Cognitive Stack
Two nootropic research peptides. Semax (NACL-PGP) and Selank (TKPRPGP).
2 vials · Bacteriostatic water sold separately
What's in this stack
Why this stack
Semax and Selank are the two best-known products of the same programme at the Institute of Molecular Genetics in Moscow, and they are paired here because their pharmacology is complementary rather than overlapping. Both are short peptides carrying a C-terminal Pro-Gly-Pro extension, and that tail is a deliberate design element rather than an accident of sequence: it resists aminopeptidase cleavage and gives both molecules a usable duration that their parent fragments do not have.
Semax is an analogue of ACTH(4-10) with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its published mechanism centres on neurotrophic signalling, with reported increases in BDNF and TrkB expression in rodent hippocampus alongside effects on NGF, dopaminergic and serotonergic transmission. The pharmacologically important point is that it retains the neurotropic activity of the parent ACTH fragment while being devoid of its corticotropic activity, so it does not drive adrenal steroidogenesis.
Selank is an analogue of tuftsin, the immunomodulatory tetrapeptide Thr-Lys-Pro-Arg derived from the Fc region of immunoglobulin G, again with the Pro-Gly-Pro extension. Its research literature concerns GABAergic transmission, reported changes in GABA-A receptor subunit gene expression, inhibition of enkephalin degradation in plasma, and immunomodulatory activity inherited from its tuftsin parentage.
The honest caveat applies to both and should be read before either. Almost the entire evidence base is Russian-language, originates from a small cluster of affiliated institutions, and has been replicated only sparsely in independent Western laboratories, with very few placebo-controlled trials indexed in the major English-language databases. Both compounds are registered pharmaceuticals in Russia and neither holds a marketing authorisation in the UK, the EU or the US.
Both ship as stable lyophilised powders requiring bacteriostatic water reconstitution (sold separately). Each vial carries its own batch-specific certificate of analysis. Research use only, see CoA for lot-specific purity data.
How to use
- Reconstitute each peptide using bacteriostatic water (sold separately) per the lot-specific CoA instructions.
- Store reconstituted peptides at 2-8°C, use within 30 days of mixing.
- Research use only. See CoA for purity data.
Stack FAQ
Why are Semax and Selank studied together?
They come from the same laboratory and share a design principle but target different systems. Semax is an ACTH(4-10) analogue whose published mechanism centres on BDNF and NGF signalling; Selank is a tuftsin analogue whose mechanism centres on GABAergic transmission and enkephalin stability. Both carry a C-terminal Pro-Gly-Pro extension for protease resistance, which is why they are so often described as a pair, but their pharmacology is complementary rather than overlapping.
What is the difference between Semax and Selank?
Semax research concerns neurotrophic signalling and cognitive endpoints, and it is registered in Russia for stroke and cognitive indications. Selank research concerns anxiolytic activity, GABA-A receptor subunit expression and immunomodulation via its tuftsin parentage, and it is registered in Russia for generalised anxiety disorder. Neither holds a marketing authorisation in the UK, the EU or the US.
How reliable is the evidence base for these two compounds?
It should be treated with caution. Almost the entire published literature on both compounds is Russian-language and originates from a small cluster of affiliated institutions, with sparse independent replication in Western laboratories and very few placebo-controlled trials indexed in the major English-language databases. That is a genuine limitation and it is stated here rather than left out.
Can I buy these peptides individually instead?
Yes. Every component in this stack is also sold as a standalone vial on our shop. The stack price reflects a discount applied when the components are purchased together.
Will the stack ship as one parcel?
Yes. All vials in a stack ship together in a single Royal Mail Tracked parcel from our UK facility. Same-day dispatch on orders placed before 2pm GMT.
Do I get a separate Certificate of Analysis for each peptide?
Yes. Each component vial includes its own batch-specific HPLC-UV/MS Certificate of Analysis. CoAs are also published on each individual product page.