Semax
Chemical compound From Wikipedia, the free encyclopedia
Semax is a medication which is used in Russia and Eastern Europe for the treatment of a broad range of conditions like brain trauma but predominantly for its claimed nootropic, neuroprotective, and neurorestorative effects.[1]
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Trade names | Semax |
Other names | L-Methionyl-L-α-glutamylhistidyl-L-phenylalanyl-L-prolylglycyl-L-proline, (Pro8,Gly9,Pro10)ACTH-(4-10) |
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Formula | C37H51N9O10S |
Molar mass | 813.93 g·mol−1 |
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The mechanism of action of Semax is unknown.[2][3] It might interact with certain melanocortin receptors or inhibit enkephalinase enzymes.[2][3] Chemically, Semax is a peptide and a synthetic analogue of a fragment of adrenocorticotropic hormone (ACTH).[4][5]
Semax was first described by 1991.[5] Although used as a prescription drug in Russia and Eastern Europe, Semax has not been evaluated, approved for use, or marketed in most other countries.[6][7] The drug is widely sold by online vendors and used as a purported nootropic (cognitive enhancer).[1][8]
Medical uses
Summarize
Perspective

Semax has undergone extensive study in Russia and is on the Russian List of Vital & Essential Drugs approved by the Russian Federation government on December 7, 2011.[9] Medical uses for Semax include treatment of stroke, transient ischemic attack, memory and cognitive disorders, peptic ulcers, optic nerve disease, and to boost the immune system.[10][11][12][13]
Clinical trials
In a 1996 study, 250 to 1000 μg Semax improved attention and short-term memory in 11 healthy subjects performing 8 hour work shifts, though the effects were most pronounced when subjects were fatigued (after the shift was over) and the effects lasted going into the next day.[14] In a follow-up memory test administered the morning after Semax administration, the treatment group made more correct responses (71%) than the control group (41%).[14]
A 2018 study involving 110 patients recovering from ischemic stroke reported increases in brain-derived neurotrophic factor (BDNF) (correlated with early rehabilitation) in patients administered Semax.[15]
In another 2018 study involving 24 healthy participants, Semax was shown to increase fMRI default mode network activity relative to placebo.[16]
As of November 2023, there are no published clinical trials involving Semax outside of Russia and post-Soviet states.[7]
Pharmacology
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Perspective
Pharmacodynamics
In animals, Semax rapidly elevates the levels and expression of brain-derived neurotrophic factor (BDNF) and its signaling receptor tropomyosin receptor kinase B (TrkB) in the hippocampus,[17] and rapidly activates serotonergic and dopaminergic brain systems.[18][19] Accordingly, it has been found to produce antidepressant-like and anxiolytic-like effects,[20][21] attenuate the behavioral effects of exposure to chronic stress,[20][21] and potentiate the locomotor activity produced by D-amphetamine.[19][22] As such, it has been suggested that Semax may be effective in the treatment of depression.[23]
Though the exact mechanism of action of Semax is unclear, there is evidence that it may act through melanocortin receptors. Specifically, there is a report of Semax competitively antagonizing the action of the melanocortin receptor full agonist α-melanocyte-stimulating hormone (α-MSH) at the MC4 and MC5 receptors in both in vitro and in vivo experimental conditions, indicating that it may act as an antagonist or partial agonist of these receptors.[2] Semax did not antagonize α-MSH at the MC3 receptor, though this receptor could still be a target of the drug.[2] As for the MC1 and MC2 receptors, they were not assayed.[2] In addition to actions at receptors, Semax, as well as a related peptide drug, Selank, have been found to inhibit enzymes involved in the degradation of enkephalins and other endogenous regulatory peptides (IC50 = 10 μM), though the clinical significance of this property is uncertain.[3]
Pharmacokinetics
As a peptide, Semax has poor oral bioavailability and hence is administered parenterally as a nasal spray or subcutaneous injection.
Chemistry
Semax is a heptapeptide and synthetic analogue of a fragment of adrenocorticotropic hormone (ACTH), ACTH (4-10), of the following amino acid sequence: Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP in single-letter form).[4]
History
Semax was first described in the scientific literature by 1991.[5]
Society and culture
Etymology
Semax is composed of seven amino acid residues: Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP), which is reflected in the name - from an abbreviation of "seven amino acids"—in Russian: СЕМь АминоКиСлот—СЕМАКС.
Marketing
Semax was developed, produced, and marketed by Peptogen in the Russian Federation with participation of the Institute of Molecular Genetics of the Russian Academy of Sciences.[citation needed]
See also
References
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