Selank: Three Russian Trials, and Not One of Them Says How Much
The whole human record is three papers from the institutes that created the compound, tested against a sedative rather than a fake treatment, and not one reports a dose. The Semax it is sold alongside has never been given with it in any study.
What it is
Selank is a seven amino acid peptide, a short chain of amino acids linked end to end. The first four are tuftsin, a peptide fragment found in antibodies, to which three more amino acids are added at the tail to slow its breakdown by enzymes. Russia registered it with its Ministry of Health in 2009 and it is marketed there as nasal drops for anxiety.
What the trials found
Search PubMed, the United States database of medical abstracts, for clinical trials of Selank.
Three results, all in Russian, all in the Korsakov Journal of Neurology and Psychiatry. All three include N.F. Miasoedov of the Institute of Molecular Genetics, who created Selank.
Zozulya 2008: 62 patients diagnosed with generalized anxiety and neurasthenia, an older word for persistent exhaustion, received either Selank or the benzodiazepine medazepam, 30 on Selank and 32 on the sedative. Both treatments reduced anxiety scores by about the same amount. Selank additionally showed antiasthenic and psychostimulant effects, meaning it reduced the fatigue rather than adding to it, which is the direction that separates it from a sedative. (PMID 18454096)
Medvedev 2014: 60 patients with phobias and anxiety disorders plus somatoform diagnoses, meaning physical symptoms with no physical cause found, received either Selank or another benzodiazepine, phenazepam. The effect on anxiety was strong, with minor impairments of thinking, and still noticeable a week after treatment ended. (PMID 25176261)
Medvedev 2015: 30 patients received phenazepam and 40 received it together with Selank. Here is where it gets interesting: the claim is not that adding Selank reduced the dose of phenazepam, but that it reduced phenazepam's side effects, the loss of memory and attention, the sedation, the flattened mood and the sexual dysfunction. (PMID 26356395)
None of these trials used an untreated control group, the inert comparison that separates a treatment's effect from everything else that could produce an improvement, like anxiety settling on its own. All three trials compared Selank only to an established drug, which means the researchers cannot say whether two separate interventions each worked, or whether both arms improved for a reason that had nothing to do with either. No abstract mentions a control group, and the Russian full texts were not openly accessible for cross checking.
None of the trials report a dose or a treatment length. None of the three trials can be reproduced from what is published, and none of them can show the signature of a real drug effect, which is a response that grows with the dose. The 1350 mcg per day that vendors attribute to the 2008 trial is absent from every primary source I could find.
The Semax pairing nobody has tested
Selank is usually sold as one half of a pair with Semax, another peptide with its own entry in this reference. Search PubMed for both names and you get 11 articles. I read all of them, and in none of them did researchers give both peptides to the same subjects.
The only study containing both names gives the opposite of what a stack implies. Panikratova 2020 used a brain scan to show how connections between the right amygdala and the rest of the brain change when a person is given Semax, or Selank, or nothing. (PMID 32342318) Three separate arms in 52 healthy subjects, scanned at rest. This is also the only Selank study I found that includes a control group.
Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro and Semax is Met-Glu-His-Phe-Pro-Gly-Pro. They share the last three amino acids. Peptides carrying that ending, given to rats after a stroke, changed the expression of 29 genes at three hours and 57 at 24 hours. (PMID 25850296) That shared tail is a plausible route to a shared mechanism, and it is also a reason two compounds that act alike may not add up to more when taken together.
The only combinations that appear in the published literature are with benzodiazepines: diazepam in a rat stress model (PMID 28280289) and the 2015 phenazepam trial above. The effect in both is a reduction of the other drug's side effects.
Where the mechanism was measured
Almost all of it in a dish, and the rest in rats.
GABA is the neurotransmitter responsible for damping activity down, and benzodiazepines work by enhancing it, so it is an obvious place to look. Two gene expression studies went there. One used the frontal cortex of rats (PMID 26924987) and the other used human tumour cells in culture, where Selank had no detectable effect on the genes expressed. (PMID 28293190) The only study that looked directly at GABA receptors also used cells in a dish. (PMID 30255741) The single mention of BDNF, a protein that helps neurons survive and connect, is a rat gene expression study from 2008 that PubMed carries no abstract for.
The most cited mechanism has an exposure problem. Selank inhibits the breakdown of enkephalins, the body's own opioid-like signals, halving the activity of the degrading enzyme in a test tube. (PMID 11443939) That was measured at 20 micromolar, which is a concentration in the fluid around the cells and not a dose you can put in a syringe. Converting one to the other needs a volume of distribution that nobody has published for this peptide, so I am not going to pretend the two numbers can be compared. What can be said is that the Russian label describes nasal drops at 1.5 mg per mL and blood clearance within about five minutes, and a test tube experiment lets the researcher choose the incubation time.
How it compares to the other Russian peptides
Buyers treat these peptides' shared origin in Russian institutes as though it were a shared evidence base.
| Approved? | Human trials behind it | What that evidence covers | |
|---|---|---|---|
| Selank | Registered in Russia in 2009, nowhere else | Three, all Russian, all against a sedative, none reporting a dose | Anxiety scores in 192 patients, given as nasal drops |
| Semax | A prescription medicine in Russia, unapproved in the United States | Eight human references in the FDA's search, two left standing after the Russian stroke papers were set aside on a filing rule | Stroke and migraine, all of it up the nose. The FDA found no literature on the injected route |
| Epithalon | No approved product in any market the FDA checked | Three in which the four amino acid peptide itself was given to people | Sprays under the tongue in night shift workers, and one eye condition. The famous life extension trial used a bovine gland extract instead |
Each of these three was tested in a form or by a route that is not the one being sold, and none of the three evidence bases carries across to either of the others.
The registry, and what the FDA has actually done
Two notes on the registry. First, I searched ClinicalTrials.gov three ways, by intervention, by term and by exact quoted term, and found no Selank trials at all. Second, every record on that registry carries an identifier beginning with the letters NCT, so any NCT number you are shown for a Selank trial is fabricated, and you can check that yourself in about ten seconds.
The FDA, the United States drug regulator, has never reviewed Selank. It approved Semax for its compounding list in July 2026 on an 8 to 5 vote with one abstention, but Selank was not on the agenda, because the request to review it had been withdrawn in 2024. The name does turn up in FDA enforcement correspondence, which is not a review: warning letter 594743, sent on 1 April 2020 to Tailor Made Compounding LLC of Nicholasville, Kentucky, lists Selank under that exact spelling among the bulk substances the firm had been compounding with, under the heading "Failure to Meet the Conditions of Section 503A". That is one pharmacy being written to about its own compounding, an eligibility question under a statute rather than a finding on safety or on whether the peptide works, and it is not an action against the compound itself or against any other seller.
The source of doses
Every documented use is intranasal, which means up the nose, as drops.
The Russian instructions are the only official source I could read in the original. Nasal drops at a concentration of 1.5 mg per mL, two drops per nostril, three times a day, for two weeks, with courses repeated every one to three months on a physician's advice. That is 12 drops a day, with no milligram figure stated anywhere. The 900 mcg per day number in circulation comes from assuming 20 drops to a millilitre, which gives 0.075 mg per drop. It is a derivation from an assumed dropper, not a number on the label.
What could go wrong
Almost nothing has been published on the harms, so this section is short for the wrong reason.
The Russian instructions go further than the marketing does, stating the drug is contraindicated in pregnancy and breastfeeding and not indicated under 18, with no efficacy or safety data in those groups.
The one unwanted effect recorded inside the trials themselves is in Medvedev 2014, where the effect on anxiety came with minor impairments of thinking.
Nothing in the record describes what the injected solution does in a person, at any amount, over any length of time. And route is not a detail you can wave through, because it has already changed the answer once in an animal. The only head to head route comparison I found gave the peptide to two different mouse strains by two different routes and found it effective in only one. (PMID 29787664)
My take
The three trials are probably not misleading. Somebody enrolled real patients and used real anxiety scales, and dismissing that work because it is in Russian would be its own kind of error. My problem is with the product being sold, which is not the one that was tested: a different route, a dose with no source I can find, and a second peptide that has never been given alongside it in any study of anything. Translating and publishing those three Russian papers tomorrow would change this entry more than any other source cited in it.
If you have taken Selank and Semax together, where did you first see the claim that the two belong in the same protocol? Because it is not in the studies.
Frequently asked
Is Selank approved?
Russia registered Selank with its Ministry of Health in 2009 and it is marketed there as nasal drops for anxiety. It has not been approved anywhere else.
Is there any real human evidence for Selank?
Three trials, all of them from the Russian network that created the compound. That is 192 patients across the three, of whom about half received Selank. None used an untreated or dummy control group, and I could not find a placebo controlled trial of Selank in any language.
Have Selank and Semax ever been studied together?
Not in the published record. Searching PubMed for both names returns 11 articles and I read all of them; in none did researchers give both peptides to the same subjects. I could not find a study in any species that has given both.
Is Selank safe?
I could not find safety or blood level data for the injected form in any species, and injection is what is mostly sold outside Russia. The Russian instructions state that the drug is contraindicated in pregnancy and breastfeeding and not indicated under 18, with no efficacy or safety data in those groups.
This content is for educational and informational purposes only and is not medical advice. Peptides discussed are research compounds and may not be approved for human use. Nothing here should be used to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional before starting any peptide, supplement, or protocol. Individual responses vary. Do not self-administer compounds without proper medical supervision.
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