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Semax

Last reviewed: April 18, 2026 by The Peptide Catalog Team

A cognitive-enhancing peptide for focus, memory, and neuroprotection. Semax is a synthetic peptide derived from ACTH (4-10) with neuroprotective and cognitive-enhancing properties. Developed in Russia for stroke recovery and cognitive disorders. Studied for memory, focus, neuroplasticity, and BDNF stimulation.

Overview

Semax Results Timeline

Progression
1
First dose
Physical Changes
Minimal physical effects
Performance & Recovery
Noticeable focus/clarity within 30-90 min for many
Other Benefits
Acute onset — effects felt same day
2
Days 2–5
Physical Changes
No significant physical changes
Performance & Recovery
Performance benefits become more predictable
Other Benefits
Improved task initiation, mental energy
3
Week 2–4
Physical Changes
Better recovery from mental fatigue
Performance & Recovery
Enhanced memory, learning, sustained focus
Other Benefits
BDNF stimulation supporting neuroprotection
4
4+ Weeks
Physical Changes
Plateau possible
Performance & Recovery
Some cycle to avoid diminishing returns
Other Benefits
Effects fade quickly after stopping (same day/next day); often cycled

Timeline is illustrative and non-guaranteed. Outcomes vary and are commonly discussed alongside training, nutrition, sleep, and cycling practices.

Read the full Semax results timeline →

Evidence at a glance

Two parallel grades per outcome — clinical RCT depth and real-world community adoption. See the Research Overview below for citations and detail.

OutcomeClinical EvidenceCommunity Evidence
Acute ischemic stroke neuroprotectionModerateModerate
BDNF / neurotrophin upregulation (mechanism)ModerateModerate
Cognitive enhancement in healthy adultsPreliminaryModerate
ADHD in childrenPreliminaryModerate
How It WorksNootropic Peptide — Cognitive Enhancer / BDNF Stimulator

Target → BDNF Stimulation → Cognitive Enhancement → Outcomes

1
Target

BDNF/TrkB Pathway + Melanocortin Receptors

Semax is a synthetic fragment of ACTH (adrenocorticotropic hormone) that stimulates Brain-Derived Neurotrophic Factor (BDNF) production. BDNF is the brain's primary "growth factor" for neurons — supporting learning, memory, and cognitive function.

2
Cellular Signal

BDNF Upregulation → Neuroplasticity + Neuroprotection

BDNF activation of TrkB receptors promotes neuronal growth, synaptic plasticity, and neuroprotection. Semax also modulates dopamine and serotonin metabolism, contributing to improved motivation and mood. Unlike Selank (calming), Semax is activating and focus-enhancing.

3
Systemic Effect

Enhanced Cognition + Neuroprotection

Improved focus, attention, and mental clarity. Enhanced memory formation and recall. Neuroprotective effects support brain health. Originally developed in Russia for cognitive rehabilitation after stroke.

4
What You Notice

Mental Clarity → Focus → Motivation (30-90 min onset)

Improved focus and mental clarity, often noticeable within 30-90 minutes. Enhanced motivation and task initiation. Better memory and learning. Effects are activating rather than calming — the complement to Selank's anxiolytic profile.

What Makes This Peptide Different

Semax is the cognitive complement to Selank. Where Selank reduces anxiety (calming), Semax enhances focus and drive (activating). Its BDNF-stimulating mechanism provides genuine neuroprotective benefits beyond just "nootropic" effects. The NA-Semax-Amidate version has enhanced potency and duration.

Research overview

Outcome-by-outcome look at what the evidence actually supports for Semax, including human vs. animal study counts and our editorial take on each.

Acute ischemic stroke neuroprotection

Clinical:ModerateCommunity:Moderate

Gusev 2001 reported on the use of intranasal semax 12 mg/day for 5 days in acute hemispheric ischemic stroke patients with improved neurological recovery vs standard care. Multiple smaller Russian trials have replicated this in similar populations. Mechanism (Dolotov 2009 and others) involves neurotrophin (BDNF, NGF) upregulation and modulation of immune/vascular gene expression in cortical neurons.

3 human studies · 12 animal studies

Key findings & citations
  • Gusev 2001: improved neurological recovery vs standard care in acute stroke (n~30).
  • Mechanism: BDNF, NGF, and other neurotrophin upregulation in injured cortex.
  • Genome-wide transcriptomic studies confirm immune/vascular gene modulation.
  • Russian regulatory approval; no FDA / EMA approval.

Our take

Real signal in stroke research, almost entirely from Russian groups. As a community 'nootropic' for healthy users, the evidence is much thinner.

Cognitive enhancement in healthy adults

Clinical:PreliminaryCommunity:Moderate

Most healthy-adult cognitive claims for semax come from observational reports and uncontrolled clinical practice, primarily in Russia. No Western-standard RCT in healthy users has been published. The translation from BDNF upregulation in injured cortex to subjective cognitive enhancement in healthy adults is an extrapolation, not data.

0 human studies · 8 animal studies

Key findings & citations
  • BDNF upregulation is mechanistically plausible for cognitive effects.
  • Zero RCTs in healthy adults to support nootropic claims.
  • Community use widespread despite the evidence gap.

Our take

Stroke benefit doesn't automatically generalize to 'smarter healthy brain.' Treat the nootropic claim as community-level until a real RCT shows up.

What Semax doesn't do

Claims that current evidence does not support. Worth knowing before you set expectations.

Top Semax Vendors

Dosing ProtocolCognition / Focus

Educational reference only. Individual responses vary. Consult healthcare provider before use.

Vial Size
30 mg
Reconstitution
3 ml BAC water
Dose
1 mg (10 units on 1ml syringe)
Timing
AM
Frequency
2-3 days per week
Duration
8 weeks on, 8 weeks off
Protocol Notes
Best used intranasally for cognitive effects. NA-Semax-Amidate is the enhanced version.

Why This Dosing Protocol

Why intranasal preferred? Provides rapid CNS access and fast onset (30-60 min). The nasal route bypasses the blood-brain barrier more effectively for cognitive effects.

Why morning? Semax is activating — enhances focus, motivation, and mental energy. Morning dosing aligns with the workday and avoids potential sleep interference.
Popular Semax Stacks

Pre-made bundles ranked by value. Cost per mg is based on the Semax portion of each stack.

Reconstitution Calculator

Dilution math and unit conversions. Prefilled using a common vial size for this peptide.

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Storage & Handling

Storage at a glance

Proper storage temperatures, shelf life, reconstitution best practices, and travel tips for lyophilized and reconstituted peptides.

Powder: Freezer
1+ year at -20°C
Reconstituted: Fridge
4 weeks max at 2-8°C
View Complete Storage Guide

Handling specifics

Educational overview on storage, labeling, and traceability considerations for lab environments. Consult primary literature and vendor documentation for specifics.

Powder storage (very stable)
  • Freezer (-20°C): 1+ year
  • Refrigerator (2-8°C): 1-3 months
  • Room temperature: 2-3 weeks (emergency only)
Reconstituted storage (fragile)
  • MUST refrigerate at 2-8°C
  • 4-week maximum shelf life
  • NEVER freeze after reconstitution
  • Use bacteriostatic water for multi-dose
Molecular Structure

Semax sequence

Click any residue to see its properties.

HydrophobicPolarAcidic (−)Basic (+)Special

Sequence-derived properties

Length
7 residues
Molecular weight
813.9 Da
backbone only
Avg hydrophobicity
-0.80
Kyte–Doolittle scale

Residue classes

Hydrophobic: 2 (29%)Acidic (−): 1 (14%)Basic (+): 1 (14%)Special: 3 (43%)

Net charge distribution

Positive1 (14%)
Neutral5 (71%)
Negative1 (14%)

Amino acid frequency

P×2E×1F×1G×1H×1M×1

Modifications

  • ACTH(4–7) analog with Pro-Gly-Pro C-terminal extension

Sequence and properties provided for educational reference. Not for clinical dosing decisions.

  • Length: 7 amino acids
    (Heptapeptide from ACTH fragment.)
  • Origin: ACTH (4-10)
    (Modified pituitary hormone fragment.)
  • Administration: Intranasal
    (Commonly used as nasal spray.)
  • Primary Use: Cognitive enhancement
    (Focus, memory, neuroprotection.)
Peptide sequence
Met-Glu-His-Phe-Pro-Gly-Pro
Semax extends the ACTH(4-7) sequence (Met-Glu-His-Phe) with Pro-Gly-Pro to improve stability and duration of action. Stimulates BDNF and has neuroprotective effects.
Key takeaway: Semax enhances cognitive function through BDNF stimulation and neuroprotective mechanisms. Used for focus, memory, and stroke recovery. Often compared with Selank which has more anti-anxiety effects.

FAQ

How does Semax differ from Selank?

While both are Russian-developed neuropeptides, Semax is derived from ACTH (4-10) and focuses more on cognitive enhancement, neuroprotection, and BDNF stimulation. Selank is derived from tuftsin and has more pronounced anti-anxiety effects. They're sometimes used together.

What is Semax and how does it work?

Semax is a synthetic peptide derived from ACTH (adrenocorticotropic hormone), specifically the 4-10 fragment with an added Pro-Gly-Pro sequence. It works primarily by increasing BDNF (brain-derived neurotrophic factor) and modulating dopamine and serotonin systems. Unlike ACTH, it has no hormonal effects on cortisol.

What is BDNF and why does Semax increasing it matter?

BDNF is a protein that supports neuron growth, survival, and plasticity — essentially "fertilizer for the brain." Higher BDNF is associated with better learning, memory, and mood. BDNF levels decline with age and in depression. By increasing BDNF, Semax may support cognitive function and neural health.

How is Semax administered?

Semax is most commonly used as a nasal spray for direct CNS delivery. Typical dosages range from 200-1000 mcg per day, divided into 2-3 doses. Effects are usually noticeable within 15-30 minutes. It can also be injected subcutaneously. In Russia, it's available as prescription nasal drops.

What cognitive effects does Semax have?

Users report improved focus, concentration, and mental clarity. Research suggests benefits for memory formation and recall, attention, and learning capacity. Some describe it as providing "clean" mental energy without the jitteriness of stimulants. It's used by students, professionals, and those seeking cognitive enhancement.

Is Semax used for any medical conditions?

In Russia, Semax is approved for stroke recovery, traumatic brain injury, cognitive disorders, and optic nerve diseases. It's shown neuroprotective effects in ischemia and may help with ADHD symptoms. Western clinical trials are limited, but Russian medical use provides substantial human data.

Can Semax and Selank be used together?

Yes, the combination is popular. Semax provides cognitive enhancement and focus, while Selank adds anxiolytic and calming effects. Together they may offer balanced mental enhancement — clarity and focus without anxiety. Some find the combination superior to either alone for productivity and well-being.

What are the side effects of Semax?

Semax is generally well-tolerated. Possible side effects include mild nasal irritation (with spray), occasional headache, and rarely dizziness. Some users report hair loss concerns, though evidence is limited. Unlike stimulants, it doesn't cause jitteriness, insomnia, or crash effects. Most users report minimal to no side effects.

How long does reconstituted peptide last?

Once mixed with bacteriostatic water, peptides remain stable for up to 4 weeks when refrigerated at 2-8°C (36-46°F). Unopened powder can last 1+ year in the freezer. Get our complete Storage & Travel Guide.

Is this peptide legal to purchase?

Peptides sold "for research purposes only" are legal to purchase in the US, but are not FDA-approved for human use outside of specific medical applications. Always consult a healthcare provider before use.

New to peptides?

Take our Peptide Match tool to find the best peptide for your goals. You can also read our Complete Guide to Peptides to learn the basics.

Scientific Sources

The following peer-reviewed studies and official resources provide additional scientific context for this peptide:

Semax Research Articles

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Side-by-side mechanism, dose, half-life, and vendor pricing.

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