Intranasal route comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-05-31. Where a claim depends on a specific study, the study is described rather than over-claimed.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
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.
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.
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.
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.
=== Calcium === Calcium intake in vegetarians and vegans can be similar to non-vegetarians, as long as the diet is properly planned. Lacto-ovo vegetarians that include dairy products can still obtain calcium from dairy sources like milk, yogurt, and cheese. Non-dairy milks that are fortified with calcium, such as soymilk and almond milk can also contribute a significant amount of calcium in the diet. Broccoli, bok choy, and kale have also been found to have calcium that is well absorbed in the body. Though the calcium content per serving is lower in these vegetables than a glass of milk, the absorption of the calcium into the body is higher. Other foods that contain calcium include calcium-set tofu, blackstrap molasses, turnip greens, mustard greens, soybeans, tempeh, almonds, okra, dried figs, and tahini. Though calcium can be found in Spinach, swiss chard, beans and beet greens, they are generally not considered to be a good source since the calcium binds to oxalic acid and is poorly absorbed into the body. Phytic acid found in nuts, seeds, and beans may also impact calcium absorption rates. See the National Institutes of Health Office of Dietary Supplements for calcium needs for various ages, the Vegetarian Resource Group and the Vegetarian Nutrition Calcium Fact Sheet from the Academy of Nutrition and Dietetics for more specifics on how to obtain adequate calcium intake on a vegetarian or vegan diet.
=== Treatment of deficiency === Severe vitamin B12 deficiency is initially corrected with daily intramuscular injections of 1000 μg of the vitamin, followed by maintenance via monthly injections of the same amount or daily oral dosing of 1000 μg. The oral daily dose far exceeds the vitamin requirement because the normal transporter protein-mediated absorption is absent, leaving only inefficient intestinal passive absorption. Injection side effects include skin rash, itching, chills, fever, hot flushes, nausea and dizziness. There are not enough studies on whether pills are as effective in improving or eliminating symptoms as parenteral treatment.
Original – Classic brewed hard tea. Tea + Lemonade – A combination of sweet tea and citrus. Peach – A bold, juicy peach twist. Green Tea – A smooth and earthy green tea blend. Packaging includes 12 U.S. fl oz (350 mL) variety packs and 24 US fl oz (710 mL) singles, as well as 16 US fl oz (473 mL) depending on the flavor.
== Environmental record == According to the 2022 "Top 100 Polluters Indexes" published by the University of Massachusetts, Amherst's "Political Economy Research Institute" (PERI), BASF was ranked the #2 largest polluter of air and #14 largest polluter of water in 2020, the most recent year for which data is available from the U.S. Environmental Protection Agency. In 2006, BASF was included in the Climate Leadership Index for their efforts in relation to climate change and greenhouse gas emissions. The BASF Company and Columbia University formed a partnership to further research "environmentally benign and sustainable energy sources". The company has recently reported their emissions in 2006 to be "1.50 million metric tons of waste," which is a decrease from previous years. The amount of waste BASF produces has continued to fall. While BASF publishes its environmental information in the US and Europe, Greenpeace has expressed deep concerns at BASF's refusal to release environmental information on its operations in China. In May 2009, a BASF Plant in Hannibal, Missouri, United States, accidentally discharged chromium into the Mississippi River. The local Department of Natural Resources performed tests in December 2009 showing the chromium levels did not exceed regulatory safety limits. BASF worked with the Missouri Department of Natural Resources (MoDNR) to resolve questions regarding the elevated level of hexavalent chromium that was detected in the effluent from one of its permitted outfalls into the Mississippi River.
While not as life-threatening as a bite from a venomous species, the bite can be at least temporarily debilitating and could lead to dangerous infections if improperly dealt with. While most snakes must open their mouths before biting, African and Middle Eastern snakes belonging to the family Atractaspididae can fold their fangs to the side of their head without opening their mouth and jab a person.
Sources: en.wikipedia.org
=== HIV long-term nonprogressors === About 1 in 500 people infected with HIV can remain symptom-free for many years without medication, a group known as long-term nonprogressors. The presence of HLA-B27, as well as HLA-B5701, is significantly common among this group.
Hormone replacement therapy, including gender-affirming hormone therapy, stimulates the growth of glandular and adipose tissue through estrogen supplementation. In menopausal women, HRT helps restore breast volume and skin elasticity diminished by declining estrogen levels, typically using oral or transdermal estradiol. In gender-affirming hormone therapy, breast development is induced through feminizing HRT, often combining estrogen with anti-androgens to suppress testosterone. Maximum growth is usually achieved after 2–3 years. Factors such as age, genetics, and hormone dosage influence outcomes.
At the time, low-potency creatine supplements were available in Britain, but creatine supplements designed for strength enhancement were not commercially available until 1993 when the company Experimental and Applied Sciences (EAS) introduced the compound to the sports nutrition market under the name Phosphagen. In 1996, researchers found that carbohydrate consumption augments the effects of creatine supplementation on skeletal muscle creatine accumulation.
During this meeting, he asked what Weizmann's objections had been to the 1903 Uganda Scheme that Herzl had supported to provide a portion of British East Africa to the Jewish people as a homeland. The scheme, which had been proposed to Herzl by Joseph Chamberlain, Colonial Secretary in Balfour's Cabinet, following his trip to East Africa earlier in the year, had been subsequently voted down following Herzl's death by the Seventh Zionist Congress in 1905 after two years of heated debate in the Zionist Organization. Weizmann responded that he believed the English are to London as the Jews are to Jerusalem. In January 1914, Weizmann first met Baron Edmond de Rothschild, a member of the French branch of the Rothschild family and a leading proponent of the Zionist movement, in relation to a project to build a Hebrew university in Jerusalem. The Baron was not part of the World Zionist Organization, but had funded the Jewish agricultural colonies of the First Aliyah and transferred them to the Jewish Colonization Association in 1899. This connection was to bear fruit later that year when the Baron's son, James de Rothschild, requested a meeting with Weizmann on 25 November 1914, to enlist him in influencing those deemed to be receptive within the British government to the Zionist agenda in Palestine. Through James's wife Dorothy, Weizmann was to meet Rózsika Rothschild, who introduced him to the English branch of the family – in particular her husband Charles and his older brother Walter, a zoologist and former Member of Parliament (MP).
== List of nucleosides and corresponding nucleobases == This list does not include modified nucleobases and the corresponding nucleosides Each chemical has a short symbol, useful when the chemical family is clear from the context, and a longer symbol, if further disambiguation is needed. For example, long nucleobase sequences in genomes are usually described by CATG symbols, not Cyt-Ade-Thy-Gua (see Nucleic acid sequence § Notation).
Sources: en.wikipedia.org
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.