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Nootropic peptides for focus, and the trial nobody has run

Semax and Selank are the two compounds sold as nootropic peptides. Their published human record is stroke rehabilitation and anxiety treatment, both in Russian, and no controlled trial has measured attention in a person who was not already ill.

Published · 12 min
Quick answer

No randomized, placebo-controlled trial has tested whether Semax, Selank, or any other peptide sold as a nootropic improves focus in a healthy adult, and a PubMed search in August 2026 returns none. A nootropic is a compound taken to improve thinking in someone who is not ill, and healthy people are exactly who is missing from the record. The strongest human evidence for Semax, a nasal spray copy of a fragment of the pituitary stress hormone ACTH, comes from 110 people recovering from an ischemic stroke who received 6000 mcg a day in two 10-day courses, a Russian study that measured walking and daily-living scores rather than attention and had no placebo group [[2]]. The mechanism everyone quotes for it, a rise in BDNF, the protein that helps brain cells grow and survive, was measured in rat brain tissue [[1]]. Selank's human trials were run in anxiety patients against a benzodiazepine [[7]]. Methylphenidate, the prescription stimulant, is the one compound in this conversation pooled in a meta-analysis of randomized trials in healthy volunteers, and that review concluded expectations of the drug exceed its actual effects [[6]]. Neither peptide is FDA-approved, and a doctor is the right person to work through persistent brain fog with.

What to take

Peptides commonly discussed for focus and cognition

Safety: Semax and Selank are not FDA-approved for any use in the United States, and neither has long-term safety data in healthy adults. Research-grade powder reconstituted at home and sprayed into the sinuses puts unverified material next to the venous drainage of the brain, and no regulator checks what is in a research-chemical vial. A 1999 Russian study recorded episodes of paroxysmal activity on EEG after Semax dosing in patients with posthypoxic encephalopathy, and the authors advised monitoring brain activity during the first dose [[9]], so a personal or family history of seizures is a reason to stay out of this entirely. New or worsening cognitive decline, trouble finding words, one-sided weakness, or a sudden change in personality is a same-week clinician visit, not a peptide question. Anyone with bipolar disorder, an active mania or hypomania, a seizure history, or who is pregnant or breastfeeding has no safety data to work from here at all.

Where to buy

Where to get peptides for focus and cognition

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Two compounds carry the nootropic peptide category, Semax and Selank. The strongest human evidence for either was collected in a rehabilitation ward, where 110 people relearning to dress and walk after an ischemic stroke, a blockage that cuts blood supply to part of the brain, were given Semax as a nasal spray in two 10-day courses 2. The mechanism everyone quotes for focus, a rise in BDNF (brain-derived neurotrophic factor, the protein neurons release when they are active to strengthen and keep their connections), was measured in rat brain tissue 1. Nobody has run the trial in a healthy adult.

One person tries Semax and describes a clean, quiet lift. The next describes a jittery hour and a wasted afternoon. Both reports are real and neither is evidence, because nobody was blinded and nobody was measured.

Put plainly: Semax is a real medicine in Russia, for strokes. Selank is a real medicine there for anxiety. Neither is a fraud, neither has been tested for the thing people in the US buy it for, and the amount sold for focus is roughly a tenth of the only dose anyone has published.

What are nootropic peptides, and which ones do people buy?

Semax is a seven-amino-acid analog of ACTH(4-10), a fragment of the pituitary stress hormone, modified so it lasts longer and does not trigger the hormone's usual stress response. Selank is a seven-amino-acid analog of tuftsin, a short peptide the immune system produces. Both are sprayed into the nose, and both were developed at Russian institutes 8.

Sales pages usually place them alongside racetams (a family of synthetic study-drug compounds sold online, of which piracetam is the original), prescription stimulants and modafinil in a single ranked list, as though the four sat on one evidence ladder. They do not. Two of those four have been through randomized, placebo-controlled trials in healthy volunteers. The two peptides have been through no such trial, in any population, for any cognitive endpoint. Anyone arriving here new to the category should read peptides for beginners first, because the gap between how these compounds are marketed and how they were studied is the whole story on this page.

Which focus peptides have been tested, and in whom?

Graded by who was enrolled and what was measured, the ranking runs opposite to the way the products are priced. The two peptides sit at the bottom, and the compounds with healthy-adult trial data are the ones that need a prescription.

OptionBest human evidenceWho was studiedAttention measured in healthy people?US status
Semax, intranasal110 patients after ischemic stroke, 6000 mcg/day in two 10-day courses, followed about five months 2Stroke rehabilitation, mean age 58, Russian centersNot in a controlled trialNot FDA-approved, not scheduled
Selank, intranasal62 patients with generalized anxiety disorder or neurasthenia (an older fatigue-and-irritability diagnosis), 30 on Selank against 32 on medazepam, a benzodiazepine 7Anxiety patients at Moscow centersNoNot FDA-approved, not scheduled
MethylphenidateSystematic review and meta-analysis of single- and double-blind randomized trials in healthy volunteers 6Healthy adultsYes. Memory improved; no consistent evidence for other enhancing effectsFDA-approved, Schedule II
ModafinilSame systematic review 6Healthy adults, rested and sleep-deprivedYes. Attention improved in rested people; wakefulness, memory and executive function held up better than placebo when sleep-deprivedFDA-approved for narcolepsy, shift-work sleep disorder and as adjunct for obstructive sleep apnea, Schedule IV
Sleeping longer, when sleep is the problemThe size of the prize is visible in modafinil's own record: the drug's clearest measured effect was preserving cognition in people who had been kept awake 6Healthy adults under sleep deprivationIndirectly, yesNot a purchase
Treating an anxiety disorder, when rumination is the problemStandard care for anxiety carries a far larger trial base than any compound here, and peptides for anxiety grades the peptide alternatives against itPeople with diagnosed anxietyNo attention endpoint, but distraction is the targetStandard care

Neither peptide has a randomized trial, a placebo arm, or a published effect size for any cognitive measure. The study that would settle it is not an expensive one. Forty healthy adults, a placebo spray, two weeks on each arm in crossover order, a standard attention battery scored before and after, and an endpoint registered in advance. Semax has been in clinical use in Russia since the 1990s 8, and that study still does not exist.

The strongest human Semax data comes from stroke rehabilitation

Gusev and colleagues followed 110 people for about five months after an ischemic stroke, 43 men and 67 women, mean age 58 2. Patients were split into an early rehabilitation group starting around 89 days after the stroke and a late group starting around 214 days, and each group was subdivided into those who received Semax and those who did not. The Semax regimen was 6000 mcg a day intranasally, two courses of 10 days with a 20-day gap. The outcomes were plasma BDNF, muscle strength on the British Medical Research Council scale, and the Barthel index, a 100-point score of how independently someone dresses, bathes, eats and climbs stairs. Blood BDNF was higher in the Semax subgroups, and higher BDNF tracked with faster Barthel recovery. Because patients were not randomized to Semax, the study cannot show that Semax caused either.

6000 mcg/daythe only Semax dose in a published human trialGiven to stroke patients in two 10-day courses 20 days apart, and what the study measured was how independently they could dress and bathe.

Three things limit what that study can carry. Patients were assigned to groups by when their rehabilitation started rather than randomized to Semax or placebo, so the Semax and non-Semax subgroups were not built to be comparable. No effect sizes were reported. And it was published in Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova, in Russian, with no clinical replication outside Russia to date. A person recovering the ability to dress themselves after a brain injury and a person trying to hold attention through a Tuesday afternoon are not being measured on the same thing.

What Semax does in a rat brain, and where the evidence stops

The BDNF chain, step by step, and the step nobody has climbed

1
The peptide reaches the basal forebrain and binds there
Cell membranes taken from rat basal forebrain, the patch of tissue that supplies the cortex with acetylcholine, carried binding sites for Semax that were specific, reversible and dependent on calcium, with a dissociation constant of 2.4 nM [[1]]. A low dissociation constant means the peptide holds on tightly at low concentrations.
2
BDNF protein rises within three hours
Intranasal Semax at 50 and 250 mcg per kg of body weight raised BDNF protein in rat basal forebrain three hours after a dose, and did not raise it in the cerebellum [[1]]. The effect was regional rather than a whole-brain wash, which is the detail that makes the mechanism plausible rather than generic.
3
BDNF is the protein that lets connections stick
BDNF is released by neurons when they are active and helps them strengthen and maintain their connections. Every cognitive claim made for Semax rests on this one protein moving.
4
The same protein moves in a stress model
In Sprague-Dawley rats put through chronic unpredictable stress, daily abdominal injections of Semax at 60 nmol per kg reversed or substantially attenuated the loss of hippocampal BDNF, the loss of interest in sugar water, and the adrenal enlargement that the stress model produces, in male rats only, which is the limit the authors state [[3]]. Anyone reading that as a human protocol should note the route: those rats were injected in the abdomen, not sprayed in the nose.
5
Nobody has climbed this chain in a person who was not ill
Every measurement above came from a rat. In humans, the only Semax study to measure BDNF measured it in blood, in stroke patients, and blood BDNF is a different reading from protein inside a specific brain region [[2]]. No study has followed the chain in a healthy adult, and no study has connected any link in it to a score on an attention task in anyone.
The mechanism is well characterized in rodents and untested in people. Every focus claim made for Semax is built on that gap being invisible to the reader.
These results point to the presence of specific binding sites for Semax in the rat basal forebrain. In addition, these findings indicate that the cognitive effects exerted by Semax might be associated, at least in part, with increased BDNF protein levels in this brain region.Dolotov OV et al., Journal of Neurochemistry, 2006 [[1]]

The authors' own hedges carry the weight here. The phrases "might be associated" and "at least in part" are careful descriptions of a rat experiment, and they are a long way from the sentence a product page builds out of them.

Selank sits in the anxiety file, and gets borrowed for distraction

Selank is the second compound in the category, and it is usually recommended for poor focus of the ruminating kind, where the problem is not that attention will not start but that it will not stay anywhere. Its human trials were run on anxiety scales in anxiety patients 7, so the evidence for it belongs to a different question, and peptides for anxiety owns the grading.

Selank was tested in about 192 patients across three Russian trials published between 2008 and 2015, each against a benzodiazepine rather than a placebo, and the last of them as an add-on to one. Semax, BPC-157 and every other compound on a best-peptides-for-anxiety list has no human anxiety trial at all.

PeptidesDNA, [peptides for anxiety](/peptides-for/anxiety)

One finding from that literature matters for anyone buying Selank to concentrate. In the 2008 trial, 30 patients on Selank and 32 on medazepam finished with similar anxiolytic effects, and Selank additionally showed antiasthenic and psychostimulant effects, meaning lifted drive and less fatigue 7. A compound that does both will not read as steadying to everybody. The practical detail and the safety profile live on best peptides for anxiety.

The only compound here pooled in healthy adults is a prescription stimulant

Repantis and colleagues collected the randomized trials of methylphenidate and modafinil in healthy people and pooled the ones with extractable data 6. Methylphenidate improved memory. Nothing else came out consistently. Modafinil improved attention in well-rested volunteers and protected wakefulness, memory and executive function in sleep-deprived ones, though repeated doses could not stop performance sliding over a long stretch of sleep loss and may have left people overconfident about how well they were doing.

Based on a systematic review and meta-analysis we show that expectations regarding the effectiveness of these drugs exceed their actual effects, as has been demonstrated in single- or double-blind randomised controlled trials.Repantis D, Schlattmann P, Laisney O, Heuser I, Pharmacological Research, 2010 [[6]]

That sentence is the ceiling of the field, written about the two drugs with the best data in it. The peptides sold beside them have no meta-analysis, because there are no healthy-adult trials to pool.

Semax against the drug it gets compared to

SemaxA mechanism characterized in rats, human data collected in stroke rehabilitation, and nothing measured under control in a healthy brain.
Unapproved research compound, intranasal
What it isSeven-amino-acid ACTH(4-10) analog, intranasal
US regulatory statusNot FDA-approved for any indication, not a scheduled substance
Best human evidence110 stroke patients, groups assigned by rehabilitation timing rather than randomized, published in Russian [[2]]
Healthy adults testedNo controlled trial. A 1997 Russian review by the developers claims improved memory and attention in healthy men under extreme operational conditions, with no trial design, control group or effect size published [[8]]
What was measuredPlasma BDNF, motor strength, Barthel index of daily function
Effect size publishedNone, for any outcome
Side-effect recordDescribed as mild in Russian clinical use, with one report of paroxysmal EEG activity after dosing in encephalopathy patients [[9]]; no systematic safety collection in healthy adults
How you get itResearch-chemical suppliers, no purity or content verification
MethylphenidateTested in healthy adults and pooled across trials; the pooled result was modest and confined to memory.
Prescription stimulant
What it isPrescription stimulant that blocks reuptake of dopamine and noradrenaline
US regulatory statusFDA-approved for ADHD and narcolepsy, Schedule II controlled substance
Best human evidenceSystematic review and meta-analysis of single- and double-blind randomized trials in healthy volunteers [[6]]
Healthy adults testedYes, repeatedly, against placebo
What was measuredMemory, attention and executive function tasks
Effect size publishedYes, pooled; the review's own conclusion is that expectations exceed actual effects [[6]]
Side-effect recordDocumented: appetite loss, disturbed sleep, raised blood pressure and heart rate, dependence potential
How you get itPrescription after evaluation, with a diagnosis behind it
This table is a description of two evidence bases, not a recommendation to use either. A Schedule II stimulant is a controlled drug with real risks, and the point of the comparison is that even the well-studied option delivered less than people expect.

Four things worth ruling out before buying anything for brain fog

Fog is a symptom with a short list of common upstream causes, and all four below are cheaper to check than a year of nasal spray. A clinician can order the whole set in one visit.

  1. Short or broken sleepSleep loss costs more cognition than any compound on this page has been shown to return. Modafinil's clearest measured effect was holding function together in sleep-deprived volunteers [[6]], which is a backhanded way of showing how much sleep debt takes. If sleep is the problem, the compounds sold to fix it are covered on [peptides for sleep](/peptides-for/sleep) and the honest summary there is not encouraging.
  2. Low iron storesFerritin, the blood marker of stored iron, can be low enough to cause fatigue and poor concentration well before hemoglobin drops far enough to be called anemia. It is a single line on a standard blood panel, and in menstruating adults it is the most commonly missed cause on this list.
  3. An underactive thyroidSlowed thinking, fatigue and cold intolerance together are a classic hypothyroid pattern, and TSH with free T4 settles it. Treating it is a prescription, not a purchase, and no peptide protocol substitutes for thyroid hormone.
  4. An untreated anxiety loadWhen attention is being pulled away by rumination rather than failing to engage, the target is the anxiety. [Peptides for anxiety](/peptides-for/anxiety) grades what the peptide market offers there against standard care, and standard care wins on evidence by a wide margin.

No peptide sold for sleep has a modern human trial showing it improves sleep. The sleep-laboratory evidence that exists is either 30 to 45 years old and inconsistent, or it points the wrong way.

PeptidesDNA, [peptides for sleep](/peptides-for/sleep)

If the complaint is fatigue rather than distraction, the compounds discussed for cellular energy production sit on peptides for mitochondrial health, and the grading there lands the same way: human trials in people with a diagnosed disease, and none in tired but otherwise healthy adults.

What the studies dosed, and what circulates instead

The table below reports what researchers gave, in what species, by what route. It is a record of published protocols, not a set of instructions, and the bottom row is in the table because it has no study behind it.

SourceSpeciesRouteDoseScheduleWhat was measured
Gusev 2018, ischemic stroke rehabilitation 2Human, n = 110Intranasal6000 mcg/dayTwo 10-day courses, 20 days apart, followed about 5 monthsPlasma BDNF, motor strength, Barthel index
Dolotov 2006, BDNF mechanism 1RatIntranasal50 and 250 mcg per kg body weightSingle dose, tissue sampled at 3 hoursBDNF protein in basal forebrain and cerebellum, peptide binding
Inozemtseva 2024, chronic stress model 3Male Sprague-Dawley ratsIntraperitoneal injection60 nmol per kg body weightDaily through the stress protocolSucrose preference, body weight, adrenal size, hippocampal BDNF
What circulates for focusHuman, no studyIntranasal200 to 600 mcg/dayUnverified community practice, no study behind it, and not a protocol we are describing or endorsingNothing. Self-report only

The 5-days-on, 2-days-off pattern that circulates alongside those doses comes from forums rather than from a study, and no trial has tested any cycling schedule for either peptide. What cycling is meant to do, and where the idea came from, is covered in peptide cycling protocols.

When the published courses were given, and when the circulating protocol is taken

Morningon waking
Middaybefore about 2pm
Afternoon or eveningafter about 4pm
With foodDoes not apply. Semax is sprayed into the nose rather than swallowed, so food timing does not appear in any published protocol.
How oftenGusev 2018 gave 6000 mcg a day intranasally for 10 consecutive days, paused 20 days, then repeated the 10-day course [[2]]. No human study has tested an open-ended daily schedule at any dose.
Keep apart fromThe circulating focus protocol, 200 to 600 mcg in the morning and often 5 days on with 2 off, has no study behind it at that dose, that frequency or that endpoint.Russian clinical reports describe disturbed sleep onset when the dose lands in the afternoon or evening, which is the only reason the morning slot is the one people use.In the rat mechanism work, BDNF was sampled 3 hours after a single intranasal dose [[1]]. That is a tissue sampling point, not evidence about how long a morning dose lasts in a person.
What researchers gave and when, alongside what circulates with no study behind it. A record of published protocols, not a dosing instruction.

What a vial costs, how it is stored, and what nobody verifies

Semax is sold either as lyophilized powder, meaning freeze-dried, in glass vials of 5 mg to 30 mg, or as a pre-mixed nasal spray. The figures below are observations from vendor listings rather than research data, and they move.

FormTypical listing priceRoughly, per milligramStorage
Lyophilized powder, 5 mg vialAbout $30 to $60About $6 to $12 per mgSealed, months in a freezer or weeks to months in a refrigerator
Pre-mixed nasal sprayAbout $50 to $100Varies with the fill volume the seller choosesRefrigerated and out of light
Once reconstitutedNot sold in this formNot applicableRefrigerated, out of light, and it does not survive repeated freeze-thaw cycles or a warm shipping box in July

We do not publish a dosing schedule, so we cannot tell you how long a vial lasts. The arithmetic for getting from milligrams in a vial to micrograms in a dose is on how to reconstitute peptides.

The harder problem is content. Nothing external verifies purity, identity, or bacterial contamination in a research-chemical vial, and the buyer has no way to confirm what arrived. Third-party certificates of analysis supplied by the seller are a weaker check than an independent one. We track vendor testing and pricing on our comparison page; those are affiliate links, meaning we earn a commission if you buy through them, and that arrangement does not change a word of the evidence grading above.

What gets reported as a side effect, and why that is not a safety record

The Russian literature on Semax reports few adverse events: mild stimulation, occasional headache, insomnia when dosed late in the day. Read that with the design in mind. Those studies were not built to collect safety data systematically, they were run in patients under medical supervision, they are largely not indexed where an independent reviewer can check them, and none of them followed healthy adults taking a compound daily for years. Absence of reported harm from studies that were not designed to find harm is not a safety record.

  • Reported in use: mild stimulation and headache, with disturbed sleep onset when the dose lands late in the day (see the timing card above).
  • Reported once in a clinical setting: a 1999 Russian study of 73 patients with posthypoxic encephalopathy recorded episodes of paroxysmal activity on EEG after Semax administration in some patients, and the authors recommended monitoring brain activity during the first dose 9. Nothing similar has been looked for in healthy adults, because no study has looked.
  • Unknown in humans: long-term safety at any dose, tolerance, whether daily use shifts anything at baseline, interaction with prescription stimulants or antidepressants.
  • No safety data at all: pregnancy, breastfeeding, adolescents, anyone with a personal or family history of seizures, and anyone with bipolar disorder, where a stimulating compound carries a plausible risk of destabilizing mood.
  • Not established: any monitoring protocol. There are no lab tests that tell you whether Semax is doing something good or something bad.

Semax is not FDA-approved for any indication and is not a scheduled controlled substance. It ships in the US labeled for laboratory use only, which is what vendors rely on. That label does not make the compound lawful to sell or market for human use, it carries no approval behind it, and no regulator checks what is in the vial.

The compounding file moved twice in 2026, and neither move is approval. FDA announced on 15 April 2026 that Semax was removed from Category 2 of its interim 503A bulk drug substances list, the category for substances flagged with significant safety risks, because the parties who had nominated it withdrew their nominations. Coming off Category 2 does not authorize compounding on its own, because Semax is still not on the 503A bulks list, so a compounding pharmacy has no lawful route to it. Then at its meeting on 23 and 24 July 2026, FDA's Pharmacy Compounding Advisory Committee voted 8 to 5 to recommend Semax for that list. A committee recommendation is not an approval, the agency is not bound by it, and no efficacy evidence entered the file. Categorization has changed more than once, so check the current lists on fda.gov rather than relying on any summary, including this one. Selank sits in the same position.

For anyone weighing this compound against the rest of the category, the framework we use to rank compounds by evidence rather than by marketing is set out in which peptides your DNA points to.

Why two people report opposite things from the same nasal spray

Two well-documented pieces of brain biology make that split predictable in principle, and neither has ever been tested against a peptide.

  • How well you tolerate stimulation depends partly on how fast your prefrontal cortex clears dopamine away. An enzyme called COMT does that clearing, and the rs4680 variant sets its speed. Fast clearers run lower on prefrontal dopamine and tolerate stimulation well; slow clearers already sit high on the curve. Brain imaging shows the genotypes activating the prefrontal cortex and amygdala differently while processing emotional images 5. That study says nothing about peptides, and no peptide trial has ever stratified by it.
  • BDNF rs6265, the Val66Met variant, cuts how much BDNF a neuron releases when it is active, and carriers have shown differences in memory and hippocampal function 4, though those findings have replicated inconsistently in larger samples. Raising BDNF is the mechanism Semax is credited with in rats, which makes the pairing look tidy on paper. Whether carrying the variant changes anyone's response to Semax has never been measured in a person. It is common rather than rare in people of European ancestry, which is another way of saying it cannot explain why one person in a forum thread had a good day.
  • The DRD4 and SLC6A3 variants that turn up in popular attention genetics are repeat-length changes rather than single letters, and consumer genotyping arrays cannot read them. Imputation, the statistical guess at unmeasured markers from nearby ones, does not recover them either. Any report grading your focus from those two is reporting something your uploaded file does not contain, and our review of the SelfDecode peptide report shows how those grades get built.

One line here is tempting to act on, and worth resisting. Slow COMT clearers sit higher on the prefrontal dopamine curve in theory, which is a mechanistic reason a stimulating compound might land as jitter rather than sharpness. The studies testing whether COMT genotype predicts stimulant response are small and have replicated inconsistently, none of them involved a peptide, and 5 measured emotional-image processing rather than drug response. Genotype is not a reason to start or stop anything here, and what any of it means for you specifically is a conversation for a clinician rather than a rule this page can hand you.


Anything anyone tries in this category is a personal experiment with an unapproved compound, run at their own risk, with no trial behind it. We are not recommending it. If someone is going to do it anyway, the thing worth saying is that whoever prescribes your other medicines needs to know, and that no published evidence anywhere says the effect builds with time.

Upload the raw DNA data you already have and see which of your variants sit in the pathways these 39 peptides act on, including COMT dopamine clearance and BDNF Val66Met. The report maps your genotype onto published mechanisms and grades each peptide on the strength of its human evidence. It does not predict how you will respond to any peptide, because no peptide trial has ever stratified results by these variants, and it does not diagnose anything or tell you what to take.

See what your DNA says
The distinctions
  1. Every human trial behind the focus peptides enrolled people with a deficit

    Semax's human record is 110 patients recovering from a stroke [[2]]. Selank's largest published human trial enrolled 62 patients with generalized anxiety disorder or neurasthenia, an older diagnosis for persistent fatigue, irritability and difficulty concentrating [[7]]. Both asked whether a lost function could be recovered. The marketing asks whether an intact function can be pushed higher, which is a different question, and a PubMed search in August 2026 returns no randomized, placebo-controlled trial of either compound with an attention, reaction-time or working-memory endpoint in healthy adults.

  2. Methylphenidate has a pooled healthy-adult result; the peptides have nothing to pool

    Repantis and colleagues pooled randomized trials of methylphenidate and modafinil in healthy people and found a memory improvement for methylphenidate and no consistent evidence for other enhancing effects [[6]]. That is a modest result, and it is still more than exists for any peptide, because no peptide has produced a healthy-adult trial with extractable data to pool. When a sales page compares a nootropic peptide to Adderall, it is comparing a number to the absence of one.

  3. The protocol people follow matches no study on any axis

    The one published Semax protocol was given to stroke patients in two 10-day courses 20 days apart, at roughly ten times the daily amount that circulates for focus, and what it measured was muscle strength and how independently people could dress and bathe [[2]]. Dose, population and outcome all differ from the way the compound is used, so the trial cannot be used as evidence for the protocol people follow.

For focus and cognitionSee your match for focus and cognitionUpload your DNA. Your personalized report ranks peptides by genetic markers relevant to you.Get your report — $99

Frequently asked questions

Do peptides for energy and focus actually work?

Nobody can answer that from evidence, because the trial that would answer it has never been run. Semax and Selank, the two compounds sold under that heading, have published human trials only in stroke rehabilitation [[2]] and in anxiety [[7]], and no controlled trial has measured attention, reaction time, or working memory in a healthy person. What exists is rat data for the mechanism [[1]], Russian clinical data in patients with a diagnosis, and self-reports from people who paid for the product and knew they were taking it. If the problem is fatigue rather than distraction, the compounds discussed for cellular energy sit on [peptides for mitochondrial health](/peptides-for/mitochondrial-health), and the evidence there is not stronger.

Is Semax stronger than Adderall for focus?

There is no basis for the comparison in either direction. Amphetamine and methylphenidate are FDA-approved, Schedule II, and have been tested against placebo in healthy volunteers many times over; Repantis and colleagues pooled that work and found a memory improvement for methylphenidate and no consistent evidence for other enhancing effects [[6]]. Semax has no controlled measurement on any attention or memory task in a healthy adult, so there is no number on its side of the comparison. For attention problems that have been present since childhood, a psychiatric evaluation for ADHD unlocks treatments with an evidence base, and a nasal spray does not substitute for the diagnosis.

How fast does Semax work, and how long does it last?

Community reports describe an effect within about 30 minutes of an intranasal dose and a return to baseline within 4 to 6 hours. Those come from people who knew what they had taken and had paid for it, which is the weakest form of evidence there is. Treat them as reports about expectation rather than measurements of a drug, and do not use them to time anything. No pharmacokinetic study indexed in English has measured onset, peak or duration for a cognitive effect in humans, and the peptide's own developers claimed in a 1997 Russian review that effects persist 20 to 24 hours after an intranasal dose [[8]], which is nothing like the figure circulating in forums. When two sources disagree by a factor of five and neither published data, there is no answer to give.

Are there peptides for memory?

No peptide has controlled human memory evidence. Semax's memory claim traces to rodent learning experiments and to a rat study showing BDNF protein rising in the basal forebrain three hours after an intranasal dose [[1]]. The Russian-language literature does claim human effects: a 1997 review by the peptide's own developers states that Semax significantly improves memory and attention in healthy men under extreme conditions of activity [[8]], but it reports no trial design, no control group and no effect size, and the primary studies behind it are not retrievable. Memory is the one cognitive domain where a pooled analysis in healthy volunteers found a real if modest effect, and the compound that produced it was methylphenidate, a controlled prescription stimulant [[6]].

Sources9
  1. Dolotov OV, Karpenko EA, Seredenina TS, et al. Semax, an analogue of adrenocorticotropin (4-10), binds specifically and increases levels of brain-derived neurotrophic factor protein in rat basal forebrain. Journal of Neurochemistry, 2006;97(Suppl 1):82-86.
  2. Gusev EI, Martynov MY, Kostenko EV, Petrova LV, Bobyreva SN. The efficacy of semax in the treatment of patients at different stages of ischemic stroke. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova, 2018;118(3 Pt 2):61-68.
  3. Inozemtseva LS, Yatsenko KA, Glazova NY, Kamensky AA, Myasoedov NF, Levitskaya NG, et al. Antidepressant-like and antistress effects of the ACTH(4-10) synthetic analogs Semax and Melanotan II on male rats in a model of chronic unpredictable stress. European Journal of Pharmacology, 2024;984:177068.
  4. Egan MF, Kojima M, Callicott JH, et al. The BDNF val66met polymorphism affects activity-dependent secretion of BDNF and human memory and hippocampal function. Cell, 2003;112(2):257-269.
  5. Smolka MN, Schumann G, Wrase J, et al. Catechol-O-methyltransferase val158met genotype affects processing of emotional stimuli in the amygdala and prefrontal cortex. Journal of Neuroscience, 2005;25(4):836-842.
  6. Repantis D, Schlattmann P, Laisney O, Heuser I. Modafinil and methylphenidate for neuroenhancement in healthy individuals: a systematic review. Pharmacological Research, 2010;62(3):187-206.
  7. Zozulia AA, Neznamov GG, Siuniakov TS, Kost NV, Gabaeva MV, Sokolov OIu, et al. Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova, 2008;108(4):38-48.
  8. Ashmarin IP, Nezavibatko VN, Myasoedov NF, Kamensky AA, Grivennikov IA, Ponomareva-Stepnaya MA, et al. A nootropic adrenocorticotropin analog 4-10-semax (15 years experience in its design and study). Zhurnal Vysshei Nervnoi Deiatelnosti imeni I.P. Pavlova, 1997;47(2):420-430.
  9. Alekseeva GV, Bottaev NA, Goroshkova VV. Use of semax at a follow-up of patients with posthypoxic encephalopathy. Anesteziologiia i Reanimatologiia, 1999;(1):40-43.

This article is for informational and educational purposes only. It is not medical advice and does not diagnose, treat, cure, or prevent any disease. Consult a qualified healthcare professional before starting any peptide protocol. Individual results vary. Some outbound links are affiliate links, at no extra cost to you.

This page is educational and is not medical advice. Peptides are not intended to diagnose, treat, cure, or prevent any disease, and most are not FDA-approved. Talk to a qualified healthcare provider before starting anything. Availability and legal status of peptides vary by jurisdiction.

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