Semax
Semax is the nootropic peptide built on stroke medicine, used today far more for everyday focus, memory, and mood than for its original purpose. People come to it wanting sharper concentration through a demanding stretch of work or study, or a steadier mood day to day. It's a staple of the cognitive-enhancement and biohacking community, taken as intranasal drops rather than a pill or shot. Typical use is short courses rather than continuous daily dosing.
What it does
Focus, memory, and mood
People reach for Semax on a day that demands more concentration than usual, or when mood and mental energy have been flat for a while, taking it as drops before the stretch that needs it. The community use for this, focus and mood in otherwise healthy people, is the single biggest reason it's sold today. Every clinical study of Semax was run in stroke patients, not in healthy volunteers looking for an edge, so this everyday use has no trial of its own behind it.
Sources: Gusev EI, Skvortsova, 1997, Gusev EI, Skvortsova, 2005, Gusev EI, Martynov, 2018
Built for stroke recovery
Semax's real track record is in stroke recovery, not cognitive enhancement. It's registered in Russia for acute ischemic stroke and related brain conditions, and a series of Russian trials in stroke patients found it helped their recovery. All of it lives in a single Russian-language journal, never independently repeated by a Western group.
Sources: Wikipedia, 'Semax' (secondary, Gusev EI, Skvortsova, 1997, Gusev EI, Skvortsova, 2005, Gusev EI, Martynov, 2018
Nasal drops, the studied route
Semax on the studied protocol is drops in the nose, not a pill or a shot, dosed at 6,000 mcg a day across two 10-day courses with a break in between, the schedule used in the Russian stroke trials. That is the only dose with any published human data behind it. Semax is also sold as an injectable and used off-label for cognitive enhancement rather than stroke recovery, but no published dosing exists for either of those uses.
Sources: Gusev EI, Skvortsova, 1997, Gusev EI, Skvortsova, 2005, Gusev EI, Martynov, 2018
Dosing
Clinical trialIntranasal, Russian stroke-trial literature6,000 mcg/day, daily
| Timeframe | Dosage | Frequency | Note |
|---|---|---|---|
| Two 10-day courses | 6,000 mcg/day | daily | 20-day interval between courses1 |
- Figure comes from a secondary summary of the 2018 Gusev et al. trial, not a directly reviewed primary dosing table, and should be treated as provisional. Broader Russian trial literature describes intranasal Semax generally as 0.1% or 1% nasal drops over multi-day courses without one confirmed per-dose figure across all three cited trials.
Subcutaneous/injectable route – No citable dose
No citable figure. Subcutaneous injectable Semax is sold commercially alongside intranasal forms, but no published human dosing data for the injectable route were located.
Community cognitive-enhancement dosing – No citable dose
No citable figure. Community-practice doses for cognitive enhancement in healthy adults, commonly circulated as specific mcg/day intranasal ranges on vendor and forum sites, are not standardized and have no peer-reviewed source; mark any such figure as unpublished.
Primary structure
MMetEGluHHisFPhePProGGlyPPro
Full research
Evidence tier
Human trials, not approved for this use
Three Russian-language clinical publications support the stroke indication: a 1997 clinical and electrophysiological study in acute hemispheric ischemic stroke, a 2005 study of prevention in chronic cerebrovascular insufficiency, and a 2018 efficacy study across stages of ischemic stroke. All three appear only in a single non-English Russian journal, none has been independently replicated by a Western research group, and the compound has never been reviewed by the FDA or EMA. An earlier version of this entry described this literature as randomized, double-blind and placebo-controlled; that characterization rested on a citation that pointed at an unrelated paper, could not be verified against any indexed record, and has been removed rather than repeated. The stroke-recovery claim should be treated as unverified foreign clinical literature, not as RCT-grade evidence by international standards, and the popular nootropic and cognitive-enhancement use in healthy people is unsupported by any of these publications, which studied stroke patients rather than healthy volunteers.
Identity
| Full name | Semax |
|---|---|
| Class | Synthetic heptapeptide analog of the ACTH(4-10) fragment of adrenocorticotropic hormone |
| Molecular weight | 813.93 g/mol |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP) |
Mechanism of action
Plain language
Semax is chemically related to a stress hormone fragment (ACTH 4-10) but its effects in animal and cell studies look more like a growth-factor booster for the brain than a hormone effect; the exact human mechanism is not established.
Technical
Proposed activity includes interaction with melanocortin receptors, with evidence in animal and lab systems suggesting it may act as an antagonist or partial agonist at MC4 and MC5 receptors rather than a classic agonist, inhibition of enkephalin-degrading peptidases (IC50 = 10 micromolar in an enzymatic assay, of uncertain clinical significance), and increases in BDNF expression and serotonergic/dopaminergic activity in rodent brain. A genome-wide transcriptional analysis in a rat middle-cerebral-artery-occlusion stroke model found Semax altered expression of immune- and vascular-system-related genes, suppressing inflammatory gene expression and activating neurotransmitter-related genes. This transcriptomic mechanism work is animal only.
Sources: Wikipedia, 'Semax' (secondary, The peptide semax, Novel Insights into, 2020
What it’s used for
Human trials, not approved for this use
- Semax is registered in Russia and included on the Russian List of Vital and Essential Drugs, approved by the Russian government on 7 December 2011, for acute ischemic stroke, cerebrovascular insufficiency, cognitive/asthenic disorders, and optic nerve disease; this is a Russian government formulary listing, not an FDA or EMA approval. A series of Russian trials by Gusev, Skvortsova, and colleagues evaluated intranasal Semax in acute ischemic stroke, including a trial described as randomized, double-blind, and placebo-controlled, and a 2018 trial across different stages of ischemic stroke treatment. All three trials are published only in a single non-English Russian journal and have not been independently replicated in Western, English-language RCTs.
Sources: Wikipedia, 'Semax' (secondary, Gusev EI, Skvortsova, 1997, Gusev EI, Skvortsova, 2005, Gusev EI, Martynov, 2018
Off-label / community use
- Nootropic and cognitive-enhancement use in healthy adults, ADHD-adjacent focus use, and mood use are all community practice with no cited controlled human trial for those specific uses; the cited stroke trials were conducted in stroke patients, not healthy volunteers.
Sources: Gusev EI, Skvortsova, 1997, Gusev EI, Skvortsova, 2005, Gusev EI, Martynov, 2018
Pharmacokinetics
| Half-life, Tmax, and bioavailability |
Not established No citable figure. As a peptide, Semax has poor oral bioavailability and is administered intranasally or by injection. No published human half-life, Tmax, or systemic bioavailability figures were located in this research pass; vendor claims of a specific plasma half-life in minutes could not be traced to a primary source and are reported here as unsourced. |
|---|
Reconstitution
| Vial strength | 10 mg (also sold as a ready-to-use 10 mg/10 mL nasal spray solution, and in 30 mg lyophilized vials) |
|---|---|
| Diluent | Bacteriostatic water |
| Diluent volume | 2 mL |
| Concentration | 5 mg/mL (5,000 mcg/mL) |
Sources: Cenexa Labs, Semax
Dose calculator
Enter a vial strength, diluent volume, and desired dose to see the resulting concentration, dose volume, and units on a standard U-100 insulin syringe. Nothing entered here is saved, stored, or sent anywhere – the calculation runs only in your browser.
This calculator needs JavaScript. The arithmetic it runs is: concentration = vial strength in mg divided by diluent volume in mL; dose volume in mL = dose in mg divided by concentration; units on a U-100 syringe = dose volume in mL times 100.
Storage and post-reconstitution stability
Unopened storage
Lyophilized powder or ready-to-use nasal spray stored frozen or refrigerated, protected from light, per standard peptide-handling practice; no Semax-specific stability study was located.
Post-reconstitution stability – Not established
No citable figure. No Semax-specific post-reconstitution stability study (refrigerated shelf life in days) was located, and no vendor-stated shelf-life claim was found either, not even an unverified range.
Safety
Notable risks
- Russian secondary sources describe Semax as generally well tolerated in the cited trial populations, with nasal irritation and occasional headache as the most commonly reported effects, and less frequent reports of nasal-mucosa discoloration and mild blood-glucose increases in diabetic patients; these adverse-effect figures come from secondary summaries rather than a directly reviewed primary safety table in this pass and should be treated as provisional. No FDA/EMA-grade contraindication list, monitoring protocol, or independent pharmacovigilance dataset exists, because Semax has never been reviewed by either agency.
Sources: Wikipedia, 'Semax' (secondary
Sources
- PubChem/vendor chemical data consistent across sources: CAS 80714-61-0, MW 813.93, formula C37H51N9O10S
- Wikipedia, 'Semax' (secondary, consistent with primary chemical/regulatory data; used for structural, regulatory-listing, and mechanism-summary claims only)
- The peptide semax affects the expression of genes related to the immune and vascular systems in rat brain focal ischemia: genome-wide transcriptional analysis. Animal (rat).
- Novel Insights into the Protective Properties of ACTH(4-7)PGP (Semax) Peptide at the Transcriptome Level Following Cerebral Ischaemia-Reperfusion in Rats. MDPI Genes. Animal (rat). (2020)
- Gusev EI, Skvortsova VI, Miasoedov NF, et al. Effectiveness of semax in the acute period of hemispheric ischemic stroke, a clinical and electrophysiological study. Zh Nevrol Psikhiatr Im S S Korsakova (1997). Non-English (Russian), human trial. Identifier corrected 2026-08-19: this entry previously carried PMID 9381719, which is an unrelated Polish vascular-surgery case report (1997)
- Gusev EI, Skvortsova VI, Chukanova EI. Semax in prevention of disease progress and development of exacerbations in patients with cerebrovascular insufficiency. Zh Nevrol Psikhiatr Im S S Korsakova (2005). Non-English (Russian), human trial in CHRONIC cerebrovascular insufficiency, not an acute-stroke trial. Repointed 2026-08-19: this entry previously carried PMID 15554370, an unrelated Croatian rheumatology review, described as a 2004 Skvortsova randomized double-blind placebo-controlled stroke trial. No such paper could be located in PubMed (2005)
- Gusev EI, Martynov MY, Kostenko EV, Petrova LV. Zh Nevrol Psikhiatr Im S S Korsakova. Non-English (Russian), human trial. (2018)
- The Potential of the Peptide Drug Semax and Its Derivative for Correcting Pathological Impairments in the Animal Model of Alzheimer's Disease. Animal.
- Cenexa Labs, Semax Peptide Spray product page (commercial source, form/strength only)
This is a research and educational reference, not medical advice. Nothing on this site is a recommendation to use any compound.