This is a working overview of lyophilized, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-03-08. Anything still debated is marked as such rather than presented as settled.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Calculated for the free peptide |
| Molecular weight | About 751.9 g/mol | Derived from the sequence |
| Appearance | White to off-white powder | Typical lyophilised form |
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Posterior pituitary In the hypothalamic–pituitary–adrenal axis, neurohypophysial hormones are released from the posterior pituitary, which is actually a prolongation of the hypothalamus, into the circulation.
Only a few troops were directly registered and the practice was soon discontinued with new "mixed" groups being encouraged to join the WOSM member organization of their country of residence. In 1955, only two such groups were still active, a troop in Iraq that disbanded that year, and the first group to be so registered, the International Troop 1 in Yokohama. The only remaining directly registered Troop is the International Boy Scouts, Troop 1 located in Yokohama, Japan. Temporary recognition was extended to Scouts in displaced persons camps after World War II. In 1947, at WOSM's 11th conference the "Displaced Persons Division" of WOSM's bureau was established to register and support Scouts in displaced person camps in Austria, Northern Italy, and Germany. These Scouts did not receive the right of WOSM membership but gained recognition as Scouts under WOSM's bureau until they took up residence in a country that had a recognized national Scout organization, which they could join. The D.P. Division was closed on 30 June 1950.
== See also == Animal testing on invertebrates Microbiome in the Drosophila gut Eating behavior in Insects (Measurement) Fruit flies in space Genetically modified insect Gynandromorphism JETLAG gene List of Drosophila databases Spätzle (gene) Time flies like an arrow; fruit flies like a banana Transgenesis Zebrafish – another widely-used model organism in scientific research Enhancer-FACS-seq
=== Membrane spanning === α-Helices are also the most common protein structure element that crosses biological membranes (transmembrane protein), presumably because the helical structure can satisfy all backbone hydrogen-bonds internally, leaving no polar groups exposed to the membrane if the sidechains are hydrophobic. Proteins are sometimes anchored by a single membrane-spanning helix, sometimes by a pair, and sometimes by a helix bundle, most classically consisting of seven helices arranged up-and-down in a ring such as for rhodopsins (see image at right) and other G protein–coupled receptors (GPCRs). The structural stability between pairs of α-Helical transmembrane domains rely on conserved membrane interhelical packing motifs, for example, the Glycine-xxx-Glycine (or small-xxx-small) motif.
== External links == Kristin Tillotson, "Minnesota Opera co-commissions Cold Mountain, Minneapolis Star Tribune (Artcetera blog), 6 May 2014 Heidi Waleson, "Creating Cold Mountain: Student Singers Help to Shape a Major Modern Opera", Overtones (Curtis Institute of Music), Spring 2014 Cold Mountain, Opera Philadelphia page "Cold Mountain makes East Coast Premiere February 5–14, 2016, at the Academy of Music." Opera Philadelphia press release, 5 January 2016 Tom Huizenga, "Great Expectations: A New Season Of New Music". National Public Radio (Deceptive Cadence blog), 3 September 2014 "Jennifer Higdon writes an opera", The Musicalist podcast, 12 February 2014 Jim Cotter, "Jennifer Higdon on Cold Mountain". WRTI, 90.1 FM, 16 November 2012 Mark Gresham, "Jennifer Higdon completes her new opera, Cold Mountain". EarRelevant blog, 17 September 2013 Pentatone Records page on Cold Mountain Peter Dobrin, "Cold Mountain scores", The Philadelphia Inquirer, Blogs the Arts, 16 May 2016
Sources: en.wikipedia.org
== Physical activity == The Global Matrix 2.0 on Physical Activity for Children and Youth (2016) gave Thailand a score of D-minus (A=best, B-C-D, F=worst). The only other ASEAN country in the study of 38 nations was Malaysia, which received a score of D.
In the process prior to filling and sealing, individual bottles are always rinsed with deionised water to remove any particles that could cause a change in taste. Deionised and distilled water are used in lead–acid batteries to prevent erosion of the cells, although deionised water is the better choice as more impurities are removed from the water in the creation process.
== 3-Dimensional proximity-based technology (YoctoReactor technology) == The YoctoReactor (yR) is a 3D proximity-driven approach which exploits the self-assembling nature of DNA oligonucleotides into 3, 4 or 5-way junctions to direct small molecule synthesis at the center of the junction. Figure 5 illustrates the basic concept with a 4-way DNA junction.
=== Addiction === PCP is self-administered and induces ΔFosB expression in the D1-type medium spiny neurons of the nucleus accumbens, and accordingly, excessive PCP use is known to cause addiction. PCP's rewarding and reinforcing effects are at least partly mediated by blocking the NMDA receptors in the glutamatergic inputs to D1-type medium spiny neurons in the nucleus accumbens. PCP has been shown to produce conditioned place aversion and conditioned place preference in animal studies.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.
Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.
Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.