Overview
A synthetic heptapeptide based on the ACTH(4-10) fragment with a Pro-Gly-Pro extension. It is studied primarily in neuroprotection, ischaemic stroke recovery and attention or memory endpoints, and carries no corticotropic hormonal activity.
Mechanism of Action
Semax is derived from adrenocorticotropic hormone fragment 4-10, but the sequence retained does not stimulate cortisol release, so its activity is described as neurotropic rather than hormonal.
Published work reports increased expression of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) along with their receptors in hippocampal tissue.
Studies describe modulation of the dopaminergic and serotonergic systems and inhibition of enkephalin-degrading enzymes, extending endogenous regulatory peptide activity.
Reported anti-inflammatory and antioxidant effects in ischaemia models are attributed to changes in expression of genes involved in the vascular and immune response.
Areas Being Studied
- Ischaemic stroke and neurorehabilitation research
- Attention, memory and cognitive endpoints
- Optic nerve and retinal research
- Stress adaptation
Listing a research area does not imply efficacy, approval, or suitability for any use.
Research Summary
- Animal ischaemia models report reduced infarct volume and improved functional recovery relative to control.
- Russian clinical work in acute ischaemic stroke reports improvements on neurological rating scales; the peptide is registered as a medicine in Russia, though it holds no approval in the EU or the United States.
- Studies in healthy volunteers report changes in attention and short-term memory task performance, generally with small cohorts.
- Gene-expression profiling studies report broad and durable transcriptional changes in brain tissue after single administration.
Potential Adverse Effects Reported in Research
- Published tolerability data describe a low adverse-event rate, with nasal irritation the most commonly reported finding for intranasal formulations.
- Headache and transient irritability or overstimulation appear in some reports.
- Sleep disturbance has been described where administration occurred late in the day.
- Long-term safety data outside Russian clinical practice is limited.
Reconstitution Basics
Supplied as a lyophilised powder; published protocols describe both intranasal solutions and injectable preparations reconstituted with bacteriostatic water.
Bacteriostatic water
Sterile water containing roughly 0.9% benzyl alcohol as a preservative, which inhibits bacterial growth in multi-access vials.
Sterile technique
Laboratory documentation describes disinfecting the stopper, using a fresh sterile needle for each access, and avoiding contact with non-sterile surfaces.
After reconstitution
Solutions are refrigerated, protected from light, and not subjected to repeated freeze–thaw cycles.
This section is educational background on laboratory handling. It is not an instruction or protocol.
Open the reconstitution calculator →Dosing & Reconstitution Guide
Semax is an ACTH(4-10) analogue studied intranasally, most often as a short daily course in Russian clinical research on cognition and ischaemic events.
Protocol overview
- Intranasal drops are the studied route; systemic peptide half-life is minutes.
- Higher-concentration formulations (0.1%) appear in stroke research; lower concentrations in cognitive studies.
- Later-in-day administration is generally avoided in protocols because of reported alerting effects.
Dosing protocol — standard titration
| Phase | Reported dose | Notes |
|---|---|---|
| Days 1–2 | Low end of cited intranasal rangeTolerability observation. | Tolerability observation. |
| Days 3–14 | Cited range, split 2–3× dailyTypical published course. | Typical published course. |
| After 14 days | BreakAcute-setting studies used 10–14 day courses. | Acute-setting studies used 10–14 day courses. |
Dosing protocol — gradual titration
| Phase | Reported dose | Notes |
|---|---|---|
| Week 1 | Lowest amount once dailyMorning administration in most protocols. | Morning administration in most protocols. |
| Weeks 2–4 | Cited amount split twice dailySecond administration kept away from bedtime. | Second administration kept away from bedtime. |
| Week 5+ | Off-cycleNo long-duration data. | No long-duration data. |
Schedules summarise what appears in published studies, trial protocols or manufacturer documentation. They are reference material, not a recommendation.
Where to Buy Compounds & Supplies
External link. PepDex does not sell products and does not endorse any supplier.
Supplies needed
Lyophilised peptide vial
Sealed vial with an intact stopper and a legible mass label (mg or mcg).
Bacteriostatic water
Sterile water with ~0.9% benzyl alcohol, used where a vial will be accessed more than once. Sterile water for injection is used for single-access work.
Reconstitution syringe
A 1–3 mL syringe with a larger-gauge needle for drawing and transferring solvent.
Insulin syringe (U-100)
Fine-gauge syringe graduated in units; 100 units = 1 mL. Used for accurate small-volume measurement.
Alcohol prep pads
70% isopropyl swabs for disinfecting both vial stoppers before every access.
Sharps container
Rigid, puncture-resistant container for single-use needle disposal.
Refrigeration and light protection
2–8 °C storage plus an opaque box or the original carton for reconstituted vials.
Labels
Date of reconstitution, resulting concentration and compound name on every vial.
Reconstitution steps
- 01
Bring the vial to room temperature
Lyophilised powder is allowed to equilibrate out of the refrigerator before the stopper is pierced, which reduces condensation inside the vial.
- 02
Disinfect both stoppers
The peptide vial and the bacteriostatic water vial are each swabbed with 70% isopropyl alcohol and allowed to air dry.
- 03
Draw the calculated solvent volume
Solvent volume is chosen to produce a convenient concentration — the reconstitution calculator converts vial mass and solvent volume into concentration and syringe units.
- 04
Add the solvent slowly down the vial wall
The stream is directed against the glass rather than onto the powder cake. Peptides are shear-sensitive and direct jetting is avoided.
- 05
Dissolve without shaking
The vial is left to stand, then gently swirled or rolled. Shaking introduces foam and mechanical stress that can denature peptide chains.
- 06
Inspect the solution
Documentation describes checking for a clear, particle-free solution. Cloudiness, visible particulate or discolouration is treated as a failed preparation.
- 07
Label and refrigerate
The vial is labelled with compound, concentration and date, then stored at 2–8 °C protected from light.
Storage instructions
- Before reconstitution: lyophilised powder is kept sealed, dry and away from light; most suppliers specify refrigeration at 2–8 °C, with freezer storage for long-term holding.
- After reconstitution: refrigerated at 2–8 °C and used within the window described in the literature (commonly cited as ~14–30 days refrigerated).
- Protection from light: the vial is kept in its carton or an opaque container; repeated exposure to daylight is avoided.
- Handling: repeated freeze–thaw cycles are avoided, and vials are not left at room temperature between accesses.
- Integrity checks: any solution that becomes cloudy, discoloured or shows particulate is discarded rather than filtered.
Half-Life
Minutes in plasma; central effects reported for hours
The intact peptide is degraded rapidly in plasma, but published pharmacodynamic work reports central effects lasting many hours after a single dose, attributed to downstream neurotrophic signalling.
Storage
- Before reconstitution
- Lyophilised powder stored frozen at −20 °C for long-term storage.
- After reconstitution
- Refrigerated at 2–8 °C after reconstitution.
- Light protection
- Protected from light.
- Shelf-life considerations
- Reconstituted solutions are typically described as usable for a few weeks refrigerated.
Frequently Asked Questions
References
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Educational reference only. Figures are compiled from published research literature. PepDex does not provide medical advice, dosing recommendations, or instructions for use.