If you have been reading about freeze-thaw 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.
Updated 2025-12-30. Numbers and descriptions here follow the published literature rather than marketing material.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Stabilized analog of tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Monoisotopic mass about 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in common polar solvents |
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
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.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
He argued that the two food products are made of the same ingredient and that genetically speaking, soybeans are from China, though the specific variety was never mentioned. Food journalist Andreas Maryoto supported this idea, saying that tempeh might have been accidentally produced as the by-product of the tofu industry in Java in the 17th century, as discarded soybeans caught the spores of a whitish fungus that was found to be edible. In 2025, Zaelani formalized this as the "Okara-Tempe Hypothesis", proposing that tempeh originated from okara (tofu residue) that was naturally fermented before being adapted to whole soybeans. However, tahu was (and is still) made of white soybeans (Glycine max, native to Japan and China), as opposed to the earliest version of tempe dhele that was made of native black soybeans (Glycine soja). Tahu (tofu) made its way to Kediri in the 13th century and was consumed by the Mongolians who arrived in Java. Later, it was popular only among the rich (the complex production process and imported white soybeans led to its high price). Around the 17th or 19th century, tahu became available to everyone. Tempeh later began to be made with white soybeans, leading to the decreased use of its native black variety. Black soybeans have been replaced by other commodity plants since. The original version of tempe dhele has been forgotten as tahu has become the common people's food, and dependence on imported white soybeans grows.
In June 1884, Jan Gerrit Bantjes (1843–1914) discovered signs of gold at Vogelstruisfontein (the first gold sold directly to Cecil Rhodes at Bantjes's camp for £3,000) followed in September by the Struben brothers at Wilgespruit near Roodepoort which started the Witwatersrand Gold Rush and modern-day Johannesburg. The first gold mines of the Witwatersrand were the Bantjes Consolidated Mines. By 1886 it was clear that there were massive deposits of gold in the main reef. Increasingly Uitlanders (non-Afrikaner European expatriates and settlers, mainly from Britain but also including other Europeans, Americans and Australians), had come into the republic in search of employment and fortune. The discovery of gold made the Transvaal overnight the richest and potentially the most powerful nation in southern Africa, but it attracted so many Uitlanders (in 1896 approximately 60,000) that they quickly outnumbered the Boers (approximately 30,000 white male Boers). Fearful of the Transvaal's losing independence and becoming a British colony, the Boer government adopted policies of protectionism and exclusion, to include restrictions requiring Uitlanders to be resident for at least four years in the Transvaal to obtain the franchise, or right to vote. They heavily taxed the growing gold mining industry which was more dominated by incoming Uitlanders. Due to this taxation, the Uitlanders became increasingly resentful and aggrieved about the lack of representation.
At least 18 microbial VOCs (MVOCs) have been characterized including 1-octen-3-ol (mushroom alcohol), 3-Methylfuran, 2-pentanol, 2-hexanone, 2-heptanone, 3-octanone, 3-octanol, 2-octen-1-ol, 1-octene, 2-pentanone, 2-nonanone, borneol, geosmin, 1-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol, and thujopsene. The last four are products of Stachybotrys chartarum, which has been linked with sick building syndrome.
Subsequently, some defensins can aggregate to form 'channel-like' pores; others might bind to and cover the microbial membrane in a 'carpet-like' manner. The net outcome is the disruption of membrane integrity and function, which ultimately leads to the lysis of microorganisms. Some defensins are synthesized as propeptides which may be relevant to this process. Alpha defensins of the mouse bowel were historically called cryptdins when first discovered.
Sources: en.wikipedia.org
=== Antiandrogens === Antiandrogens are a class of drug which bind and inhibit the androgen receptor, blocking the growth- and survival-promoting effects of testosterone on certain prostate cancers. Flutamide and bicalutamide are antiandrogens which are frequently used in the treatment of prostate cancer, either as long-term monotherapy, or in the initial few weeks of GnRH analog therapy. (See also Androgen deprivation therapy)
== Models == Several theoretical models and possible mechanisms of de novo gene birth have been described. The models are generally not mutually exclusive, and it is possible that multiple mechanisms may give rise to de novo genes. An example is the type III antifreeze protein gene, which originates from an old sialic acid synthase (SAS) gene, in an Antarctic zoarcid fish.
===== Explantation deformity ===== The autologous fat graft replacement of breast implants (saline and silicone) resolves medical complications such as: capsular contracture, implant shell rupture, filler leakage (silent rupture), device deflation, and silicone-induced granulomas, which are medical conditions usually requiring re-operation and explantation (breast implant removal). The patient then has the option of surgical or non-implant breast corrections, either replacement of the explanted breast implants or fat-graft breast augmentation. Moreover, because fat-grafts are biologically sensitive, they cannot survive in the empty implantation pocket, instead, they are injected to and diffused within the breast-tissue matrix (recipient site), replacing approximately 50% of the volume of the removed implant – as permanent breast augmentation. The outcome of the explantation correction is a bust of natural appearance; breasts of volume, form, and feel, that – although approximately 50% smaller than the explanted breast size – are larger than the original breast size, pre-procedure.
=== United Kingdom === The National Health Service (NHS) makes several treatments available for people with sickle cell disease. These include pain management, antibiotics, and vaccinations to reduce the risk of infection, and blood transfusions where appropriate. Other treatments include Voxelotor which reduces the need for blood transfusions, and the gene therapy Casgevy. In England, a number of regional centres coordinate treatment for sickle cell disease and other haemoglobinopathies.
=== Bone === Leptin's role in regulating bone mass was identified in 2000. Leptin can affect bone metabolism via direct signalling from the brain. Leptin decreases cancellous bone, but increases cortical bone. This "cortical-cancellous dichotomy" may represent a mechanism for enlarging bone size, and thus bone resistance, to cope with increased body weight. Bone metabolism can be regulated by central sympathetic outflow, since sympathetic pathways innervate bone tissue. A number of brain-signalling molecules (neuropeptides and neurotransmitters) have been found in bone, including adrenaline, noradrenaline, serotonin, calcitonin gene-related peptide, vasoactive intestinal peptide, and neuropeptide Y. Leptin binds to its receptors in the hypothalamus, where it acts through the sympathetic nervous system to regulate bone metabolism. Leptin may also act directly on bone metabolism via a balance between energy intake and the IGF-I pathway. There is a potential for treatment of diseases of bone formation - such as impaired fracture healing - with leptin.
Sources: en.wikipedia.org
Interchim is a privately owned French company specialized in manufacturing and distribution of reagents, consumables and dedicated instruments for the R&D and industry laboratory in the fields of fine chemistry, chromatography and bio-analysis. It has become a provider of reference methods, products for analytics (analytical chemistry and bioassays) serving research and quality control in the biomedical field, pharmaceutical industry, but also cosmetics and environment.
While a variety of theories have been postulated for the etymological origins of Canada, the name is now accepted as coming from the St. Lawrence Iroquoian word kanata, meaning 'village' or 'settlement'. In 1535, Indigenous inhabitants of the present-day Quebec City region used the word to direct French explorer Jacques Cartier to the village of Stadacona. Cartier later used the word Canada to refer not only to that particular village but to the entire area subject to Donnacona (the chief at Stadacona); by 1545, European books and maps had begun referring to this small region along the Saint Lawrence River as Canada. From the 16th to the early 18th century, Canada referred to the part of New France that lay along the Saint Lawrence River. Following the British conquest of New France, this area was known as the British Province of Quebec from 1763 to 1791. In 1791, the area became two British colonies called Upper Canada and Lower Canada. These two colonies were collectively referred to as the Canadas until their union as the Province of Canada in 1841. Upon Confederation in 1867, Canada was adopted as the legal name for the new country at the London Conference and the word dominion was conferred as the country's title, reflecting its status as a self-governing nation within the British Empire.
== History == The origin of Aleppo soap is unknown. Unverified claims of its great antiquity abound, such as its supposed use by Queen Cleopatra of Egypt and Queen Zenobia of Syria. Although it has been claimed that soap-making was introduced to the West from the Levant after the First Crusades, in fact, soap was known to the Romans in the first century AD and Zosimos of Panopolis described soap and soapmaking in c. 300 AD. Today most Aleppo soap, especially that containing more than 16% of laurel oil (considered higher in quality), is exported to Europe and East Asia. In December 2024, the "craftsmanship of Aleppo Ghar soap" was recognized by UNESCO as an Intangible cultural heritage.
The two substrates of this enzyme are D-mannonic acid and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are D-mannuronic acid (shown in open-chain form), reduced NADH, and a proton. The enzyme can also use the alternative cofactor, nicotinamide adenine dinucleotide phosphate. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is D-mannonate:NAD(P)+ 6-oxidoreductase. Other names in common use include mannonate dehydrogenase, mannonate (nicotinamide adenine dinucleotide, (phosphate))dehydrogenase, mannonate dehydrogenase, mannuronate reductase, mannonate dehydrogenase (NAD(P)+), D-mannonate:nicotinamide adenine dinucleotide (phosphate, and oxidoreductase (D-mannuronate-forming)).
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.
It was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences, during the 1990s. Most published research originates from Russian institutions. Independent international replication remains limited.
Tuftsin is a natural tetrapeptide with the sequence Thr-Lys-Pro-Arg that participates in immune signaling. Selank extends that sequence with Pro-Gly-Pro at the C-terminus. The added residues are linked to greater resistance to enzymatic breakdown.
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.