This is a working overview of peptide purity, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-02-01 and is reviewed periodically as new material appears.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Principal proposed target | GABA-A receptor complex | Hypothesis derived mainly from animal pharmacology |
| Common behavioral assay | Elevated plus maze | Rodent test for anxiety-like behavior |
| Reported molecular marker | Hippocampal BDNF expression | Measured by immunoassay or mRNA quantification |
| Typical dosing route | Intranasal | Chosen to reduce first-pass metabolism |
| Reported plasma half-life | Minutes | Based on limited peptide stability data |
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
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.
=== Prescription drug monitoring === In 2016, the CDC published its "Guideline for Prescribing Opioids for Chronic Pain", recommending opioids only be used when benefits for pain and function are expected to outweigh risks, and then used at the lowest effective dosage, with avoidance of concurrent opioid and benzodiazepine use whenever possible. Silvia Martins, an epidemiologist at Columbia University, has suggested getting out more information about the risks:The greater "social acceptance" for using these medications (versus illegal substances) and the misconception that they are "safe" may be contributing factors to their misuse. Hence, a major target for intervention is the general public, including parents and youth, who must be better informed about the negative consequences of sharing with others medications prescribed for their own ailments. Equally important is the improved training of medical practitioners and their staff to better recognize patients at potential risk of developing nonmedical use, and to consider potential alternative treatments as well as closely monitor the medications they dispense to these patients. As of April 2017, prescription drug monitoring programs (PDMPs) exist in every state. A person on opioids for more than three months has a 15-fold (1,500%) greater chance of becoming addicted. The CDC's "Guideline for Prescribing Opioids for Chronic Pain" offers many non-pharmacological options as alternatives to prescribing opioids. Physical therapist interventions is an example that is offered in regards to an alternative to prescribing opioids.
=== With materials === Generally, humans can regenerate injured tissues in vivo for limited distances of up to 2mm. The further the wound distance is from 2mm the more the wound regeneration will need inducement. By 2009, via the use of materials, a max induced regeneration could be achieved inside a 1 cm tissue rupture. Bridging the wound, the material allowed cells to cross the wound gap; the material then degraded. This technology was first used inside a broken urethra in 1996. In 2012, using materials, a full urethra was restored in vivo. Macrophage polarization is a strategy for skin regeneration. Macrophages are differentiated from circulating monocytes. Macrophages display a range of phenotypes varying from the M1, pro-inflammatory type to the M2, pro-regenerative type. Material hydrogels polarise macrophages into the key M2 regenerative phenotype in vitro. In 2017, hydrogels provided full regeneration of skin, with hair follicles, after partial excision of scars in pigs and after full thickness wound incisions in pigs.
Twin Peaks is an American chain of sports bars and restaurants based in Lewisville, Texas, which has been described as an "ultimate sports lodge" and breastaurant. The chain is known for having its waitresses, primarily young women and typically referred to as "Twin Peaks Girls", dress in revealing uniforms that consist of cleavage- and midriff-revealing red plaid tops, as well as khaki shorts or denim short shorts. At other times, waitresses wear revealing seasonal or themed outfits. Restaurants are decorated in the theme of a wilderness lodge and serve a mix of American, Southwest and Southern cuisines as well as alcohol. The chain's slogan is "Eats. Drinks. Scenic Views."
Sources: en.wikipedia.org
=== Disadvantages === Typically the cost of a single synthesis or sample assessment are expensive to set up and start up cost for automation can be expensive (but see above "Low-cost laboratory robotics"). Many techniques have not been developed for automation yet. Additionally there is difficulty automating instances where visual analysis, recognition, or comparison is required such as color changes. This also leads to the analysis being limited by available sensory inputs. One potential disadvantage is an increases job shortages as automation may replace staff members who do tasks easily replicated by a robot. Some systems require the use of programming languages such as C++ or Visual Basic to run more complicated tasks.
=== Leucomatous corneal opacity (leucoma simplex) === Leucomatous corneal opacity is a dense white opacity which results due to scarring of more than half of the stroma. A number of different presentations of leucomatous corneal opacity exist:
Negroponte examines Dimitri Mobengo Mugianis's long, clandestine career of treating heroin addicts with ibogaine. One of the five segments of "Hallucinogens DMT" (2012), Season 2, Episode 4 of Drugs, Inc. on National Geographic Channel, a former heroin user treats addicts with ibogaine in Canada. He himself used ibogaine to stop his abuse of narcotics. The "Underground Heroin Clinic" segment of "Addiction" (2013). Season 1, episode 7 of the HBO documentary series Vice examines the use of ibogaine to interrupt heroin addiction. The Ibogaine Safari (2014). A documentary by filmmaker Pierre le Roux which investigates the claims of painless withdrawal from opiates such as nyaope/heroin in South Africa by taking several addicts on an adventure "safari" while taking ibogaine. The documentary won the award for 'Best Documentary Short' at the 2014 Canada International Film Festival. Iboga Nights (2014). Directed by David Graham Scott. Dosed. A documentary by Tyler Chandler and Nicholas Meyers. Synopsis- After years of no success with prescription drugs, a suicidal Adrianne seeks help from underground healers with her depression, anxiety, and opioid addiction by utilizing illegal psychedelics like magic mushrooms and iboga. "Synthetic Ibogaine – Natural Tramadol" (2021). This episode of the documentary series Hamilton's Pharmacopeia on Vice on TV follows a struggling local addict to an ibogaine ritual. Lamar Odom Reborn (2022).
=== Vocals === Toufouti did not consider himself a singer when recording 2010's Leaving Paris. At that time, he was mainly inspired by voices he described as "a bit broken, a bit gravelly" over stoner and bluesy riffs, mentioning the band Down. On Hope /// Dope /// Rope, his bandmates encouraged him to abandon that vocal style and sing, telling him, "think crooner", which led him to learn to "desaturate" his voice. Toufouti felt that his voice retained a certain harshness on this album, though it was "clearer". On subsequent albums, he continued the improvements he had begun to reduce saturation as much as possible.
Sources: en.wikipedia.org
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.
Behavioral endpoints include time spent in open arms of the elevated plus maze and avoidance latencies. Biochemical endpoints include BDNF concentration, cytokine levels, and monoamine metabolite ratios in brain tissue.
Most published studies are small, originate from a limited number of laboratories, and lack independent replication. Dose-response relationships, measured brain exposure, and long-term outcomes are not well characterized.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.