If you have been reading about nootropic and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-06-02. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
| 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 |
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
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.
=== Central nervous system === Adropin is produced in the brain, particularly in the hypothalamus. The hypothalamus is a crucial region for the regulation of various physiological processes, including metabolism and energy balance. The presence of adropin in the brain suggests that it may have additional roles in the central nervous system, although the specifics are still being explored.
On March 11, 1997, National Semiconductor Corporation announced the US$550 million sale of a reconstituted Fairchild to the management of Fairchild with the backing of Sterling LLC, a unit of Citicorp Venture Capital. Fairchild carried with it what was mostly the Standard Products group previously segregated by Amelio. Incidentally, the effective price of acquisition of Cyrix was also US$550 million. On November 17, 1997, National Semiconductor and Cyrix announced the merger of the companies. Cyrix would become an autonomous wholly owned subsidiary. Halla had earlier emphasized that National was after the low-end CPU market as part of the system-on-a-chip pursuit and therefore would not place emphasis on Cyrix's current development of high-end 6x86MX design. However, Cyrix later announced that its merger with National Semiconductor would not change its development or marketing plans. The acquisition of an independent-minded Cyrix subsequently turned National Semiconductor from a collaborator into a competitor with Intel. National lost its business with Intel. Intel reinstated the relationship after the sale of Cyrix. The acquisition of Cyrix also carried with it a business obligation to use the IBM Microelectronics Division to fabricate the Cyrix chips, as well as technical constraint to do the same, while National Semiconductor had plans to transfer their fabrication to its South Portland fab. National incurred huge losses in its processor business and announced the sale of Cyrix to VIA in 1999.
== Distinguishing similar minerals == Pyrite is distinguishable from native gold by its hardness, brittleness and crystal form. Pyrite fractures are very uneven, sometimes conchoidal because it does not cleave along a preferential plane. Native gold nuggets, or glitters, do not break but deform in a ductile way. Pyrite is brittle, gold is malleable. Natural gold tends to be anhedral (irregularly shaped without well defined faces), whereas pyrite comes as either cubes or multifaceted crystals with well developed and sharp faces easy to recognise. Well crystallised pyrite crystals are euhedral (i.e., with nice faces). Pyrite can often be distinguished by the striations which, in many cases, can be seen on its surface. Chalcopyrite (CuFeS2) is brighter yellow with a greenish hue when wet and is softer (3.5–4 on Mohs' scale). Arsenopyrite (FeAsS) is silver white and does not become more yellow when wet.
Merchandising can be extremely lucrative too: The Lion King also sold $3 billion of merchandise, while Pixar's Cars—which earned $462 million in theatrical revenues and was only a modest hit by comparison to other Pixar films—generated global merchandise sales of over $8 billion in the five years after its 2006 release. Pixar had another huge hit with Toy Story 3, which generated almost $10 billion in merchandise retail sales in addition to the $1 billion it earned at the box office. On this chart, films are ranked by the revenues from theatrical exhibition at their nominal value, along with the highest positions they attained. Eight films in total have grossed in excess of $2 billion worldwide, with Avatar ranked in the top position. All of the films have had a theatrical run (including re-releases) in the 21st century, and films that have not played during this period do not appear on the chart because of ticket-price inflation, population size and ticket purchasing trends not being considered.
Bullae (blisters) Crepitus (palpable gas in tissues) Reduced or absent sensation over the skin of the affected area Ecchymosis (bruising) that progresses to skin necrosis. This is because the skin changes color from red to purple and black due to clotting blood vessels Rapid progression to shock despite antibiotic therapy is another indication of necrotizing fasciitis. However, those who are immunocompromised may not show typical symptoms. This includes but is not limited to patients with:
Sources: en.wikipedia.org
== Preservatives == Frozen products do not require any added preservatives because microorganisms do not grow when the temperature of the food is below −9.5 °C (15 °F), which is sufficient on its own in preventing food spoilage. Long-term preservation of food may call for food storage at even lower temperatures. Carboxymethylcellulose (CMC), a tasteless and odorless stabilizer, is typically added to frozen food because it does not adulterate the quality of the product.
=== 2019 recall of Ranitidine products === In 2019, Dr. Reddy's recalled all ranitidine products in the US market due to contamination with the carcinogen N-nitrosodimethylamine (NDMA). Months later, all brands of ranitidine were recalled and it was taken off the US market, as the carcinogen was an unavoidable byproduct.
== Metabolism == The bacteria rely on the enzyme glycerol-3-phosphate dehydrogenase (GPDH). GPDH is an alternative when managing electrons that are produced during metabolism. In the absence of the electron transport chain, T. pallidum uses GPDH to recycle the NAD+ by oxidizing glycerol-3-phosphate to dihydroxyacetone phosphate and make NAD+ to keep glycolysis and other redox-dependent energy reactions. By doing this, it helps balance the ATP yield without weighing down the protein's limited supply for essential tasks. T. pallidum uses an enzyme called pyrophosphate-dependent phosphofructokinase rather than ATP as a way to save energy and optimize its limited resources. T. pallidum manages without a complete tricarboxylic acid cycle and oxidative phosphorylation by using different efficient strategies including redox balancing and substrate-level to survive the nutrient-limited host environment. T. pallidum lacks enzyme orthologs for superoxide dismutase, however it does possess a superoxide reductase, maintaining the ability to reduce reactive oxygen species. In addition, T. pallidum encodes an alkyl hydroperoxide reductase C, which allows for the reduction of hydrogen peroxide to water and alcohols. This enzyme relies on TP0919, a protein present in the cytoplasm of T. pallidum. T.pallidum primarily relies on glucose as its primary carbon source through glycolysis, but one study has proposed the bacterium uses an acetogenic-energy conservation pathway as a way to catabolize D-lactate as an alternative carbon source.
=== Shortage === In the US, some compounding pharmacies prepare compounded versions of a drug on the FDA's drug shortages list if the compounded drug meets certain conditions detailed in federal law. The US Food and Drug Administration (FDA) declared a shortage of tirzepatide in December 2022. It declared the shortage over in October 2024, but enforcement was delayed until the end of 2024, after a lawsuit by compounding pharmacies challenged the declaration. The US National Association of Boards of Pharmacy says there are tens of thousands of online pharmacies operating out of compliance with state and federal regulations or the association's recommendations. The FDA has not evaluated these for safety and effectiveness and they are thus considered not to have been shown to be safe or effective.
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.
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.