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.
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
Day 1–3Community
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
Day 3–7Community
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
Day 7–14Community
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
Day 14–28Community
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
With SelankCommunity
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
Any dayClinical
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 to22 units
0.3 mL insulin syringe · 30 units
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)
Compared with.
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.
Reference.
- Cadence
Daily
- Half-life
Very short
Very short (~minutes); CNS effects persist longer
- Research basis
●●
●ModerateAnimal studies + some human data
PepVault for iPhone
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