Heptapeptide 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 2026-02-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analog of the tetrapeptide tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Reported consistently across pharmacopoeial descriptions |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| Solubility | Freely soluble in water | Aqueous buffers; poor in nonpolar solvents |
| Typical storage temperature | -20 degrees Celsius | Lyophilized powder; protect from moisture |
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.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
In the Egyptian, Greek and Roman Empires, women usually fed only their own children. However, breastfeeding began to be seen as something too common to be done by royalty. Wet nurses were employed to breastfeed the children of the royal families. This extended over time, particularly in western Europe, where noble women often used wet nurses. Lower-class women breastfed their infants and used a wet nurse only if they were unable to feed their own infant. Attempts were made in 15th-century Europe to use cow or goat milk, but these attempts were unsuccessful. In the 18th century, flour or cereal mixed with broth was introduced as a substitute for breastfeeding, but this provided inadequate nutrition. The appearance of improved infant formulas in the mid-19th century and their increased use caused a decrease in breastfeeding rates, which accelerated after World War II. For some in the US, Canada, and the UK, breastfeeding was seen as uncultured. From the 1960s onwards, breastfeeding experienced a revival that continued into the 2000s, though negative attitudes towards the practice were still entrenched in some countries up to the 1990s.
In a general sense, the conclusion of puberty is reproductive maturity. Criteria for defining the conclusion may differ for different purposes: attainment of the ability to reproduce, achievement of maximal adult height, maximal gonadal size, or adult sex hormone levels. Maximal adult height is achieved at an average age of 15 years for an average female and 18 years for an average male. Potential fertility (sometimes termed nubility) usually precedes completion of growth by 1–2 years in females and 3–4 years in males. Stage 5 typically represents maximal gonadal growth and adult hormone levels.
Oxytocin stimulates powerful uterine contractions, which trigger labour and delivery of an infant, and milk ejection in nursing women. Its release is mediated reflexively by the hypothalamus and represents a positive feedback mechanism. Antidiuretic hormone stimulates the kidney tubules to reabsorb and conserve water, resulting in small volumes of highly concentrated urine and decreased plasma osmolality. Antidiuretic hormone is released in response to high solute concentrations in the blood and inhibited by low solute concentrations in the blood. Hyposecretion results in diabetes insipidus.
Necrotizing periodontal diseases are non-contagious infections but may occasionally occur in epidemic-like patterns due to shared risk factors. The milder form, necrotizing ulcerative gingivitis (also termed "trench mouth"), is characterized by painful, bleeding gums and ulceration and necrosis of the interdental papilla. There may also be intra-oral halitosis, cervical lymphadenitis (swollen lymph nodes in the neck) and malaise. Predisposing factors include psychological stress, sleep deprivation, poor oral hygiene, smoking, immunosuppression and/or malnutrition. Necrotizing ulcerative periodontitis (NUP) is where the infection leads to attachment loss, and involves only the gingiva, periodontal ligament and alveolar ligament. Progression of the disease into tissue beyond the mucogingival junction characterizes necrotizing stomatitis (cancrum oris).
Sources: en.wikipedia.org
Emperor Franz Joseph died of bronchitis and pneumonia at the age of 86 on 21 November 1916. "I remember the dear plump figure of Prince Lobkowitz going up to my husband," Zita later recounted, "and, with tears in his eyes, making the sign of the cross on Charles's forehead. As he did so he said, 'May God bless Your Majesty.' It was the first time we had heard the Imperial title used to us."
Preventing DAMP release – proapoptotic therapies, platinums, ethyl pyruvate Neutralizing or blocking DAMPs extracellularly – anti-HMGB1, rasburicase, sRAGE, etc. Blocking the DAMP receptors or their signaling – RAGE small molecule antagonists, TLR4 antagonists, antibodies to DAMP-R DAMPs can be used as biomarkers for inflammatory diseases and potential therapeutic targets. For example, increased S100A8/A9 is associated with osteophyte progression in early human osteoarthritis, suggesting that S100 proteins can be used as biomarkers for the diagnosis of the progressive grade of osteoarthritis. Furthermore, DAMP can be a useful prognostic factor for cancer. This would improve patient classification, and a suitable therapy would be given to patients by diagnosing with DAMPs. The regulation of DAMP signaling can be a potential therapeutic target to reduce inflammation and treat diseases. For example, administration of neutralizing HMGB1 antibodies or truncated HMGB1-derived A-box protein ameliorated arthritis in collagen-induced arthritis rodent models. Clinical trials with HSP inhibitors have also been reported. For nonsmall-cell lung cancer, HSP27, HSP70, and HSP90 inhibitors are under investigation in clinical trials. In addition, treatment with dnaJP1, which is a synthetic peptide derived from DnaJ (HSP40), had a curative effect in rheumatoid arthritis patients without critical side effects. Taken together, DAMPs can be useful therapeutic targets for various human diseases, including cancer and autoimmune diseases.
=== NIKS motif === The NIKS motif is a highly conserved amino acid sequence located on the N-Terminus in Domain 1 (amino acid residues 61-64). The NIKS motif contains the amino acids Asparagine (N), Isoleucine (I), Lysine (K), and Serine (S). The main function of the NIKS motif is to recognize the first nucleotide in the stop codon, which is always uracil. Additionally, mutations in this region has been associated with decrease ribosomal binding and catalytic activity.
== Sample inlet == The sample inlet provides a stream of neutral molecules, so that the ion source can ionize them. There are several classes. The classical design produces the stream of molecules in the form of a low-pressure gas. It is low-pressure, so that molecules within the stream do not frequently collide with each other. Ions must travel without frequent collisions, because the instrument separates ions by their motion in electric and magnetic fields. Collisions disturb that motion. Despite being low-pressure, the sample stream is still at a much higher pressure than the rest of the system, which is held in a greater vacuum. Consequently, the sample stream can only enter the ion source chamber via a small pinhole, called a molecular leak. If the sample itself is already a gas, then the sample inlet can simply be a gas inlet with pressure valve. If the sample is a volatile liquid or solid, then it can simply be placed in a chamber, vacuum-pumped to a low pressure. If the sample is not sufficiently volatile, the sample inlet can be fitted within an oven. Be careful not to decompose the sample. If the sample is too nonvolatile to be turned into a low-pressure gas, then one can use a direct probe. The direct probe is a probe with a tip of thin wire loop, pin, or a capillary tube. The sample is placed in the tip. The probe is inserted through a vacuum lock into the ionization chamber, so that the tip is close to the ion source. The probe can be heated to increase vapor pressure further. Such a system is effective for samples with vapor pressures lower than
== Biosynthesis == A novel aspect of PQQ is its biosynthesis in bacteria from a ribosomally translated precursor peptide, PqqA. A glutamic acid and a tyrosine in PqqA are cross-linked by the radical SAM enzyme PqqE with the help of PqqD in the first step of PqqA modification. A protease then liberates the Glu-Tyr molecule from the peptide backbone. PqqB oxidizes the 2 and 3 positions on the tyrosine ring, forming a quinone which quickly becomes AHQQ, finishing the pyridine ring. PqqC then forms the final pyrrole ring.
Sources: en.wikipedia.org
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.
The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.
It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.
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.