Cognitive · Reference
Selank vs Semax: Anxiety vs Focus, Evidence, Cost, and the Combined Vial
This page explains each peptide on its own terms, puts them side by side, covers what the research does and does not show, where each stands with the FDA, how each is dosed, what each costs at Pepti, and who tends to suit which.
Medically reviewed by Dr. Gene, MD · November 4, 2026
Treatments mentioned
Selank and Semax are sibling peptides from the same Russian institute, built on the same design, but they are aimed at opposite sides of the same problem. Selank is a fragment of tuftsin described around GABA signalling and stress reactivity, and its human evidence is small Russian trials in anxiety disorders. Semax is a fragment of ACTH described around BDNF and attention, and its human evidence is Russian clinical work in stroke and cerebrovascular disease. Prescribers reach for Selank when the complaint is anxiety or stress, Semax when it is focus, and the combined Semax + Selank vial when it is both. All three are prescription-only, compounded by a licensed US pharmacy, and none is FDA approved.
This page explains each peptide on its own terms, puts them side by side, covers what the research does and does not show, where each stands with the FDA, how each is dosed, what each costs at Pepti, and who tends to suit which.
Selank vs Semax
The short answer
| If your main goal is | The usual prescription | What is in it | Price |
|---|---|---|---|
| Calm, less stress reactivity, anxiety | Selank | 10 mg Selank in a 5 mL vial | $229/mo |
| Focus, mental energy, getting started on tasks | Semax | 10 mg Semax in a 5 mL vial | $229/mo |
| Focus that is undermined by stress or anxiety | Semax + Selank | 1 mg Semax and 1 mg Selank in one vial | $259/mo |
| Stress and poor sleep together | SERENITY Blend | DSIP, Selank, CJC-1295 and ipamorelin | $279/mo |
| Focus plus energy and body composition | SYNAPSE Blend | Semax, Selank, MOTS-c and tesamorelin | $279/mo |
| Focus plus recovery and inflammation | ELEVATE Blend | Semax, Selank, BPC-157 and KPV | $249/mo |
Every figure is an all-in monthly price covering the medication, physician review, refill management and shipping. There is no separate membership fee. Current pricing always lives on each product page; the table is a guide to which product fits which goal.
Selank vs Semax
Selank on its own terms
What it is
Selank is a heptapeptide, seven amino acids long: Thr-Lys-Pro-Arg-Pro-Gly-Pro. The first four are tuftsin, a fragment the body cuts from immunoglobulin G and that was first characterised for its effects on immune cells. The last three, Pro-Gly-Pro, were added to slow its breakdown. It is not a hormone, not a steroid and not a benzodiazepine, even though the Russian trials compared it with benzodiazepines. The full reference is at what is Selank.
Where it came from
Selank was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences with the Zakusov Institute of Pharmacology in Moscow. It is registered in Russia as a prescription medicine in an intranasal form, used there as an anxiolytic. Nearly all of the published research comes from the groups that developed it.
How Selank is described to work
- GABA-A receptor modulation. A 2018 paper in Protein and Peptide Letters used rat brain-cell membranes and reported that Selank changed how GABA itself bound to the receptor, in the manner of a positive allosteric modulator. A 2016 study in Frontiers in Pharmacology reported changes in 45 of 84 neurotransmission genes in rat frontal cortex an hour after Selank, in a pattern resembling GABA's own.
- Slowing enkephalin breakdown. A 2001 paper in the Bulletin of Experimental Biology and Medicine reported that Selank inhibited the enzymes that degrade leu-enkephalin in human plasma. The 2008 clinical paper below measured the same marker in patients, which makes this the one Selank mechanism with a human correlate.
- BDNF in the hippocampus. A 2008 report in Doklady Biological Sciences described intranasal Selank changing BDNF expression in the rat hippocampus, and a 2019 rat paper reported it prevented an ethanol-related shift in BDNF alongside better object-recognition performance.
The picture is a peptide that modifies GABA signalling rather than driving it. The mechanism work is in animals and cells.
What human data exists for Selank
Selank has controlled human trials. They are Russian, small, compared against an active drug rather than placebo, and not described as randomised or blinded in the published abstracts:
Study Who What was reported 2008, Korsakov Journal (Zozulya) 62 patients with generalised anxiety disorder or neurasthenia, Selank vs medazepam Similar anxiolytic effect; Selank also described as anti-asthenic and mildly activating 2014, Korsakov Journal (Medvedev) 60 patients with anxiety-phobic and somatoform disorders, Selank vs phenazepam Pronounced anxiolytic effect, mild nootropic effect, effect persisting about a week after the last dose 2015, Korsakov Journal (Medvedev) 70 patients, phenazepam alone vs phenazepam plus Selank The combination brought the benzodiazepine's effect on earlier and reduced its side effects What does not exist: a placebo-controlled trial in the PubMed-indexed literature, an independent replication outside Russia, or any trial of the subcutaneous form. A 2021 review in the Journal of Clinical Pharmacology described Selank as poorly studied outside its country of origin.
Selank vs Semax
Semax on its own terms
What it is
Semax is also a heptapeptide: Met-Glu-His-Phe-Pro-Gly-Pro. The first four are positions 4 to 7 of adrenocorticotropic hormone (ACTH), and the last three are the same Pro-Gly-Pro tail Selank carries. The design keeps the part of ACTH studied for attention and learning and drops the part that raises cortisol, so Semax is described as having no corticotropic activity. It is not a stimulant. The full reference is at what is Semax.
Where it came from
Semax came out of the same Institute of Molecular Genetics. It is a registered medicine in Russia, sold as nasal drops, and has been used in Russian neurology since the 1990s for acute ischaemic stroke and chronic cerebrovascular disease.
How Semax is described to work
- BDNF and TrkB in the hippocampus. A 2006 paper in Brain Research reported that Semax raised BDNF protein and activated its receptor, TrkB, in the rat hippocampus. BDNF is the growth factor most closely tied to synaptic plasticity, which is the basis of the "cognitive" label.
- Neurotrophins in the injured brain. A 2010 paper in Cellular and Molecular Neurobiology reported increased transcription of BDNF, NGF and their receptors selectively in ischaemic rat cortex, and a 2014 genome-wide study in BMC Genomics found the largest effect was on immune-response genes.
- The stress axis. A 2024 paper in the European Journal of Pharmacology reported that daily low-dose Semax counteracted several markers of chronic unpredictable stress in male rats, including the fall in hippocampal BDNF. It is a rat finding, and it is the thread connecting Semax to the reason it is paired with Selank.
- Dopamine. A mouse study reported Semax increasing amphetamine-induced dopamine release, which is why anyone taking a stimulant should tell their physician.
What human data exists for Semax
Study Who What was reported 1997, Korsakov Journal 30 acute stroke patients vs 80 matched controls Faster regression of neurological deficits on rating scales and EEG 2005, Korsakov Journal 187 patients with chronic cerebrovascular disease Clinical improvement and good tolerability, including in older patients 2018 clinical trial 110 patients in stroke rehabilitation Plasma BDNF rose and Barthel Index scores improved faster with Semax 2018, Bulletin of Experimental Biology and Medicine 14 healthy adults, single dose Changes in the brain's default mode network on functional MRI What does not exist: a randomised, placebo-controlled trial in an English-language peer-reviewed journal, or any trial of Semax for focus or memory in healthy adults.
Selank vs Semax
Head to head
| Selank | Semax | |
|---|---|---|
| Built from | Tuftsin (an immunoglobulin G fragment) plus Pro-Gly-Pro | ACTH positions 4 to 7 plus Pro-Gly-Pro |
| Main described mechanism | GABA-A modulation, slower enkephalin breakdown | BDNF and TrkB signalling in the hippocampus |
| Usually chosen for | Anxiety, stress reactivity, a racing mind | Focus, mental energy, sustained attention |
| Registered use in Russia | Anxiolytic, nasal form | Stroke and cerebrovascular disease, nasal drops |
| Human trials | Small Russian comparator trials in anxiety disorders (60 to 70 patients) | Russian clinical studies in stroke and cerebrovascular disease (up to 187 patients) |
| Placebo-controlled trial | None | None in English-language journals |
| Feel at the time of dosing | No "kick"; described as subtle | No "kick"; some people feel over-alert if dosed late |
| Key safety question | Untested alongside SSRIs, SNRIs and stimulants | Interaction with stimulants (mouse dopamine finding) |
| Vial at Pepti | 5 mL, 2 mg/mL (10 mg) | 5 mL, 2 mg/mL (10 mg) |
| Standard directions | 0.25 mL (25 units) once daily, Monday to Friday | 0.25 mL (25 units) once daily, Monday to Friday |
| Doses per vial | 20, about 4 weeks | 20, about 4 weeks |
| Price at Pepti | $229 a month | $229 a month |
| FDA history | Category 2 in 2023, removed September 2024, never reviewed by the advisory committee | Category 2 in 2023, out by April 2026, advisory committee voted 8 to 5 to recommend it in July 2026 |
The real difference is direction, not strength
No study has measured both in the same people, so "which is stronger" has no answer. The useful difference is what each is aimed at: Selank's trials measured anxiety scales, Semax's measured recovery after stroke. That is why the two are so often prescribed together rather than chosen between.
Selank vs Semax
Which is better for anxiety, and which for focus
Anxiety: Selank
Selank is the one with anxiety trials behind it. The Russian studies reported an anxiolytic effect similar to two benzodiazepines, without the sedation, memory impairment or dependence signal of that class. That is a reported finding from small trials without placebo arms, not a settled result, but it is direct evidence in the condition, which Semax does not have. Prescribers describe any change as a lower anxious baseline rather than an effect you feel at the moment of injection. More on the category is at peptides for anxiety and mood.
Focus: Semax
Semax is the usual choice when the complaint is focus, mental fatigue late in the day, or trouble getting started. Its BDNF work and its clinical history in brain injury are the reason. No trial has measured Semax for focus in healthy adults, so this is a prescribing rationale, not a trial result. More is at peptides for brain fog and focus, and the comparison with a different cognitive peptide is at Dihexa vs Semax.
Both: the combined vial
The case the pairing is built for is the person whose concentration is undermined by a racing, anxious baseline. Selank is described as settling the reactive side without sedation, which would otherwise defeat the point of Semax. If you cannot tell whether the problem is stress or attention, that ambiguity is itself a reason prescribers consider the pair.
Selank vs Semax
The Semax + Selank vial, explained
Semax + Selank is not a new molecule. It is the two peptides dissolved together in one vial by a compounding pharmacy: 1 mg of Semax and 1 mg of Selank per vial, dosed at the same 0.25 mL once daily on weekdays. Across 20 doses, each injection delivers 0.05 mg of each peptide. The full reference is at what is Semax + Selank.
| Selank alone | Semax alone | Semax + Selank | |
|---|---|---|---|
| Per vial | 10 mg Selank | 10 mg Semax | 1 mg Semax and 1 mg Selank |
| Per 0.25 mL dose | 0.5 mg Selank | 0.5 mg Semax | 0.05 mg of each |
| Injections a day | One | One | One |
| Price | $229/mo | $229/mo | $259/mo |
| Best fit | Stress is the whole picture | Focus is the whole picture | Both, from the start |
Two things are worth knowing. First, the combined vial is not a bigger dose of anything; each single vial carries ten times the amount of its peptide. Second, the pairing has never been studied as a pairing, in people or in animals. The evidence is per component. The split is fixed by the pharmacy, so if your physician wants a different balance, the two are prescribed as separate vials.
Selank vs Semax
When neither is the right first step
| Situation | What makes more sense |
|---|---|
| A psychiatric diagnosis under active treatment (SSRI, SNRI, benzodiazepine, antipsychotic) | That treatment comes first; raise any peptide with the prescriber managing it |
| Poor sleep is the main problem | DSIP or the SERENITY Blend, aimed at sleep directly |
| The real problem is fatigue | NAD+ injection or MOTS-c, aimed at cellular energy |
| Recall and learning specifically | Dihexa, a different mechanism with no human data |
| ADHD or panic disorder | Your treating physician; neither peptide is a treatment for either |
Selank vs Semax
Where each stands with the FDA
The two have very different regulatory histories, and much of what is online is out of date. As of the FDA pages checked in September 2026:
| Selank | Semax | |
|---|---|---|
| 2023 | Placed in Category 2 of the 503A bulks list (generic immunogenicity concern) | Placed in Category 2 (possible immunogenicity, limited safety data) |
| Removal | 27 September 2024, after the nominator said it had meant to nominate a different substance | Out of Category 2 by April 2026; listed as "nominated but withdrawn" |
| Advisory committee | Never reviewed | 24 July 2026: voted 8 to 5, one abstention, to recommend adding Semax to the 503A bulks list, against the FDA staff proposal |
| Final FDA determination | No active nomination | Pending |
Neither is banned. Both remain legal for a physician to prescribe and a state-licensed pharmacy to compound. Compounded medications are not FDA approved, and neither Selank nor Semax is an FDA-approved drug for anything. Are peptides FDA approved explains the difference between not approved and not legal.
Selank vs Semax
Dosing, side by side
All three products are injected under the skin (subcutaneously) into the abdomen or thigh, rotating sites, once a day on weekdays with weekends off. The volume is the same, 0.25 mL, which is 25 units on a U-100 insulin syringe. You do not need to calculate anything: your directions are printed on the vial, and your physician sets them after reviewing your intake.
Twenty doses per vial covers about four weeks, which is why refills run every 28 days, one vial at a time. All ship refrigerated with ice packs and stay in the fridge between doses. Morning dosing is usual, because Semax is occasionally described as causing restlessness if taken late in the day. The 2014 Selank trial reported the effect persisting about a week after the last dose, so the weekend gap is not described as a loss of effect.
One honest gap applies to both: the Russian products and every Russian trial used the nasal route. Neither peptide has a published trial by subcutaneous injection.
Bloodwork is not required for any Pepti treatment. If your physician wants labs for your care, they'll ask through your account.
Selank vs Semax
Side effects
Selank. The Russian trials used a formal side-effect scale and a benzodiazepine comparator, and the finding reported most consistently is what was absent: no sedation, no memory impairment, no dependence signal and no withdrawal over the study periods. With the injection, prescribers report redness, mild soreness or bruising at the site, and some people describe early fatigue or a flat feeling, or less often a wired feeling, usually settling.
Semax. The Russian clinical series describe it as well tolerated, including in older stroke patients. Reported with the injection: site redness or soreness, an occasional early headache, and restlessness if dosed late in the day.
Both. There is no established interaction list. The one combination studied is Selank with a benzodiazepine, under supervision. Neither has been studied alongside SSRIs, SNRIs, stimulants or antipsychotics, which is why the intake asks for every medication you take. Stop and contact your physician for any reaction that is severe, spreading, involves difficulty breathing, or involves a marked change in mood.
Selank vs Semax
Who should not take either, or should discuss it first
| Situation | Why |
|---|---|
| Pregnancy or breastfeeding | Not used; safety data is absent |
| Existing psychiatric treatment | Combinations with SSRIs, SNRIs and antipsychotics have not been studied |
| Taking a stimulant | Especially for Semax, because of the mouse dopamine finding |
| Tested athletes | Check your sport's current prohibited list before starting |
Selank vs Semax
What the evidence shows, honestly
Selank has a real but limited base: small Russian comparator trials in anxiety disorders, on validated scales, never placebo-controlled and never replicated abroad. Semax has a coherent BDNF mechanism and Russian clinical studies in stroke and cerebrovascular disease, which the FDA's 2026 review did not weigh because full English translations were not supplied. Neither has a trial in healthy adults for anxiety, focus or memory, and the combination has never been studied as a combination. Any provider claiming either has been shown to work for calm or focus in healthy people is overstating it. Prescribers describe changes over two to four weeks of weekday dosing in some people; response varies.
Selank vs Semax
Where to get Selank or Semax prescribed
Neither can be bought legitimately without a prescription. Sites selling them "for research use only" are not accountable for what is in the vial: identity, purity, sterility and concentration are untested. The prescription route:
- Complete a free online intake covering your history, medications and what you want help with.
- A physician licensed in your state reviews it, usually within 24 hours.
- If it is appropriate, a state-licensed, FDA-registered US pharmacy compounds it to that prescription. Lot test results are published at /quality/lab-results.
- It ships refrigerated with your directions printed on the vial.
- Your physician stays reachable for questions and dose changes.
Pepti prescribes Selank, Semax and Semax + Selank in all 50 states and DC. Step-by-step pages: how to get Selank prescribed online and how to get Semax prescribed online.
References
What this is based on.
References
- Kozlovskaya MM, Kozlovskii II, Val'dman EA et al.. Selank and short peptides of the tuftsin family in the regulation of adaptive behavior in stress · Neurosci Behav Physiol (2003) · PMID 14969422
- Zozulia AA, Neznamov GG, Siuniakov TS et al.. Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia · Zh Nevrol Psikhiatr Im S S Korsakova (2008) · PMID 18454096
- Medvedev VE, Tereshchenko ON, Israelian AIu et al.. A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders · Zh Nevrol Psikhiatr Im S S Korsakova (2014) · PMID 25176261
- Medvedev VE, Tereshchenko ON, Kost NV et al.. Optimization of the treatment of anxiety disorders with selank · Zh Nevrol Psikhiatr Im S S Korsakova (2015) · PMID 26356395
- Uchakina ON, Uchakin PN, Miasoedov NF et al.. Immunomodulatory effects of selank in patients with anxiety-asthenic disorders · Zh Nevrol Psikhiatr Im S S Korsakova (2008) · PMID 18577961
- Zozulya AA, Kost NV, Sokolov OY et al.. The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity · Bull Exp Biol Med (2001) · PMID 11550013
- Vyunova TV, Andreeva L, Shevchenko K, Myasoedov N. Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity · Protein Pept Lett (2018) · PMID 30255741
- Volkova A, Shadrina M, Kolomin T et al.. Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission · Front Pharmacol (2016) · PMID 26924987
- Filatova E, Kasian A, Kolomin T et al.. GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells · Front Pharmacol (2017) · PMID 28293190
- Inozemtseva LS, Karpenko EA, Dolotov OV et al.. Intranasal administration of the peptide Selank regulates BDNF expression in the rat hippocampus in vivo · Dokl Biol Sci (2008) · PMID 18841804
- Kolik LG, Nadorova AV, Antipova TA et al.. Selank, Peptide Analogue of Tuftsin, Protects Against Ethanol-Induced Memory Impairment by Regulating of BDNF Content in the Hippocampus and Prefrontal Cortex in Rats · Bull Exp Biol Med (2019) · PMID 31625062
- Doyno CR, White CM. Sedative-Hypnotic Agents That Impact Gamma-Aminobutyric Acid Receptors: Focus on Flunitrazepam, Gamma-Hydroxybutyric Acid, Phenibut, and Selank · J Clin Pharmacol (2021) · PMID 34396551
Citations are provided for educational purposes. They do not constitute medical advice. Always discuss any peptide protocol with your prescribing physician.
Common questions
Selank vs Semax, answered.
Selank. It is the one with Russian trials in anxiety disorders, which reported effects similar to benzodiazepines without their sedation. Semax is described around focus and has no anxiety trials. Neither has a placebo-controlled trial.
Semax is the usual choice for focus and mental energy, based on its BDNF work and clinical history in brain injury. Selank is sometimes described as easing concentration under pressure by lowering stress reactivity. No trial has measured either for focus in healthy adults.
Yes. They are often prescribed together, either as the combined Semax + Selank vial or as two separate vials. No study has tested the pair as a pair, so the case rests on their different mechanisms. Some people start with one, keep a simple log for four weeks, and add the second only if there is a reason to.
Both are seven-amino-acid peptides from the same Russian institute with the same stabilising tail. Selank is built from tuftsin and described around GABA and calm; Semax is built from ACTH and described around BDNF and attention.
It contains less of each peptide: 1 mg of each per vial against 10 mg in each single vial. It is a smaller amount of two things in one injection, not a stronger version of either.
It is not described as sedating. The Russian trials reported no sedation or memory impairment, in contrast to the benzodiazepines it was compared with. Some people describe early fatigue or a flat feeling that usually settles.
No. It is not a stimulant and is not expected to raise cortisol. Some people feel over-alert if they dose late in the day, which is why morning dosing is usual.
There is no trial-established timeline for the injectable form of either. Prescribers describe any change emerging over two to four weeks of weekday dosing rather than on the first day; response varies. Each vial is sized at about four weeks.
At Pepti, Selank and Semax are each $229 a month, and Semax + Selank in one vial is $259 a month, all-in, including the medication, physician review, refill management and shipping.
Selank with the benzodiazepine phenazepam was studied in one supervised Russian trial of 70 patients. Neither peptide has been studied with SSRIs, SNRIs, stimulants or antipsychotics. List every medication on your intake so your physician can review it.
Yes, with a valid prescription, as compounded medications from a licensed US pharmacy. Neither is FDA approved and neither is banned. Semax was recommended for the 503A bulks list by the FDA's advisory committee in July 2026; Selank has never been reviewed.
No. Bloodwork is not required for any Pepti treatment. If your physician wants labs for your care, they'll ask through your account. The free assessment goes to a physician licensed in your state. A consultation does not guarantee a prescription.
Next step
See what a physician recommends for you.
A licensed physician in your state reviews your intake and decides what is appropriate. A consultation does not guarantee a prescription.