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 2025-10-20. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analog of the tetrapeptide tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Reported consistently across pharmacopoeial descriptions |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| Solubility | Freely soluble in water | Aqueous buffers; poor in nonpolar solvents |
| Typical storage temperature | -20 degrees Celsius | Lyophilized powder; protect from moisture |
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.
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 hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Seltorexant, also known by its developmental code names MIN-202 and JNJ-42847922, is an orexin antagonist medication which is under development for the treatment of depression, insomnia, and Alzheimer's disease. It is a selective antagonist of the orexin OX2 receptor (2‑SORA). The medication is taken orally.
=== Lactogenesis III === Prolactin and oxytocin are vital for establishing milk supply initially; however, once the milk supply is well established, the volume and content of the milk produced are controlled locally. Although prolactin levels are higher on average among breastfeeding mothers, prolactin levels themselves do not correlate to milk volume. At this stage, production of milk is triggered by milk drainage from the breasts. The only way to maintain milk supply is to drain the breasts frequently. Infrequent or incomplete drainage of the breasts, decreases blood flow to the alveoli and signals the milk-producing cells to produce less milk. Breast pumps are often used to drain the breasts when the infant is not feeding. A condition called Mastitis sometimes occurs in this stage, resulting from incomplete milk drainage. The Academy of Breastfeeding Medicine recommends against trying to "empty" the breasts, whether through pushing the baby to feed more or through over use of a breast pump, to prevent causing milk oversupply.
Adenosine production and lack of ammonia overproduction seem to strongly suppress rhabdomyolysis down to the purine nucleotide energy charge level, where the cell is able to signal pain, or where individual muscle fibers start cramping (fail to relax from contraction in sync with the rest of the muscle), or the whole muscle fails to contract (when walking quickly downhill), allowing the person to appropriately modulate the exertion. Most of the AMP probably spills into blood unchanged, and is gradually returned to the muscle cell, if its concentration there falls due to gradual recharge to ATP. The blood thus plays a role of a big AMP buffer. Idle muscles may also take up some free AMP. The spillover also limits, how much the residual AMPD activity can be amplified in this state. Thus, it may take the residual AMPD activity less time to build up citric acid cycle intermediates, when the whole body is warmed up for an exercise at the same time, rather than a specific group of muscles needed in the exercise. In case of leg muscles, where circulation is substantially dependent on their cyclical contraction when the body is upright, a small but useful degree of initial up-regulation of the citric acid cycle may be achieved just by standing still for a few minutes. It is most useful when a long period of rest, or sitting in a vehicle, must be followed by brisk walking. If the person keeps standing still for longer, rather than restoring circulation in the leg muscles (e.g.
=== Aroma === Aroma compounds giving B. edulis mushrooms their characteristic fragrance include some 100 components, such as esters and fatty acids. In a study of aroma compounds, 1-octen-3-one was the most prevalent chemical detected in raw mushrooms, with pyrazines having increased aroma effect and elevated content after drying.
Sources: en.wikipedia.org
==== Physical performance ==== Amphetamine is used by some athletes for its psychological and athletic performance-enhancing effects, such as increased endurance and alertness; however, non-medical amphetamine use is prohibited at sporting events that are regulated by collegiate, national, and international anti-doping agencies. In healthy people at oral therapeutic doses, amphetamine has been shown to increase muscle strength, acceleration, athletic performance in anaerobic conditions, and endurance (i.e., it delays the onset of fatigue), while improving reaction time. Amphetamine improves endurance and reaction time primarily through reuptake inhibition and release of dopamine in the central nervous system. Amphetamine and other dopaminergic drugs also increase power output at fixed levels of perceived exertion by overriding a "safety switch", allowing the core temperature limit to increase in order to access a reserve capacity that is normally off-limits. At therapeutic doses, the adverse effects of amphetamine do not impede athletic performance; however, at much higher doses, amphetamine can induce effects that severely impair performance, such as rapid muscle breakdown and elevated body temperature.
amplification of the CCND1 gene / overexpression of cyclin D1; chromosomal translocation of the CCND1 gene; mutations in the degradation motif recognized by the CRL4-AMBRA1 E3 ubiquitin ligase; disruption of nuclear export and proteolysis of cyclin D1; induction of transcription by oncogenic Ras, Src, ErbB2 and STATs; Cyclin D1 overexpression is correlated with shorter cancer patient survival and increased metastasis. Amplification of the CCND1 gene is present in:
=== Disputed roles === There has been a long discussion that lysine, when administered intravenously or orally, can significantly increase the release of growth hormones. This has led to athletes using lysine as a means of promoting muscle growth while training, however, no significant evidence to support this application of lysine has been found to date. Because herpes simplex virus (HSV) proteins are richer in arginine and poorer in lysine than the cells they infect, lysine supplements have been tried as a treatment. Since the two amino acids are taken up in the intestine, reclaimed in the kidney, and moved into cells by the same amino acid transporters, an abundance of lysine would, in theory, limit the amount of arginine available for viral replication. Clinical studies do not provide good evidence for effectiveness as a prophylactic or in the treatment for HSV outbreaks. In response to product claims that lysine could improve immune responses to HSV, a review by the European Food Safety Authority found no evidence of a cause–effect relationship. The same review, published in 2011, found no evidence to support claims that lysine could lower cholesterol, increase appetite, contribute to protein synthesis in any role other than as an ordinary nutrient, or increase calcium absorption or retention.
Sources: en.wikipedia.org
=== Gender === Women typically make up some 80% of autoimmune disease patients. Whilst many proposals have been made for the cause of this high weighting, no clear explanation is available. A possible role for hormonal factors has been suggested. For example, some autoimmune diseases tend to flare during pregnancy (possibly as an evolutionary mechanism to increase health protection for the child), when hormone levels are high, and improve after menopause, when hormone levels decrease. Women may also naturally have autoimmune disease trigger events in puberty and pregnancy. Under-reporting by men may also be a factor, as men may interact less with the health system than women.
== Gameplay == Sven Co-op is a first-person shooter based on Half-Life, using its GoldSrc game engine. The modification enables a server to be hosted, so many players can cooperate (along with any allied non-player characters) to complete levels against creatures and other enemies that are controlled by the computer. The modification was initially based around the levels from Half-Life, but since have expanded to include the other Half-Life games and user-made levels. Multiple levels may be connected to make a longer campaign by the level designer. The game can also be played in single-player mode, taking advantage of improvements over the original Half-Life that were made by the modifications, particularly the artificial intelligence used by non-player characters.
==== Eyes ==== Rattlesnake eyes, which contain many rod cells, are well adapted to nocturnal use. Rattlesnakes, though, are not exclusively nocturnal, and their vision is more acute during daylight conditions. Rattlesnakes also possess cone cells, which means they are capable of some form of color vision. The rattlesnake eye lacks a fovea, making vision of sharply defined images impossible. Instead, they mostly rely on the perception of movement. Rattlesnake eyes are capable of horizontal rotation, but they do not appear to move their eyeballs to follow moving objects.
Sources: en.wikipedia.org
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.
The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.
It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.