Selank is a synthetic 7-amino-acid peptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) built on tuftsin, a natural fragment of the antibody protein immunoglobulin G, with a stabilising Pro-Gly-Pro tail. It comes from the same research programme as Semax, is registered for clinical use in Russia only, and is not approved by the FDA, EMA or MHRA.
What is Selank?
Selank is a synthetic peptide seven amino acids long: Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP).
Its first four residues – Thr-Lys-Pro-Arg – are tuftsin, a naturally occurring tetrapeptide. Tuftsin is not a brain molecule by origin: it is a fragment released from an antibody protein (immunoglobulin G) and is studied mainly for its effects on immune cells such as macrophages. It was named after Tufts University, where it was characterised.
As with Semax, a Pro-Gly-Pro tail was attached. The purpose is the same: tuftsin on its own is broken down quickly by enzymes, and the tail slows that down considerably, giving the molecule a usable working life.
This origin is worth sitting with, because it is often glossed over. Selank’s parent molecule is an immune peptide, and much of the research on it examines immune signalling alongside nervous-system measures. A molecule described online purely in terms of the brain has an immunological family tree.
Key facts at a glance
| Type | Synthetic heptapeptide (7 amino acids) |
|---|---|
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP) |
| Design basis | Tuftsin (TKPR), extended with a Pro-Gly-Pro tail |
| Parent peptide origin | Tuftsin is a fragment of immunoglobulin G, studied in immunology |
| Molar mass | ~751.9 g/mol (free peptide) |
| Appearance | White lyophilised (freeze-dried) powder |
| Regulatory status | Registered for clinical use in Russia; NOT approved by the FDA, EMA or MHRA |
This page does not print a CAS number: the value differs with salt form, which also shifts the mass a laboratory observes. Take it from the certificate for the batch in hand.
What the research has actually examined
The Selank literature is smaller than Semax’s and similarly concentrated. Most of it is rodent work and gene-expression analysis. Read the “Model” line first.
Volkova et al., 2016, Frontiers in Pharmacology
Model: rat brain tissue, gene-expression analysis
Researchers measured expression of genes involved in GABAergic signalling – the system built around GABA, the main inhibitory (calming) signalling molecule in the brain – and reported changes in a subset of those genes after the peptide was given.
Limitations: rats, not humans; measures gene expression, an upstream molecular event, not a behavioural or clinical outcome; single research group.
Konstantinopolsky et al., 2022, Bulletin of Experimental Biology and Medicine
Model: rats, experimental morphine-withdrawal model
Researchers scored observable withdrawal signs in rats and reported differences in those scores in the peptide-treated group relative to controls.
Limitations: rats; a specific pharmacological withdrawal model that does not generalise to other contexts; behavioural scoring in animals; published in a specialist regional journal without independent replication.
Fomenko et al., 2019, Bulletin of Experimental Biology and Medicine
Model: rats exposed to chronic experimental foot-shock stress; liver tissue examined
Rather than measuring brain endpoints, this study examined structural measurements in liver tissue in a chronic-stress model, reporting differences between groups.
Limitations: rats; an artificial chronic-stress protocol; tissue morphology measurements; small single-group study.
Panikratova et al., 2020, Doklady Biological Sciences
Model: functional brain-imaging study examining Selank and Semax
A connectivity-based imaging analysis examining measurable changes in brain-network signal associated with the two peptides.
Limitations: small exploratory imaging study; network-level signal is not a clinical outcome; specialist regional journal, not independently replicated at scale.
The honest summary: a modest, geographically concentrated literature, mostly rodent and gene-expression work, with one small imaging study. No large independent placebo-controlled human trials published in high-visibility international journals. Compared with Semax, the body of work is thinner still.
How researchers think it works
The mechanism most often described is GABAergic modulation. GABA is the brain’s principal inhibitory signal – the counterweight to excitatory signalling. The Volkova work reported changes in the expression of genes tied to that system in rat brain tissue, which is the basis for describing Selank as acting on GABA-related signalling. This remains an observation about gene expression in an animal model, not a demonstrated receptor-level mechanism.
A second thread follows the molecule’s origins: because tuftsin is an immune peptide, part of the literature examines immune signalling, including cytokine measurements. Some researchers frame Selank as acting at the interface between immune and nervous-system signalling, which would be consistent with its parentage.
As with Semax, the Pro-Gly-Pro tail is a confounder rather than a neutral addition: the same tail appears in Semax and has been reported to have activity of its own, so attributing measured effects specifically to the tuftsin portion is not straightforward.
All of this is mechanism observed in animal models. It explains why researchers study the molecule; it does not establish what it does in a person.
What is known about safety and regulatory status
- Registered in Russia, not in the West. Selank has been registered for clinical use in Russia. It is not approved by the FDA, the EMA or the MHRA and has not completed those processes. Different jurisdictions apply different evidentiary standards; a registration is not a transferable safety finding.
- No large independent human trial base. There is no set of large, well-controlled, independently replicated human trials in high-visibility international journals. Absence of reported harm is not demonstrated safety.
- Research material is not clinical material. A research-grade powder is manufactured under a different regime from a registered medicine, with no pharmaceutical oversight.
- The immune dimension is under-discussed. A molecule derived from an immune-signalling peptide, whose literature includes cytokine measurements, is not obviously “just” a calm-signalling compound. That is a reason for caution, not reassurance.
PeptSelect does not publish preparation or usage guidance for Selank, or for any peptide. Not as a legal formality – for a compound unapproved in this market, there is no such guidance that could responsibly be given.
How to verify what you actually received
Selank and Semax are both seven-residue peptides ending in the same Pro-Gly-Pro tail, which is precisely why the certificate matters: a name on a label does not distinguish them, but a mass does.
- Identity by mass – a mass-spectrometry result matching the expected mass for TKPRPGP in the stated salt form. Selank (~752) and Semax (~814) are clearly distinguishable by mass, so this check is decisive.
- Purity from a real chromatogram – an HPLC trace you can inspect; see reading a chromatogram and related substances.
- Net peptide content versus gross powder weight – see net peptide content.
- Batch matching and a named lab – see batch verification and why third-party testing matters.
Every PeptSelect batch is matched to a published third-party certificate in the COA Vault, and the full testing process is documented in How we test.
What is Selank in simple terms?
What is tuftsin?
Is Selank related to Semax?
What does GABAergic mean?
Is Selank approved anywhere?
How can Selank be distinguished from Semax on a certificate?
Every batch, published
Look up any batch identifier and read the third-party certificate it resolves to.
