Educational reference, not medical advice. This page summarizes information from published research and regulatory filings for educational purposes. It is not a recommendation to use any compound and should not replace guidance from a licensed healthcare provider. Most peptides discussed here are not approved for the uses described.
What it is
Semax + Selank is a combination of two short peptides marketed within research-peptide channels as a "Russian nootropic" pairing. Both peptides were developed at the Institute of Molecular Genetics of the Russian Academy of Sciences in Moscow and are administered intranasally:
- Semax is a synthetic heptapeptide derived from ACTH(4-7) with a C-terminal Pro-Gly-Pro extension to resist enzymatic degradation. It has been approved in Russia since 1996 for ischemic stroke and cognitive indications.
- Selank is a synthetic heptapeptide based on the human immunoglobulin fragment tuftsin (Thr-Lys-Pro-Arg) with a Pro-Gly-Pro extension. It was approved in Russia in 2009 for generalized anxiety disorder.
The two peptides are commonly sold as separate vials and used in alternating or paired intranasal doses, rather than as a single co-formulated product, because both are dispensed as nasal sprays at low microgram concentrations.
History
Both peptides emerged from the same Russian research program on regulatory peptide fragments engineered for stability against amino- and carboxypeptidases:
- Semax was developed in the late 1980s by Ashmarin and colleagues and reached Russian approval in 1996. Most published clinical work appears in Russian-language journals (often translated in Zh Nevrol Psikhiatr Im S S Korsakova) and centers on ischemic stroke, transient ischemic attack, and cognitive recovery.
- Selank was developed in the 1990s as a tuftsin analog with anxiolytic activity. Russian Phase III work compared it with phenazepam (a benzodiazepine commonly prescribed in Russia) and reported comparable anxiolytic effect with a different side-effect profile.
Neither peptide has been submitted to the FDA or EMA for review. The combined-use convention is a research-peptide retail practice rather than a documented clinical program.
Regulatory status
- Russia: Semax is approved for ischemic stroke and certain cognitive indications; Selank is approved for generalized anxiety disorder.
- United States, European Union, most jurisdictions: neither peptide is approved for any indication. Sales in these markets are through research-chemical channels labeled not for human use.
The combination as a product has no regulatory standing.
How researchers describe its action
- Semax is described in published mechanism work as an upregulator of neurotrophic gene expression, including brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), and as a modulator of inflammatory gene transcription after focal cerebral ischemia (Medvedeva et al., BMC Genomics 2014; Dergunova et al. 2021). It does not bind ACTH-relevant melanocortin receptors at the doses studied.
- Selank is described as an anxiolytic acting through modulation of GABAergic transmission and through effects on the serotonergic and noradrenergic systems. Filatova et al. (2017) showed Selank affects the expression of GABA-receptor-related genes in human neuroblastoma cells.
Whether the two peptides interact pharmacologically when administered together has not been formally studied. The shared Pro-Gly-Pro stabilization tail and shared intranasal route are the technical commonalities; mechanism-wise the peptides act on distinct pathways.
Half-life and dosing intervals
Both peptides have very short circulating half-lives — measured in minutes — but the practical duration of central effect is longer due to intranasal delivery and the persistence of downstream signaling.
- Semax: approximately 2–5 minutes circulating, with reported behavioral effects lasting several hours.
- Selank: approximately 2–10 minutes circulating, with reported anxiolytic effects lasting hours.
Russian product labels for Semax (0.1%) describe 1–4 drops per nostril 1–3 times daily for stroke recovery; for Selank (0.15%), 1–3 drops per nostril 1–3 times daily for generalized anxiety. Per-dose mass is in the low microgram range.
Reconstitution example
Both peptides are commonly supplied as lyophilized powders to be reconstituted as intranasal sprays. A typical 5 mg vial of Semax reconstituted with 2.5 mL of bacteriostatic water yields a 0.2% solution (2 mg/mL); one drop from a standard nasal applicator (~0.05 mL) delivers approximately 100 mcg.
For Selank, a 5 mg vial reconstituted with 3.3 mL of bacteriostatic water yields a 0.15% solution; one drop delivers roughly 75 mcg.
Both products require refrigeration after reconstitution and are typically used within 2–4 weeks.
What to know
- Two separate products. Although marketed as a "stack" in some retail channels, Semax and Selank are typically supplied as separate intranasal vials and used in alternating or paired doses.
- Region-specific approval. Both peptides are approved as drugs only in Russia. They have no approval in the United States, the European Union, or most other jurisdictions.
- Mostly Russian-language evidence. Most clinical data appears in Russian-language journals; English-language pharmacology and mechanism work is more limited but growing.
- Storage. Refrigerate lyophilized vials. After reconstitution, refrigerate and use within the manufacturer's stated window — typically 2–4 weeks for intranasal preparations.
- Reported side effects. Russian post-marketing data describes mild nasal irritation as the most common adverse event for both peptides. Long-term combined safety has not been characterized outside Russia.
Sources
- 1.Medvedeva EV et al. (2014). The peptide semax affects the expression of genes related to the immune and vascular systems in rat brain focal ischemia. BMC Genomics.
- 2.Gusev EI et al. (2018). The efficacy of semax in the treatment of patients at different stages of ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova.
- 3.Medvedev VE et al. (2014). A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders. Zh Nevrol Psikhiatr Im S S Korsakova.
- 4.Filatova E et al. (2017). GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells. Frontiers in Pharmacology.