA's pattern had flipped negative, suggesting a more complex, time-dependent relationship rather than Selank simply mimicking GABA throughout (Volkova et al., Frontiers in Pharmacology, 2016). The authors are explicit that this is rat brain tissue and that "further research is needed to identify all aspects of the mechanisms of action of Selank." A separate rat study found Selank alone reduced anxiety-like behavior on the elevated plus maze and, combined with diazepam under chronic mild stress, normalized anxiety measures back to pre-stress levels more effectively than either compound alone — the authors attribute part of this to Selank affecting GABA-A receptor binding characteristics (Kasian et al., Behavioural Neurology, 2017). The Kolomin review also credits Selank, like Semax, with inhibiting enkephalin-degrading enzymes, which would slow the breakdown of the body's own opioid-like signaling peptides — a proposed but not conclusively proven mechanism.

What people use it for

What the research actually shows

The best-known human trial: 62 patients, an active comparator, no placebo arm

The best-known clinical study of Selank is a Russian trial of 62 patients diagnosed with generalized anxiety disorder or neurasthenia, with 30 receiving Selank and 32 receiving medazepam, an older benzodiazepine-class anxiolytic, assessed with the Hamilton and Zung anxiety scales and clinical global impression ratings (Zozulya et al., 2008). The reported result: Selank's anxiolytic effect was similar in size to medazepam's, but Selank also had antiasthenic and psychostimulant effects, which the abstract does not report for medazepam. The study also measured the half-life of leu-enkephalin in blood serum, which was reduced in these patients, correlated with disease duration and the severity of anxiety and asthenia symptoms, and increased during Selank treatment, mostly in patients with generalized anxiety disorder. That's a real, comparative finding — but there was no placebo arm, and it's one 2008 study from one Russian research group. Two later Russian studies also tested Selank in anxiety disorders: a 2014 comparison with phenazepam in 60 patients, and a 2015 study of 70 patients comparing phenazepam alone (30) with Selank added (40), again with no placebo group described (Medvedev et al., Zh Nevrol Psikhiatr, 2014; Medvedev et al., 2015). We could not locate a replication outside Russia.

Two design choices matter here for anyone weighing how much to trust this result. First, medazepam is a real, established anxiolytic on its own — showing Selank performs similarly to an active drug is a meaningfully different (and harder) bar to clear than beating a placebo, but it also means the study can't tell you how much of either drug's effect was itself a placebo response, since there was nothing to compare either arm against. Second, a 62-patient study without a placebo arm is exactly the kind of result that calls for outside replication before treating it as settled — and as far as we could determine, no replication outside Russia has been published.

Brain imaging in healthy adults: a real signal, not a treatment outcome

The same 2020 imaging study that scanned Semax users also gave Selank to healthy adults among its 52 total participants (with a placebo-injection comparison group) and mapped changes in resting-state functional connectivity between the amygdala and temporal-lobe regions tied to emotional processing (Panikratova et al., 2020). That shows Selank does something measurable to brain network activity in living humans — a step beyond pure animal data — but the study didn't test or report anxiety symptoms, mood, or any clinical outcome. Connectivity changes and symptom relief are not the same thing.

Rat data: consistent, but rat data

Two rat studies form the rest of the case. In the elevated-plus-maze study, 48 male rats were split into stressed and non-stressed groups, each further divided into four treatment arms: saline, Selank alone, diazepam alone, or the combination, with the stressed animals undergoing 14 days of unpredictable mild stress before testing. Selank alone reduced anxiety-like behavior versus saline, and the Selank-plus-diazepam combination in stressed animals brought anxiety measures back down to levels seen before the stress period began, outperforming either drug alone in that specific comparison (Kasian et al., 2017). The gene-expression study, described above, is the other leg: a time-dependent shift in GABA-pathway gene activity in rat frontal cortex following intranasal dosing (Volkova et al., 2016). Both are consistent with an anxiolytic, GABA-modulating profile. Neither is a human study, and we found no published trial testing whether these rodent mechanisms actually predict Selank's effect size in people beyond the small Russian clinical studies above.

Side effects and risks

We could not verify a dedicated human safety trial for Selank. The published human studies we found — the Russian clinical studies from 2008 to 2015 and the 2020 imaging study — weren't designed as dedicated safety trials. Selank appears among the peptide products registered in Russia in the 2022 review cited above, but that review gives no registration date, and we could not confirm a prescription status, or the "approved since around 2009" claim some vendor and blog sources make, from a primary source we opened. FDA has not approved Selank. Its bulk-substances page (current as of April 22, 2026) lists Selank acetate under 'nominated but withdrawn', says compounded Selank may pose an immunogenicity risk for certain routes of administration, and says FDA lacks important information about safety issues raised by selank acetate administered to humans (FDA). That is a compounding-nomination screen, not a drug review, and Selank was not among the peptides FDA's advisory committee considered in July 2026.

On the grey-market side, our data shows the same practical issue we see with Semax, only more pronounced: overfill. As of September 29, 2026, Selank vials in our database ran a median of 25.2% over their labeled amount — the heaviest overfill skew of any compound in our current data — with only 1 vial landing within ±5% of label and 6 of 9 measuring more than 20% over. Purity, separately, was strong (7 of 9 vials at 99%+). Extra peptide in the vial isn't a safety problem the way underfill or contamination would be, but it does mean the label amount tells you very little about what's actually there, and it's one more sign of inconsistent fill-volume quality control at the vendor level. If you're trying to gauge how much you're actually getting relative to what you paid for, the label number for this compound is close to meaningless on its own — treat it as a rough starting point, not a measurement.

What the lab tests show

Today, our database includes 9 Selank vials from 5 vendors, drawn from 6 lab reports dated March 2025 through October 2025 — a small sample where a single vendor's results can move the numbers substantially. Purity: 9 of 9 vials had a result, 7 at 99%+, median 99.79%. Dose versus label: median 25.2% over, with 1 of 9 within ±5% and 6 of 9 more than 20% over. As of September 29, 2026, no vials had failed our definition (empty, under 95% pure, more than 20% under label, or more than 50% over) — the overfill, again, mostly stayed under that upper threshold even though it's heavy.

Here's how the ranked vendors for Selank look right now; the table shows current verdicts and flags any vendor whose failed-vial rate is above 5%. With 9 vials tested for this compound, this table is likely to be short:

Buying smarter

Check a specific vendor's full Selank record on our Selank results page rather than trusting one or two reports — a vendor needs five or more lab reports for this specific compound before we rank them. Treat any vendor-posted COA as a starting point, not proof: how to read a peptide COA and fake peptide COAs cover the checks worth running before you trust a number you didn't see tested yourself.

Given how heavily Selank runs over label in our data, a quantity test on your own vial is arguably more informative than another purity check — purity has looked solid across most reports, dose-versus-label is where the real spread is. How to get a peptide tested walks through ordering independent identity, purity and quantity testing from a lab.

If your report comes back a fail, stop using that batch, tell anyone who bought from the same run, bring the report to the vendor, and submit it to VendorVerify so the next buyer checking Selank has one more data point than you did.

Database figures without a date update automatically from VendorVerify's lab results; dated figures are snapshots. This isn't medical advice. Selank is sold for research use only in the U.S., and we found no FDA-approved Selank product.