# Semax — dosage, half-life & reference guide | PepVault

Source: https://pepvault.app/peptides/semax

Last updated: 2026-09-26

[Library](https://pepvault.app/peptides) [Cognitive](https://pepvault.app/peptides#cognitive) reviewed September 2026

# Semax Dosage, half-life & reference guide

Also known as ACTH 4-7 Pro8Gly9Pro10 · N-acetyl Semax

A nasal spray nootropic derived from ACTH but modified to remove hormonal effects. In rats it raises BDNF and nerve growth factor; human data are small, mostly open-label Russian studies, chiefly in stroke.

- **Studied range:** 200–900 mcg
- **How often:** Daily
- **Half-life:** Very short
- **Evidence:** Moderate
- **Route:** Nasal spray

Studied in research — not a recommendation.

[Semax dose guide](https://pepvault.app/lab/dosage/semax)

## How it works.

Synthetic heptapeptide derived from ACTH. In rats it raises BDNF and NGF expression, lifts serotonin turnover and amplifies stimulated dopamine release, which supports cognition, focus and neuroprotection. Used clinically in Russia for stroke recovery.

**Commonly reported:** A quick lift in focus, alertness and mental energy within minutes to an hour, nasal stinging, and irritability or poor sleep at high doses or late in the day. Approved in Russia for stroke recovery and memory problems after brain injury. Often paired with Selank — Semax for drive, Selank for calm.

## Where Semax works.

- ### Brain, nerves & sleep

  **In people.** Approved in Russia for stroke recovery and memory problems after brain injury.

An area lights for what a peptide is used for and what people report, with the evidence beside it. It isn’t a promise that it works there.

## Week by week.

What to expect in the first 8 weeks

- **Onset:** Minutes
- **Peak effect:** 2–4 weeks (cumulative)
- **Duration:** 10–30 days

1. Day 1–3 Community

   ### Focus snaps into place

   Semax is one of the fastest-acting nootropics available. Commonly reported: sharper focus within 15–30 minutes of the first nasal spray, with brain fog lifting and motivation clicking on. The quick effect involves serotonin and dopamine signalling; users say the deeper benefits build over days.

   The science

   In rodents Semax raises serotonin turnover and amplifies stimulated dopamine release (Eremin 2005). Nasal Semax reaches the brain within minutes, partly bypassing the blood-brain barrier, though only about 0.1% of the dose per gram of brain arrived in rats (Shevchenko 2006).

   Sources

   - Eremin et al. (2005)
   - Shevchenko et al. (2006)

   Updated Sep 2026
2. Day 3–7 Community

   ### Each dose builds on the last

   The immediate focus effect is nice, but the real value is cumulative: in rats, Semax raises BDNF and NGF, which support new neural connections. Commonly reported: motivation and cognitive endurance feel better than baseline by now.

   The science

   In rats, Semax raises BDNF (Dolotov 2006) and NGF (Agapova 2007) expression in the hippocampus. These neurotrophins support synaptogenesis, neuronal survival and long-term potentiation; whether that produces lasting cognitive change in people hasn't been tested.

   Sources

   - Dolotov et al. (2006)
   - Agapova et al. (2007)

   Updated Sep 2026
3. Day 7–14 Community

   ### Learning speed is up

   Commonly reported two weeks in: learning new information feels easier, memory recall crisper and problem-solving more fluid. This is the window where most users decide whether it's a keeper.

   The science

   Sustained BDNF elevation increases synaptic plasticity and hippocampal long-term potentiation. Human cognitive data are thin: in healthy volunteers, memory and attention effects were seen 20–24 hours after a nasal dose (Ashmarin 1997), and no trial has tested week-by-week cognitive gains.

   Sources

   - Ashmarin et al. (1997)

   Updated Sep 2026
4. Day 14–28 Community

   ### The end of a typical cycle

   Commonly reported at this point: focus, mood, motivation and memory running above baseline. Russian courses run up to two weeks, and many users say gains persist for weeks after stopping, so there's no pressure to wrap up on a fixed schedule. Continuing, cycling off and pausing are all common from here.

   The science

   No Semax study has measured cognitive benefits after a course ends; the Russian label says a single dose acts for 20–24 hours. In a 5-month stroke study with two 10-day courses, plasma BDNF stayed raised (Gusev 2018). Neuroprotective effects are shown in stroke models.

   Sources

   - Gusev et al. (2018)
   - Dolotov et al. (2006)

   Updated Sep 2026
5. With Selank Community

   ### Drive meets calm

   The Semax + Selank stack is a community classic. Commonly reported: Semax delivers the focus and motivation while Selank smooths the edges and keeps anxiety from spiking. Together they cover both sides of cognitive performance.

   The science

   Complementary mechanisms in rat studies: Semax raises serotonin turnover and BDNF (drive, focus), while Selank changes GABA-A receptor gene expression (anxiolysis without sedation; Volkova 2016). Both inhibit enkephalin-degrading enzymes (Kost 2001), so their actions partly overlap; no harmful interaction is known.

   Sources

   - Dolotov et al. (2006)
   - Volkova et al. (2016)

   Updated Sep 2026
6. Any day Clinical

   ### What Semax is built on

   Semax is an approved medication in Russia and Ukraine for stroke recovery, memory problems after vascular disease or brain injury, and optic nerve disease. Derived from ACTH but modified to remove hormonal effects. The human data are small, mostly open-label Russian studies, chiefly in stroke; there is little evidence on cognition in healthy people.

   The science

   A synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) derived from ACTH 4-10 with Pro-Gly-Pro modifications for stability. Approved by the Russian Ministry of Health. Clinical use spans stroke, TBI, cognitive decline, and optic neuropathy. In 73 patients with post-hypoxic brain injury, some showed EEG paroxysmal activity after dosing, and the authors advised giving the first dose under EEG monitoring (Alekseeva 1999).

   Sources

   - Gusev et al. (2018)
   - Alekseeva et al. (1999)

   Updated Sep 2026

Day 1 is the day you start it.

Approved medication in Russia/Ukraine. Clinical use for stroke recovery and cognitive enhancement. Not studied in Western RCTs.

Moderate evidence

## Mixing and a typical run.

Example numbers

### Reconstitution example

Reconstitute a 5 mg vial of Semax with 2 mL of bacteriostatic water and a 550 mcg dose is 22 units on a U-100 syringe, about 9 doses per vial.

- **Vial:** 5 mg
- **Water:** 2 mL
- **Amount:** 550 mcg

Draw to **22 units**

0.3 mL insulin syringe · 30 units

[Mix it in the Reconstitution Lab](https://pepvault.app/lab) [Open the calculator](https://pepvault.app/tools/reconstitution-calculator)

### Run notes

- **Cycle:** 2–4 week cycles. Some use daily long-term without noted issues. Cycling still advised. Community practice — opinions vary. Not a clinical recommendation.
- **Timing:** Morning nasal spray for focus/energy. Avoid late dosing — can disrupt sleep.
- **Route:** Nasal spray
- **Stacks:** Selank, Dihexa, BPC-157

## Safety.

### Common side effects

- Nasal irritation
- Headache
- Anxiety
- Increased energy (can disrupt sleep)

## Goes with.

- [Selank](https://pepvault.app/peptides/selank)
- [Dihexa](https://pepvault.app/peptides/dihexa)
- [BPC-157](https://pepvault.app/peptides/bpc-157)

- ### In the Limitless stack

  Cognitive enhancement & neuroprotection stack

  With [Selank](https://pepvault.app/peptides/selank) and [Dihexa](https://pepvault.app/peptides/dihexa)

## Compared with.

- [Selank vs Semax](https://pepvault.app/peptides/compare/selank-vs-semax)

## Questions people ask.

### What is Semax?

A nasal spray nootropic derived from ACTH but modified to remove hormonal effects. In rats it raises BDNF and nerve growth factor; human data are small, mostly open-label Russian studies, chiefly in stroke.

### How is Semax dosed in research?

The research range for Semax is 200–900 mcg, daily. Studied in research — not a recommendation.

### How long does Semax last?

The half-life of Semax is very short (~minutes); CNS effects persist longer.

### What do people report on Semax?

Commonly reported on Semax: A quick lift in focus, alertness and mental energy within minutes to an hour, nasal stinging, and irritability or poor sleep at high doses or late in the day. Approved in Russia for stroke recovery and memory problems after brain injury. Often paired with Selank — Semax for drive, Selank for calm.

### Is Semax safe?

The research basis for Semax is moderate: animal studies + some human data. Common side effects in the library: nasal irritation, headache, anxiety and increased energy (can disrupt sleep).

### What does Semax stack with?

Common stacks for Semax: Selank, Dihexa and BPC-157. Curated stacks with Semax: Limitless.

## Research.

The literature

### Search the latest research

[PubMed](https://pubmed.ncbi.nlm.nih.gov/?term=Semax) [Google Scholar](https://scholar.google.com/scholar?q=Semax)

## Reference.

- **Cadence:** Daily
- **Half-life:** Very short Very short (~minutes); CNS effects persist longer
- **Research basis:** Moderate Animal studies + some human data

## More cognitive peptides

- [NSI-189 40–80 mg](https://pepvault.app/peptides/nsi-189)
- [P21 100–300 mcg](https://pepvault.app/peptides/p21)
- [Cerebrolysin 5–10 ml](https://pepvault.app/peptides/cerebrolysin)
- [N-Acetyl Semax Amidate 100–600 mcg](https://pepvault.app/peptides/n-acetyl-semax-amidate)
- [Adamax No reference dose](https://pepvault.app/peptides/adamax)

## Free tools

- [Semax dose guide](https://pepvault.app/lab/dosage/semax)
- [Reconstitution Lab (3D)](https://pepvault.app/lab)
- [Peptide Sky (3D)](https://pepvault.app/lab/sky)
- [Peptide tier list](https://pepvault.app/lab/tiers)
- [Reconstitution calculator](https://pepvault.app/tools/reconstitution-calculator)
- [Half-life & active level](https://pepvault.app/tools/peptide-half-life-calculator)

PepVault for iPhone

## Track Semax in PepVault

Log every dose and keep your vial and the doses left in it. 7 days free on the yearly plan for new subscribers.

[Download on the App Store](https://apps.apple.com/app/apple-store/id6779318649?pt=129020030&ct=peptides-cta&mt=8)

[Open the calculator](https://pepvault.app/tools/reconstitution-calculator) [How the vial count works](https://pepvault.app/peptide-vial-tracker-app) [Explore the live demo](https://pepvault.app/login)

Reviewed September 2026 [How we check the library](https://pepvault.app/about#library)

PepVault is a research and tracking resource, not medical advice. Ranges are what studies used, never a dose for you. Brand names are trademarks of their owners; PepVault is independent of them.

PepVault is a private research and tracking tool, not medical advice. The information here is reference material from published literature and community use — always verify it and discuss any protocol with a qualified clinician before changing it.

© 2026 PepVault