Semax (NA-Semax)
Synthetic ACTH Analog · Nootropic & Neuroprotective Peptide
Overview
Semax is a synthetic heptapeptide derived from adrenocorticotropic hormone (ACTH) fragment 4-10, originally developed in Russia for stroke recovery. It achieves 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).
Improved short-term and working memory performance in fatigued individuals (71% vs 41% accuracy).
sustained attention during demanding cognitive tasks.
Faster acquisition of new information and improved retention.
Mechanism
Semax is a synthetic heptapeptide derived from adrenocorticotropic hormone (ACTH) fragment 4-10, originally developed in Russia for stroke recovery. It achieves 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).
Improved short-term and working memory performance in fatigued individuals (71% vs 41% accuracy).
Research areas
- Semax is a synthetic heptapeptide derived from adrenocorticotropic hormone (ACTH) fragment 4-10, originally developed in Russia for stroke recovery. It achieves 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).
- Improved short-term and working memory performance in fatigued individuals (71% vs 41% accuracy).
- sustained attention during demanding cognitive tasks.
- Faster acquisition of new information and improved retention.
Research notes
- 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
References
- pubmed.ncbi.nlm.nih.gov/29798983/
- pubmed.ncbi.nlm.nih.gov/30225715/
- pubmed.ncbi.nlm.nih.gov/24661604/
- pubmed.ncbi.nlm.nih.gov/16996037/
- pubmed.ncbi.nlm.nih.gov/9173745/
Questions
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…
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…
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.