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Noopept vs Semax

Last updated: October 3, 2026 · 5 min read · By the Grey Peptides Editorial Board

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Grey Peptides
Grey Peptides Editorial Board
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Key takeaways
  • Noopept and semax are both approved as medicines only in Russia. Noopept is taken by mouth; semax is given as nasal drops.
  • Their human evidence comes mainly from small, open-label Russian studies in people with stroke or brain injury, not healthy people.
  • Neither is approved in the US, and their status in sport is unsettled.

Side by side

Noopept Medium and semax Medium are often mentioned together as Russian cognitive enhancers. They are chemically unrelated and work differently 1. The table is read from our encyclopedia entries.

FieldNoopeptSemax
Encyclopedia entryNoopept Full entrySemax Full entry
Molecule classPeptidomimeticPeptide
CategoryCognitiveCognitive
FDA statusNot FDA ApprovedNot FDA Approved
Approved elsewhereRussiaRussia
Evidence gradeMediumMedium
Half-life≈ 30 minutesNot measured in humans
FormulaC17H22N2O4C37H51N9O10S
Molecular weight318.4 g/mol813.9 g/mol
WADA 2026Unsettled (S0 may apply)Unsettled (S0 may apply)
WADA 2027Unsettled (S0 may apply)Unsettled (S0 may apply)
In one lineA Russian capped-dipeptide nootropic (omberacetam) with rodent memory data, two small open human studies, and a habit of turning up in US supplements.A synthetic ACTH-derived heptapeptide approved in Russia for stroke rehabilitation and optic nerve disorders, with documented BDNF upregulation and broad nootropic activity.
MechanismMetabolized to cycloprolylglycine (CPG), which upregulates BDNF and NGF expression in the hippocampus and cortex. Additional actions include modulation of AMPA and NMDA receptor function, inhibition of glutamate excitotoxicity, and anxiolytic effects mediated through the cholinergic system. In-vivo potency is approximately 1000× that of piracetam by weight.In rats, a single dose raised hippocampal BDNF protein 1.4-fold and exon III BDNF mRNA threefold, with more trkB activation, and intranasal doses raised basal-forebrain BDNF within three hours; it binds specific sites there. It increased striatal serotonin turnover and strongly amplified amphetamine's dopamine and locomotor effects. In rat stroke models it shifts immune-response gene expression. How these findings translate to people is not established.
Sources in the entry1013
Study cards811
Dosage pageNoneDosage page

Noopept: an oral drug that may work through a metabolite

Noopept is approved in Russia for cognitive impairment associated with organic brain disorders 1. Its clearest human study was open and prospective: in 60 stroke patients, 20 mg a day for two months improved MMSE scores and verbal fluency compared with controls (open human study) 2. In patients with cognitive problems after brain trauma or vascular disease, it shifted EEG rhythms in a pattern the authors considered typical of nootropics (human study) 3.

A curious finding shapes how it might work. An hour after injection in rats, noopept itself was undetectable in the brain; of its possible metabolites, only cyclo-prolylglycine rose, 2.5-fold (animal study) 4. In rats, a single dose lowered NGF and BDNF messenger RNA in the cortex but raised both in the hippocampus (animal study) 5. It also showed anticoagulant and clot-weakening activity in rats, as did its metabolite (animal study) 6, which matters for anyone on blood thinners.

Semax: a nasal ACTH fragment used after stroke

Semax is a stabilised fragment of ACTH given as nasal drops, approved in Russia and used in stroke and optic-nerve disease 1. In rats a single dose raised hippocampal BDNF by up to 1.4 times (animal study) 7. In 110 patients months after ischaemic stroke, courses alongside rehabilitation raised plasma BDNF, without blinding (human study) 8. In motor neuron disease, an open study found it did not change the disease course (human study) 9. An imaging study in 24 healthy adults found brief changes in brain network activity 10.

Comparing the evidence

Both rest on small studies, mostly open-label and mostly from Russian groups. Noopept's strongest human result is the 60-patient stroke study; semax's is the 110-patient rehabilitation study. Neither has a large, placebo-controlled, independent trial. Neither has been tested in healthy people as a cognitive enhancer, which is how both are mostly sold outside Russia. The mechanisms overlap at BDNF in rodent work, but noopept's effect may run largely through a metabolite, and semax through ACTH-related receptors.

Practical differences follow from form: noopept is a pill, semax a nasal drop. Noopept's rat data on clotting are a specific caution for anyone on anticoagulants 6; semax's small studies report few problems but were not designed to detect uncommon harms.

Questions to ask before choosing either

  • What problem am I trying to solve, and has either peptide been tested for it in a controlled trial?
  • Am I on anticoagulants or antiplatelet drugs? Noopept weakened clot stabilisation in rats 6.
  • Is the product the Russian pharmaceutical or an unlabelled research powder?
  • Am I subject to anti-doping testing, where the status of both is unsettled 1?
  • Would a doctor's assessment of memory or concentration problems find a treatable cause first?

How the differences add up (as of October 3, 2026)

Choosing between them on evidence is choosing between two thin files. Neither is approved in the US, EU, UK, Canada or Australia 1, and both have unsettled WADA status, because whether S0 applies depends on how their Russian approvals are treated 1. Our semax vs selank and cerebrolysin vs semax comparisons cover related questions. Doses on this page are those in our entries' sources, not recommendations.

Frequently asked questions

What is the difference between noopept and semax?

Noopept is an oral drug approved in Russia for cognitive impairment with brain disorders; semax is a nasal ACTH fragment approved there and used after stroke. They are chemically unrelated.

Is noopept or semax better for memory?

Neither has been tested for memory in healthy people in a controlled trial. Their human studies are small and mostly in stroke patients.

Are noopept and semax legal in the US?

Neither is FDA-approved. Both are approved as medicines only in Russia.

Sources

  1. Grey Peptides dataset records for noopept and semax (Russian approvals, FDA status, WADA status unsettled, studied doses as sourced on each entry); read October 3, 2026.
  2. Amelin, A. V., et al. (2011). [Noopept in the treatment of mild cognitive impairment in patients with stroke]. Zh Nevrol Psikhiatr Im S S Korsakova, 111(10 Pt 1), 44-6. PMID: 22500312
  3. Bochkarev, V. K., et al. (2008). [Clinical and electroencephalographic characteristic of noopept in patients with mild cognitive impairment of posttraumatic and vascular origin]. Zh Nevrol Psikhiatr Im S S Korsakova, 108(11), 47-54. PMID: 19008801
  4. Gudasheva, T. A., et al. (1997). The major metabolite of dipeptide piracetam analogue GVS-111 in rat brain and its similarity to endogenous neuropeptide cyclo-L-prolylglycine. Eur J Drug Metab Pharmacokinet, 22(3), 245-52. PMID: 9358206
  5. Ostrovskaya, R. U., et al. (2008). Noopept stimulates the expression of NGF and BDNF in rat hippocampus. Bull Exp Biol Med, 146(3), 334-7. PMID: 19240853
  6. Ostrovskaia, R. U., et al. (2002). [Multicomponent antithrombotic effect of the neuroprotective prolyl dipeptide GVS-111 and its major metabolite cyclo-L-prolylglycine]. Eksp Klin Farmakol, 65(2), 34-7. PMID: 12109290
  7. Dolotov, O. V., et al. (2006). Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Brain Res, 1117(1), 54-60. PMID: 16996037
  8. Gusev, E. I., et al. (2018). [The efficacy of semax in the tretament of patients at different stages of ischemic stroke]. Zh Nevrol Psikhiatr Im S S Korsakova, 118(3. Vyp. 2), 61-68. PMID: 29798983
  9. Serdiuk, A. V., et al. (2007). [The study of chronic partial denervation and quality of life in patients with motor neuron disease treated with semax]. Zh Nevrol Psikhiatr Im S S Korsakova, 107(4), 29-39. PMID: 18379501
  10. Lebedeva, I. S., et al. (2018). Effects of Semax on the Default Mode Network of the Brain. Bull Exp Biol Med, 165(5), 653-656. PMID: 30225715

Educational information, not medical advice. Each dose in this guide names its source, an approved label or a published study. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose.

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