Everything below concerns ACTH(4-10). We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-11-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | ACTH(4-7) analogue |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Free N terminus, unmodified side chains |
| Molecular weight | 813.9 Da | Free base; salt forms differ |
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility | Freely soluble in water | Hydrophilic; polar solvents preferred |
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.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
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.
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.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
== History and development == The first site was launched in 2001 by the American Association for Clinical Chemistry, the scientific society for clinical laboratory science. This led to a collaboration with professional societies in 17 other countries representing the laboratory medicine community. Each site is separately managed to allow both appropriate languages and information that matches local needs.
==== UN Single Convention on Narcotic Drugs ==== On 8 March 2016 at its 59th Session, the Commission on Narcotic Drugs (CND) added Phenazepam to relevant schedules of the Convention on Psychtropic Substances of 1971.
== Animal toxicity == κ-Bungarotoxin can selectively bind to neuronal nAChRs, by which it inhibits or blocks neurotransmission. The toxin shows different effects in diverse animals. For instance, in insects, κ-bungarotoxin blocks transmission at the cholinergic synapse between mechanosensory neurons and an interneuron in the terminal abdominal ganglion. It also blocks nAChRs on a motor neuron in the metathoracic ganglion of a cockroach. Muscle nAChRs in nematodes show a higher sensitivity to κ-bungarotoxin than the alpha-version of the bungarotoxin. Compared to another toxin, only a concentration of 10 nM was needed to block the muscle receptor instead of 100 nM. This also means that there is a difference in effects of the toxin on different animals, because it appears that nematodes are more sensitive to κ-bungarotoxin than insects. In chicks, the κ-bungarotoxin seems to bind with a low affinity to skeletal muscle nicotinic receptors[12]. Although the effects on the chicks have not been described, following the mechanism it is expected that there will be either none or a small amount of muscle paralysis at a low concentration of κ-bungarotoxin. However, the toxin does bind with high affinity to the neuronal nicotinic receptors in the autonomic ganglia, which can block the synaptic transmission already at a low concentration. This would cause effects like respiratory failure.
=== DNA damage === Arsenic is reported to cause DNA modifications such as aneuploidy, micronuclei formation, chromosome abnormality, deletion mutations, sister chromatid exchange and crosslinking of DNA with proteins. It has been demonstrated that arsenic does not directly interact with DNA and it is considered a poor mutagen, but instead, it helps mutagenicity of other carcinogens. For instance, a synergistic increase in the mutagenic activity of arsenic with UV light has been observed in human and other mammalian cells after exposing the UV-treated cells to arsenic. A series of experimental observations suggest that the arsenic genotoxicity is primarily linked to the generation of reactive oxygen species (ROS) during its biotransformation. The ROS production is able to generate DNA adducts, DNA strand breaks, crosslinks and chromosomal aberrations. The oxidative damage is caused by modification of DNA nucleobases, in particular 8-oxoguanine (8-OHdG) which leads to G:C to T:A mutations. Inorganic arsenic can also cause DNA strand break even at low concentrations.
Sources: en.wikipedia.org
Relaxin/insulin-like family peptide receptor 2, also known as RXFP2, is a human G-protein coupled receptor. The receptors for glycoprotein hormones such as follicle-stimulating hormone (FSH; see MIM 136530) and thyroid-stimulating hormone (TSH; see MIM 188540) are G protein-coupled, 7-transmembrane receptors (GPCRs) with large N-terminal extracellular domains. Leucine-rich repeat (LRR)-containing GPCRs (LGRs) form a subgroup of the GPCR superfamily. [supplied by OMIM].
=== Battery === Nuclear Magnetic Resonance (NMR) is a powerful analytical tool for investigating the local structure and ion dynamics in battery materials. NMR provides unique insights into the short-range atomic environments within complex electrochemical systems such as batteries. Electrochemical processes rely on redox reactions, in which 7Li or 23Na are often involved. Accordingly, their NMR spectroscopies are affected by the electronic structure of the material, which makes NMR an essential technique for probing the behavior of battery components during operation. Some of the applications of NMR in battery research include:
== Epidemiology == In the United States, approximately 550,000 people die each year from heart-related arterial embolism and thrombosis. Approximately 250,000 of these individuals are female, and approximately 100,000 of all these deaths are considered premature, that is, prior to the age of average life expectancy.
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=== Thiol/disulfide chemistry === Glutathione reductase (GR) catalyzes the reduction of glutathione disulfide (GSSG) to glutathione (GSH). GR requires FAD and NADPH to facilitate this reaction; first a hydride must be transferred from NADPH to FAD. The reduced flavin can then act as a nucleophile to attack the disulfide, this forms the C4a-cysteine adduct. Elimination of this adduct results in a flavin-thiolate charge-transfer complex.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.
It contains the 4-7 fragment of adrenocorticotropic hormone extended at the C terminus. That truncation removes the region associated with steroidogenic activity. The design intent was to keep neurotrophic properties while avoiding full hormonal effects.
No natural source of the intact heptapeptide is known. It is produced by solid-phase peptide synthesis. Some related ACTH fragments arise as hormone processing products, but the Pro-Gly-Pro extension is a designed addition rather than a natural sequence.
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.