Everything below concerns neuropeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-05-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analogue of the ACTH(4-10) fragment |
| Amino acid sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Single-letter form MEHFPGP |
| Molecular formula | C37H51N9O10S | Free peptide, nominal mass near 814 Da |
| First registration | 1994, Russia | Nasal formulation for neurological indications |
| Typical purity grade | 95% or higher by HPLC | Research material; higher grades used as reference standards |
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
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.
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.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
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.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Given n and m, one can reverse this theoretical operation by drawing the vector w on the graphene lattice, cutting a strip of the latter along lines perpendicular to w through its endpoints A1 and A2, and rolling the strip into a cylinder so as to bring those two points together. If this construction is applied to a pair (k,0), the result is a zigzag nanotube, with closed zigzag paths of 2k atoms. If it is applied to a pair (k,k), one obtains an armchair tube, with closed armchair paths of 4k atoms.
=== 18 June === Ukrainian forces retook the village of Tykhe, west of Vovchansk. In Russia, the governor of Rostov Oblast claimed that several oil storage tanks were set on fire by a drone strike in Azov that destroyed 5,000 cubic metres of petroleum products. An oil depot in Krasnodar Krai was struck by Neptune missiles according to local sources, damaging a pipeline, “technical facilities” and starting a fire. No casualties were reported. A Ukrainian court sentenced a resident of Donetsk Oblast to 15 years' imprisonment for spying on Ukrainian positions on behalf of Russia during the Battle of Bakhmut. Swiss authorities claimed to have foiled an assassination attempt aimed at the Ukrainian peace summit, saying that a Russian diplomat was arrested a “few weeks” prior after trying to buy firearms. Ukrainian military observer Kostyantyn Mashovets claimed that the Russian Central Grouping of Forces has about 87,000 personnel, 365 tanks, 864 armored combat vehicles, of which about 68,000-70,000 personnel, 310-320 tanks, and about 576 armored fighting vehicles are currently deployed in the Pokrovsk direction.
== Further reading == Morris, S., Otto, N. C., Golemboski, K. (2013). Improving patient safety and healthcare quality in the 21st century—Competencies required of future medical laboratory science practitioners. Clinical Laboratory Science, 26, 200–204. Archibong, F., Atangwho, A., Ayuk, E. A., Okoye, E. I., Atroger, M., Okokon, B. I. (2019). Medical law: exploring doctor's knowledge on the laws regulating clinical and medical laboratories in Nigeria. Nigerian Journal of Medicine, 28(4), 386–392. Plebani, M., Laposata, M., Lippi, G. (2019). Driving the route of laboratory medicine: a manifesto for the future. Internal and Emergency Medicine, 14, 337–340. Goulding, M. H., Graham, L., Chorney, D., Rajendram, R. (2020). The use of interprofessional stimulation to improve collaboration and problem solving among undergraduate BHSc medical laboratory science and BScN nursing students. Canadian Journal of Medical Laboratory Science, 82(2), 25–33.
=== Microdosing === There is some evidence that a buprenorphine microdosing regime, started before opioid withdrawal symptoms have started, can be effective in helping people transition away from opioid dependence.
=== Research === Dihydromorphine, often labelled with the isotope tritium in the form of [3H]-dihydromorphine, is used in scientific research to study binding of the opioid receptors in the nervous system.
Sources: en.wikipedia.org
Chemical information, Clinical information and Biochemical information. The chemical data includes >40,000 metabolite structures with detailed descriptions, extensive chemical classifications, synthesis information and observed/calculated chemical properties. It also contains nearly 10,000 experimentally measured NMR, GC-MS and LC/MS spectra from more than 1,100 different metabolites. The clinical information includes data on >10,000 metabolite-biofluid concentrations, metabolite concentration information on more than 600 different human diseases and pathway data for more than 200 different inborn errors of metabolism. The biochemical information includes nearly 6,000 protein (and DNA) sequences and more than 5,000 biochemical reactions that are linked to these metabolite entries. The HMDB supports a wide variety of online queries including text searches, chemical structure searches, sequence similarity searches and spectral similarity searches. This makes it particularly useful for metabolomic researchers who are attempting to identify or understand metabolites in clinical metabolomic studies. The first version of the HMDB was released in Jan. 1 2007 and was compiled by scientists at the University of Alberta and the University of Calgary. At that time, they reported data on 2,500 metabolites, 1,200 drugs and 3,500 food components. Since then these scientists have greatly expanded the collection. The version 3.5 of the HMDB contains >16,000 endogenous metabolites, >1,500 drugs and >22,000 food constituents or food metabolites.
Tibetan Buddhist scholars rely on the north Indian works of scholars such as Asanga, Vasubandhu and Nagarjuna in their interpretation of the 12 nidanas. For example, according to Wayman, Tsongkhapa, attempted to harmonize the presentations of the 12 links found in Nagarjuna and in Asanga. Tsongkhapa also explains how the twelve nidanas can be applied to one life of a single person, two lives of a single person, and three lives of a single person. Discussing the three lifetimes model, Alex Wayman states that the Theravada interpretation is different from the Vajrayana view, because the Vajrayana view places a bardo or an intermediate state (which is denied in Theravada) between death and rebirth. The Tibetan Buddhism tradition allocates the twelve nidanas differently between various lives. Madhyamaka is interpreted in different ways by different traditions. Some scholars accept a version of the shentong view introduced by Dolpopa (1292–1361), which argues that buddha-nature and buddhahood was not dependently originated and thus not empty of itself (but empty of what is not itself). The Gelug school which follows Tsongkhapa's thought rejects this view, and instead holds that all phenomena are said to lack 'inherent' existence (svabhava) and thus, everything is empty and dependently originated. Other Tibetan madhyamakas like Gorampa argue for a more anti-realist view, negating the very existence of all phenomena and seeing them all as illusions.
Sedation is attributed to clonidine's activity on noradrenergic neurons of the locus coeruleus and thalamus. Somatodendritic α2 adrenoceptors reduce locus coeruleus firing, and presynaptic α2 adrenoceptors reduce norepinephrine release along noradrenergic pathways, in turn lowering noradrenergic modulation of arousal in the ascending reticular activating system. α2 adrenoceptors are also expressed on axon terminals that release several other neurotransmitters (i.e., serotonin, dopamine, acetylcholine, GABA, and glutamate), and their activation can suppress release at these synapses as well. Clonidine produces analgesic effects in part through α2 adrenoceptors in the dorsal horn of the spinal cord. In primary nociceptive neurons, α2A and α2C adrenoceptors are present on axon terminals and can be co-localized with neuropeptides involved in nociceptive signaling (e.g., substance P and calcitonin gene-related peptide), and clonidine inhibits their release in preclinical models. Activation of α2 adrenoceptors in the spinal cord reduces excitatory input to dorsal horn neurons and decreases dorsal horn neuron firing, thereby inhibiting nociceptive signaling. In addition to the synergistic effect clonidine has with opioids, naloxone, an opioid antagonist, can reverse clonidine overdose. The discovery of imidazoline receptors has prompted investigation of I1 receptor contributions to Clonidine's cardiovascular effects. I1 receptors are widely distributed, including in the central nervous system, and I1 activation has been implicated in clonidine's sympatholytic effect.
=== National advisory and leadership roles === Eaton was elected to the Institute of Medicine (now the National Academy of Medicine) in 2011 and has led key national scientific committees. He presided over NASEM committees on the health effects of e-cigarettes (2018), dioxin exposure (2004–2006), and engineered nanoscale materials (2008). He led the 2018 cell phone radiation review panel, advised the NIEHS/NTP Director (2023–2024), and chaired the Board of Scientific Counselors (2020–2022) for the National Toxicology Program. He was Chair of the Health Effects Institute Research Committee (2010–2018) and President of the Society of Toxicology (2001–2002) and the Academy of Toxicological Sciences (2025–2026).
Sources: en.wikipedia.org
=== Skin === Deficiencies in vitamin A have been linked to an increased susceptibility to skin infection and inflammation. Vitamin A appears to modulate the innate immune response and maintains homeostasis of epithelial tissues and mucosa through its metabolite, retinoic acid (RA). As part of the innate immune system, toll-like receptors in skin cells respond to pathogens and cell damage by inducing a pro-inflammatory immune response which includes increased RA production. The epithelium of the skin encounters bacteria, fungi and viruses. Keratinocytes of the epidermal layer of the skin produce and secrete antimicrobial peptides (AMPs). Production of AMPs resistin and cathelicidin, are promoted by RA.
== History == Studies conducted in the 1970s found that a series of N-formylmethionine-containing oligopeptides, including the most potent and best known member of this series, N-Formylmethionine-leucyl-phenylalanine (FMLP or fMet-Leu-Phe), stimulated rabbit and human neutrophils by an apparent receptor-dependent mechanism to migrate in a directional pattern in classical laboratory assays of chemotaxis. Since these oligopeptides were produced by bacteria or synthetic analogs of such products, it was suggested that the N-formyl oligopeptides are important chemotactic factors and their receptors are important chemotactic factor receptors that act respectively as signaling and signal-recognizing elements to initiate Inflammation responses in order to defend against bacterial invasion. Further studies cloned a receptor for these N-formyl oligopeptides, FPR1. Two receptors where thereafter discovered and named FPR2 and FPR3 based on the similarity of their genes' predicted amino acid sequence to that of FPR1 rather than on any ability to bind or be activated by the formyl oligopeptides. The latter two receptors were subsequently found to have very different specificities for the formyl oligopeptides and very different functions than those for FPR1. FPR1 is the premiere receptor for the pro-inflammatory actions of formyl peptides.
==== Nervous system ==== The connections between neurons, the primary cell of the nervous system, forms neural pathways, neural circuits, and large-scale brain networks. Subsystems of the human nervous system include:
Sources: en.wikipedia.org
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.
No. The peptide is synthetic, although it is modelled on a fragment of a naturally occurring hormone. ACTH(4-10) is generated when ACTH is cleaved, but the Pro-Gly-Pro extension is not a known endogenous sequence. It is therefore a designed analogue rather than a natural metabolite.
The label reflects reported effects on attention, memory and recovery after neurological injury in regional clinical reports. Those reports are mostly small and have not been widely replicated outside the region. The classification is descriptive and does not imply a single defined mechanism.
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.