The short version of heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-07-20. Anything still debated is marked as such rather than presented as settled.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analogue of the ACTH(4-10) fragment |
| Amino acid sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Single-letter form MEHFPGP |
| Molecular formula | C37H51N9O10S | Free peptide, nominal mass near 814 Da |
| First registration | 1994, Russia | Nasal formulation for neurological indications |
| Typical purity grade | 95% or higher by HPLC | Research material; higher grades used as reference standards |
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
GLP-1 possesses several physiological properties making it (and its functional analogs) a subject of intensive investigation as a potential treatment of diabetes mellitus, as these actions induce long-term improvements along with the immediate effects. Although reduced GLP-1 secretion has previously been associated with attenuated incretin effect in patients with type 2 diabetes, further research indicates that GLP-1 secretion in patients with type 2 diabetes does not differ from healthy subjects. The most noteworthy effect of GLP-1 is its ability to promote insulin secretion in a glucose-dependent manner. As GLP-1 binds to GLP-1 receptors expressed on pancreatic β cells, the receptors couple to G-protein subunits and activate adenylate cyclase, which increases the production of cAMP from ATP. Subsequently, activation of secondary pathways, including protein kinase A (PKA) and Epac2, alters cell ion channel activity, causing elevated levels of cytosolic Ca2+ that enhance exocytosis of insulin-containing granules. During the process, influx of glucose ensures sufficient ATP to sustain the stimulatory effect. Additionally, GLP-1 ensures the β cell insulin stores are replenished to prevent exhaustion during secretion by promoting insulin gene transcription, mRNA stability and biosynthesis. GLP-1 also increases β cell mass by promoting proliferation and neogenesis while inhibiting apoptosis. As both type 1 and 2 diabetes are associated with reduction of functional β cells, this effect is desirable in diabetes treatment.
== Medications == Anti-anxiety medication is any drug that can be taken or prescribed for the treatment of anxiety disorders, which may be mediated by neurotransmitters like norepinephrine, serotonin, dopamine, and gamma-aminobutyric acid (GABA) in the central nervous system. Anti-anxiety medication can be classified into six types according to their different mechanisms: antidepressants, benzodiazepines, azapirones, antiepileptics, antipsychotics, and beta blockers. Antidepressants include selective serotonin reuptake inhibitors (SSRIs), serotonin–norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs). SSRIs are used in all types of anxiety disorders while SNRIs are used for generalized anxiety disorder (GAD). Both of them are considered as first-line anti-anxiety medications. TCAs are second-line treatment as they cause more significant adverse effects when compared to the first-line treatment. Benzodiazepines are effective in emergent and short-term treatment of anxiety disorders due to their fast onset but carry the risk of dependence. Buspirone is indicated for GAD, which has much slower onset but with the advantage of less sedating and withdrawal effects.
== Occurrence == It occurs in tree fern fronds, a specialty called fiddlehead (furled fronds of a young tree fern in the order Cyatheales, harvested for use as a vegetable). These fronds are edible, but can be roasted to remove shikimic acid. Shikimic acid is also the glycoside part of some hydrolysable tannins. The acid is highly soluble in water and insoluble in nonpolar solvents, and this is why shikimic acid is active only against Gram-positive bacteria, due to outer cell membrane impermeability of Gram-negatives.
Adrenocorticotropic hormone release is triggered by corticotropin-releasing hormone and inhibited by rising glucocorticoid levels. The gonadotropins—follicle-stimulating hormone and luteinizing hormone regulate the functions of the gonads in both sexes. Follicle-stimulating hormone stimulates sex cell production; luteinizing hormone stimulates gonadal hormone production. Gonadotropin levels rise in response to gonadotropin-releasing hormone. Negative feedback of gonadal hormones inhibits gonadotropin release. Prolactin promotes milk production in human females. Its secretion is prompted by prolactin-releasing hormone and inhibited by prolactin-inhibiting hormone. The intermediate lobe of the pituitary gland secretes only one enzyme that is melanocyte stimulating hormone. It is linked with the formation of the black pigment in our skin called melanin. The neurohypophysis stores and releases two hypothalamic hormones:
A top-secret White paper, compiled by the Royal Air Force and produced for the British Government in 1959, estimated that British V bombers carrying nuclear weapons were capable of destroying key cities and military targets in the Soviet Union, with an estimated 16 million deaths in the Soviet Union (half of whom were estimated to be killed on impact and the rest fatally injured) before bomber aircraft from the U.S. Strategic Air Command reached their targets.
Sources: en.wikipedia.org
Commercialized as the Model 470A protein sequencer, it allowed scientists to determine partial amino acid sequences of proteins that had not previously been accessible, characterizing new proteins and better understanding their activity, function, and effects in therapeutics. These discoveries had significant ramifications in biology, medicine, and pharmacology. The first automated DNA synthesizer resulted from a collaboration with Marvin H. Caruthers of the University of Colorado Boulder, and was based on Caruthers' work elucidating the chemistry of phosphoramidite oligonucleotide synthesis. Caltech staff scientist Suzanna J. Horvath worked with Hood and Hunkapiller to learn Caruthers' techniques in order to design a prototype that automated the repetitive steps involved in Caruthers' method for DNA synthesis. The resulting prototype was capable of forming short pieces of DNA called oligonucleotides, which could be used in DNA mapping and gene identification. The first commercial phosphoramidite DNA synthesizer was developed from this prototype by Applied Biosystems, who installed the first Model 380A in Caruthers' lab at the University of Colorado in December 1982, before beginning official commercial shipment of the new instrument. Revolutionizing the field of molecular biology, the DNA synthesizer enabled biologists to synthesize DNA fragments for cloning and other genetic manipulations. Molecular biologists were able to produce DNA probes and primers for use in DNA sequencing and mapping, gene cloning, and gene synthesis.
Similarly, 1,3-dibromopropane reacts with sodium cyanide to form glutaronitrile, and 1-iodooctane reacts with potassium cyanide to give nonannitrile. Cyanations can also be carried out using hydrogen cyanide in combination with triethylaluminum or with diethylaluminum cyanide; for example, in the ring opening of an epoxide to a β-cyanohydrin or in the 1,4-addition of cyanide to an enone. Trimethylsilylcyanide is another cyanating reagent capable of opening epoxides to β-cyanohydrins, with concomitant silylation of the oxygen atom. Trimethylsilyl cyanide also enables substitution of tertiary alkyl halides, which is not feasible under Kolbe nitrile synthesis conditions. In the presence of suitable transition metal catalysts, hydrocyanation allows addition of hydrogen cyanide to the multiple bonds of alkenes and alkynes to afford nitriles. Nickel catalysts are typically employed. Direct handling of hydrogen cyanide is often unnecessary, as synthetic equivalents such as acetone cyanohydrin or isovaleronitrile may be used. An important industrial process is the hydrocyanation of butadiene to adiponitrile.
The branched-chain α-ketoacid dehydrogenase complex (BCKDC or BCKDH complex) is a multi-subunit complex of enzymes that is found on the mitochondrial inner membrane. This enzyme complex catalyzes the oxidative decarboxylation of branched, short-chain alpha-ketoacids. BCKDC is a member of the mitochondrial α-ketoacid dehydrogenase complex family, which also includes the pyruvate dehydrogenase complex (PDHC) and alpha-ketoglutarate dehydrogenase complex (OGDC), key enzymes that function in the Krebs cycle, as well as the 2-oxoadipate dehydrogenase complex (OADHC), which plays a critical role in the degradation of the amino acids lysine, hydroxylysine, and tryptophan.
In chemistry and physics, cohesion (from Latin cohaesiō 'cohesion, unity'), also called cohesive attraction or cohesive force, is the action or property of like molecules sticking together, being mutually attractive. It is an intrinsic property of a substance that is caused by the shape and structure of its molecules, which makes the distribution of surrounding electrons irregular when molecules get close to one another, creating an electrical attraction that can maintain a macroscopic structure such as a water drop. Cohesion allows for surface tension, creating a "solid-like" state upon which light-weight or low-density materials can be placed. Water, for example, is strongly cohesive as each molecule may make four hydrogen bonds to other water molecules in a tetrahedral configuration. This results in a relatively strong Coulomb force between molecules. In simple terms, the polarity (a state in which a molecule is oppositely charged on its poles) of water molecules allows them to be attracted to each other. The polarity is due to the electronegativity of the atom of oxygen: oxygen is more electronegative than the atoms of hydrogen, so the electrons they share through the covalent bonds are more often close to oxygen rather than hydrogen. These are called polar covalent bonds, covalent bonds between atoms that thus become oppositely charged. In the case of a water molecule, the hydrogen atoms carry positive charges while the oxygen atom has a negative charge.
Sources: en.wikipedia.org
Registered medical products are most often 0.1% nasal drops. Research suppliers ship lyophilized powder, usually in milligram quantities, which is dissolved before use. The active peptide is the same in both cases; presentation and excipients differ.
No. The peptide is synthetic, although it is modelled on a fragment of a naturally occurring hormone. ACTH(4-10) is generated when ACTH is cleaved, but the Pro-Gly-Pro extension is not a known endogenous sequence. It is therefore a designed analogue rather than a natural metabolite.
The label reflects reported effects on attention, memory and recovery after neurological injury in regional clinical reports. Those reports are mostly small and have not been widely replicated outside the region. The classification is descriptive and does not imply a single defined mechanism.
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.