Semax vs Selank

Same lab, same length, built for different problems. Semax was made for alertness and stroke recovery, Selank for anxiety. Both are prescription nasal sprays in Russia, neither is FDA approved, and nearly every paper you would want to read is in Russian.

Cognitive and mood
7 amino acids each
Not FDA approved

By the Peptide Decoding Editorial Team

Published August 13, 2026 · Updated August 14, 2026

Two research vials labeled Semax and Selank, ten milligrams each, under low blue light

The short answer

Semax for alertness. Selank for anxiety.

Both are prescription nasal sprays in Russia. Neither is FDA approved. Nearly every paper you would want to read is in Russian.

Semax and Selank at a glance
Attribute	Semax	Selank
Length	7 amino acids	7 amino acids
Built from	A fragment of ACTH, a hormone	Tuftsin, an antibody fragment
Formula	C37H51N9O10S, about 814 daltons	C33H57N11O9, about 752 daltons
Russian approval	1994	2009
Human trials	Several, small, mostly not randomized	One, 62 people
FDA status	Not approved. Reviewed by advisory committee July 2026	Not approved. Never reviewed

Doses in the published trials are in micrograms, not milligrams.

Alertness · Stroke recovery

Semax

Built from a piece of ACTH, a hormone. The fragment they used reaches the brain without touching cortisol.

Approved in Russia1994

Human trialsSeveral, small

RandomizedMostly not

FDANot approved

Anxiety · Stress tolerance

Selank

Built from tuftsin, a fragment that comes off an antibody. The only one of the two measured head to head against a benzodiazepine.

Approved in Russia2009

Human trialsOne, 62 people

ComparatorA benzodiazepine

FDANot approved

The structure

The last three are identical.

Everything that separates these two sits in the first four positions. The tail is scaffolding, added to both so the body cannot break them apart in seconds.

Semaxfrom ACTH, a hormone

Met

Glu

His

Phe

Pro

Gly

Pro

Selankfrom tuftsin, an antibody fragment

Thr

Lys

Pro

Arg

Pro

Gly

Pro

Pro-Gly-Pro

The first four work. Semax borrows from a hormone. Selank borrows from an antibody.

The last three protect. Without them, both would break down almost immediately.

Two names, both correct. Semax is an analog of ACTH(4-10). The last three residues were swapped out, so the surviving ACTH portion is 4-7.

The evidence

Semax was approved three years before the first study we can cite.

Years between Semax approval and its earliest published trial

Patients in the single trial Selank's approval rests on

Trials for either compound run outside Russia

1994

Semax

Approved in Russia

Cleared by the Ministry of Health for stroke and other problems with blood flow to the brain.

1997

Semax

Gusev stroke study

30 patients given Semax during an acute stroke, measured against 80 patients on standard care.

Журнал неврологии и психиатрии им. С.С. Корсакова1997;97(6):26-34 · Published in Russian only

not randomized
no placebo
never replicated

2005

Semax

Cerebrovascular insufficiency study

Gusev and colleagues publish a study of Semax for preventing progression in patients with cerebrovascular insufficiency, meaning long-term poor blood flow to the brain rather than an acute stroke. [10]

2008

Selank

Zozulia trial

62 patients with generalized anxiety disorder and neurasthenia, an older Russian diagnosis covering chronic fatigue and nervous exhaustion. 30 got Selank, 32 got medazepam, a benzodiazepine. Both groups improved by similar amounts on the Hamilton, Zung and CGI scales. Selank also produced anti-fatigue and mild stimulant effects the benzodiazepine did not.

Журнал неврологии и психиатрии им. С.С. Корсакова2008;108(4):38-48 · PMID 18454096 · Published in Russian only

active comparator
no placebo arm
randomization not stated

2009

Selank

Approved in Russia

Registered as Selank 0.15%, an intranasal solution for generalized anxiety disorder and neurasthenia, on the strength of the trial above.

2018

Semax

Gusev and Martynov follow-up

110 stroke patients through two ten-day courses. Reported higher BDNF in blood along with better movement scores and better Barthel index results, a standard scale for everyday tasks like dressing and walking.

This was an open study. Patients and doctors both knew who was getting what. That is the weakest design for measuring recovery, because expectation affects both effort and scoring.

not randomized
no placebo
no effect sizes
unblinded

2023

Both

Category 2 at the FDA

The FDA places both Semax and Selank acetate in Category 2 of its 503A bulk substances list, the category for substances that may present significant safety risks. [4]

2024

Selank

Out of the process

Selank acetate comes off Category 2 in September after the nominator withdraws the nomination entirely. That takes it out of the review process altogether. [5]

Apr 2026

Semax

Off Category 2, still in review

Semax comes off Category 2 in a batch of twelve peptides, also because nominations were withdrawn. Unlike Selank, it stays in the process. [5]

Jul 2026

Semax

Advisory committee vote

The FDA's advisory committee reviews Semax and recommends it for the compounding list, 8 votes to 5 with one abstention. A recommendation is not approval. [6]

Selank's approval followed its trial by one year. Semax's approval came three years ahead of its earliest published study. The two files are weak in different ways. Semax has more studies built more loosely, and the largest of them was open label, meaning nobody was blinded. Selank has one study built more carefully.

Side by side

Everything that differs

Semax compared with Selank
Attribute	Semax	Selank
Mechanism	Reported to raise BDNF and NGF and to shift dopamine and serotonin signaling. No effect on cortisol.	Reported to act on GABA-A receptors and to slow the breakdown of enkephalins, the body's own calming signals.
Studied for	Ischemic stroke, poor blood flow to the brain, optic nerve damage, attention	Generalized anxiety disorder, and neurasthenia, an older Russian diagnosis for chronic fatigue and nervous exhaustion
Evidence	Several small trials, mostly Russian language. Most were not randomized or placebo controlled. [1][2]	One head to head trial, 62 patients, against a benzodiazepine. No placebo arm. [3]
Russian status	Approved 1994. Sold as a 0.1% and 1% nasal solution.	Approved 2009. Sold as Selank 0.15%, a nasal solution.
FDA status	Never approved. Advisory committee recommended it for compounding in July 2026, which is not approval. [6]	Never approved. Withdrawn from the review process entirely in 2024. [5]
WADA status	Not named on the 2026 list. May be addressed under S2.2.2 as an ACTH analogue; this is one possible reading. [7]	Not named on the 2026 list. No obvious hook in any section. [7]
Side effects	Nasal irritation, headache, trouble sleeping if taken late in the day	Nasal irritation and dryness
Long-term safety	Nothing published outside Russia	Nothing published outside Russia

Mechanism

How each one works

Semax

ACTH is a hormone that tells the adrenal glands to release cortisol. Researchers found that a small piece of it affected the brain without touching cortisol at all. That piece is the core of Semax.

Because the part that triggers the adrenal glands was left out, Semax does not raise cortisol. That much is well established.

The rest is less settled. Semax is reported to raise BDNF and NGF, two proteins that keep neurons alive. The 2018 study did measure higher BDNF in patient blood. Whether that rise produced the recovery scores has not been shown.

Selank

Tuftsin is a four amino acid fragment that comes off the tail end of an antibody. It affects both the immune system and the brain, and on its own it falls apart in the bloodstream almost immediately.

Selank is reported to work on GABA-A receptors, the same broad system benzodiazepines act on, through a different site. It is also reported to slow the breakdown of enkephalins, the body's own calming signals.

The GABA work is mostly from animal brain tissue and cell models, not from people.

Structural schematics. Sequences and parent molecules are real; bar positions and residue numbering are simplified for the diagrams.

Key differences

What separates them

Shared: 7 residues · Pro-Gly-Pro tail · intranasal · Russian origin · not FDA approved

Semax

Studied forIschemic stroke, low cerebral perfusion, optic nerve damage, attention

Reported actionRaises BDNF and NGF; shifts dopamine and serotonin signalling

Approved in Russia1994

Human evidenceSeveral small trials, mostly Russian, mostly uncontrolled

WADA exposurePossible S2.2.2 hook as an ACTH analogue

Selank

Studied forGeneralised anxiety disorder, neurasthenia

Reported actionGABA-A modulation at a separate site; slows enkephalin breakdown

Approved in Russia2009

Human evidenceOne 62-patient head-to-head vs a benzodiazepine, no placebo arm

WADA exposureNo clear hook in any section

Summary comparison compiled from published trials and regulatory documents. The WADA rows are one possible reading of the 2026 Prohibited List, not a ruling.

What nobody has answered

Three open questions, and the size of the gap around each

How long is long term?The published Russian trials ran days to weeks. The stroke studies used courses of five to ten days. Nobody has published a study of either compound taken for months or years, in any country.

What happens in the people most likely to take them?Neither has been studied in pregnancy, in children, or alongside common psychiatric medications. Selank has been reported as producing no dependence, no tolerance and no withdrawal. That is the whole reason anyone compared it to a benzodiazepine, and that comes from short trials rather than long ones. [3]

Do they do anything for healthy people?Almost every published human trial recruited patients with a diagnosis: stroke, cerebrovascular insufficiency, anxiety, neurasthenia. There are two exceptions worth knowing about, and neither settles much. Kaplan and colleagues published a study in 1996 reporting nootropic-like activity in humans, in a small journal that is difficult to obtain. [11] And a pair of brain imaging studies in 2018 and 2020 looked at what Semax and Selank do to connectivity patterns in the brain. [12][13] Those measure brain activity, not whether anyone thinks or works better. So a small amount of work exists in healthy people, it is old or indirect, and the productivity claims still rest mostly on extrapolation from patient studies.

Safety and gaps

What is known, and how big the hole around it is

Both peptides have been used clinically in Russia, but the published safety record is thin and the US supply chain is unregulated.

Evidence register3 fields · 12 entriesCompiled from published trials and US market conditions

01Observed

Reported effects

Minor and local in the published trials.

Nasal irritation, both compoundsmost reported
Headachesemax
Nasal drynessselank
Trouble sleeping when dosed latesemax

02Unstudied

Nobody has looked

No data at all, which is not the same as a clean result.

Either one taken for months or yearsno data
Use in pregnancy or in childrenno data
Use alongside psychiatric medicationno data
The two taken togetherno trial

03Supply

What is in the vial

Neither has an approved product in the US to compare against.

Seized peptides tested 5 to 75 percent pure, plus arsenic and lead [8]analysis
A US lab reported problems in almost 30 percent of samples, including bacteria [9]testing
A high purity certificate does not rule out contaminants standard testing misses [14]caveat
Prescription nasal sprays in Russia, with none of these problemsru

*Where this page says nothing is established, it means nobody has studied it. It does not mean a compound is safe.

In the US both are sold as research chemicals, usually labeled not for human use, and identity rests entirely on the seller's word. Our guide on reading a certificate of analysis covers what to actually look for.

Where we disagree with the consensus

Whether these are banned in sport is not settled

This reflects the 2026 Prohibited List, in force from 1 January 2026. WADA publishes a new list each September, so check the current version if you are reading this later in the year. Neither Semax nor Selank appears by name. The argument for treating them as banned runs through S0, the catch-all category.

Any pharmacological substance which is not addressed by any of the subsequent sections of the List and with no current approval by any governmental regulatory health authority for human therapeutic use is prohibited at all times.

WADA Prohibited List · category S0 [7]

Two conditions have to be met for S0 to apply. The substance has to be missing from every other section of the list, and it has to have no approval from any government health authority anywhere.

Russia's Ministry of Health approved Semax in 1994 and Selank in 2009. On the second condition, the plain wording does not appear to catch either one.

The first condition is where Semax and Selank split. Section S2.2.2 covers corticotrophins, the class ACTH belongs to. Semax is built from an ACTH fragment, so it is possible that it may be addressed there regardless of what S0 says. The counterargument is that Semax was designed to strip out the hormonal activity, and it does not raise cortisol, so it may not do the thing corticotrophins are banned for doing. Selank comes from an antibody fragment and has no obvious hook anywhere on the list.

WADA also states that absence from the list does not mean a substance is permitted, and that a compound can be caught by having a similar structure or a similar effect to something listed. Treat both as unsettled. If you compete under a testing body, ask that body directly, and know that contaminated research vials have caused positive tests for compounds the athlete never intended to take.

The FDA story

Same starting point in 2023, different positions today

503A bulk substances process

Semax+Selank

BothSemaxSelank

SelankThr · Lys · Pro · Arg · Pro · Gly · Pro

Shared C-terminal tail · Pro-Gly-Pro

01Sep 2023Both
Placed in Category 2
FDA put Semax and Selank acetate in Category 2 of the 503A bulk substances process, the bucket for substances that may present significant safety risks. Compounding pharmacies could no longer make either one. [4]
02Sep 2024Selank only
Nomination withdrawn
Selank acetate came off Category 2 because the party that nominated it pulled the nomination. That was not a clearance. It removed Selank from the framework entirely, and it has not been scheduled for review since. [5]
03Apr 2026Semax only
FDA kept evaluating Semax
Semax-related nominations were withdrawn too, in a batch of twelve peptides. Unlike Selank, Semax stayed on the review schedule anyway.
04Jul 2026Semax only
PCAC review and recommendation
The Pharmacy Compounding Advisory Committee reviewed Semax and voted 8 to 5, with one abstention, to recommend adding it to the 503A bulks list - against its own FDA scientists, who advised against all seven peptides heard. [6]
Advisory only. Not FDA approval, and compounding is still not permitted.
Vote8 for · 5 against · 1 abstain

SemaxMet · Glu · His · Phe · Pro · Gly · Pro

Shared C-terminal tail · Pro-Gly-Pro

Semax today

Has a favorable advisory committee vote and a possible path forward through the rulemaking process. Still not approved or allowed to be compounded until the FDA acts.

Selank today

No active FDA review. Nobody has nominated it for the compounding list since the 2024 withdrawal. No route forward in the US at the moment.

What that vote does not mean. It is not FDA approval. It is not a finding that Semax is safe or effective. It is a non-binding recommendation from an advisory panel. Before anything changes, the FDA has to accept the recommendation and run a formal rulemaking process that typically takes many months. As things stand today, Semax still cannot legally be compounded.

So the current position is this. Neither compound is FDA approved for anything. Neither can legally be compounded. Semax has a favorable advisory vote behind it and a possible route forward. Selank has neither, because nobody is asking for one.

Common questions

Questions people ask

Is Semax stronger than Selank?

Stronger does not really apply here, because they were built for different problems. Semax was studied for alertness and stroke recovery. Selank was studied for anxiety. Which one fits depends entirely on what you are asking it to do.

Can you take Semax and Selank at the same time?

People do. No trial has tested it. There is no published data on how they interact or whether the combination is safe.

Are Semax and Selank FDA approved?

No. Neither has been approved by the FDA for any use, and neither has been submitted for review. Both are approved as prescription nasal sprays in Russia. Russian approval carries no legal weight in the US.

Did the FDA just approve Semax?

No. An advisory committee recommended in July 2026 that it be added to the list of substances compounding pharmacies may use. That is a non-binding recommendation about compounding, not a drug approval, and the FDA has not acted on it yet.

How long do Semax and Selank take to work?

The Russian stroke trials used courses of five to ten days, and the 2018 study ran two ten-day courses with a break between them. The Selank anxiety trial ran over weeks. Forum reports of same-day effects are not backed by any published measurement.

Are Semax and Selank banned in sport?

Neither is named on the 2026 Prohibited List. Whether the S0 catch-all applies is genuinely unclear, because S0 turns on having no approval anywhere and both are approved in Russia. Semax may also raise a possible question under section S2.2.2. Check with your own anti-doping authority before assuming either answer.

The published record

What Europe PMC and ClinicalTrials.gov hold for each, on the same rule.

Semax has 398 records to Selank's 70. 78 original human studies against 10. Semax has 0 registered trials to Selank's 2.

Semax: FDA: Nominated but withdrawn; previously category 2

Selank: FDA: Nominated but withdrawn; previously category 2

The published record

Research index

398

Records indexed for Semax

105 in humans, 78 of them original studies.

FDA: Nominated but withdrawn; previously category 2.

Browse the records

In animalsPro

In the labPro

ReviewsPro

Senior author sharePro

Counted from Europe PMC indexing, not read by a person. Human means indexed under humans, which includes reviews and work on human cells. Original studies exclude reviews and lab work on human cells.Last updated 11 September 2026.

The published record

Research index

Records indexed for Selank

16 in humans, 10 of them original studies.

2 registered trials, 0 with posted results.

FDA: Nominated but withdrawn; previously category 2.

Browse the records

In animalsPro

In the labPro

ReviewsPro

Senior author sharePro

References

What this page is built on

01Gusev EI, Skvortsova VI, Miasoedov NF, Nezavibatko VN, Zhuravleva EYu, Vanichkin AV. Effectiveness of Semax in acute period of hemispheric ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova. 1997;97(6):26-34. Human clinical study, Russian language, not randomized.
02Gusev EI, Martynov MY, Kostenko EV, Petrova LV, Bobyreva SN. The efficacy of Semax in the treatment of patients at different stages of ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova. 2018;118(3, Vyp. 2):61-68. PMID 29798983. DOI 10.17116/jnevro20181183261-68. Human clinical study, Russian language. Open label, not randomized, no placebo, no published effect sizes. Endpoints were NIHSS, motor performance, Barthel index and plasma BDNF.
03Zozulia 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. Zh Nevrol Psikhiatr Im S S Korsakova. 2008;108(4):38-48. PMID 18454096. Human clinical trial, active comparator, no placebo arm, Russian language.
04US Food and Drug Administration. 503A bulk drug substances category updates, September 29, 2023. Semax (heptapeptide) and Selank acetate (TP-7) added to Category 2. Regulatory document.
05US Food and Drug Administration. Category 2 removals, September 20, 2024 (Selank acetate) and April 2026 (Semax), both following withdrawal of nominations. Regulatory documents.
06US Food and Drug Administration. Pharmacy Compounding Advisory Committee meeting and vote record, July 23 to 24, 2026. Semax recommended 8 to 5 with one abstention. Regulatory document. Non-binding recommendation.
07World Anti-Doping Agency. The 2026 Prohibited List, categories S0 and S2.2.2. Effective 1 January 2026. Regulatory document.
08Janvier S, Cheyns K, Canfyn M, Goscinny S, De Spiegeleer B, Vanhee C, Deconinck E. Impurity profiling of the most frequently encountered falsified polypeptide drugs on the Belgian market. Talanta. 2018;188:795-807. DOI 10.1016/j.talanta.2018.06.023. Peer-reviewed analytical study.
09NBC Washington. Lab finds problems in 30% of peptide vials tested. December 2024. News report of commercial laboratory testing, not peer reviewed.
10Gusev EI, Skvortsova VI, Chukanova EI, et al. Semax in prevention of disease progress and development of exacerbations in patients with cerebrovascular insufficiency. Zh Nevrol Psikhiatr Im S S Korsakova. 2005;105(2):35-40. PMID 15792140. Human clinical study, Russian language. Note: one secondary source gives PMID 15768548. Confirm before citing.
11Kaplan AY, Kochetova AG, Nezavibathko VN, Rjasina TV, Ashmarin IP. Synthetic ACTH analogue Semax displays nootropic-like activity in humans. Neurosci Res Commun. 1996;19(2):115-123. Human study in a minor journal, difficult to obtain. The only published work we found on Semax in people without a diagnosis.
12Lebedeva IS, Panikratova YR, Sokolov OY, et al. Effects of Semax on the default mode network of the brain. Bull Exp Biol Med. 2018;165(5):653-656. PMID 30225715. DOI 10.1007/s10517-018-4234-3. Human brain imaging study.
13Panikratova YR, Lebedeva IS, Sokolov OY, et al. Functional connectomic approach to studying Selank and Semax effects. Dokl Biol Sci. 2020;490(1):9-11. Human brain imaging study covering both compounds.
14Castellino F, et al. Mutagenic contaminants in azide-coupled synthetic peptides. 1991. Peer-reviewed analytical study.