If you have been reading about ACTH analog 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.
Updated 2026-06-16. Numbers and descriptions here follow the published literature rather than marketing material.
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 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.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
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.
| 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 |
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.
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.
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.
=== Coagulation test === The liver is responsible for the production of the vast majority of coagulation factors. In patients with liver disease, international normalized ratio (INR) can be used as a marker of liver synthetic function as it includes factor VII, which has the shortest half life (2–6 hours) of all coagulation factors measured in INR. An elevated INR in patients with liver disease, however, does not necessarily mean the patient has a tendency to bleed, as it only measures procoagulants and not anticoagulants. In liver disease the synthesis of both are decreased and some patients are even found to be hypercoagulable (increased tendency to clot) despite an elevated INR. In liver patients, coagulation is better determined by more modern tests such as thromboelastogram (TEG) or thomboelastrometry (ROTEM). Prothrombin time (PT) and its derived measures of prothrombin ratio (PR) and INR are measures of the extrinsic pathway of coagulation. This test is also called "ProTime INR" and "INR PT". They are used to determine the clotting tendency of blood, in the measure of warfarin dosage, liver damage, and vitamin K status.
=== Available forms === Nalbuphine is available in two concentrations, 10 mg and 20 mg of nalbuphine hydrochloride per mL. Both strengths contain 0.94% sodium citrate hydrous, 1.26% citric acid anhydrous, 0.1% sodium metabisulfite, and 0.2% of a 9:1 mixture of methylparaben and propylparaben as preservatives; pH is adjusted, if necessary, with hydrochloric acid. The 10 mg/mL strength contains 0.1% sodium chloride. The drug is also available in a sulfite and paraben-free formulation in two concentrations, 10 mg and 20 mg of nalbuphine hydrochloride per mL. One mL of each strength contains 0.94% sodium citrate hydrous, 1.26% citric acid anhydrous; pH is adjusted, if necessary, with hydrochloric acid. The 10 mg/mL strength contains 0.2% sodium chloride. An investigational extended-release oral formulation is under development by Trevi Therapeutics.
== External links == Drug Interactions: What You Should Know. U.S. Food and Drug Administration, Center for Drug Evaluation and Research, September 2013 COVID 19 Drug interaction check tool University of Liverpool
== Epidemiology == With the difficulty in diagnosing a TIA due to its nonspecific symptoms of neurologic dysfunction at presentation and a differential diagnosis including many mimics, the exact incidence of the disease is unclear. It was estimated to have an incidence of approximately 200,000 to 500,000 cases per year in the US in the early 2000s according to the American Heart Association. TIA incidence trends similarly to stroke, such that incidence varies with age, gender, and different race/ethnicity populations. Associated risk factors include age greater than or equal to 60, blood pressure greater than or equal to 140 systolic or 90 diastolic, and comorbid diseases, such as diabetes, hypertension, atherosclerosis, and atrial fibrillation. It is thought that approximately 15 to 30 percent of strokes have a preceding TIA episode associated.
== Research and applications == Advances in this area are inhibited by the lack of synthetic methods. In this context, theoretical modeling has emerged as a pivotal tool to understand the self-assembly or -disassembly processes in these systems. Possible applications have been demonstrated for AMMs, including those integrated into polymeric, liquid crystal, and crystalline systems for varied functions. Homogenous catalysis is a prominent example, especially in areas like asymmetric synthesis, utilizing noncovalent interactions and biomimetic allosteric catalysis. AMMs have been pivotal in the design of several stimuli-responsive smart materials, such as 2D and 3D self-assembled materials and nanoparticle-based systems, for versatile applications ranging from 3D printing to drug delivery. AMMs are gradually moving from the conventional solution-phase chemistry to surfaces and interfaces. For instance, AMM-immobilized surfaces (AMMISs) are a novel class of functional materials consisting of AMMs attached to inorganic surfaces forming features like self-assembled monolayers; this gives rise to tunable properties such as fluorescence, aggregation and drug-release activity. Most of these "applications" remain at the proof-of-concept level. Challenges in streamlining macroscale applications include autonomous operation, the complexity of the machines, stability in the synthesis of the machines and the working conditions.
Sources: en.wikipedia.org
Israel–Hezbollah conflict (2023–present): The Ministry of Defence announces that 700 British troops will be deployed to Cyprus in anticipation of an evacuation of British citizens from Lebanon. Starmer advises British nationals in Lebanon to "leave immediately" as tension between Hezbollah and Israel increases. 25 September – Petrol prices fall to their lowest level in three years, with the average price for a litre of unleaded costing about £1.35. 27 September Lexi Secker, a transgender woman who raped a woman on a night out prior to identifying as a woman, is jailed for six and a half years with the sentence to be served in a male prison. Two 13-year-old boys are detained for at least eight and a half years for the 2023 murder of Shawn Seesahai in Wolverhampton, carried out using a machete when they were 12. They are the youngest killers to be sentenced since the murder of James Bulger in 1993. Sir Brian May resigns as vice president of the Royal Society for the Prevention of Cruelty to Animals (RSPCA) over what he describes as "damning evidence" of animal welfare failings related to its food certification label. 28 September – Labour MP Rosie Duffield quits the party over what she describes as leader Keir Starmer's "cruel" policies and "staggering hypocrisy" over his acceptance of gifts. In her resignation letter to Starmer she says, "The sleaze, nepotism and apparent avarice are off the scale.
=== Doping in sport === LGD-4033 is on the World Anti-Doping Association (WADA) list of prohibited drugs and has been found in drug testing samples of some athletes. Since at least June 2015, LGD-4033 has been available via the internet. In that month, German scientists proposed a new test to detect its metabolites present in human urine, and suggested an expansion of the WADA regime. LGD-4033 has been found in WADA samples and in racehorses as well.
Synthetic oxytocin, sold under the brand name Pitocin among others, is a medication made from the peptide oxytocin. As a medication, it is used to cause contraction of the uterus to start labor, increase the speed of labor, and to stop bleeding following delivery. For this purpose, it is given by injection either into a muscle or into a vein. Oxytocin is also available in intranasal spray form for psychiatric, endocrine and weight management use as a supplement. Intranasal oxytocin works on a different pathway than injected oxytocin, primarily along the olfactory nerve crossing the blood–brain barrier to the olfactory lobe in the brain, where dense magnocellular oxytocin neurons receive the nerve impulse quickly. The natural occurrence of oxytocin was discovered in 1906. It is on the World Health Organization's List of Essential Medicines.
The album was noted for its performance style, that occasionally veered towards funk, and for Burrell's scat singing on the improvised pieces, but was criticised for its poor sound quality. Better-quality live recordings from this era would be released in 2002 as Ladies of the Road and in 2017 on the Sailors' Tales (1970–1972) box set. By this time the musical rift between Fripp and the rest of the band had grown very wide. Wallace, Burrell, and Collins favoured improvised blues- and funk-influenced music; Fripp would later describe the 1971–1972 line-up as more of a jam band than an "improvising" band, an opinion with which Wallace disagreed. Personal relations, however, improved during the tour to the point where most of the band wanted to continue; nonetheless, Fripp opted to part company with the other three and reconstitute King Crimson with new musicians, as he felt the other members would not fully engage with the musical direction he now had in mind. Collins went on to join Camel, Burrell co-formed Bad Company, and Wallace became a session musician, most notably playing on several Bob Dylan albums and the Traveling Wilburys' first album.
Sources: en.wikipedia.org
Okcuoglŭ, A.; Arcasoy, A.; Minnich, V.; Tarcon, Y.; Cin, S.; Yörükoğlu, O.; Demirag, B.; Renda, F. (August 1966). "Pica in Turkey. 1. The incidence and association with anemia". The American Journal of Clinical Nutrition. 19 (2): 125–131. doi:10.1093/ajcn/19.2.125. ISSN 0002-9165. PMID 5222998. Minnich, V.; Okçuoğlu, A.; Tarcon, Y.; Arcasoy, A.; Cin, S.; Yörükoğlu, O.; Renda, F.; Demirağ, B. (January 1968). "Pica in Turkey. II. Effect of clay upon iron absorption". The American Journal of Clinical Nutrition. 21 (1): 78–86. doi:10.1093/ajcn/21.1.78. ISSN 0002-9165. PMID 5237295. Glutathione synthesis
Cocaine use during pregnancy can affect a pregnant woman and her unborn baby in many ways. During the early months of pregnancy, it may increase the risk of miscarriage. Later in pregnancy, it can trigger preterm labor (labor that occurs before 37 weeks of pregnancy) or cause the baby to grow poorly. As a result, cocaine-exposed babies are more likely than unexposed babies to be born with low birth weight (less than 5.5 lb or 2.5 kg). Low-birthweight babies are 20 times more likely to die in their first month of life than normal-weight babies, and face an increased risk of lifelong disabilities such as mental retardation and cerebral palsy. Cocaine-exposed babies also tend to have smaller heads, which generally reflect smaller brains. Some studies suggest that cocaine-exposed babies are at increased risk of birth defects, including urinary tract defects and, possibly, heart defects. Cocaine also may cause an unborn baby to have a stroke, irreversible brain injury, or a myocardial infarction.
=== Magnetic immunoassay === Magnetic immunoassay (MIA) is a novel type of diagnostic immunoassay utilizing magnetic nanobeads as labels in lieu of conventional, enzymes, radioisotopes or fluorescent moieties. This assay involves the specific binding of an antibody to its antigen, where a magnetic label is conjugated to one element of the pair. The presence of magnetic nanobeads is then detected by a magnetic reader (magnetometer) which measures the magnetic field change induced by the beads. The signal measured by the magnetometer is proportional to the analyte (virus, toxin, bacteria, cardiac marker, etc.) quantity in the initial sample.
The current epidemic of opioid abuse is the most lethal drug epidemic in U.S. history. The crisis can be distinguished by waves of opioid overdose deaths as described by the Centers of Disease Control and Prevention. The first wave began in the 1990s, related to the rise in prescriptions of natural opioids (such as codeine and morphine), semisynthetic opioids (oxycodone, hydrocodone, hydromorphone, and oxymorphone), and synthetic opioids like methadone. In the U.S., "the age-adjusted drug poisoning death rate involving opioid analgesics increased from 1.4 to 5.4 deaths per 100,000 population between 1999 and 2010". The second wave dates to around 2010 with the rapid increase in opioid overdoses due to heroin. By this time, there were already four times as many deaths by overdose than in 1999. The age-adjusted drug poisoning death rate involving heroin doubled from 0.7 to 1.4 deaths per 100,000 people between 1999 and 2011 and continued to increase to 4.1 in 2015. The third wave of overdose deaths began in 2013, related to synthetic opioids, particularly illicitly produced fentanyl. While the illicit fentanyl market has continuously changed, the drug is generally sold as an adulterant in heroin. Research suggests that the rapid increase of fentanyl into the illicit opioid market has been largely supply-side-driven and dates to 2006.
=== Derivatives === A number of derivatives of 18-MC have been developed, with several of them being superior to 18-MC itself, the methoxyethyl congener ME-18-MC being more potent than 18-MC with similar efficacy, and the methylamino analogue 18-MAC being more effective than 18-MC with around the same potency. These compounds were also found to act as selective α3β4 nicotinic acetylcholine antagonists, with little or no effect on NMDA receptors.
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 consists mainly of animal experiments and small clinical reports, with much of the clinical material published in Russian-language journals. Large independent trials are scarce. Separating reliable effects from chance findings is consequently difficult.