Everything below concerns heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-12-17. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
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.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
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.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
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.
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.
The British government did not recognize the settlement as a colony for fear of provoking a Spanish attack. This delay in government oversight enabled the settlers to establish their own laws and forms of government. During this period, a few settlers gained control of the local legislature, known as the Public Meeting, as well as of most of the settlement's land and timber. The British did not appoint their first superintendent over the Belize area until 1786. Throughout the 18th century, the Spanish attacked Belize every time war broke out with Britain. The Battle of St. George's Caye was the last of such military engagements, in 1798, between a Spanish fleet and a force of Baymen and their slaves. From 3 to 5 September, the Spaniards tried to force their way through Montego Caye shoal, but were blocked by defenders. Spain's last attempt occurred on 10 September, when the Baymen repelled the Spanish fleet in a short engagement with no known casualties on either side. The anniversary of the battle has been declared a national holiday in Belize and is celebrated to commemorate the "first Belizeans" and the defence of their territory taken from the Spanish empire.
== Causes == Most presentations of CTS have no known disease cause (idiopathic). The association of other factors with CTS is a source of notable debate. It is important to distinguish factors that provoke symptoms and factors that are associated with seeking care from factors that make the neuropathy worse. Genetic factors are believed to be the most important determinants of who develops carpal tunnel syndrome. In other words, one's wrist structure seems programmed at birth to develop CTS later in life. A genome-wide association study (GWAS) of carpal tunnel syndrome identified 50 genomic loci significantly associated with the disease, including several loci previously known to be associated with human height. Some other factors that contribute to carpal tunnel syndrome are conditions such as diabetes, alcoholism, vitamin deficiency or toxicity as well as exposure to toxins. Conditions such as these don't necessarily increase the interstitial pressure of the carpal tunnel. One case-control study noted that individuals classified as obese (BMI >29) are 2.5 times more likely than slender individuals (BMI <20) to be diagnosed with CTS. It is not clear whether this association is due to an alteration of pathophysiology, a variation in symptoms, or a variation in care-seeking.
"Candidatus Magnetoglobus multicellularis" is a species of multicellular magnetotactic bacteria (MMB). Samples of "Ca. M. multicellularis" were first collected at the Araruama Lagoon in Rio de Janeiro, Brazil. It has a multicellular structure and consists of an organised sphere of flagellated, gram-negative bacterial cells. As it has not yet been cultured under laboratory conditions, it retains the title Candidatus.
Sources: en.wikipedia.org
=== Victims === On 17 September 2008, Health Minister Chen Zhu stated tainted milk formula had "sickened more than 6,200 children, and that more than 1,300 others, mostly newborns, remain hospitalized with 158 suffering from acute kidney failure". By 23 September, about 54,000 children were reported to be sick and four had died. An additional 10,000 cases were reported from the provinces by 27 September. A World Health Organization official said 82% of the children made ill were 2 years of age or below. The Hong Kong Centre for Food Safety said that 99 per cent of the victims were aged under 3 years. Ten Hong Kong children were diagnosed with kidney problems, at least four cases were detected in Macau, and six in Taiwan. Non-human casualties included a lion cub and two baby orangutans which had been fed Sanlu infant formula at Hangzhou Zoo. The government said on 8 October it would no longer issue updated figures "because it is not an infectious disease, so it's not absolutely necessary for us to announce it to the public". Reuters compiled figures reported by local media across the country, and said the toll stood at nearly 94,000 at the end of September, excluding municipalities. Notably, 13,459 children had been affected in Gansu, Reuters quoted Xinhua saying Henan had reported over 30,000 cases, and Hebei also had nearly 16,000 cases. In late October, the government announced health officials had surveyed 300,000 Beijing families with children less than 3 years old.
For example, 5α-pregnane-3α,17α-diol-20-one has a hydrogen atom at the 5α position (hence the "5α-" prefix), two hydroxy groups (-OH) at the 3α and 17α positions (hence "3α,17α-diol" suffix) and an oxo group (=O) at the position 20 (hence the "20-one" suffix). However, erroneous use of suffixes can be found, e.g., "5α-pregnan-17α-diol-3,11,20-trione" [sic] — since it has just one hydroxy group (at 17α) rather than two, then the suffix should be -ol, rather than -diol, so that the correct name to be "5α-pregnan-17α-ol-3,11,20-trione". According to the rule set in the Nomenclature of Steroids, the terminal "e" in the parent structure name should be elided before the vowel (the presence or absence of a number does not affect such elision). This means, for instance, that if the suffix immediately appended to the parent structure name begins with a vowel, the trailing "e" is removed from that name. An example of such removal is "5α-pregnan-17α-ol-3,20-dione", where the last "e" of "pregnane" is dropped due to the vowel ("o") at the beginning of the suffix -ol. Some authors incorrectly use this rule, eliding the terminal "e" where it should be kept, or vice versa. The term "11-oxygenated" refers to the presence of an oxygen atom as an oxo (=O) or hydroxy (-OH) substituent at carbon 11. "Oxygenated" is consistently used within the chemistry of the steroids since the 1950s. Some studies use the term "11-oxyandrogens" as an abbreviation for 11-oxygenated androgens, to emphasize that they all have an oxygen atom attached to carbon at position 11.
== Structure == Catecholamines have the distinct structure of a benzene ring with two hydroxyl groups, an intermediate ethyl chain, and a terminal amine group. Phenylethanolamines such as norepinephrine have a hydroxyl group on the ethyl chain.
(ICH E6) Any board, committee, or other group formally designated by an institution to review biomedical research involving humans as subjects, to approve the initiation of and conduct periodic review of such research. (21CFR50.3) Intent to treat
Sources: en.wikipedia.org
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.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
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.