A practical reference on heptapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-11-29. Anything still debated is marked as such rather than presented as settled.
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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
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.
| 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 |
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
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.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
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.
==== United States ==== In the United States, mescaline was made illegal in 1970 by the Comprehensive Drug Abuse Prevention and Control Act, categorized as a Schedule I hallucinogen. The drug is prohibited internationally by the 1971 Convention on Psychotropic Substances. Mescaline is legal only for certain religious groups (such as the Native American Church by the American Indian Religious Freedom Act of 1978) and in scientific and medical research. In 1990, the Supreme Court ruled that the state of Oregon could ban the use of mescaline in Native American religious ceremonies. The Religious Freedom Restoration Act (RFRA) in 1993 allowed the use of peyote in religious ceremony, but in 1997, the Supreme Court ruled that the RFRA is unconstitutional when applied against states. Many states, including the state of Utah, have legalized peyote usage with "sincere religious intent", or within a religious organization, regardless of race. Synthetic mescaline, but not mescaline derived from cacti, was officially decriminalized in the state of Colorado by ballot measure Proposition 122 in November 2022. While mescaline-containing cacti of the genus Echinopsis are technically controlled substances under the Controlled Substances Act, they are commonly sold publicly as ornamental plants.
Samples are dissolved or suspended in a "cocktail" containing a solvent (historically aromatic organics such as xylene or toluene, but more recently less hazardous solvents are used), typically some form of a surfactant, and "fluors" or scintillators which produce the light measured by the detector. Scintillators can be divided into primary and secondary phosphors, differing in their luminescence properties. Beta particles emitted from the isotopic sample transfer energy to the solvent molecules: the π cloud of the aromatic ring absorbs the energy of the emitted particle. The energized solvent molecules typically transfer the captured energy back and forth with other solvent molecules until the energy is finally transferred to a primary scintillator. The primary phosphor will emit photons following absorption of the transferred energy. Because that light emission may be at a wavelength that does not allow efficient detection, many cocktails contain secondary phosphors that absorb the fluorescence energy of the primary phosphor and re-emit at a longer wavelength. Two widely used primary and secondary fluors are 2,5-diphenyloxazole (PPO) with an emission maximum of 380 nm and 1,4-bis-2-(5-phenyloxazolyl)benzene (POPOP) with an emission maximum of 420 nm. The radioactive samples and cocktail are placed in small transparent or translucent (often glass or plastic) vials that are loaded into an instrument known as a liquid scintillation counter. Newer machines may use 96-well plates with individual filters in each well.
== Operations == UPS's primary business is the time-definite delivery of packages and documents worldwide. In recent years, UPS has extended its service portfolio to include less-than-truckload (LTL) transportation and supply chain services, primarily in the U.S. UPS reports its operations in three segments:
=== Tempe satay === Tempeh skewered and grilled as satay. Sate kere (Javanese for 'poor man's satay') from Solo in Central Java is made from fluffy tempe gembus. Ground tempeh can also be made into a thick sauce, such as in sate ambal, a chicken satay from Kebumen, Central Java where tempeh flavored with chili and spices replaces the more common peanut sauce.
Sources: en.wikipedia.org
=== Effects in females === LH supports theca cells in the ovaries that provide androgens and hormonal precursors for estradiol production. At the time of menstruation, FSH initiates follicular growth, specifically affecting granulosa cells. With the rise in estrogens, LH receptors are also expressed on the maturing follicle, which causes it to produce more estradiol. Eventually, when the follicle has fully matured, a spike in 17α-hydroxyprogesterone production by the follicle inhibits the production of estrogens. Previously, the preovulatory LH surge was attributed to a decrease in estrogen-mediated negative feedback of GnRH in the hypothalamus, subsequently stimulating the release of LH from the anterior pituitary. Some studies, however, attribute the LH surge to positive feedback from estradiol after production by the dominant follicle exceeds a certain threshold. Exceptionally high levels of estradiol induce hypothalamic production of progesterone, which stimulates elevated GnRH secretion, triggering a surge in LH. The increase in LH production only lasts for 24 to 48 hours. This "LH surge" triggers ovulation, thereby not only releasing the egg from the follicle, but also initiating the conversion of the residual follicle into a corpus luteum that, in turn, produces progesterone to prepare the endometrium for a possible implantation. LH is necessary to maintain luteal function for the second two weeks of the menstrual cycle.
Among the 16 genes, the analysis identified two for which rare mutations are known to cause monogenic obesity: MC4R and PCSK1 (proprotein convertase subtilisin/kexin type 1). One study provides genetic evidence linking rare coding variation to BMI and obesity-related phenotypes. MC4R gene mutations are associated with early-onset severe obesity. The effect of two exemplary heterozygous coding variants in the MC4R gene (C293R and S94N) are: • Rapid weight gains from early age (the most important feature). • Development of severe obesity (BMI ≫97th percentile) at early ages, usually <3 years of age. • Persistent food-seeking behavior, mostly reported from six months of age. • Parental/siblings anthropometric data: suspect if relatives present normal anthropometric data. • Tall stature/increased growth velocity (MC4R monogenic diabetes). There is limited treatment options for the most common form of monogenic obesity, MC4R mutations symptoms can be treated with a Glucagon-like Peptide-1 Receptor Agonist liraglutide which cause weight loss by reducing appetite. They found that the effects of liraglutide 3.0 mg daily for 16 weeks causes weight reducing and glucose lowering and may be relevant treatment in the most common form of monogenic obesity.
The aromatic acids 3-phenylpropionic acid (3PPA) and 3-(4-hydroxyphenyl)propionic acid (HPPA) are important commodities used in the chemical, pharmaceutical, and food industrial sectors. A biosynthetic route to synthetize these compounds was designed by combining the Escherichia coli phenylalanine pathway with non-native enzymes like tyrosine ammonia lyase (TAL) and the clostridial EnoR. The full pathway was assembled in Escherichia coli, which led to the production of HPPA and cinnamyl alcohol. Optimization of individual enzyme expression levels produced 3PPA and HPPA with a concentration of 367 and 225 mg/L, in this case the oxygen-sensitive EnoRs were catalytically active under the microaerophilic fermentation conditions. The 2-methylsuccinic acid (2-MSA) is used to synthetize polymers that have application as bioplastics, cosmetic solvents and coatings. A pathway for its synthesis was designed using Escherichia coli, combining native pyruvate and acetyl-CoA biosynthesis with methanogenic citramalate synthase (CimA), isopropylmalate isomerase (LeuCD), and the ER YqjM or KpnER from Klebsiella pneumoniae. The successful production of 2-MSA was achieved with a concentration of 0.96 g/L using KpnER.
Sources: en.wikipedia.org
=== Opines === The T-DNA contains genes for encoding enzymes that cause the plant to create specialized amino acid derivatives which the bacteria can metabolize, called opines. Opines are a class of chemicals that serve as a source of nitrogen for A. tumefaciens, but not for most other organisms. The specific type of opine produced by A. tumefaciens C58 infected plants is nopaline. Two nopaline type Ti plasmids, pTi-SAKURA and pTiC58, were fully sequenced. "A. fabrum" C58, the first fully sequenced pathovar, was first isolated from a cherry tree crown gall. The genome was simultaneously sequenced by Goodner et al. and Wood et al. in 2001. The genome of strain C58consists of a circular chromosome, two plasmids, and a linear chromosome. The presence of a covalently bonded circular chromosome is common to Bacteria, with few exceptions. However, the presence of both a single circular chromosome and single linear chromosome is unique to a group in this genus. The two plasmids are pTiC58, responsible for the processes involved in virulence, and pAtC58, once dubbed the "cryptic" plasmid. The pAtC58 plasmid has been shown to be involved in the metabolism of opines and to conjugate with other bacteria in the absence of the pTiC58 plasmid. If the Ti plasmid is removed, the tumor growth that is the means of classifying this species of bacteria does not occur.
{\displaystyle {\boldsymbol {\sigma }}=-p\mathbf {I} +\mu \left(\nabla \mathbf {u} +(\nabla \mathbf {u} )^{\mathsf {T}}\right)+\left(\zeta -{\tfrac {2}{3}}\mu \right)(\nabla \cdot \mathbf {u} )\mathbf {I} .}
The Foreign Ministry also confirmed that no Malaysians in the country were affected by the strikes, stating that the situation is closely monitored and actively obtaining updates to ensure safety of Malaysians. Prime Minister Anwar Ibrahim described the operation on Facebook as "unusual in scope and nature" as well as constitutes a "clear violation of international law and amounts to an unlawful use of force against a sovereign state". Oman: The Ministry of Foreign Affairs stated that it respects state sovereignty and independence and fully supports international law. In order to avoid escalation and bring about reconciliation, it urged all sides to use moderation and promote communication. Pakistan: The Ministry of Foreign Affairs stated that it attaches "great importance" to the wellbeing of the Venezuelan people, and urges the need for restraint and de-escalation in line with the principles of the Charter of the United Nations. It added that it is engaged with the situation on the ground to ensure the safety and security of Pakistanis in Venezuela. Philippines: The Department of Foreign Affairs stated that it is monitoring the situation in Venezuela and urged "concerned parties to resolve disputes through peaceful means, and to exercise restraint to prevent escalation of conflict". It said the Philippine Embassy in Bogotá, the non-resident mission for Venezuela, had "issued a travel and safety advisory to Filipinos in Venezuela" and was prepared to provide assistance.
Is increased apolipoprotein B-A major factor enhancing the risk of coronary artery disease in type 2 diabetes? J Assoc Physicians India. 2002 Aug;50:1036-8. PMID 12421026. Plasma homocysteine concentration and coronary artery disease in Asian Indians. J Assoc Physicians India. 2002 Oct;50:1229-31. PMID 12568203.
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 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.