What is Selank?
Selank is a synthetic heptapeptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro (PubChem CID 11765600). Its first four residues are the tetrapeptide tuftsin, followed by Pro-Gly-Pro (Semenova et al., 2008); tuftsin itself was first reported as a natural phagocytosis-stimulating peptide (Najjar and Nishioka, 1970). Published work on the Selank peptide covers enzyme assays in human plasma, rodent behavior, brain and spleen gene expression, brain-slice electrophysiology and a small number of human studies.
Selank is approved as a drug in Russia, where it is officially indicated for mild anxiety (Renke and Chinellato, 2026). The Selank that Disguised Alpha sells is a research-grade lyophilized peptide for laboratory use. It is not that medicine, it is not intended for any clinical use, and it is not for use in people.
Selank reference data
| Property | Value |
|---|---|
| Name | Selank |
| Aliases | TP-7, TKPRPGP (PubChem CID 11765600) |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro, free N-terminus and C-terminal acid (PubChem CID 11765600) |
| Peptide class | Tuftsin analog heptapeptide |
| Molecular formula | C₃₃H₅₇N₁₁O₉ |
| Molecular weight | 751.87 g/mol |
| CAS number | 129954-34-3 |
| Form | Lyophilized powder |
| Size carried | 10MG |
| Testing | Third-party tested, with the certificate for each lot published on the product page and in the COA portal |
Formula, molecular weight, CAS number and peptide class are from the Compound Information section of the Selank product page, and the 10 mg size is the labeled amount shown there; sequence and aliases are from PubChem (CID 11765600, which lists 751.9 g/mol and also records a diacetate form). Confirm identity and measured content against your lot's certificate.
What the research covers
Published work on Selank falls into six areas. Each summary below states the model used. Human studies used a Selank drug preparation, not the research material sold here.
Enkephalin-degrading enzymes and opioid signaling
In human plasma in vitro, Selank inhibited enzymatic hydrolysis of enkephalin with a half-maximal inhibitory concentration of about 15 µM, more potently than the peptidase inhibitors bacitracin and puromycin; the same report described shorter enkephalin half-life in the blood of patients with generalized anxiety disorder (Zozulya et al., 2001).
In human serum, Selank and Semax both inhibited enkephalin-degrading enzymes, and their pentapeptide fragments kept that activity while tri-, tetra- and hexapeptide fragments did not (Kost et al., 2001). In mice, Selank lengthened the plasma half-life of leu-enkephalin and changed open-field behavior in the BALB/c strain but not in C57Bl/6 mice (Sokolov et al., 2002).
GABAergic gene expression and synaptic activity
In rat frontal cortex, Selank or GABA changed the expression of 45 of 84 neurotransmission genes at 1 hour and 22 at 3 hours, with a positive correlation between the two treatments at 1 hour, which the authors read as consistent with allosteric modulation of the GABAergic system (Volkova et al., 2016).
In human IMR-32 neuroblastoma cells, Selank alone did not change mRNA levels of these genes, but with GABA it almost completely suppressed the changes GABA produced, and with olanzapine more genes changed than with olanzapine alone (Filatova et al., 2017). In rat hippocampal slices, Selank increased the amplitude and frequency of spontaneous inhibitory postsynaptic currents in CA1 pyramidal neurons, with no significant concentration dependence between 1 and 8 µM (Povarov et al., 2017).
Immune and inflammation gene expression
In mouse spleen, a single systemic administration of Selank changed the expression of 34 of 84 inflammation-related genes at 6 and 24 hours, including the immune regulator Bcl6 and its target genes (Kolomin et al., 2011). A time-course study found a 3-fold fall in complement C3 mRNA 30 minutes after Selank and similar changes after its Gly-Pro fragment, suggesting that the dipeptide contributes to the parent peptide's activity (Kolomin et al., 2014).
Rodent behavioral models
In outbred rats under naloxone-precipitated morphine withdrawal, Selank lowered the total withdrawal index by 39.6 percent, attenuated convulsive reactions, ptosis and posture disorders and raised the tactile sensitivity threshold 9-fold, performing slightly below diazepam in the same model (Konstantinopolsky et al., 2022). In rats under unpredictable chronic mild stress, anxiety-related measures in the elevated plus maze after combined Selank and diazepam did not differ from pre-stress values (Kasian et al., 2017).
Stability, metabolism and analytical identification
Studies with uniformly tritium-labeled peptide found that Selank is broken down in blood plasma mainly to Thr-Lys-Pro-Arg-Pro, Thr-Lys-Pro, Arg-Pro and Gly-Pro (Zolotarev et al., 2006). Its Pro-Gly-Pro tail places it among the glyproline peptides, which a review described as about as stable as major pharmacological preparations (Ashmarin et al., 2005). For identity testing, a medicines control laboratory that found Selank and Semax in seized preparations developed and validated a liquid chromatography tandem mass spectrometry screen covering ten such peptides (Vanhee et al., 2020).
Human studies
A randomized comparison in 62 patients with generalized anxiety disorder or neurasthenia assigned 30 to Selank and 32 to medazepam; the authors reported similar changes on anxiety rating scales in both groups and a rise in serum leu-enkephalin half-life in the Selank group, mostly in generalized anxiety disorder (Zozulia et al., 2008). In 52 healthy participants, resting-state functional MRI before and after Selank, Semax or placebo found group differences in connectivity between the right amygdala and right temporal cortex (Panikratova et al., 2020).
Key studies
- Zozulya AA, et al. "The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity." Bull Exp Biol Med. 2001. PMID 11550013. DOI 10.1023/a:1017979514274. Human plasma in vitro: enkephalinase inhibition, with a clinical cohort.
- Sokolov OY, et al. "Effects of Selank on behavioral reactions and activities of plasma enkephalin-degrading enzymes in mice with different phenotypes of emotional and stress reactions." Bull Exp Biol Med. 2002. PMID 12432865. DOI 10.1023/a:1015582302311. BALB/c and C57Bl/6 mice: plasma leu-enkephalin half-life and open-field behavior.
- Kolomin T, et al. "Expression of inflammation-related genes in mouse spleen under tuftsin analog Selank." Regul Pept. 2011. PMID 21609736. DOI 10.1016/j.regpep.2011.05.001. Mouse spleen: 84 inflammation-related genes by real-time PCR.
- Volkova A, et al. "Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission." Front Pharmacol. 2016. PMID 26924987. DOI 10.3389/fphar.2016.00031. Rat frontal cortex: 84 neurotransmission genes, Selank compared with GABA.
- Filatova E, et al. "GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells." Front Pharmacol. 2017. PMID 28293190. DOI 10.3389/fphar.2017.00089. Human neuroblastoma cell culture: gene expression alone and with GABA or olanzapine.
- Povarov IS, et al. "Effect of Selank on Spontaneous Synaptic Activity of Rat Hippocampal CA1 Neurons." Bull Exp Biol Med. 2017. PMID 28361410. DOI 10.1007/s10517-017-3676-3. Rat hippocampal slices: spontaneous inhibitory postsynaptic currents.
- Panikratova YR, et al. "Functional Connectomic Approach to Studying Selank and Semax Effects." Dokl Biol Sci. 2020. PMID 32342318. DOI 10.1134/S001249662001007X. Resting-state fMRI in 52 healthy participants.
- Konstantinopolsky MA, et al. "Selank, a Peptide Analog of Tuftsin, Attenuates Aversive Signs of Morphine Withdrawal in Rats." Bull Exp Biol Med. 2022. PMID 36322304. DOI 10.1007/s10517-022-05624-x. Outbred rats: naloxone-precipitated morphine withdrawal, compared with diazepam.
Handling and storage of lyophilized Selank
General laboratory practice for this material:
- Store the lyophilized powder at -20°C, protected from light, until use (storage guidance on the product page).
- Let the sealed vial reach room temperature before opening so moisture does not condense on the powder.
- Selank has no methionine or cysteine, so it lacks the sulfur oxidation risk of Semax; its lysine and arginine give it a net positive charge at neutral pH, which matters for buffer choice and surface adsorption.
- Plasma and tissue peptidases cleave Selank into smaller fragments (Zolotarev et al., 2006), and the Gly-Pro fragment has shown activity of its own in gene-expression work (Kolomin et al., 2014), so confirm stability in biological media over the experiment.
- After reconstitution, keep solutions at 2 to 8°C and protected from light, and split stock into single-use aliquots to avoid freeze/thaw cycles.
- Record the lot number and keep its certificate with your notes. For quantitative work, use the measured content on the certificate rather than the label mass.
Frequently asked questions
What is Selank?
Selank is a synthetic heptapeptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro (PubChem CID 11765600), that extends tuftsin with Pro-Gly-Pro (Semenova et al., 2008). It is studied in enzyme assays, rodent models, cell culture and gene-expression work.
What is the Selank peptide made of?
Seven amino acids: threonine, lysine, proline, arginine, proline, glycine and proline. The Thr-Lys-Pro-Arg portion is tuftsin, and the Pro-Gly-Pro tail is shared with Semax. In plasma it breaks down to fragments including Thr-Lys-Pro-Arg-Pro and Gly-Pro (Zolotarev et al., 2006).
How does Selank compare with Semax?
Semax (Met-Glu-His-Phe-Pro-Gly-Pro, PubChem CID 9811102) starts from an adrenocorticotropic hormone fragment instead of tuftsin. Both inhibited enkephalin-degrading enzymes in human serum (Kost et al., 2001) and were compared in one imaging study (Panikratova et al., 2020). See our Semax research guide.
Does Selank bind GABA or opioid receptors directly?
The evidence so far is indirect. Selank did not displace dopamine D2 or delta and mu opioid ligands from rat brain membranes, although naloxone blocked one of its behavioral effects in mice (Meshavkin et al., 2006), and in neuroblastoma cells it changed GABAergic gene expression only in the presence of GABA (Filatova et al., 2017). Authors have proposed allosteric modulation of the GABAergic system (Volkova et al., 2016) and inhibition of enkephalin-degrading enzymes (Zozulya et al., 2001).
How should Selank powder be stored?
Keep the lyophilized powder at -20°C and protected from light. After reconstitution, store the solution at 2 to 8°C, protected from light, and avoid freeze/thaw cycles, as listed on the product page.
Where can researchers buy Selank?
Disguised Alpha sells it for laboratory research, third-party tested with the certificate published on the product page: Selank (10MG).
Related compounds and guides
- Semax and its research guide
- Semax & Selank, a lyophilized blend of both peptides, and its research guide
- Adalank (NA-Selank Amidate) and its research guide
- COA portal: every published certificate, by lot
This product is for research use only. It has not been evaluated for safety or effectiveness in humans. Not for human consumption. All products are intended for laboratory research purposes only.