Semax
Synthetic ACTH-derived neuropeptide · Also known as ACTH 4-10 analog, Semax 0.1%, N-acetyl semax amidate (NASA)
What is Semax?
A synthetic peptide based on a fragment of adrenocorticotropic hormone (ACTH 4-10) developed in Russia as a neuroprotective and nootropic agent. It is approved in Russia and Ukraine for stroke recovery and cognitive enhancement.
Semax was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences in the late 1980s. It has been approved in Russia for clinical use since the 1990s for conditions including ischemic stroke, dyscirculatory encephalopathy, optic nerve atrophy, and cognitive impairment. Russian clinical studies include a 110-patient stroke rehabilitation trial showing elevated BDNF levels and improved functional outcomes. While it lacks FDA approval or large Western RCTs, it has decades of clinical use in Russia and a strong safety profile.
Benefits & evidence
How it works
Semax is derived from ACTH but engineered to isolate cognitive and neuroprotective properties while eliminating hormonal (adrenal) activity. It rapidly increases brain-derived neurotrophic factor (BDNF) expression in the hippocampus, which supports neuronal survival, synaptic plasticity, and memory formation.
It also modulates multiple neurotransmitter systems, including dopaminergic and serotonergic pathways, and inhibits enkephalin-degrading enzymes, prolonging the activity of endogenous neuropeptides. Additionally, Semax has shown anti-inflammatory effects in brain tissue and may influence gene expression related to immune and vascular function, which contributes to its neuroprotective effects in ischemic conditions.
Dosing information
Typical dosing protocol
200-400 mcg intranasal, 1-2x daily
Weeks 1-2300-600 mcg intranasal, 1-2x daily
10-14 day cyclesRussian clinical guidelines use the 0.1% intranasal solution. Subcutaneous injection at 200-300 mcg daily is also used but has less clinical data behind it. Cycle 10-14 days on, then take a break. Consult your healthcare provider.
Side effects
Most side effects tend to improve as your body adjusts.