A practical reference on ACTH(4–10): what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-01. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
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.
The smelling organs of the terrestrial coconut crab are similar to those of insects. In an odd cross-phyla example, an insect, the hummingbird hawk-moth (Macroglossum stellatarum), also feeds by hovering in front of flowers and drinking their nectar in the same way as hummingbirds and sunbirds. Pill bugs and pill millipedes have evolved near-identical defensive plates, even being difficult to tell apart at a glance. The giant isopod also provides a large, deep-sea equivalent. Silk: spiders, silk moths, larval caddis flies, and the weaver ant all produce silken threads. The praying mantis body type – raptorial forelimb, prehensile neck, and extraordinary snatching speed - has evolved not only in mantises but also independently in neuropteran insects Mantispidae. Gripping limb ends have evolved separately in scorpions and in some decapod crustaceans, like lobsters and crabs. These chelae or claws have a similar architecture: the next-to-last segment grows a projection that fits against the last segment. Agriculture: some kinds of ants, termites, and ambrosia beetles have for a long time cultivated and tend fungi for food. These insects sow, fertilize, and weed their crops. A damselfish also takes care of red algae carpets on its piece of reef; the damselfish actively weeds out invading species of algae by nipping out the newcomer. Slave-making behavior has evolved several times independently in the ant subfamilies Myrmicinae and Formicinae, and more than ten times in total in ants. Proleg: a fleshy leg on many larvae of insects has independently evolved in several orders.
Masa or masa de maíz (English: ; Spanish pronunciation: [ˈmasa]) is a dough made from ground nixtamalized corn. It is used for making corn tortillas, gorditas, tamales, pupusas, and many other Latin American dishes. It is dried and powdered into a flour form called harina de maíz or masa harina. Masa is reconstituted by mixing with water before using it in cooking. In Spanish, masa translates simply to "dough" and harina translates to "flour", but the name masa harina does not follow Spanish grammar and the term does not exist in Spanish.
===== Light collector ===== Using graphene as a photoactive material requires its bandgap to be 1.4–1.9 eV. In 2010, single cell efficiencies of nanostructured graphene-based PVs of over 12% were achieved. According to P. Mukhopadhyay and R. K. Gupta organic photovoltaics could be "devices in which semiconducting graphene is used as the photoactive material and metallic graphene is used as the conductive electrodes". In 2008, chemical vapor deposition produced graphene sheets by depositing a graphene film made from methane gas on a nickel plate. A protective layer of thermoplastic is laid over the graphene layer and the nickel underneath is then dissolved in an acid bath. The final step is to attach the plastic-coated graphene to a flexible polymer sheet, which can then be incorporated into a PV cell. Graphene/polymer sheets range in size up to 150 square centimeters and can be used to create dense arrays. Silicon generates only one current-driving electron for each photon it absorbs, while graphene can produce multiple electrons. Solar cells made with graphene could offer 60% conversion efficiency.
Sources: en.wikipedia.org
=== Relapse === Rates of relapse after treatment range 30–72% over a period of 2–26 months, with a rate of approximately 50% in 12 months after weight restoration. Relapse occurs in approximately a third of people in hospital, and is greatest in the first six to eighteen months after release from an institution. BMI or measures of body fat and leptin levels at discharge were the strongest predictors of relapse, as well as signs of eating psychopathology at discharge. Duration of illness, age, severity, the proportion of AN binge-purge subtype, and presence of comorbidities are also contributing factors.
== Personal life == Larson is married to Leslie Best. They have three children and reside in East Hartford. On February 11, 2025, while speaking on the floor of the House, Larson froze for about 30 seconds mid-sentence. His office later responded that it was likely an "adverse reaction" to new medication, and underwent tests conducted by the Attending Physician of the United States Congress. His office later clarified that Larson had experienced a complex partial seizure caused by a heart valve replacement fifteen years earlier. Larson returned to his duties and was present for voting on the House floor on February 13.
Juxtarestiform body A bundle of fibers within the inferior cerebellar peduncle that connects the vestibular nuclei to the cerebellum, involved in balance and eye movement coordination. Junctional complex A structural region where neurons, glia, or epithelial cells make close contact. In the nervous system, includes tight junctions and adherens junctions that help form the blood–brain barrier.
Sources: en.wikipedia.org
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.