Semax
Also known as: ACTH(4-10) analog, Met-Glu-His-Phe-Pro-Gly-Pro
Semax (also called ACTH(4-10) analog or Met-Glu-His-Phe-Pro-Gly-Pro) is an ACTH fragment nootropic. Semax is a synthetic analog of ACTH(4-10) with a Pro-Gly-Pro tail added to the C-terminus, a modification that markedly slows enzymatic degradation while removing the corticotropic activity of the parent hormone.
For research use only.
Key Facts
- CAS
- 80714-61-0
- Molecular Weight (MW)
- 813.92 g/mol
- Half-life
- ~20-30 minutes (nasal)
- FDA status
- Not Approved
- Evidence level
- Limited Human Evidence
- Human dose established
- No
- Administration Route
- Not established in humans
- Frequency
- Not established in humans
- Last updated
- Sep 26, 2026
- Reviewed
- Aug 30, 2026
- Targets
- Melanocortin-related CNS pathwaysBDNF
Vendor price snapshot
Each vendor counts once, at the median price per mg of its own listings; the typical range is the middle half of vendors. From public vendor listings collected between Dec 2025 and Sep 2026, so confirm the live price on the vendor site. Peptide Library does not sell peptides.
- Vendors listing this peptide
- 32
- Listed offers
- 57
- Median price per mg
- $4.00/mg
- Typical $3.10–$6.50/mg
Research summary
Synthetic analog of the ACTH(4-10) fragment with a stabilising tail added, developed in Russia and used there as an intranasal nootropic and neuroprotective agent for stroke and cognitive indications. It has no corticotropic activity despite its ACTH origin. Reported activity centres on brain-derived neurotrophic factor expression and monoamine modulation. Not FDA-approved, and the clinical literature is almost entirely Russian-language with limited independent replication.
Peptide Library's Semax profile summarises 5 cited studies listed in the Science section, the compound's regulatory status, and research-protocol parameters reported for it. It is a research reference, not medical advice.
Semax dosage: no established human dose
Semax has no established human dosage outside Russia. Four clinical publications exist, all Russian-language and mostly in a single national journal, covering ischaemic stroke and optic nerve disease. No trial is registered on ClinicalTrials.gov, no regulator outside Russia has approved it, and the doses used are not available in the indexed English-language record.
No established human dosage.
Human clinical evidence: None identified.
Preclinical research: Semax is a synthetic analogue of an ACTH(4-10) fragment, developed in Russia, with preclinical work on neuroprotection and cognition in rodents. Its human evidence is clinical rather than preclinical, but it is confined to Russian-language publications, is not replicated in trials registered internationally, and does not report doses in the indexed English record. There is no dose this profile can cite as established.
Animal dosing is not converted into a human dose anywhere on this page. Where research figures appear below, they are reported as studied, not recommended.
| Human dosing established | No |
|---|---|
| Route | Intranasal (the route used in the Russian clinical literature) |
| Evidence level | Limited Human Evidence |
| Last reviewed | 2026-09-05 |
Human research reported
Doses as studied, one row per regimen. Different trials used different regimens; they are listed separately rather than averaged.
| Study / context | Population | Dose | Route | Frequency | Duration | Outcome studied | Source |
|---|---|---|---|---|---|---|---|
| Ischaemic stroke, different stages (2018)Clinical trial · Clinical study, Russian-language publication | Patients at different stages of ischaemic stroke | Not available in the indexed English record | Intranasal | — | — | Neurological recovery | The efficacy of semax in the treatment of patients at different stages of ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova. 2018. |
| Acute hemispheric ischaemic stroke (1997)Clinical trial · Clinical trial, Russian-language publication | Patients in the acute period of hemispheric ischaemic stroke | Not available in the indexed English record | Intranasal | — | — | Clinical outcome in acute stroke | Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study). Zh Nevrol Psikhiatr Im S S Korsakova. 1997. |
| Optic nerve disease (2000)Clinical trial · Clinical study, Russian-language publication | Patients with optic nerve disease | Not available in the indexed English record | Intranasal | — | — | Therapeutic effect in optic nerve disease | Evaluation of therapeutic effect of new Russian drug semax in optic nerve disease. Vestn Oftalmol. 2000. |
Where sources disagree
- Protocols of 300–600 mcg intranasally per day are widely published for semax. The Russian clinical literature is the likely origin of figures in that range, but the doses are not retrievable from the indexed record, so this profile does not restate them as established.
- Semax and selank are both Russian-developed peptides with the same evidence problem: registered as medicines in Russia, absent from ClinicalTrials.gov, and reported in a literature that is difficult to verify from outside. Registration in one jurisdiction does not transfer an approved dose elsewhere.
- Most published work is in acute stroke, a hospital setting. The nootropic and focus uses semax is sold for have no corresponding trial.
Reconstitution
Common research vial sizes: 5 mg, 10 mg.
| Vial | Bacteriostatic water | Concentration | Per 0.01 mL |
|---|---|---|---|
| 5 mg | 2 mL | 2.5 mg/mL | 25 mcg per 0.01 mL |
| 10 mg | 2 mL | 5 mg/mL | 50 mcg per 0.01 mL |
These figures are arithmetic only — they convert a vial and a volume into a concentration. They are not a recommendation to take any dose.
Calculate reconstitution & dose →Handling & administration
- Reconstitution Guide
- 3 mL BAC for 30 mg vial
- Injection Sites
- Abdomen
- Concentration Example
- 30 mg / 10 mL = 3 mg/mL (nasal)
- Timing Notes
- Morning/early PM
- Expected Onset
- 15-30 min
How to reconstitute Semax
- Check the vial size and diluent volume. The profile example for Semax is: 3 mL BAC for 30 mg vial.
- Swab both vial stoppers and draw the bacteriostatic water into a sterile syringe.
- Add the water slowly down the inside wall of the peptide vial so it does not jet onto the powder, then swirl gently until the solution is clear. Do not shake.
- Record the resulting concentration: 30 mg / 10 mL = 3 mg/mL (nasal).
- Label the vial with the date and concentration, refrigerate it (see Storage & stability below), and use the calculator preset to convert a dose in mcg into syringe units.
Sequence & molecular data
| Amino acid sequence | Met-Glu-His-Phe-Pro-Gly-Pro |
|---|---|
| Molecular formula | C37H51N9O10S |
| Molecular weight | 813.92 g/mol |
| CAS number | 80714-61-0 |
| Half-life | ~20-30 minutes (nasal) |
| Appearance | White lyophilized powder |
| Formulation | Lyophilized Powder |
| PubChem CID | 9811102 |
| FDA UNII | I5FAL2585H |
Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.
Science
Mechanism of Action
Semax is a synthetic analog of ACTH(4-10) with a Pro-Gly-Pro tail added to the C-terminus, a modification that markedly slows enzymatic degradation while removing the corticotropic activity of the parent hormone. It does not stimulate the adrenal cortex. Reported activity centres on the neurotrophin system: animal and small human studies describe increased expression of brain-derived neurotrophic factor and nerve growth factor in the hippocampus and cortex, alongside modulation of dopaminergic and serotonergic transmission. Most of the clinical literature is Russian-language, where it is used for stroke and cognitive indications; it has no FDA-approved use, and independent replication outside Russia is limited.
Origin
Synthetic Met-Glu-His-Phe-Pro-Gly-Pro.
Targets
Studies
- [Place of oligopeptide H-Met-Glu-His-Phe-Pro-Gly-Pro-OH in the therapy and rehabilitation of patients with ischemic stroke]
- [Prospects for use of short peptides in pharmacotherapeutic correction of Alzheimer's disease.]
- [Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study)]
- [The Peptide Drug ACTH(4-7)PGP (Semax) Suppresses mRNA Transcripts Encoding Proinflammatory Mediators Induced by Reversible Ischemia of the Rat Brain]
- [Nootropic and analgesic effects of Semax following different routes of administration]
Regulatory & research status
Semax is not an FDA-approved product. It is sold for laboratory research and has no approved medical use.
| FDA status | Not Approved |
|---|---|
| Availability | Research-Only |
| WADA (sport) | Unknown / Not Listed |
| Library classification | Research-Only |
Benefits
Semax side effects
Semax has only limited human data, so the list below is incomplete and its side-effect profile is not well established.
Side Effects
- Nasal irritation
- Headache
Contraindications
- Epilepsy
Stacking
Common stacking partners
Combinations that include Semax, with the proposed rationale, an evidence grade and what is not established, are catalogued in the peptide stacks directory.
Storage & stability
Lyophilized (freeze-dried) peptide powder is far more stable than the reconstituted solution. Keep sealed vials cold, dry and away from light; long-term storage is typically frozen, with short-term refrigeration for vials in use.
Once reconstituted in bacteriostatic water, keep the solution refrigerated, avoid repeated freeze–thaw cycles and agitation, and label the vial with the reconstitution date and concentration. Discard any solution that turns cloudy or shows particulates.
Degradation rates differ by sequence: peptides containing methionine, cysteine, asparagine or glutamine are more prone to oxidation and deamidation, so shelf life after reconstitution is compound-specific rather than universal.
Read the full guide: how to store peptides before and after reconstitution →
Source: Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575. (PMID 20143256). General guidance for research handling; not product-specific instructions.
Semax: frequently asked questions
What is Semax?
Synthetic analog of the ACTH(4-10) fragment with a stabilising tail added, developed in Russia and used there as an intranasal nootropic and neuroprotective agent for stroke and cognitive indications. It has no corticotropic activity despite its ACTH origin. Reported activity centres on brain-derived neurotrophic factor expression and monoamine modulation. Not FDA-approved, and the clinical literature is almost entirely Russian-language with limited independent replication.
What are the side effects of Semax?
Semax has only limited human data, so its side-effect profile is not well established. Effects recorded on this profile include nasal irritation and headache. Cautions recorded on this profile: epilepsy. This is reference information, not medical advice.
How does Semax work?
Semax is a synthetic analog of ACTH(4-10) with a Pro-Gly-Pro tail added to the C-terminus, a modification that markedly slows enzymatic degradation while removing the corticotropic activity of the parent hormone. It does not stimulate the adrenal cortex.
Is Semax FDA approved?
No. Semax is not approved by the FDA for any indication and is categorised as research-only. It has not been reviewed for safety or efficacy as a medicine, and published research should be read as investigation rather than established use.
What is the half-life of Semax?
Reported half-life for Semax is ~20-30 minutes (nasal). Half-life describes how long the compound persists in circulation, not how long any effect lasts, and published figures vary with route of administration, formulation and the population studied.
What is the amino acid sequence of Semax?
Semax has the sequence Met-Glu-His-Phe-Pro-Gly-Pro, giving a chain of 7 amino acids. Its molecular formula is C37H51N9O10S.
What peptides are similar to Semax?
Compounds most often compared with Semax include N-Acetyl Semax Amidate, Adamax, Selank and Cerebrolysin. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.
How long does Semax take to show effects in research protocols?
The research protocol on this profile lists an expected onset of 15-30 min. This is a protocol note describing when studies and researchers report observing changes, not a measured clinical outcome, and it varies with the model, dose and endpoint studied.
Where is Semax administered in research protocols?
Research protocols on this profile use intranasal or subq administration, with recorded sites including abdomen. Site rotation and sterile technique are standard practice in the research literature; this describes protocol conditions and is not guidance for use.
References
- [Place of oligopeptide H-Met-Glu-His-Phe-Pro-Gly-Pro-OH in the therapy and rehabilitation of patients with ischemic stroke] — Zh Nevrol Psikhiatr Im S S Korsakova, 2024External reference
- [Prospects for use of short peptides in pharmacotherapeutic correction of Alzheimer's disease.] — Adv Gerontol, 2024External reference
- [Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study)] — Zh Nevrol Psikhiatr Im S S Korsakova, 1997External reference
- [The Peptide Drug ACTH(4-7)PGP (Semax) Suppresses mRNA Transcripts Encoding Proinflammatory Mediators Induced by Reversible Ischemia of the Rat Brain] — Mol Biol (Mosk), 2021External reference
- [Nootropic and analgesic effects of Semax following different routes of administration] — Ross Fiziol Zh Im I M Sechenova, 2010External reference
Related research, comparisons & guides
- Semax vs. Selank: Two Russian Peptides That Are Not Interchangeable
- Adamax vs Semax: A Thin Literature and an Almost Empty One
- Selank Dosage: What the Nasal Route Changes
- Semax Benefits: What the Research Reports and How to Weigh It
- Dihexa: The Angiotensin IV Analogue and Its Very Preclinical Evidence
- Selank
- Cognitive and nootropic peptidesCategory
- Peptide stacks: combinations by research goalStacks
- Peptide dosage chart: dose, route and frequencyCategory
- Peptide calculator with the Semax preset
- How to store peptides before and after reconstitution
Related peptides
Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Sep 26, 2026 · Version 7
This Semax profile is compiled from published literature (5 cited studies linked above), public regulatory records and chemical registries. It describes what research reports; it is not medical advice, and nothing here is a dosing recommendation for humans. Peptide Library does not sell peptides. Editorial policy · How profiles are compiled · Report an error
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