A practical reference on nootropic: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-03-18 and is reviewed periodically as new material appears.
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.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Modeled on tuftsin |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues |
| Approximate molecular mass | Around 750 Da | Depends on counter-ion and hydration |
| Common forms | Lyophilized powder | Also described as aqueous solution |
| Primary origin of research | Russian laboratories | Mid-1990s onward |
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
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.
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.
== Discovery == The first long-acting (depot) injections were antipsychotics fluphenazine and haloperidol. The concept of a depot injection arose before 1950, and originally was used to describe antibiotic injections that lasted longer to allow for less frequent administration.
In any case, suvorexant is a controlled substance in the United States due to concerns about the possibility of misuse. Besides its subjective side effects, suvorexant has been found to cause dose-dependent increases in serum cholesterol levels in clinical trials. These changes in cholesterol levels were +1.2 mg/dL at 10 mg, +2.3 mg/dL at 20 mg, +3.1 mg/dL at 40 mg, and +6.0 mg/dL at 80 mg relative to –3.7 mg/dL for placebo. Although the increases in cholesterol levels with approved doses of suvorexant (10–20 mg) are small, they could be important over a long duration of treatment. Early studies in rodents found that orexins (derived from Greek "orexis" meaning "appetite") stimulate appetite, feeding behavior, and weight gain while orexin receptor antagonists block these effects. However, subsequent animal studies were more mixed, with the effects being limited and depending on the animal strain. In humans, orexin receptor antagonists including suvorexant have not been found to affect body weight in rigorous clinical trials that lasted up to 12 to 14 months.
==== Necessary and sufficient conditions ==== Ajahn Brahm has argued that the Buddhist doctrine of conditionality includes two main elements of the logical concepts of conditionality: necessity and sufficiency. According to Brahm, "when this is, that is; from the arising of this, that arises." refers to a "sufficient condition" while "when this is not, that is not; from the ceasing of this, that ceases" refers to a "necessary condition". Like Brahm, Bodhi also argues that there are two main characterizations of conditionality in the early sources. One is positive, indicating "a contributory influence passing from the condition to the dependent state," while the other is negative, indicating "the impossibility of the dependent state appearing in the absence of its condition." He compares these two with the first and second phrases of the general principle definition respectively. Regarding the second, positive characterization, other early sources also state that a condition "originates (samudaya) the dependent state, provides it with a source (nidāna), generates it (jātika), gives it being (pabhava), nourishes it (āhāra), acts as its foundation (upanisā), causes it to surge (upayāpeti)" (see: SN 12.11, 23, 27, 66, 69). However, according to Harvey and Brahm, while the 12 nidanas are necessary conditions for each other, not all of them are necessary and sufficient conditions (some are, some are not). As Harvey notes, if this was the case, "when a buddha or arahat experienced feeling they would inevitably experience craving" (but they do not).
=== Adhesion molecules of the immune system === Springer began his research career in immunology by studying the molecular basis for cellular immunity using as an example the interaction of cytotoxic T lymphocytes with antigen-bearing target cells. None of the molecules involved in this interaction had yet been defined, including the long postulated antigen-specific T cell receptor. However, it was known that Mg2+ was required for immune cell-cell interactions, and that interaction between fibroblasts and the extracellular matrix was similarly Mg2+-dependent. Postulating that adhesion receptors were likely to be similar to antibodies and were unlikely to require magnesium, Springer hypothesized that other molecules must be required for antigen-specific interactions. He immunized animals with cytotoxic T lymphocytes and screened for monoclonal antibodies that blocked antigen-specific killing. Using this functional assay, his laboratory identified a set of lymphocyte function-associated (LFA) antigens required for cytotoxic T-cell-mediated killing and other T cell-dependent responses, including LFA-1 (CD11a/CD18), LFA-2 (CD2), and LFA-3 (CD58). Springer's group then identified ICAM-1 as a ligand for LFA-1, demonstrating that this interaction is required for efficient antigen recognition by cytotoxic T cells, and later discovered ICAM-2 (CD102) and ICAM-3 (CD50), which have two to five immunoglobulin (Ig)-like domains and comprise a subfamily of the Ig superfamily.
Sources: en.wikipedia.org
=== Designed nucleic acid systems === Scientists can encode digital information onto a single strand of synthetic DNA. In 2012, George M. Church encoded one of his books about synthetic biology in DNA. The 5.3 Mb of data was more than 1000 times greater than the previous largest amount of information to be stored in synthesized DNA. A similar project encoded the complete sonnets of William Shakespeare in DNA. More generally, algorithms such as NUPACK, ViennaRNA, Ribosome Binding Site Calculator, Cello, and Non-Repetitive Parts Calculator enables the design of new genetic systems. Many technologies have been developed for incorporating unnatural nucleotides and amino acids into nucleic acids and proteins, both in vitro and in vivo. For example, in May 2014, researchers announced that they had successfully introduced two new artificial nucleotides into bacterial DNA. By including individual artificial nucleotides in the culture media, they were able to exchange the bacteria 24 times; they did not generate mRNA or proteins able to use the artificial nucleotides.
Soon after inoculation, yeast begin to rapidly consume the available assimilable nitrogen with up to 46% of YAN being fully consumed by the onset of full fermentation. Because inorganic nitrogen, such as the ammonium salts in DAP, are toxic to yeast in high levels, it is never added during inoculation when the biomass of the newly re-hydrated yeast is low. Many winemakers split up the dosage of DAP with the first addition being made at the end of the lag phase when the yeast enter their period of exponential growth and alcoholic fermentation begins. In most must this is around 48 to 72 hours after inoculation. A second dosage is then often added around a third of the way through sugar fermentation and often before the sugar levels hit 12-10 Brix (6.5 to 5.5 Baumé, 48.3 to 40.0 Oechsle) because as the fermentation progresses yeast cells are no longer able to bring the nitrogen into the cell due to the increasing toxicity of ethanol surrounding the cells. This leaves the nitrogen unused and available for spoilage organisms that may come afterwards.
retention times of trailing and heading n-alkanes, respectively. NOTE: TPGC index does depend on temperature program, gas velocity and the column used ! ASTM method D6730 defines the temperature programmed chromatography Kovats index equation:
=== Biosensors === Biosensors can be used for quality control in laboratories and at different stages of food processing. Biosensor technology is one way in which farmers and food processors have adapted to the worldwide increase in demand for food, while maintaining their food production and quality high. Furthermore, since millions of people are affected by food-borne diseases caused by bacteria and viruses, biosensors are becoming an important tool to ensure the safety of food. They help track and analyze food quality during several parts of the supply chain: in food processing, shipping and commercialization. Biosensors can also help with the detection of genetically modified organisms (GMOs), to help regulate GMO products. With the advancement of technologies, like nanotechnology, the quality and uses of biosensors are constantly being improved.
The first injector pen, branded "Penject", was introduced in 1983 to administer insulin products, following trials begun in 1981 at Southern General Hospital, Scotland, initiated by Sheila Reith who has conceived the device, and funded by Diabetes UK. The invention was announced, and the preliminary trial described, in a January 1981 paper in The Lancet. The patent rights were later sold to Novo Nordisk by Greater Glasgow Health Board. After their introduction, insulin pens had a slow adoption in the United States, with only 2% of insulin being injected via pen in 1999. A major barrier to adoption in the United States was the increased up-front cost of insulin pens compared to traditional injections. Pen adoption in the United States accelerated after studies showed that the higher up-front cost of insulin pens was offset by the increase in compliance, which decreased overall healthcare costs. Historically, pen needles were manufactured in lengths up to 12.7mm. Over time, pen needles designed for insulin pens have become shorter, and a 4mm long needle is considered sufficient for most people to administer subcutaneously correctly. In 1989, an injector pen form of human growth hormone was licensed in New Zealand.
Sources: en.wikipedia.org
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.
It originates from research in Russia, associated with the Institute of Molecular Genetics of the Russian Academy of Sciences. The first descriptions date to the mid-1990s. Most published studies come from Russian laboratories.
No, Selank itself does not occur naturally. Its backbone is based on tuftsin, which is produced in the body, but the seven-residue version is a synthetic construct. It is supplied as a manufactured peptide.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.