If you have been reading about intranasal route and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-07-16. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| 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 |
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.
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.
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.
29 September The kārearea is named Bird of the Year for 2025. The government announces a reform of the earthquake-prone building classification system which reduces the amount of buildings nationwide being classed as earthquake-prone by 55%. 30 September: Carter Holt Harvey confirms plans to close its Tokoroa plywood plant in November 2025, affecting 119 jobs. A measles case linked to international travel is reported in Queenstown, bringing the total number of cases to five.
=== Optical methods === Directed assembly or more specifically directed self-assembly, can produce a high pattern resolution (~10 nm) with high efficiency and compatibility. However, when using DSA in high volume manufacturing, one must have a way to quantify the degree of order of line/space patterns formed by DSA in order to reduce defect. Normal approaches, such as critical dimension-scanning electron microscopy (CD-SEM), to obtain data for pattern quality inspection take too much time and is also labor-intensive. On the other hand, the optical scatterometer-based metrology is a non-invasive technique and has very high throughput due to its larger spot size. These result in the collection of more statistical data than by using SEM, and that data processing is also automated with the optical technique making it more feasible than traditional CD-SEM.
7 December Storm Darragh: Hundreds of thousands are left without power, while travel is disrupted and many planned events are called off, as winds of up to 93 mph (150 km/h) hit much of the UK, along with heavy rain. A rare red weather warning is in place in Wales and south-west England, meaning the storm poses a risk to life. The deaths of two men are reported, in Birmingham and Lancashire, due to trees falling on vehicles. A 61-year-old Elizabeth line worker dies following a serious assault at Ilford railway station on 4 December. A 28-year-old man is charged with grievous bodily harm, affray, and possession of a prohibited offensive weapon. 8 December Prime Minister Sir Keir Starmer welcomes the Fall of the Assad regime in Syria, which he describes as "barbaric", and calls for the restoration of "peace and stability". Emma Pinchbeck, the new chief executive of the UK government's Climate Change Committee, says the UK is "not ready" for the kind of extreme weather brought by Storm Darragh. Prince William helps to serve lunch at The Passage, a London-based homeless charity he first visited with his mother as a boy. 9 December – The UK pauses asylum claims from Syrian refugees following the overthrow of Bashar al-Assad. 10 December The UK government recommends a 2.8% pay rise for public sector workers from April 2025. In response, the Unison trade union describes the offer as "barely above the cost of living". King Charles III presents the first Elizabeth Emblems, recognising public servants such as police officers and firefighters who died while on duty.
His magnum opus, De Sedibus et Causis Morborum per Anatomem Indagatis, published in 1761, describes the findings of over 600 partial and complete autopsies, organised anatomically and methodically correlated with the symptoms exhibited by the patients prior to their demise. Although the study of normal anatomy was already well advanced at this date, De Sedibus was one of the first treatises specifically devoted to the correlation of diseased anatomy with clinical illness. By the late 1800s, an exhaustive body of literature had been produced on the gross anatomical findings characteristic of known diseases. The extent of gross pathology research in this period can be epitomized by the work of the Viennese pathologist (originally from Hradec Kralove in the Czech Rep.) Carl Rokitansky (1804–1878), who is said to have performed 20,000 autopsies, and supervised an additional 60,000, in his lifetime.
Of Molecules and Men (Prometheus Books, 2004; original edition 1967) ISBN 1-59102-185-5 Life Itself: Its Origin and Nature (Simon & Schuster, 1981) ISBN 0-671-25562-2 What Mad Pursuit: A Personal View of Scientific Discovery (Basic Books reprint edition, 1990) ISBN 0-465-09138-5 The Astonishing Hypothesis: The Scientific Search for the Soul (Scribner reprint edition, 1995) ISBN 0-684-80158-2 Georg Kreisel: a Few Personal Recollections. In: Kreiseliana: About and Around Georg Kreisel (1996), pp. 25–32. ISBN 1-56881-061-X
Sources: en.wikipedia.org
=== Site hosting === Planet Half-Life also offered free web hosting for Half-Life themed websites. The web hosting was regulated through GameSpy, though the address of hosted sites were subsets of the Planet Half-Life domain. This was a major attraction of the site in its early days and many original Half-Life mod teams took advantage of the offer. However this feature has not been utilized nearly as much since the release of Half-Life 2. A directory of the old sites still exists, although most have been abandoned by their creators.
== Structure and interactions == DSIP is an amphiphilic peptide of molecular weight 850 daltons with the amino acid motif:N-Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu-C It has been found in both free and bound forms in the hypothalamus, limbic system and pituitary as well as various peripheral organs, tissues and body fluids. In the pituitary it co-localises with many peptide and non-peptide mediators such as corticotropin-like intermediate peptide (CLIP), adrenocorticotrophic hormone (ACTH), melanocyte-stimulating hormone (MSH), thyroid-stimulating hormone (TSH) and melanin concentrating hormone (MCH). It is abundant in the gut secretory cells and in the pancreas where it co-localises with glucagon. In the brain its action may be mediated by NMDA receptors. In another study delta-sleep-inducing peptide stimulated acetyltransferase activity through α1 receptors in rats. It is unknown where DSIP is synthesized. In vitro it has been found to have a low molecular stability with a half life of only 15 minutes due to the action of a specific aminopeptidase-like enzyme. It has been suggested that in the body it complexes with carrier proteins to prevent degradation, or exists as a component of a large precursor molecule, but as yet no structure or gene has been found for this precursor. Evidence supports the current belief that it is regulated by glucocorticoids. Gimble et al. suggest that DSIP interacts with components of the MAPK cascade and is homologous to glucocorticoid-induced leucine zipper (GILZ). GILZ can be induced by Dexamethasone.
During World War I Hahn served with a Landwehr regiment on the Western Front, and with the chemical warfare unit headed by Fritz Haber on the Western, Eastern and Italian fronts, earning the Iron Cross (2nd Class) for his part in the First Battle of Ypres. After the war he became the head of the KWIC, while remaining in charge of his own department. Between 1934 and 1938, he worked with Strassmann and Meitner on the study of isotopes created by neutron bombardment of uranium and thorium, which led to the discovery of nuclear fission. He was an opponent of Nazism and the persecution of Jews by the Nazi Party that caused the removal of many of his colleagues, including Meitner, who was forced to flee Germany in 1938. Nonetheless, during World War II, he worked on the German nuclear weapons program, cataloguing the fission products of uranium. At the end of the war he was arrested by the Allied forces and detained in Farm Hall with nine other German scientists, from July 1945 to January 1946. Hahn served as the last president of the Kaiser Wilhelm Society for the Advancement of Science in 1946 and as the founding president of its successor, the Max Planck Society from 1948 to 1960. In 1959, he co-founded the Federation of German Scientists, a non-governmental organisation committed to the ideal of responsible science. As he worked to rebuild German science, he became one of the most influential and respected citizens of post-war West Germany.
==== Nervous system ==== There are nerve cells, also known as neurons, present in the human body. They are branched out. These cells make up nervous tissue. A neuron consists of a cell body with a nucleus and cytoplasm, and cytoplasmic protrusions of an axon, and dendrites.
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.
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.