Cognitive · ACTH 4-10 analog · Compounded 503A
Semax: nootropic peptide for focus, BDNF, and neuroprotection.
Semax is a synthetic peptide derived from ACTH (4–10) developed at the Russian Academy of Sciences. It has been used clinically in Russia since the 1990s for stroke recovery and cognitive dysfunction. Its appeal is robust BDNF upregulation — the same growth factor driving exercise's brain benefits — within hours of intranasal dosing.
What Semax is
Semax is a heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) derived from amino acids 4–10 of adrenocorticotropic hormone (ACTH), with the C-terminal Pro-Gly-Pro added for metabolic stability. Unlike full ACTH, Semax has no significant cortisol-stimulating activity.
Semax has been used in Russian clinical practice for ischemic stroke, optic nerve atrophy, and cognitive impairment since the late 1990s. Outside Russia it is investigational and dispensed through compounding pharmacies for off-label use.
Patient-reported effects are usually focus, mental energy, and clarity within an hour of intranasal dosing — with cumulative effects on stress resilience over weeks.
How it works
Semax robustly upregulates BDNF (brain-derived neurotrophic factor) and NGF (nerve growth factor) — the two most important neurotrophins for synaptic plasticity, learning, and resilience after injury. BDNF rises measurably within hours of intranasal dosing.
It modulates dopaminergic and serotonergic tone in the prefrontal cortex and limbic system — the likely mechanism behind the focus and mood effects patients describe.
Semax also inhibits enkephalin-degrading enzymes, raising endogenous enkephalin tone. This is the mechanism behind its stress-resilience and analgesic properties.
What patients use it for
Focus and attention
The most-reported acute effect — improved task focus, working memory, and clarity within 30–60 minutes of intranasal dosing.
BDNF and neuroplasticity
Robust BDNF upregulation supports synaptic plasticity, learning, and the same long-term brain changes driven by exercise and SSRIs.
Stress resilience
By raising enkephalin tone, Semax buffers the cognitive impact of acute stress and supports recovery from chronic stress states.
Stroke and TBI recovery
The Russian clinical literature supports use after ischemic stroke; the mechanism (BDNF upregulation, neuroprotection) is also relevant to TBI rehab.
Evidence summary
Dolotov OV et al. (Journal of Neurochemistry, 2006) demonstrated that Semax upregulates BDNF mRNA expression in the rat hippocampus — the foundational mechanism paper for current cognitive interest.
Gusev EI et al. (Stroke, 2006) reported clinical efficacy of Semax in acute ischemic stroke in a Russian multicenter trial, with improvement in neurological recovery metrics.
Most peer-reviewed clinical literature is Russian-language and pre-dates current Western trial standards. Western RCT replication is limited. Honest framing: substantial clinical use base, modest peer-reviewed Western data.
Dosing and clinical context
General clinical context only. Kindr Health physicians determine the appropriate dose and protocol for each patient based on history and labs. This is not a prescription or dosing recommendation.
Most commonly intranasal — typical regimens are 250–600 mcg per dose, 2–3 times daily during cognitive demand or recovery windows.
Course-based use (2–4 weeks on, then reassessment) is common. Higher doses are sometimes used in clinical stroke-recovery protocols.
Compounded Semax nasal spray from licensed 503A pharmacies is the standard U.S. dispensing pathway.
Safety and contraindications
Generally well-tolerated. The most reported side effect is mild nasal irritation from the intranasal spray.
No reported dependence, tolerance, or withdrawal.
Contraindications: pregnancy, lactation, active psychosis or mania, uncontrolled hypertension. Use under physician supervision.
Who it's typically considered for
- Adults with brain fog, attention difficulties, or post-illness cognitive recovery
- Patients in stroke or TBI rehabilitation under specialist supervision
- Perimenopausal patients with cognitive complaints driven by hormonal flux
- Patients seeking cognitive support without stimulant load
Frequently asked questions
Is Semax a stimulant?
No. Semax acts through BDNF upregulation and neurotransmitter modulation — not through catecholamine release. There is no comedown or stimulant tolerance pattern.
Is Semax FDA-approved?
No. Semax is approved in Russia for stroke recovery and cognitive indications but is investigational in the U.S. Compounded Semax is prepared by licensed 503A pharmacies for off-label use.
How quickly does Semax work?
Acute focus and clarity effects are typically reported within 30–60 minutes of intranasal dosing. BDNF-mediated cumulative effects build over 2–3 weeks.
Semax vs Selank — which one?
Semax activates and energizes — better for low energy, brain fog, or attention deficits. Selank calms and stabilizes — better for anxiety and overactivation. Some protocols alternate them.
Can I take Semax with caffeine?
Combination use is common in practice. Semax does not act through the adenosine or catecholamine systems caffeine uses, so the mechanisms are non-overlapping.
Does Semax help after stroke?
The Russian clinical literature supports use in acute ischemic stroke for neurological recovery. Western trial data is limited; stroke use should be specialist-supervised.
Is Semax safe long-term?
Short-course protocols are the norm in the Russian literature. Long-term Western safety data is limited. Periodic reassessment with your physician is appropriate.
Sources
- Dolotov OV et al. Semax, an analog of ACTH(4-10), regulates expression of BDNF and trkB. Journal of Neurochemistry (2006). — pubmed.ncbi.nlm.nih.gov/16805838
- Gusev EI et al. Neuroprotective effects of semax in acute ischemic stroke. Stroke (2006). — pubmed.ncbi.nlm.nih.gov/16282537
- Shadrina MI et al. Comparison of the temporary dynamics of NGF and BDNF gene expression in rat hippocampus, frontal cortex, and retina under Semax action. Neuroscience Letters (2010). — pubmed.ncbi.nlm.nih.gov/20307628
- Medvedeva EV et al. The peptide semax affects the expression of genes related to the immune and vascular systems. Frontiers in Pharmacology (2017). — pubmed.ncbi.nlm.nih.gov/28491036
Considering Semax?
A Kindr Health physician reviews every longevity intake — peptides are prescribed only when medically indicated based on your history and labs. There is no charge for the initial review.
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Medically reviewed by Dr. Ana Lisa Carr, MD, MBA
Board-Certified Family Medicine Physician · Lead Provider / Medical Reviewer
NPI 1689841744 · Last reviewed: May 10, 2026
Last reviewed May 10, 2026. Compounded medications are prepared by FDA-registered 503A pharmacies and are not FDA-approved drug products. Prescriptions require a clinical evaluation; a Kindr Health physician determines eligibility. Not for use in pregnancy. This page provides educational information and is not medical advice.