Semax
Synthetic ACTH Analog · Nootropic & Neuroprotective Peptide
Semax is a synthetic heptapeptide derived from adrenocorticotropic hormone (ACTH) fragment 4-10, originally developed in Russia for stroke recovery. It achieves enhanced CNS penetration through direct transport via olfactory epithelium and trigeminal nerves, bypassing the blood-brain barrier.
Overview
Semax is a synthetic heptapeptide derived from adrenocorticotropic hormone (ACTH) fragment 4-10, originally developed in Russia for stroke recovery. It achieves enhanced CNS penetration through direct transport via olfactory epithelium and trigeminal nerves, bypassing the blood-brain barrier.
Rapidly increases BDNF levels, modulates dopaminergic and serotonergic systems, and achieves direct brain delivery through olfactory transport with 0.093% blood-brain barrier penetration (vs 0.01% IV).
Research indications
What the compound has been studied for, grouped by body system. Effect size is the reported magnitude where it was measured — not a recommendation.
Improved short-term and working memory performance in fatigued individuals (71% vs 41% accuracy).
Enhanced sustained attention during demanding cognitive tasks.
Faster acquisition of new information and improved retention.
Accelerated rehabilitation with increased BDNF levels in stroke patients.
Supports recovery from traumatic brain injury.
Shows anti-amyloid properties in Alzheimer's models.
Supports neurogenesis through increased brain-derived neurotrophic factor.
Enhanced neural connections and brain network activity.
Improved ability to cope with cognitive stress.
A large effect in a weak study and a small effect in a strong one are different things. Effect size is never evidence of use in people.
- Class
- ACTH(4-10) synthetic analog
- Chain length
- 7 residues
- Molecular weight
- 813.93 Da
- Half-life
- ~1.25 h
- Typical dose
- 300-600mcg per dose (up to 1000mcg for intensive use)
- Frequency
- 1-2x daily (morning recommended for cognitive boost)
- Cycle length
- 2-4 weeks on
- Storage
- Reconstituted: 2-8°C, use within recommended timeframe
Molecular data
- Type
- ACTH(4-10) synthetic analog
- Molecular weight
- 813.93 Da
- Chain length
- 7 residues
- Half-life
- 75 min
MEHFPGPDosing reference
Doses reported in the literature and by suppliers. These are a record of what has been used in research — reference, never instruction.
| Context | Route | Amount | Frequency |
|---|---|---|---|
| Cognitive enhancement | Intranasal spray/drops | 300-600mcg | 1-2x daily |
| Intensive cognitive support | Intranasal | 600-900mcg | 2-3x daily |
| Brain injury recovery | Intranasal | 900-1500mcg | 2-3x daily |
| Research protocol | SubQ | 500-750mcg | 1x daily |
| Intensive protocol | SubQ | 750-1000mcg | 1-2x daily |
Interactions
Do NOT use simultaneously. Choose one or the other - they are variants of the same peptide.
Complementary anxiolytic effects; popular combination.
Both support neuroplasticity through different mechanisms.
Comprehensive neuroprotection when combined.
May enhance stimulant effects - monitor carefully and reduce stimulant doses.
Theoretical monoamine system risk; use caution.
Quality checklist
- ✓Clear, colorless solution (nasal)
- ✓Proper concentration labeling as 0.1% or 1% Semax
- ✓Cold chain shipping with cold packs
- ✓Sterile packaging (sealed bottles/ampoules)
- ✓White lyophilized powder (injectable)
- ✓Complete dissolution in solution
- ✓Third-party testing (≥98% purity)
- !Nasal irritation potential
- !Injection site reactions (redness, swelling)
- ×Crystallization or precipitation indicates degradation
- ×Cloudy or colored solutions
- ×Any visible particles
What to expect
Safety
- Mild nasal discomfort (nasal route)
- Possible nasal sensation upon administration
- Severe nasal irritation, bleeding, or persistent congestion
- Unusual anxiety, agitation, or sleep disturbances
- Headaches worsening with use
- Signs of allergic reaction (rash, breathing difficulty)
- Significant blood pressure changes or heart palpitations
- Pregnancy or breastfeeding
- Known peptide allergies
- Do not exceed 4-week continuous use without medical supervision
FAQ
Why is intranasal Semax 9x better at crossing the blood-brain barrier than IV?
Intranasal delivery (0.093% BBB penetration) bypasses the blood-brain barrier entirely by using olfactory nerve transport directly to the brain. IV injection (0.01% BBB penetration) relies on the peptide crossing from blood into brain tissue, which is blocked by the BBB. This is why intranasal Semax is the preferred route despite being counterintuitive.
Does Semax actually reverse amyloid plaque buildup in Alzheimer's?
In mouse models, yes. A 2025 study showed 2.8-fold reduction in amyloid plaques in Alzheimer's mice. However, this is preclinical data. No human clinical trials exist for Semax and Alzheimer's. The mechanism (anti-amyloid + anti-aggregating effects) is promising, but human efficacy remains unknown.
Can I take Semax every day, or should I cycle it?
Semax is typically used in 2-4 week cycles rather than indefinitely. While it doesn't cause dependence like benzodiazepines, continuous use without breaks hasn't been extensively studied for optimal long-term results. The 4-6 hour duration per dose means daily dosing is common, but periodically cycling off allows receptor sensitivity to reset.
Will Semax help me recover faster from a stroke?
Yes. Clinical evidence supports Semax for stroke recovery. In a 110-patient trial, 6000 mcg/day intranasal increased BDNF levels and accelerated functional recovery during rehabilitation. It's one of Semax's most established therapeutic applications with actual human clinical data backing it.
References
- 1A Nootropic Adrenocorticotropin Analog 4-10 Semax: 15 Years Experience in Its Design and Study (Parent Compound)Ashmarin IP, Nezavibatko VN, Levitskaya NG, et al. · Zhurnal Vysshei Nervnoi Deiatelnosti imeni I.P. Pavlova · 1997
Foundational Semax review: intranasal doses stimulate operative memory and attention for 20-24 hours. Adamax builds on the Semax core sequence with adamantane modification for enhanced stability and BBB penetration.
reviewPubMed 9173745 ↗ - 2Semax, an Analog of ACTH(4-10), Regulates BDNF and trkB Expression in the Rat Hippocampus (Parent Compound)Dolotov OV, Karpenko EA, Inozemtseva LS, et al. · Brain Research · 2006
Single application at 50 mcg/kg produced 1.4-fold increase in BDNF protein and 1.6-fold increase in trkB tyrosine phosphorylation in rat hippocampus, supporting Adamax's BDNF-TrkB mechanism.
animalPubMed 16996037 ↗ - 3The Peptide Semax Affects the Expression of Genes Related to the Immune and Vascular Systems in Rat Brain Focal Ischemia (Parent Compound)Dergunova LV, Limborska SA, et al. · BMC Genomics · 2014
Genome-wide analysis: Semax modulated 24 vascular genes at 3h and enhanced immune-response gene expression at 24h post-ischemia, demonstrating multi-pathway neuroprotection.
animalPubMed 24661604 ↗ - 4Effects of Semax on the Default Mode Network of the Brain (Parent Compound)Dolgorukova AM, Klyushnik TP, Gusev EI, et al. · Bulletin of Experimental Biology and Medicine · 2018
24 healthy volunteers; resting-state fMRI showed increased default mode network volume in medial frontal cortex after intranasal 1% Semax vs placebo, enhancing episodic memory.
reviewPubMed 30225715 ↗ - 5The Efficacy of Semax in the Treatment of Patients at Different Stages of Ischemic Stroke (Parent Compound)Gusev EI, Barskov IV, et al. · Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova · 2018
110 ischemic stroke patients; Semax (6000 mcg/day intranasal) increased BDNF plasma levels and accelerated functional recovery, providing the clinical basis for Adamax neuroprotective applications.
reviewPubMed 29798983 ↗