Selank (Tuftsin Analogue, TKPRPGP)
A seven-residue peptide built on the tuftsin tetrapeptide with a C-terminal Pro-Gly-Pro extension, CAS 129954-34-3. The same stabilising tail that appears on Semax, applied to a different parent sequence.
Pricing and pack sizes
| Size | Cat. no. | Pack | Price per kit | Per vial |
|---|---|---|---|---|
| 5 mg | SK5 | 10 vials | $43.00 | $4.30 |
| 10 mg | SK10 | 10 vials | $60.00 | $6.00 |
| 30 mg | SK30 | 10 vials | $135.00 | $13.50 |
Prices are in USD and are per kit of 10 vials — not per vial. Both figures are shown so the two can be compared directly. Larger quantities, mixed kits and custom synthesis are quoted on request.
Monograph
| Compound | Selank — tuftsin analogue, heptapeptide |
|---|---|
| CAS Registry Number | 129954-34-3 |
| Molecular Formula | C33H57N11O9 |
| Monoisotopic Mass | 751.9 Da |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP) |
| Residue Count | 7, linear, free termini |
| Purity | ≥ 99.0% (RP-HPLC, UV 220 nm) |
| Identity Confirmation | ESI-MS, theoretical mass match |
| Available pack sizes | 5 mg, 10 mg, 30 mg — supplied as 10 vials per kit |
| Appearance | White to off-white lyophilized cake or powder |
| Solubility | Soluble in water and aqueous buffers |
| Storage | −20 °C, desiccated, protected from light |
| Documentation | Lot-specific COA with HPLC chromatogram and MS spectrum |
What Selank is
Tuftsin is a tetrapeptide (Thr-Lys-Pro-Arg) fragment of immunoglobulin G, described decades ago as an immunomodulatory sequence. Selank takes that four-residue core and appends Pro-Gly-Pro — the same C-terminal tail carried by Semax.
The tail is there for stability. Proline-rich C-termini resist peptidase attack, and the Pro-Gly-Pro motif in particular has been used as a half-life extension in several Russian-developed peptides. Practically, it means Selank survives longer in solution than bare tuftsin, which is why the two are not interchangeable as analytical standards.
Both termini are free and there are no disulfide bonds, so identity rests on a single mass match at 751.9 Da. The molecule is strongly basic — three of the seven residues are arginine or lysine — so it elutes late on a standard C18 gradient and can carry residual TFA ion-pairing that shifts retention between runs.
Regulatory status
Selank is a registered medicinal product in Russia, where it is approved for clinical use. It is not approved by the FDA, EMA, MHRA, TGA, or any other Western regulator, and it is not licensed for import as a medicine in the United States, the European Union, the United Kingdom, or Australia.
As with Semax, this creates a different customs profile from the compounds that are not medicines anywhere. A product that is an approved drug somewhere is treated differently from a research chemical. Buyers should confirm that import for their intended use is lawful in their own country before ordering.
We supply Selank as a chemical reference standard, not as a medicine, and make no representation that it is lawful to import for any purpose in any country.
Research context
Summarises mechanisms reported in preclinical and in-vitro literature, for scientific orientation only. Not a description of any approved or established clinical application.
Peptidase resistance from the Pro-Gly-Pro tail
The most measurable claim is stability rather than activity: proline-rich C-termini slow enzymatic degradation relative to the bare tuftsin sequence. This is testable in plasma or buffer systems and does not require a biological readout.
Neurotrophin and GABAergic observations
Rodent and cell studies report changes in BDNF expression and modulation of GABAergic signalling, largely from a small number of research groups. Independent replication in Western journals is limited.
Note on evidence status
There is a Russian regulatory dossier and a body of Russian-language clinical literature, but little independent replication elsewhere. Both facts should inform how much weight the mechanism claims carry.
Analytical verification
- Purity — RP-HPLC. C18 column, acetonitrile/water with 0.1% TFA, UV 220 nm, acceptance ≥ 99.0%.
- Identity — ESI-MS. Deconvoluted mass against 751.9 Da. A value near 500 Da indicates bare tuftsin rather than Selank.
- Counter-ion. The peptide is strongly basic and typically supplied as the acetate; reported on the COA because it affects net peptide content.
Look up your lot in the COA registry for the chromatogram and mass spectrum.
Frequently asked questions
What is the sequence of Selank?
Thr-Lys-Pro-Arg-Pro-Gly-Pro, seven residues, 751.9 Da. The first four residues are the tuftsin core; Pro-Gly-Pro is the stabilising tail.
Is Selank the same as tuftsin?
No. Tuftsin is the tetrapeptide Thr-Lys-Pro-Arg. Selank adds Pro-Gly-Pro, which changes both the mass (751.9 vs roughly 500 Da) and the peptidase resistance.
Is Selank an approved drug?
In Russia, yes. It is not approved by the FDA, EMA, MHRA or TGA. It is supplied here as a chemical reference standard for in-vitro research, with no representation about import legality in any country.
What purity do you guarantee?
≥ 99.0% by RP-HPLC per released lot. The measured value for your lot appears on its certificate of analysis.
What pack sizes are available?
5 mg, 10 mg and 30 mg vials, supplied as 10 vials per kit. Prices per kit are listed on this page; larger or mixed orders are quoted on request.
How should lyophilized Selank be stored?
−20 °C, desiccated, protected from light — stable for 24 months from the assay date. Ambient is acceptable during transit only.
Is Selank approved for human use in my country?
Almost certainly not. Outside Russia it is not approved by any major regulator, and we supply it strictly as a reference standard for in-vitro laboratory research.
Research use only
This product is a chemical reference standard intended exclusively for in-vitro laboratory research and analytical method development. It is not a pharmaceutical, drug, food, food additive, cosmetic, or veterinary product, and is not supplied for therapeutic use in any jurisdiction. It must not be administered to humans or animals.