What Selank is
Selank is a synthetic heptapeptide built from tuftsin — an endogenous immunomodulatory tetrapeptide — extended with a Pro-Gly-Pro tripeptide tail. That tail is the functional design decision: the proline-rich terminus resists exopeptidase cleavage, which is what makes an otherwise short and fragile sequence stable enough to be usable as a research tool. The same Pro-Gly-Pro strategy appears in Semax, which is built on an ACTH fragment instead.
- SelankTuftsin analogue with a Pro-Gly-Pro tail
- GABAergic and monoamine systemsNo single receptor identified
- Altered GABA-A expression, serotonin turnoverMechanism incompletely characterised
- Anxiolytic modelsPreclinical, plus Russian clinical work
Mechanism as described in published research. Nothing here describes an effect in a person — these compounds are supplied for laboratory research use only.
Neuropeptide signalling
Selank is studied predominantly in anxiolytic models, and the mechanistic literature associates it with GABAergic signalling and with modulation of monoamine systems. It is also examined for effects on BDNF expression — brain-derived neurotrophic factor — which is the point of overlap with Semax, and the reason the two are so frequently studied as a pair despite different origins.
Its tuftsin derivation gives it a second research literature in immunomodulation, since tuftsin itself is an immune-active fragment. That dual character — a neuropeptide with an immunological parent — is unusual and accounts for a good deal of the interest.
What the literature covers
Research areas include:
- Anxiolytic models — behavioural work in animal models.
- BDNF expression — shared endpoint with Semax.
- GABAergic and monoamine modulation — the proposed mechanistic route.
- Immunomodulation — following from the tuftsin parent sequence.
See the complete guide to research peptides for how the cognitive and neuropeptide class fits the wider catalogue.
Identity and verification
Selank has the molecular formula C33H57N11O9 and a molecular weight of 751.9 g/mol (CAS 129954-34-3). Identifiers matter more here than in most categories: research compounds are sold under trade names, development codes and abbreviations that do not always refer to the same molecule, and a formula is unambiguous where a name is not.
The lot we currently hold measured 99.43% for the 10 mg (lot 261807), tested by Freedom Diagnostics. The certificate is published in full, including the raw chromatogram and mass spectrum — so the number can be read off the underlying trace rather than taken on trust.
We use two laboratories because purity and identity are different questions. Vanguard Laboratory is ISO/IEC 17025:2017 accredited (A2LA #6377.01.01) and reports chromatographic purity and net quantity with a stated measurement uncertainty. Freedom Diagnostics reports HPLC-UV purity together with LC-MS identity confirmation — the test that catches a substituted compound rather than merely an impure one. A sample can be 99% pure and still be the wrong molecule. How we test →
Handling, reconstitution and storage
Selank ships lyophilized — freeze-dried to a solid and sealed under vacuum — which is what makes it stable in transit rather than a solution racing a clock. Reconstitute with bacteriostatic water, added slowly down the inside wall of the vial rather than directly onto the powder, then swirled gently. Do not shake: mechanical shear is one of the few things that reliably degrades a peptide in the lab.
Final concentration is a function of the volume added, not of the compound, so the same vial can be prepared at very different concentrations. The reconstitution calculator works out the volume for a target concentration and the reconstitution guide covers the procedure. Store lyophilized vials at −20 °C (−4 °F) protected from light; refrigerate once in solution, and see the storage and stability guide for how long reconstituted material holds.
Common questions
What is Selank derived from?
Tuftsin, an endogenous immunomodulatory tetrapeptide, extended with a Pro-Gly-Pro tail. The tail resists exopeptidase cleavage, which is what makes the molecule stable enough to work with.
How does Selank relate to Semax?
Both are Russian-developed synthetic peptides using the same Pro-Gly-Pro stabilising strategy, and both are studied for effects on BDNF expression. Their parent sequences differ — Selank comes from tuftsin, Semax from an ACTH(4–10) fragment — so they are usually examined as a comparison pair.
Why does Selank have both neurological and immune literature?
Because its parent peptide, tuftsin, is immunologically active. Selank inherits that context while being studied predominantly as a neuropeptide, which is an unusual combination and part of the research interest.
What does the Pro-Gly-Pro tail do?
It resists cleavage by exopeptidases, which attack peptides from the ends. Without it the core sequence would degrade too quickly to be a practical research tool.
Where to get it
Buy research-grade Selank — independently tested, certificate published, shipped from Miami with cold-chain packaging. Current pricing for every size is on the price list, and we ship worldwide.
Research use only
Everything referenced here is supplied strictly for laboratory research. These compounds are not drugs, foods, cosmetics or medical devices, are not for human or veterinary use, and are not approved for diagnostic or therapeutic application. Mechanisms are described as studied in preclinical and laboratory research; nothing above describes dosing, treatment or clinical outcome.
