A practical reference on TKPRPGP: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-01-01 and is reviewed periodically as new material appears.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
=== Phytochemistry === Natural tobacco polysaccharides, including cellulose, have been shown to be the primary precursors of acetaldehyde in tobacco smoke. The main polyphenols contained in the tobacco leaf are rutin and chlorogenic acid. Amino acids contained include glutamic acids, asparagine, glutamine, and γ-Aminobutyric acid. Pyridine alkaloids are present in tobacco as free bases and salts. Nicotine accounts for 90–95% of the plant's pyridines with nornicotine and anatabine accounting for roughly 2.5% each. Pyridyl functional groups present in minute amounts include anabasine, myosmine, cotinine and 2, 3′-bipyridyl. Indole alkaloids are also present in leaves and stems which includes harmala alkaloids as well. Yohimbine, harmine, harmaline and ajmalicine occurs in descending order, yohimbine being highest. The tobacco plant readily absorbs heavy metals from the surrounding soil and accumulates them in its leaves. These are readily absorbed into the user's body following smoke inhalation. Tobacco also contains the following phytochemicals: glucosides (tabacinine, tabacine), 2,3,6-trimethyl-1,4-naphthoquinone, 2-methylquinone, 2-Naphthylamine, propionic acid, anthalin, anethole, acrolein, cembrene, choline, nicotelline, nicotianine, and pyrene.
==== United States ==== 2003: Meloxicam was approved in the US for use in dogs for the management of pain and inflammation associated with osteoarthritis, as an oral (liquid) formulation of meloxicam. 2003 (November): An injectable formulation for use in dogs was approved by the US Food and Drug Administration (FDA). 2004 (October): A formulation for use in cats was approved for use before surgery only. This is an injectable meloxicam, indicated for as a single, one-time dose only, with specific and repeated warnings not to administer a second dose. 2005 (January): The product insert added a warning in bold-face type: "Do not use in cats." 2005: The FDA sent a Notice of Violation to the manufacturer for its promotional materials which included promotion of the drug for off-label use. 2020 (February): A meloxicam injection was approved for use in the United States. Specifically, the FDA granted the approval of Anjeso to Baudax Bio.
=== January === 2 January – Three people are killed after a fire breaks out at the New County Hotel in Perth. 16 January Teachers in Scotland begin 16 days of "rolling" strike action, with strikes occurring in two local authorities each day, beginning with Glasgow and East Lothian. The UK government announces it will block the Gender Recognition Reform (Scotland) Bill amid concerns about its impact on UK-wide equality law. 23 January – A fire breaks out in former department store Jenners on Princes Street, Edinburgh, resulting in the death of a firefighter and the injury of four others. 24 January – Following a trial at the High Court of Glasgow, transgender woman Isla Bryson is convicted of raping two women in 2016 and 2019, the offences having been committed before she began gender reassignment therapy. She is remanded to Cornton Vale women's prison, but moved to HMP Edinburgh two days later after First Minister Nicola Sturgeon says Bryson will not be allowed to serve her sentence at Cornton Vale. 28 January – Following controversy over the Isla Bryson case, the Daily Record reports that Tiffany Scott, a trans woman subject to an Order for Lifelong Restriction for stalking a 13-year-old girl, has successfully applied for a transfer from a men's prison to a women's facility. The Scottish Conservatives urge the Scottish Government to halt the move. 29 January – The Scottish Prison Service pauses the movement of all transgender prisoners while it carries out an "urgent review" into the transgender cases held in its custody.
Sources: en.wikipedia.org
Following the 1971 war with India, Pakistan hastily developed atomic weapons to deter foreign intervention and entered the atomic age. Tensions with India led to Pakistan's 1998 underground nuclear tests, making it the seventh country to possess such weapons. Pakistan is the sole Muslim nation active in Antarctica research, maintaining its Jinnah Antarctic Research Station since 1992. The government invests heavily in information technology projects, focusing on e-government and infrastructure.
==== Suicide ==== In studies in Sweden, flunitrazepam was the second most common drug used in suicides, being found in about 16% of cases. In a retrospective Swedish study of 1,587 deaths, in 159 cases benzodiazepines were found. In suicides when benzodiazepines were implicated, the benzodiazepines flunitrazepam and nitrazepam occurred in significantly higher concentrations compared to natural deaths. Of the 159 deaths where any benzodiazepines were found, 4 deaths were caused by benzodiazepines alone (in the other 155 cases, benzodiazepines were combined with something else). One conclusion of the study was that flunitrazepam and nitrazepam might be more toxic than other benzodiazepines available in the Swedish market.
Smaller mass analyzers require smaller control system to generate adequate electric field and magnetic field strength, which are two fundamental fields separating ions based on their mass-to-charge ratio. Because a compact circuit can generate a high electric field, decreasing the size of the voltage-generating system does not significantly affect to the miniaturization of time-of-flight mass spectrometry (TOF) and electric sectors which use only the electric field to separate ions. In principle, the electromagnetic field mainly depends on the shape of the mass analyzers. As a result, a smaller magnet fitting with small size MS reduces the system weight significantly. In practice, when reducing the size, the geometries of mass analyzer are distorted. For example, smaller volume in ion trap leads to lower trapping capacity and therefore results in a loss of resolution and sensitivity. However, by utilizing tandem MS resolution and selectivity can be greatly enhanced in complex mixtures. In general, beam-type mass analyzers, such as TOF and sector mass analyzers, are much larger than ion trap type such as Paul trap, Penning trap or Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR). Additionally, ion trap mass analyzers can be used to perform multistage MS/MS in a single device. As a result, ion traps are received dominant attention for building a MMS.
=== Legal status === In 2013, the Committee for Medicinal Products for Human Use of the European Medicines Agency recommended that medicines containing ergot derivatives no longer be used to treat several conditions involving problems with memory, sensation or blood circulation, or to prevent migraine headaches because the risks (increased risk of fibrosis and ergotism) were said to be greater than the benefits in these indications.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
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.