Selank + Semax Blend: Research Guide (10+10mg)
By UK Peptide Lab Research Team•19 September 2026•5 min read
Key Takeaways
- The vial co-formulates two heptapeptides at 10mg each: Selank (tuftsin analogue, 751.9 g/mol) and Semax (ACTH(4-10) analogue, 813.7 g/mol). The near-identical molecular weights make the equal-mass blend close to equimolar.
- Both compounds come from one design programme: a C-terminal Pro-Gly-Pro tail stabilising a short active fragment, tuftsin in Selank and the ACTH(4-10) core in Semax.
- The component literatures are separate and largely Russian in origin: enkephalinase inhibition and GABAergic gene expression for Selank, BDNF/trkB upregulation and ischaemia models for Semax. The blend itself has never been studied as a combination.
- Supplied for in-vitro laboratory research only: no dosing information, no human-use claims, no therapeutic promises.
What is in the Blend?
This is a pre-blended vial co-formulating two Russian-designed heptapeptides at 10mg each. Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is a synthetic analogue of tuftsin, the immunoglobulin-derived tetrapeptide; it carries CAS 129954-34-3 and a molecular weight of 751.9 g/mol. Semax (Met-Glu-His-Phe-Pro-Gly-Pro) is a synthetic analogue of the ACTH(4-10) fragment, CAS 80714-61-0, 813.7 g/mol. Because the two molecular weights differ by only 62 g/mol, the 10+10 vial is close to equimolar, roughly 13.3 µmol of Selank against 12.3 µmol of Semax. UK Peptide Lab supplies Selank + Semax 10+10mg as lyophilised powder for in-vitro laboratory research only.
Two Compounds, One Design Programme
Both peptides come from the Institute of Molecular Genetics of the Russian Academy of Sciences, and they share one design strategy. Each carries a C-terminal Pro-Gly-Pro extension added to protect a biologically active message fragment from rapid enzymatic degradation. In Selank the protected fragment is tuftsin, the tetrapeptide first described by Najjar and Nishioka (Nature, 1970). In Semax it is Met-Glu-His-Phe, the core of ACTH(4-10). The shared tail is why the pair is so often studied side by side: identical stabilisation chemistry, different parent biology, and largely non-overlapping reported endpoints.
The Two Literatures
Each component has its own evidence base, and the blend has none of its own. The Selank literature centres on anxiety-related mechanisms: Zozulya and colleagues reported inhibition of enkephalin-degrading enzymes (Bull Exp Biol Med, 2001), and Volkova and colleagues reported altered expression of GABAergic neurotransmission genes in rat brain (Front Pharmacol, 2016). The Semax literature centres on neurotrophin biology and neuroprotection: Dolotov and colleagues reported increased BDNF protein, trkB phosphorylation and BDNF mRNA in rat hippocampus (Brain Res, 2006), and Romanova and colleagues reported reduced infarct volume in a rat model of focal cerebral ischaemia (Bull Exp Biol Med, 2006). Vyunova and colleagues later reviewed the molecular pharmacology of Selank (Protein Pept Lett, 2018).
Reading the Evidence Honestly
Two caveats belong up front. The primary literature for both compounds is overwhelmingly Russian in origin, much of it from the institutes that designed the molecules, and independent Western replication is sparse. And while Selank and Semax are frequently studied alongside one another, no controlled study has evaluated this specific co-formulation, so any expectation of combined behaviour is an assumption rather than a published finding. Neither compound holds a marketing authorisation from the MHRA, EMA or FDA, and no dosing information is offered here.
Laboratory Handling and UK Sourcing
Store the lyophilised vial at -20°C, protected from light and moisture, and hold reconstituted solution at 2-8°C. Handle the blend to the standard of its more fragile component: the N-terminal methionine of Semax is oxidation sensitive, so minimise headspace and stopper-open time, and never shake or vortex. The current vial is supplied as batch UKPL-9517, supplier-tested with per-component content verified, with the certificate published on the product page and independent third-party verification pending. Same-day UK dispatch on orders placed before 2pm GMT, free Royal Mail Tracked shipping over £45. In-vitro laboratory research use only, not for human consumption.
Related Products
Disclaimer: This article is for research and educational purposes only. All information provided is not intended as medical advice. UK Peptide Lab products are not for human consumption and are sold strictly for laboratory research use only.
Frequently Asked Questions
Are Selank and Semax the same peptide?
No. They share a C-terminal Pro-Gly-Pro stabilising tail and a common design origin, but Selank is a tuftsin analogue (Thr-Lys-Pro-Arg-Pro-Gly-Pro) and Semax an ACTH(4-10) analogue (Met-Glu-His-Phe-Pro-Gly-Pro), with different parent biology and separate literatures.
Has the Selank and Semax blend been studied as a combination?
No controlled study has evaluated this specific co-formulation. The two are frequently studied alongside one another, but combination data do not exist, and expectations of combined behaviour are assumptions rather than published findings.
Is this blend 1:1?
It is 1:1 by mass and close to 1:1 by moles, because 751.9 and 813.7 g/mol differ by only 62 g/mol: 10mg of each gives roughly 13.3 µmol of Selank and 12.3 µmol of Semax, a molar ratio near 1.08 to 1.
References
- [1] 'Tuftsin': a natural phagocytosis stimulating peptide. Nature (1970). View →
- [2] The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity. Bull Exp Biol Med (2001). View →
- [3] Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission. Front Pharmacol (2016). View →
- [4] Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Brain Res (2006). View →
- [5] Neuroprotective and antiamnesic effects of Semax during experimental ischemic infarction of the cerebral cortex. Bull Exp Biol Med (2006). View →
- [6] Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity. Protein Pept Lett (2018). View →