Semax
ACTH(4-10) analogue
A synthetic fragment of adrenocorticotropic hormone developed in Russia for cognitive and stroke recovery applications. Unusually for this field, it has human trials — mostly small and mostly Russian-language.
- Category
- Cognitive
- Half-life
- Minutes in plasma; central activity persists considerably longer
- Cycle length
- 5–10 days acute, or 3–4 weeks for sustained use
- Level
- intermediate
Overview
Semax was developed at the Institute of Molecular Genetics in Moscow from a fragment of ACTH, with the goal of retaining cognitive effects while removing the hormonal activity of the parent molecule. It has been used clinically in Russia for stroke recovery, transient ischaemic attack and cognitive decline, and it has a small but genuine human literature — a rarity among nootropic peptides.
How it works
Semax raises brain-derived neurotrophic factor (BDNF) and its receptor TrkB, particularly in the hippocampus. That is the accepted core mechanism. It also appears to modulate the dopaminergic and serotonergic systems and to influence gene expression in the CNS, which fits its described profile of improving attention and memory consolidation rather than producing stimulation.
Reported benefits
- Increased BDNF expression in the hippocampus
- Improved attention and working memory in human trials
- Reduced cognitive fatigue reports
- Neuroprotective effects in stroke models
Reported benefits describe what the published literature and user reports suggest — not a promise of outcome for any individual.
Dosing reference
Reported at 300–600 mcg per day, typically as intranasal drops or spray, divided into one to three administrations. A common pattern is one dose in the morning on arising and a second around midday.
Semax is usually described in short courses of five to ten days for acute cognitive effects, or longer courses of three to four weeks for sustained use. Intranasal administration is standard; the peptide has poor oral bioavailability.
Community-reported: 200–600 mcg intranasally, once or twice daily, in courses of one to two weeks, sometimes followed by a lower maintenance dose a few days a week.
These figures are what people report using in public communities. They have not been studied, verified or checked against certificates of analysis, and they are not a recommendation, a prescription or a target to aim for.
Where the reported amounts come from
Amounts are reproduced for education only. Doses from trials cannot be assumed to suit anyone else, and community-reported amounts are frequently wrong. Self-administering unapproved compounds carries serious risk.
The research picture
Human studies — small, predominantly Russian and rarely blinded to Western standards — report improvements in attention, memory and stroke recovery outcomes. The BDNF mechanism has solid animal support. The honest read: this is one of the better-evidenced cognitive peptides available, and that bar is still well short of a large Western randomised trial.
Primary sources
Preclinical & non-clinical data
Approved in Russia as a medication, with a Russian clinical literature covering stroke and cognitive disorders, and animal work on BDNF signalling. Outside that literature, replicated human trials are scarce — worth remembering when the approval is cited as proof of effect.
Non-clinical data comes from cells and animals unless stated otherwise. It answers whether a compound is worth studying in people — not whether it is safe or effective in them.
What users report
Nootropic communities describe short intranasal courses of five to fourteen days, with focus and verbal fluency that builds over the course and fades within days of stopping. The less flattering reports are equally common: irritability, headache, anxiety, and a minority who describe the opposite of the promised effect. Much of the detailed reporting originates from users in Russia and Eastern Europe, where the compound has been a registered medicine for years.
Where these reports come from
These are unverified personal accounts collected from public sources. They are not evidence of effectiveness or safety, they have not been independently checked, and they are not a recommendation to use anything described.
Possible side effects
- Nasal irritation with intranasal use
- Headache
- Transient anxiety reported anecdotally
- Insomnia if dosed late in the day
Safety notes
Semax is derived from ACTH but has been engineered to avoid adrenal stimulation — however, anyone with pituitary or adrenal disease should be cautious. Effects on blood pressure and coagulation have been reported in the literature. Do not use during pregnancy.
Stacking
Commonly stacked with Selank — Semax for drive and focus, Selank for anxiolytic effect. Also seen alongside cholinergic compounds such as alpha-GPC.
Related compounds
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Porcine brain-derived peptide preparation
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A peptide mixture from porcine brain, used clinically in some countries and unapproved in others.
DSIP
Delta sleep-inducing peptide — nine amino acids
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A sleep peptide from the 1970s whose human evidence never matched its name.
Dihexa
N-hexanoic-Tyr-Ile-(6) aminohexanoic amide — angiotensin IV analogue
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A cognitive-enhancement candidate with striking animal data and no human testing.