A practical reference on intranasal route: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-08-27. Anything still debated is marked as such rather than presented as settled.
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.
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 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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular weight | ~813.9 Da (free heptapeptide) | N-acetylated form is about 42 Da heavier |
| Residue count | 7 (heptapeptide) | Four residues from ACTH(4-10), three added |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility class | Freely soluble in water | Also dissolves in DMSO and polar organic solvents |
| Related parent fragment | ACTH(4-10) | Parent motif is Met-Glu-His-Phe |
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.
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.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
== Clinical significance == Mutations in this gene have been associated with tardive dyskinesia (TD), an increased risk of hematotoxicity after exposure to benzene, and susceptibility to various forms of cancer. Altered expression of this protein has been seen in many tumors and is also associated with Alzheimer's disease (AD).
In series 4, Eric is retired, wealthy but professionally adrift and estranged from his children, when Harper recruits him to co-found SternTao, a fund dedicated to shorting corrupt companies, with fintech firm Tender as their first major target. Eric liquidates his family office to finance the venture, and he and Harper clash over boundaries, with Harper accusing him of losing his edge and using the partnership to compensate for his failures as a father. Eric identifies Tender’s “satellite office” in Sunderland, prompting Harper’s investigation into the company’s laundering of African revenues. He later receives a secretly recorded video of himself with a prostitute named Dolly—planted by Tender—alongside a passport indicating she is 15 years old. Despite the blackmail, Eric appears on CNN opposite Whitney Halberstram to call for a new audit. He then abruptly dissolves SternTao and ends his partnership with Harper without explanation; Harper brands him a coward. The Tender short ultimately nets £110 million, but Eric does not answer when Harper calls to share the news. Yasmin later shows Harper the incriminating video, falsely claiming Dolly misrepresented her age and that Eric was attracted to the idea of sleeping with a teenager, further devastating Harper.
== Political activity == Shawn has written many plays with socialist themes; much of his work examines the "connective tissue between private psychology and the politics of inequality". He identifies as a socialist in the 2011 essay "Why I Call Myself a Socialist: Is the World Really a Stage?", which was published online and later in his Essays. In June 2013, Shawn and many other public figures appeared in a video showing support for Chelsea Manning, a U.S. Army soldier imprisoned for leaking classified material.
=== Colette Green === Dr. Colette Green (voiced by Lani Minella) is a Black Mesa scientist and one half of the protagonist team in Half-Life: Decay. In Decay, Dr. Green's role in the experiment is to make preparations in a room below the test chamber and initiate the Anti-Mass Spectrometer to run at 105%. Dr. Gina Cross also enters the same room to fix a jam in the specimen delivery system's lift mechanism, meaning they are both in the same place when the Resonance Cascade finally occurs. Following the disaster, the two team up to fight their way through the facility for survival. They escort Dr. Rosenberg to the surface to call the military for help and then, with the help of Dr. Richard Keller, manage to start a resonance reversal to prevent the dimensional rift from becoming too large to be repaired. The outcome for Dr. Green, along with the rest of the survivors in Decay, is unknown to the other Black Mesa survivors.
=== Kinetic and equilibrium isotope effects === Isotopes differ by number of neutrons, which directly impacts physical properties based on mass and size. Normal hydrogen (protium, 1H) has no neutron. Deuterium (2H) has one neutron, and tritium (3H) has two. Neutrons add mass to the atom, leading to different chemical physical properties. This effect is especially strong for hydrogen isotopes, since the added neutron doubles the mass from 1H to 2H. For heavier elements like carbon, nitrogen, oxygen, or sulfur, the mass difference is diluted. Physical chemists often model chemical bonding with the quantum harmonic oscillator (QHO), simplifying a hydrogen-hydrogen bond as two balls connected by a spring. The QHO is based on Hooke's law and is a good approximation of the Morse potential that accurately describes bonding. Modeling H/2H in a chemical reaction demonstrates the energy distributions of isotopes in products and reactants. Lower energy levels for the heavier isotope 2H can be explained mathematically by the QHO's dependence on the inverse of the reduced mass μ. Thus, a larger reduced mass is a larger denominator and thus a smaller zero point energy and a lower energy state in the quantum well.
Sources: en.wikipedia.org
The head is as large as an ordinary flour barrel, and has the shape of a sea lion head. The neck, if the creature may be said to have a neck, is of the same diameter as the body. The mouth is on the underside of the head and is protected by two tentacle tubes about eight inches in diameter and about 30 feet long. These tubes resemble an elephant's trunk and obviously were used to clutch in a sucker like fashion any object within their reach. Another tube or tentacle of the same dimensions stands out on the top of the head. Two others, one on each side, protrude from beyond the monster's neck, and extend fully 15 feet along the body and beyond the tail. The tail, which is separated and jagged with cutting points for several feet, is flanked with two more tentacles of the same dimensions as the others and 30 feet long. The eyes are under the back of the mouth instead of over it. This specimen is so badly cut up by sharks and sawfish that only the stumps of the tentacles remain, but pieces of them were found strewn for some distance on the beach, showing that the animal had a fierce battle with its foes before it was disabled and beached by the surf. Grant describes the animal as having seven "tentacles" and a "tail". If the "tail" is interpreted as another tentacle, giving a total of eight, this would suggest an octopus as opposed to a decapod, such as the squid or cuttlefish. Furthermore, nothing in the description indicates the presence of the long feeding tentacles found in squid, as the "tentacles" are said to be of the same dimensions.
The history of mass spectrometry has its roots in physical and chemical studies regarding the nature of matter. The study of gas discharges in the mid 19th century led to the discovery of anode and cathode rays, which turned out to be positive ions and electrons. Improved capabilities in the separation of these positive ions enabled the discovery of stable isotopes of the elements. The first such discovery was with the element neon, which was shown by mass spectrometry to have at least two stable isotopes: 20Ne (neon with 10 protons and 10 neutrons) and 22Ne (neon with 10 protons and 12 neutrons). Mass spectrometers were used in the Manhattan Project for the separation of isotopes of uranium necessary to create the atomic bomb.
stimulation or inhibition of growth wake-sleep cycle and other circadian rhythms mood swings induction or suppression of apoptosis (programmed cell death) activation or inhibition of the immune system regulation of metabolism preparation of the body for mating, fighting, fleeing, and other activity preparation of the body for a new phase of life, such as puberty, parenting, and menopause control of the reproductive cycle hunger cravings A hormone may also regulate the production and release of other hormones. Hormone signals control the internal environment of the body through homeostasis.
It predominantly affects children between the ages of two and six years in the least developed countries around the world, primarily in sub-Saharan Africa. Noma survivors experience stigma, social isolation, and discrimination within their communities. These can be countered by education and community outreach programs.
Sources: en.wikipedia.org
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.
Semax is a synthetic analog of the ACTH(4-10) fragment rather than a copy of the full hormone. Truncation plus the added tail removes the steroidogenic portion of ACTH. That distinction explains why it is studied for nervous-system effects instead of adrenal stimulation.
It is registered as a prescription product in Russia and has been used there clinically, chiefly by the intranasal route. No approval exists in the United States or the European Union. Availability elsewhere typically falls under research-chemical distribution, with varying purity documentation.
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.