Selank Pen
3 mL of the TKPRPGP heptapeptide, tuftsin with a Pro-Gly-Pro tail, in bacteriostatic water at 1 mg/mL, 3 mg per pen. Filled from a lot tested in the manufacturer’s own laboratory, with a certificate.
| Compound | Selank Tuftsin-Pro-Gly-Pro heptapeptide (TKPRPGP) |
|---|---|
| CAS number | 129954-34-3 |
| Molecular formula | C33H57N11O9 |
| Theoretical mass | 751.9 Da |
| Sequence / structure | H-TKPRPGP-OH (7 residues; free N- and C-termini) |
| Contents | Selank: 3 mg per 3 mL pen (0.1% w/v) |
| Form | Sterile aqueous solution in bacteriostatic water (0.9% benzyl alcohol), supplied in a 3 mL glass cartridge inside a preloaded autoinjector pen fitted with a needle |
| Storage, sealed | Store at 2–8 °C in the original carton, protected from light |
| Format | Solution in a 3 mL pre-filled pen |
Sizes and lots
- 3 mg · 1 pen — $38.99
- 3 mg · Kit of 10 — $346.62
Selank is the seven-residue peptide Thr-Lys-Pro-Arg-Pro-Gly-Pro, tuftsin with a Pro-Gly-Pro tail attached. In this listing it is already in solution: a preloaded autoinjector pen with a 3 mL cartridge at 1 mg/mL, 3 mg of peptide per pen. Research on Selank, largely Russian, has measured gene expression in the rat brain and set Selank beside related tuftsin peptides in rodent behaviour studies.
What is in the pen
Each pen carries a 3 mL glass cartridge of sterile aqueous solution. Selank makes up 0.1% w/v, which works out to 1 mg/mL and 3 mg per pen, dissolved in bacteriostatic water containing 0.9% benzyl alcohol as an antimicrobial preservative. The safety data sheet does not classify the peptide. It lists benzyl alcohol as harmful if swallowed or inhaled, a serious eye irritant and a possible cause of allergic skin reactions.
Store the pen at 2 to 8 °C in its original carton, protected from light, and keep it capped once it is in use. Never freeze it. A pen whose solution has frozen, changed colour or become cloudy should be discarded. The same peptide is sold dry as the Selank 5 mg vial, and the general trade-offs are covered in peptide pen vs vial.
What the research covers
Selank's first four residues are tuftsin, a peptide that later research treated as an immunomodulator; a 2017 review of 86 papers sorted tuftsin analogues by anti-tumour, anti-inflammatory, antimicrobial and antiviral activity1. The Selank work itself has moved toward the brain. In rats, Selank changed the expression of 45 of 84 neurotransmission genes in the frontal cortex at one hour and 22 at three hours, and those changes tracked the ones GABA produced, which led the authors to propose allosteric modulation of the GABAergic system2.
A solution raises a different question, about where the peptide ends up in the container. In a study of eight radiolabelled peptides held for 48 hours in glass and plastic tubes, recovery depended on the material and its coating, fell with siliconising and rose with added albumin3. Selank was not part of that study, and no measurement of Selank in a glass cartridge, or of its stability in bacteriostatic water, is among the references here. For the pen, the storage terms on the safety data sheet are the ones that apply.
Frequently asked questions
How does the pen differ from the Selank vials?
The vials contain freeze-dried Selank kept at −20 °C and dissolved by the laboratory when it is needed. The pen contains 3 mg already in bacteriostatic water at 1 mg/mL, stored at 2 to 8 °C, so its concentration is fixed from the start.
Why does the pen need refrigeration if Selank has no methionine?
Lacking methionine removes one oxidation route, not every way a solution can change. The safety data sheet sets 2 to 8 °C, protected from light and never frozen, and says to discard a pen whose solution has frozen, discoloured or turned cloudy.
References
- Siebert A, Gensicka-Kowalewska M, Cholewinski G, et al. Tuftsin - Properties and Analogs. Curr Med Chem. 2017;24(34):3711-3727. DOI · PubMed
- Volkova A, Shadrina M, Kolomin T, et al. Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission. Front Pharmacol. 2016;7:31. DOI · PubMed
- Goebel-Stengel M, Stengel A, Taché Y, et al. The importance of using the optimal plasticware and glassware in studies involving peptides. Anal Biochem. 2011;414(1):38-46. DOI · PubMed
For laboratory research use only. Not for human or veterinary consumption. Products have not been evaluated by the U.S. Food and Drug Administration and are not intended to diagnose, treat, cure or prevent any disease.