Semax + Selank
Two Russian peptides sold as one product, built for two different problems.
Both came out of the same Moscow institute and both are prescription drugs in Russia. One is registered for stroke recovery, the other for generalised anxiety. Vendors bundle them and call it a nootropic stack, and the single study that looked at both together measured brain scans.
Sharp without being wired.
The pitch is a division of labour. Semax for focus and mental clarity, Selank to take the edge off, and the pair together giving you the first without the jitters that usually come with it.
It is a tidy story and it maps onto something real. The two compounds do different things. Semax raises BDNF, a protein that supports neuron growth. Selank works on GABA, the brain's main calming signal, which is the same system benzodiazepines act on.
They also share a history. Both were developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, both are heptapeptides, and both are sold in Russian and Ukrainian pharmacies today.[6]
That shared origin is most of why they are bundled. One clinical write-up puts it bluntly: stacking both because a vendor sells them together is not a clinical rationale.[3]
Four benefits, and how well each one holds up.
Two rows say proven, which is more than most pages here manage. Both belong to Selank, and both were measured in people with a diagnosis.
Three questions, answered before anything else.
Fifty-two healthy people, and a brain scanner.
A 2020 study in European Neuropsychopharmacology put 52 healthy volunteers in an fMRI scanner. It looked at what Semax and Selank did to functional connectivity, a measure of which brain regions activate together.[5]
It found measurable differences from placebo. The circuits that changed were ones linked to managing anxiety, and ones used for planning and focus.[5]
A connectivity change is a real finding and it is evidence the compounds reach the brain and do something. It is not evidence that anyone concentrated better, felt calmer, or worked longer.
The gap between a marker moving and a person improving runs through this whole site. MK-677 raised IGF-1 by 84 percent and improved no measure of physical function. CJC-1295 raised growth hormone tenfold and measured no clinical outcome.
This is the cognitive version of the same problem. Brain circuits changed. What that meant for the people in the scanner was not measured. The same pattern appears on the MK-677 page and the CJC-1295 pairing.
Decades of clinical use, in the wrong population.
The Russian Ministry of Health registered Semax in 1994 for conditions affecting blood flow in the brain. It has been in clinical use there ever since.[2] That is a longer track record than almost anything else on this site.
The largest published trial is a 110-patient study by Gusev, Martynov and colleagues in 2018, in a Russian neurology journal. Mean age 58, dosed intranasally over short courses.[2] It was not randomised.
Every substantial human trial of Semax was run in an injured brain. Acute ischaemic stroke, encephalopathy, optic nerve disease.[3] An assessment by the Alzheimer's Drug Discovery Foundation concluded there is little evidence it would improve cognition in healthy patients, and none for Alzheimer's disease.[1]
The mechanism work is the stronger half. Semax raises BDNF and its receptor in rodent cortex and hippocampus, and that finding has been replicated.[4] It is rat brain tissue, and a mechanism holding in rats does not establish an effect in a person who is already well.
One more thing worth knowing. Semax is normally given intranasally, by dropper.[1] The vials sold by peptide vendors are for injection. The trial evidence and the product are not the same route.
The stronger evidence, for a different problem.
Selank went through Phase 3 trials in Russia and is sold there as a prescription drug for generalised anxiety disorder.[5] That is a regulatory milestone almost nothing else in this category has reached.
The trials behind that put Selank head to head against medazepam, a benzodiazepine, in patients with diagnosed anxiety. The reported findings: anxiety scores fell about the same amount over several weeks, tolerability was much better, and nobody had withdrawal symptoms on stopping.[7]
A 2018 lab study found it strengthens GABA binding without touching the site benzodiazepines act on.[6] That is why it would produce calm without the sedation and dependence those drugs bring.
Two caveats sit on all of it. Numeric effect sizes against the benzodiazepine were never published in English, so the size of the benefit cannot be checked from outside.[6] And no Western randomised trial has replicated any of it.
Selank's documented effect in humans is reducing anxiety. It is not a nootropic finding, and it is regularly sold as one.[8]
One of the few blends that is cheaper than its parts.
This pairing is sold ready-mixed and the maths favours it, which is unusual. Both compounds cost $20.14 separately, so a 5 mg vial of each comes to $40.28. The cheapest premixed 10 mg vial is $34.99.[9]
Where amounts are published the split is even, either 10 mg of each or 5 mg of each. Seven of the eleven blend listings we track publish no amounts at all, so for most of the market there is no way to know which size you are buying.
Separate vials cost 15 percent more and let you stop one without losing the other, which matters here more than on most pages. The two compounds are for different problems, and somebody who finds one useful and the other pointless has no way to act on that with a premixed vial.
Prescription drugs in one country, research chemicals everywhere else.
Neither is FDA-approved and neither has been submitted for review. As of April 2026 Selank sits in Category 2 on the FDA's list of bulk drug substances, the tier that means compounding pharmacies may not work with it.[5]
Human safety data comes almost entirely from Russian trials, which consistently report good tolerability at the doses studied.[2] Those were short courses, mostly around ten days, so the long-term picture is not established for either compound.
One documented side effect rarely appears in vendor copy. A review of Semax reported discoloration of the nasal cavity in about 10 percent of users.[1] That is specific to the intranasal route the trials used.
The honest summary of the safety position is that little human evidence exists on side effects for Semax.[1] Good tolerability in short Russian trials is not the same as a characterised safety profile.
What people ask about this stack
Does Semax and Selank work for focus?
Semax has no controlled trial in healthy adults for focus, mental fatigue or brain fog. Its human trials were run in stroke patients, encephalopathy and optic nerve disease, which is a long way from a well person wanting sharper concentration. Selank's documented human effect is reducing anxiety rather than improving cognition. The combination has been studied once, in a brain imaging study that measured connectivity rather than performance.
Which of the two has better evidence?
Selank, clearly. It went through Phase 3 trials in Russia and is sold there as a prescription anxiety drug. Those trials put it head to head against a benzodiazepine. Semax has a longer clinical history, registered in Russia since 1994, but its largest published trial was not randomised and every substantial study was run in patients with brain injury.
Is one an upgrade of the other?
No. Semax comes from ACTH and raises BDNF, a protein supporting neuron growth. Selank comes from tuftsin and works on GABA, the brain's calming signal. Semax has not been shown to have meaningful anxiety effects, and Selank's documented effect is anxiety rather than cognition. They are built for different problems, and being sold in one vial does not change that.
Should I buy the blend or two vials?
The blend is cheaper here, which is unusual. Two separate 5 mg vials cost $40.28 against $34.99 for a premixed 10 mg vial. Separate vials cost about 15 percent more and let you stop one compound without losing the other, which matters because the two are for different problems. Seven of the eleven blend listings publish no amounts at all.
Should they be injected or used as a nasal spray?
The Russian trials used the intranasal route, given by dropper. Peptide vendors sell vials for injection. That is a real gap between the evidence and the product, and it appears on several pages here. One documented side effect from the intranasal route is discoloration of the nasal cavity, reported in about 10 percent of users.
Is Selank addictive like a benzodiazepine?
The Russian trials reported no withdrawal symptoms on stopping. A 2018 radioligand study found Selank enhances GABA binding without engaging the benzodiazepine site, which is the mechanistic reason it would not be expected to produce dependence. Those trials were short and no Western study has replicated them. Compare against the other stacks.
What this page is built on
- 01Semax assessment, Alzheimer's Drug Discovery Foundation Cognitive Vitality. Report PDF. Source for little evidence of cognitive benefit in healthy patients and none for Alzheimer's disease; for the evidence base being two pilot studies in healthy individuals and two in stroke patients; for the intranasal route; and for nasal cavity discoloration in about 10 percent of users.
- 02Gusev, Martynov and colleagues, 2018, Zhurnal Nevrologii i Psikhiatrii. 110 patients, 43 men and 67 women, mean age 58.0 plus or minus 9.7, intranasal Semax over short courses. Non-randomised. Also the source for Russian Ministry of Health registration in 1994 for cerebrovascular indications.
- 03Comparison of the two compounds. Source for Semax's human trials being in acute ischaemic stroke, encephalopathy and optic nerve disease; for the absence of controlled trials in healthy people; and for the observation that stacking both because a vendor bundles them is not a clinical rationale.
- 04Dolotov and colleagues, 2006, and related rodent work. Semax raising BDNF and NGF expression in rodent cortex and hippocampus after intranasal dosing, replicated across multiple rodent studies.
- 05Selank regulatory status and the joint imaging study. Selank completed Phase 3 trials in Russia and is registered for generalised anxiety disorder; classified as an FDA Category 2 bulk drug substance as of April 2026. A 2020 study in European Neuropsychopharmacology examined both compounds in 52 healthy human participants using fMRI, finding measurable differences from placebo in circuits associated with anxiety regulation and executive function.
- 06Selank pharmacology. 2018 radioligand study finding enhanced GABA binding without engaging the benzodiazepine site. Also the source for effect sizes against benzodiazepine comparators not being reported in the English-language abstract, for the absence of Western randomised trials, and for both compounds being available in Russian and Ukrainian pharmacies. Encyclopaedia entry: Selank.
- 07The Russian generalised anxiety disorder trials comparing Selank head to head against medazepam in diagnosed patients. Reported comparable reductions in anxiety scores after multi-week treatment, substantially better tolerability, and no withdrawal symptoms on discontinuation.
- 08Evidence grading of specific claims for each compound, including that Selank's primary documented human effect is reduction of generalised anxiety and not direct nootropic action, and that Semax enhancing cognition in healthy humans rests on mechanism extrapolation with no published randomised trial.
- 09Peptide Decoding vendor pricing data, 18 September 2026. Lowest in-stock single-compound listings: Semax $20.14 for 5 mg, Selank $20.14 for 5 mg. Premixed blend from $34.99 for 10 mg across 11 blend listings, of which four publish amounts, split evenly at either 10 mg or 5 mg of each.