The short version of heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-03-27 and is reviewed periodically as new material appears.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
=== EC 2.5.1: Transferring alkyl or aryl groups, other than methyl groups (only sub-subclass identified to date) === EC 2.5.1.1: dimethylallyltranstransferase EC 2.5.1.2: thiamine pyridinylase EC 2.5.1.3: thiamine-phosphate diphosphorylase EC 2.5.1.4: Now EC 4.4.1.42 adenosylmethionine cyclotransferase EC 2.5.1.5: galactose-6-sulfurylase EC 2.5.1.6: methionine adenosyltransferase EC 2.5.1.7: UDP-N-acetylglucosamine 1-carboxyvinyltransferase EC 2.5.1.8: transferred to EC 2.5.1.75, tRNA dimethylallyltransferase EC 2.5.1.9: riboflavin synthase EC 2.5.1.10: (2E,6E)-farnesyl diphosphate synthase EC 2.5.1.11: Now covered by EC 2.5.1.84 (all-trans-nonaprenyl-diphosphate synthase [geranyl-diphosphate specific]) and EC 2.5.1.85 (all-trans-nonaprenyl diphosphate synthase [geranylgeranyl-diphosphate specific]) EC 2.5.1.12: deleted, now included with EC 2.5.1.18 glutathione transferase EC 2.5.1.13: deleted, now included with EC 2.5.1.18 glutathione transferase EC 2.5.1.14: deleted, now included with EC 2.5.1.18 glutathione transferase EC 2.5.1.15: dihydropteroate synthase EC 2.5.1.16: spermidine synthase EC 2.5.1.17: cob(I)yrinic acid a,c-diamide adenosyltransferase EC 2.5.1.18: glutathione transferase EC 2.5.1.19: 3-phosphoshikimate 1-carboxyvinyltransferase EC 2.5.1.20: rubber cis-polyprenylcistransferase EC 2.5.1.21: squalene synthase EC 2.5.1.22: spermine synthase EC 2.5.1.23: sym-norspermidine synthase EC 2.5.1.24: discadenine synthase EC 2.5.1.25: tRNA-uridine aminocarboxypropyltransferase EC 2.5.1.26: alkylglycerone-phosphate synthase EC 2.5.1.27: adenylate dimethylallyltransferase EC 2.5.1.28: dimethylallylcistransferase EC 2.5.1.29: farnesyltranstransferase EC 2.5.1.30: trans-hexaprenyltranstransferase EC 2.5.1.31: ditrans,polycis-undecaprenyl-diphosphate synthase [(2E,6E)-farnesyl-diphosphate specific] EC 2.5.1.32: 15-cis-phytoene synthase EC 2.5.1.33: deleted, now covered by EC 2.5.1.82 hexaprenyl diphosphate synthase [geranylgeranyl-diphosphate specific] and EC 2.5.1.83 hexaprenyl diphosphate synthase [(2E,6E)-farnesyl-diphosphate specific] EC 2.5.1.34: tryptophan dimethylallyltransferase EC 2.5.1.35: aspulvinone dimethylallyltransferase EC 2.5.1.36: trihydroxypterocarpan dimethylallyltransferase EC 2.5.1.37: Now EC 4.4.1.20, leukotriene-C4 synthase EC 2.5.1.38: isonocardicin synthase EC 2.5.1.39: 4-hydroxybenzoate polyprenyltransferase EC 2.5.1.40: Now EC 4.2.3.9, aristolochene synthase EC 2.5.1.41: phosphoglycerol geranylgeranyltransferase EC 2.5.1.42: geranylgeranylglycerol-phosphate geranylgeranyltransferase EC 2.5.1.43: nicotianamine synthase EC 2.5.1.44: homospermidine synthase EC 2.5.1.45: homospermidine synthase (spermidine-specific) EC 2.5.1.46: deoxyhypusine synthase EC 2.5.1.47: cysteine synthase EC 2.5.1.48: cystathionine γ-synthase EC 2.5.1.49: O-acetylhomoserine aminocarboxypropyltransferase EC 2.5.1.50: zeatin 9-aminocarboxyethyltransferase EC 2.5.1.51: β-pyrazolylalanine synthase EC 2.5.1.52: L-mimosine synthase EC 2.5.1.53: uracilylalanine synthase EC 2.5.1.54: 3-deoxy-7-phosphoheptulonate synthase EC 2.5.1.55: 3-deoxy-8-phosphooctulonate synthase EC 2.5.1.56: N-acetylneuraminate synthase EC 2.5.1.57: N-acylneuraminate-9-phosphate synthase EC 2.5.1.58: protein farnesyltransferase EC 2.5.1.59: protein geranylgeranyltransferase type I EC 2.5.1.60: protein geranylgeranyltransferase type II EC 2.5.1.61: hydroxymethylbilane synthase EC 2.5.1.62: chlorophyll synthase EC 2.5.1.63: adenosyl-fluoride synthase EC 2.5.1.64: The reaction that was attributed to this enzyme is now known to be catalysed by two separate enzymes: EC 2.2.1.9 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylic-acid synthase and EC 4.2.99.20 2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate synthase EC 2.5.1.65: O-phosphoserine sulfhydrylase EC 2.5.1.66: N2-(2-carboxyethyl)arginine synthase EC 2.5.1.67: chrysanthemyl diphosphate synthase EC 2.5.1.68: (2Z,6E)-farnesyl diphosphate synthase EC 2.5.1.69: lavandulyl diphosphate synthase EC 2.5.1.70: naringenin 8-dimethylallyltransferase EC 2.5.1.71: leachianone-G 2′′-dimethylallyltransferase EC 2.5.1.72: quinolinate synthase EC 2.5.1.73: O-phospho-L-seryl-tRNA:Cys-tRNA synthase EC 2.5.1.74: 1,4-dihydroxy-2-naphthoate polyprenyltransferase EC 2.5.1.75: tRNA dimethylallyltransferase EC 2.5.1.76: cysteate synthase EC 2.5.1.77: Now EC 2.5.1.147, 5-amino-6-(D-ribitylamino)uracil—L-tyrosine 4-methylphenol transferase and EC 4.3.1.32, 7,8-didemethyl-8-hydroxy-5-deazariboflavin synthase. EC 2.5.1.78: 6,7-dimethyl-8-ribityllumazine synthase EC 2.5.1.79: thermospermine synthase EC 2.5.1.80: 7-dimethylallyltryptophan synthase EC 2.5.1.81: geranylfarnesyl diphosphate synthase EC 2.5.1.82: hexaprenyl diphosphate synthase [geranylgeranyl-diphosphate specific] EC 2.5.1.83: hexaprenyl diphosphate synthase [(2E,6E)-farnesyl-diphosphate specific] EC 2.5.1.84: all-trans-nonaprenyl-diphosphate synthase (geranyl-diphosphate specific) EC 2.5.1.85: all-trans-nonaprenyl diphosphate synthase [geranylgeranyl-diphosphate specific] EC 2.5.1.86: trans,polycis-decaprenyl diphosphate synthase EC 2.5.1.87: ditrans,polycis-polyprenyl diphosphate synthase [(2E,6E)-farnesyl diphosphate specific] EC 2.5.1.88: trans,polycis-polyprenyl diphosphate synthase [(2Z,6E)-farnesyl diphosphate specific] EC 2.5.1.89: tritrans,polycis-undecaprenyl diphosphate synthase [geranylgeranyl-diphosphate specific] EC 2.5.1.90: all-trans-octaprenyl-diphosphate synthase EC 2.5.1.91: all-trans-decaprenyl-diphosphate synthase EC 2.5.1.92: (2Z,6Z)-farnesyl diphosphate synthase EC 2.5.1.93: 4-hydroxybenzoate geranyltransferase EC 2.5.1.94: adenosyl-chloride synthase EC 2.5.1.95: xanthan ketal pyruvate transferase EC 2.5.1.96: 4,4′-diapophytoene synthase EC 2.5.1.97: pseudaminic acid synthase EC 2.5.1.98: Rhizobium leguminosarum exopolysaccharide glucosyl ketal-pyruvate-transferase EC 2.5.1.99: The activity was an artifact caused by photoisomerization of the product of EC 2.5.1.32, 15-cis-phytoene synthase EC 2.5.1.100: fumigaclavine A dimethylallyltransferase EC 2.5.1.101: N,N′-diacetyllegionaminate synthase EC 2.5.1.102: geranyl-pyrophosphate—olivetolic acid geranyltransferase EC 2.5.1.103: presqualene diphosphate synthase EC 2.5.1.104: N1-aminopropylagmatine synthase EC 2.5.1.105: 7,8-dihydropterin-6-yl-methyl-4-(β-D-ribofuranosyl)aminobenzene 5′-phosphate synthase EC 2.5.1.106: tryprostatin B synthase EC 2.5.1.107: verruculogen prenyltransferase EC 2.5.1.108: 2-(3-amino-3-carboxypropyl)histidine synthase EC 2.5.1.109: brevianamide F prenyltransferase (deoxybrevianamide E-forming) EC 2.5.1.110: 12α,13α-dihydroxyfumitremorgin C prenyltransferase EC 2.5.1.111: 4-hydroxyphenylpyruvate 3-dimethylallyltransferase EC 2.5.1.112: adenylate dimethylallyltransferase (ADP/ATP-dependent) EC 2.5.1.113: [CysO sulfur-carrier protein]-thiocarboxylate-dependent cysteine synthase EC 2.5.1.114: tRNAPhe (4-demethylwyosine37-C7) aminocarboxypropyltransferase EC 2.5.1.115: homogentisate phytyltransferase EC 2.5.1.116: homogentisate geranylgeranyltransferase EC 2.5.1.117: homogentisate solanesyltransferase EC 2.5.1.118: β-(isoxazolin-5-on-2-yl)-L-alanine synthase EC 2.5.1.119: β-(isoxazolin-5-on-4-yl)-L-alanine synthase EC 2.5.1.120: aminodeoxyfutalosine synthase EC 2.5.1.121: 5,10-dihydrophenazine-1-carboxylate 9-dimethylallyltransferase EC 2.5.1.122: 4-O-dimethylallyl-L-tyrosine synthase EC 2.5.1.123: flaviolin linalyltransferase EC 2.5.1.124: 6-linalyl-2-O,3-dimethylflaviolin synthase EC 2.5.1.125: 7-geranyloxy-5-hydroxy-2-methoxy-3-methylnaphthalene-1,4-dione synthase EC 2.5.1.126: norspermine synthase EC 2.5.1.127: caldopentamine synthase EC 2.5.1.128: N4-bis(aminopropyl)spermidine synthase EC 2.5.1.129: flavin prenyltransferase EC 2.5.1.130: 2-carboxy-1,4-naphthoquinone phytyltransferase EC 2.5.1.131: (4-{4-[2-(γ-L-glutamylamino)ethyl]phenoxymethyl}furan-2-yl)methanamine synthase EC 2.5.1.132: 3-deoxy-D-glycero-D-galacto-nonulopyranosonate 9-phosphate synthase EC 2.5.1.133: bacteriochlorophyll a synthase EC 2.5.1.134: cystathionine β-synthase (O-acetyl-L-serine) EC 2.5.1.135: validamine 7-phosphate valienyltransferase EC 2.5.1.136: 2-acylphloroglucinol 4-prenyltransferase EC 2.5.1.137: 2-acyl-4-prenylphloroglucinol 6-prenyltransferase EC 2.5.1.138: coumarin 8-geranyltransferase EC 2.5.1.139: umbelliferone 6-dimethylallyltransferase EC 2.5.1.140: N-(2-amino-2-carboxyethyl)-L-glutamate synthase EC 2.5.1.141: heme o synthase EC 2.5.1.142: nerylneryl diphosphate synthase EC 2.5.1.143: pyridinium-3,5-biscarboxylic acid mononucleotide synthase EC 2.5.1.144: S-sulfo-L-cysteine synthase (O-acetyl-L-serine-dependent) EC 2.5.1.145: phosphatidylglycerol—prolipoprotein diacylglyceryl transferase EC 2.5.1.146: 3-geranyl-3-[(Z)-2-isocyanoethenyl]indole synthase EC 2.5.1.147: 5-amino-6-(D-ribitylamino)uracil—L-tyrosine 4-hydroxyphenyl transferase EC 2.5.1.148: lycopaoctaene synthase EC 2.5.1.149: lycopene elongase/hydratase (flavuxanthin-forming) EC 2.5.1.150: lycopene elongase/hydratase (dihydrobisanhydrobacterioruberin-forming) EC 2.5.1.151: alkylcobalamin dealkylase EC 2.5.1.152: D-histidine 2-aminobutanoyltransferase EC 2.5.1.153: adenosine tuberculosinyltransferase
== Pharmacology == 4-HT is a potent agonist of the serotonin 5-HT2A receptor similarly to psilocin (EC50Tooltip half-maximal effective concentration = 38 nM and 21 nM, respectively). It also shows affinity for the serotonin 5-HT2C receptor (Ki = 40 nM), the serotonin 5-HT1A receptor (Ki = 95 nM), and the serotonin 5-HT1B receptor (Ki = 1,050 nM). The drug produces serotonergic peripheral effects in animals, shows similar metabolism and metabolic stability to psilocin, and appears to cross the blood–brain barrier and hence is centrally penetrant. Surprisingly however, the compound, similarly to baeocystin, norbaeocystin, and norpsilocin, does not produce the head-twitch response, a behavioral proxy of psychedelic effects, in animals, and hence is putatively non-hallucinogenic. In older literature, the psychoactive effects of 4-hydroxylated tryptamines have been said to increase in the series of 4-hydroxytryptamine, 4-hydroxy-N-methyltryptamine (norpsilocin], and 4-hydroxy-N,N-dimethyltryptamine (psilocin). The reason for the lack of hallucinogenic effects with 4-HT and related compounds is unknown, but may be due to biased agonism of the serotonin 5-HT2A receptor; or, more specifically, biased agonism for the β-arrestin2 signaling pathway. Norbaeocystin is thought to be a prodrug of 4-HT, analogously to how psilocybin is a prodrug of psilocin and how baeocystin is thought to be a prodrug of norpsilocin.
Alas! The bride had died in horrible agony; for no sooner had she put on Medea's gifts than a devouring poison consumed her limbs as with fire, and in his endeavor to save his daughter the old father died too. While Medea is pleased with her current success she decides to take it one step further. Since Jason brought shame upon her by trying to start a new family, Medea resolves to destroy the family he was willing to give up by killing their sons. Medea does have a moment of hesitation when she considers the pain that her children's deaths will put her through. However, she steels her resolve to cause Jason the most pain possible and rushes offstage with a knife to kill her children. Determined to stop Medea, the chorus runs after her only to hear the children scream. Jason then rushes onto the scene to confront Medea about murdering Creon and Glauce, and he quickly discovers that his children have been killed as well. Medea then appears above the stage with the bodies of her children in a chariot given to her by the sun god Helios. When this play was put on, this scene was accomplished using the mechane device usually reserved for the appearance of a god or goddess. She confronts Jason, reveling in his pain at being unable to ever hold his children again:
Sources: en.wikipedia.org
After the elections, a party system called "imperfect bipartisanship" was drawn, where two large parties or coalitions (UCD and PSOE), which were located towards the political "center", had collected 63% of the votes and shared more than 80% of the seats (283 out of 350), and two other parties or coalitions were located, with much less support, at the extremes ─ AP on the right, PCE on the left. The exception to the imperfect bipartisanship was the Basque Country, where the PNV won 8 seats and the Euskadiko Ezkerra coalition 1, and Catalonia where the Pacte Democràtic per Catalunya led by Jordi Pujol won 11 and the Esquerra de Catalunya coalition 1.
== Laboratory == biochemistry Arterial blood gas (ABG) Complete blood count (CBC) Comprehensive metabolic panel (CMP) (including CHEM-7) coagulation tests C-reactive protein Erythrocyte sedimentation rate (ESR) FibroTest urea breath test urinalysis Agostini's reaction cytogenetics and Molecular Genetics Genetic testing immunology autoantibodies microbiology blood culture mantoux test sputum culture stool culture urine culture Where available ICD-11, where not ICD-10 codes are listed. See also: https://en.m.wikipedia.org/wiki/Category:Blood_tests and Blood test,
== Metabolism == Dihydrocodeine is metabolised by the CYP450 system isoenzyme 2D6 to dihydromorphine, which mediates the majority of its analgesic effects. Owing to the low oral bioavailibility of dihydrocodeine (20%), and its subsequent metabolism to active compounds, it is likely that doses below 30mg are sub therapeutic for analgesia.
Sources: en.wikipedia.org
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.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
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.