Semax is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-01-24. Numbers and descriptions here follow the published literature rather than marketing material.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Calculated for the free peptide |
| Molar mass | 813.9 g/mol | Anhydrous free base |
| Peptide class | Synthetic heptapeptide | ACTH(4-10) analogue |
| Parent fragment | ACTH(4-10) | Adrenocorticotropic hormone segment |
| Developmental origin | Institute of Molecular Genetics, Moscow | Work began in the 1980s |
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
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.
== Discovery == Calcitonin was first purified in 1962 by Douglas Harold Copp and B. Cheney at the University of British Columbia, Canada. It was initially thought to be secreted by the parathyroid gland but was shown by Iain Macintyre and his team at the Royal Postgraduate Medical School, London, to be secreted by parafollicular cells of the thyroid gland. Dr. Copp named the discovered hormone calcitonin because of its role in 'maintaining normal calcium tone'.
== Research == A systematic review that looked at the efficacy of antidepressants for pain relief concludes that only 11 of 42 comparisons showed evidence of efficacy. Seven of the eleven comparisons belong to the SNRI drug class.
== Pharmacokinetics == The molecular weight, bioavailability, protein binding, elimination half-life, the time to achieve maximum plasma concentration and binding affinity are present in the table below.
=== Insulin resistance === Insulin resistance contributes to the accumulation of toxic fat in the liver in several ways. First, it promotes the release of free fatty acids (FFAs) from adipose tissue into the blood. Typically, adipose tissue stores lipids in the form of triglycerides, slowly releasing them into the bloodstream when insulin is low. In insulin-resistant adipose tissue, such as in people with obesity and type 2 diabetes, more triglycerides are broken down into FFAs and released into the bloodstream, promoting uptake by the liver. Second, insulin promotes the production of new FFAs in the liver via de novo lipogenesis; this production of liver fats continues to be stimulated by insulin, even when other tissues are insulin-resistant. These FFAs are combined back into triglycerides in the liver, forming the major constituent of the accumulated fat in the liver. The three sources of free fatty acids that contribute to liver triglyceride accumulation include FFAs circulating in the bloodstream (59%), FFAs derived from carbohydrates such as fructose and glucose (26%), and diet (14%). Despite the accumulation of triglycerides in the liver, they are not directly toxic to liver tissue. Instead, alteration of the profile of the other lipid subtypes present in the liver, such as diacylglycerols, phospholipids, ceramides, and free cholesterol, has a more significant role in the pathogenesis of MASLD.
Succinate-Q oxidoreductase, also known as complex II or succinate dehydrogenase, is a second entry point to the electron transport chain. It is unusual because it is the only enzyme that is part of both the citric acid cycle and the electron transport chain. Complex II consists of four protein subunits and contains a bound flavin adenine dinucleotide (FAD) cofactor, iron–sulfur clusters, and a heme group that does not participate in electron transfer to coenzyme Q, but is believed to be important in decreasing production of reactive oxygen species. It oxidizes succinate to fumarate and reduces ubiquinone. As this reaction releases less energy than the oxidation of NADH, complex II does not transport protons across the membrane and does not contribute to the proton gradient.
Sources: en.wikipedia.org
=== Military restructuring === Spain's international wars in the second half of the 18th century evidenced the empire's difficulties in reinforcing its colonial possessions and provide them with economic aid. This led to an increased local participation in the financing of the defense and an increased participation in the militias by the locally-born. Such development was at odds with the ideals of the centralized absolute monarchy. The Spanish did also formal concessions to strengthen the defense: In Chiloé Archipelago Spanish authorities promised freedom from the encomienda to those indigenous locals who settled near the new stronghold of Ancud (founded in 1768) and contributed to its defense. The increased local organization of the defenses would ultimately undermine metropolitan authority and bolster the independence movement.
=== Other uses === Acetylcysteine has been used to complex palladium, to help it dissolve in water. This helps to remove palladium from drugs or precursors synthesized by palladium-catalyzed coupling reactions. N-acetylcysteine can be used to protect the liver.
Pregnenolone acetate (brand names Antofin, Previsone, Pregno-Pan), also known as pregn-5-en-3β-ol-20-one 3β-acetate, is a synthetic pregnane steroid and an ester of pregnenolone which is described as a glucocorticoid and as a skin-conditioning and skin anti-aging agent. It has been reported to reduce wrinkles in elderly women when applied in the form of a 0.5% topical cream, effects which were suggested to be due to improved hydration of the skin. Pregnenolone acetate has been marketed in France in a topical cream containing 1% pregnenolone acetate and 10% "sex hormone" for the treatment of premature skin aging but was withdrawn from the market in 1992. Although the medication has been described by some sources as a glucocorticoid, other authors have stated that systemic pregnenolone acetate has no undesirable metabolic or toxic effects even at high doses.
Mutations may produce unstable antithrombins that either may be not exported into the blood correctly upon completion biosynthesis or exist in the blood for a shortened period of time, e.g., the deletion of 6 base pairs in codons 106–108. Minor insertions or deletions may lead to frame shift mutations and premature termination of the antithrombin gene. Point mutations may also result in the premature generation of a termination or stop codon e.g. the mutation of codon 129, CGA→TGA (UGA after transcription), replaces a normal codon for arginine with a termination codon. Mutations near the intron-exon border and in non-coding regions can lead to aberrant splicing. In a small percentage of antithrombin deficiency cases, no (likely) pathogenic variants can be found in the SERPINC1 gene. There is evidence that post-translational glycosylation defects can explain the antithrombin deficiency in some of these cases.
Sources: en.wikipedia.org
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.
It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.
The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.