A practical reference on melanocortin signalling: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-03-22 and is reviewed periodically as new material appears.
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.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
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.
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 |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized solid from research suppliers |
| Solubility | Freely soluble in water | Also dissolves in aqueous buffers; solutions are used fresh |
| Typical storage temperature | -20 °C for lyophilized powder | Short-term transport at 2-8 °C is common |
| Common analytical method | Reverse-phase HPLC | Paired with mass spectrometry for identity confirmation |
| Common synonyms | ACTH(4-10) analogue; MEHFPGP | N-terminal methionine retained in the chain |
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
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.
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.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
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.
== Function == The gene is expressed in spindle-shaped cells located along nerve fibers between the auditory ganglion and sensory epithelium. These cells accompany neurites at the habenula perforata, the opening through which neurites extend to innervate hair cells. This and the pattern of expression of this gene in chicken inner ear paralleled the histologic findings of acidophilic deposits, consistent with mucopolysaccharide ground substance, in temporal bones from DFNA9 (autosomal dominant nonsyndromic sensorineural deafness 9) patients. Mutations that cause DFNA9 have been reported in this gene. Cochlin has been identified in the trabecular meshwork (TM) of glaucoma patients, but not in healthy controls. The TM is a filter like area of tissue in the eye; cochlin may have a role in cell adhesion, mechanosensation, and modulation of the TM filter. It is also expressed in follicular dendritic cells in spleen and lymph nodes. Here, cochlin is cleaved by aggrecanases and secreted into blood circulation during inflammation, contributing to the antibacterial innate immune response.
=== Lungs === Fibrothorax Pulmonary fibrosis Cystic fibrosis Idiopathic pulmonary fibrosis (idiopathic meaning 'of unknown cause') Radiation-induced lung injury (following radiation therapies commonly used to treat cancer)
Scottish scientist James W. Black developed propranolol in the 1960s. It was the first beta blocker effectively used in the treatment of coronary artery disease and hypertension. Black received the Nobel Prize in Physiology or Medicine in 1988 for this discovery. Propranolol is on the WHO Model list of essential medicines. Newer, more cardio-selective beta blockers (such as bisoprolol, nebivolol, carvedilol, or metoprolol) are used preferentially in the treatment of hypertension.
Sources: en.wikipedia.org
Critical fission reactors are the most common type of nuclear reactor. In a critical fission reactor, neutrons produced by fission of fuel atoms are used to induce yet more fissions, to sustain a controllable amount of energy release. Devices that produce engineered but non-self-sustaining fission reactions are subcritical fission reactors. Such devices use radioactive decay or particle accelerators to trigger fissions. Critical fission reactors are built for three primary purposes, which typically involve different engineering trade-offs to take advantage of either the heat or the neutrons produced by the fission chain reaction:
=== Research === 1ST-103 – undefined mechanism of action [140] LXM-5 – undefined mechanism of action [141] Parkinson's disease siRNA therapeutic - Argo Biopharma – RNA interference [142] Research programme: Parkinson's disease therapeutics - Beech Tree Labs (PD-A) – undefined mechanism of action – parkinsonian disorders [143]
=== Chemical and electrochemical techniques === Conversion coating Autophoretic, the registered trade name of a proprietary series of auto-depositing coatings specifically for ferrous metal substrates Anodising Chromate conversion coating Plasma electrolytic oxidation Phosphate (coating) Ion beam mixing Pickled and oiled, a type of plate steel coating Plating Electroless plating nickel plating coating using a different material to preserve mechanical properties Electroplating
=== E1 subunit === E1 uses thiamine pyrophosphate (TPP) as a catalytic cofactor. E1 catalyzes both the decarboxylation of the α-ketoacid and the subsequent reductive acylation of the lipoyl moiety (another catalytic cofactor) that is covalently bound to E2.
Sources: en.wikipedia.org
It consists mainly of animal experiments and small clinical reports, with much of the clinical material published in Russian-language journals. Large independent trials are scarce. Separating reliable effects from chance findings is consequently difficult.
A fraction of an intranasal dose is thought to reach the central nervous system, and this route is favoured partly for that reason. The proportion is not well characterized. Direct measurement in humans remains difficult with current methods.
Raised BDNF and NGF expression has been reported across several animal studies, which makes the signal fairly consistent. Whether the same change occurs in humans at usable doses is not established. It is best treated as a working hypothesis rather than a confirmed clinical mechanism.
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.