Semax comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-07-26. Where a claim depends on a specific study, the study is described rather than over-claimed.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
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.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
=== America's "first opioid crisis" === The 1880s saw opiate addiction surge among housewives, doctors, and Civil War veterans, creating America's "first opioid crisis". By the end of the century, an estimated one in 200 Americans were addicted to opiates, 60% of them women, typically white and middle- to upper-class. Medical journals of the later 1800s were replete with warnings against overprescription. As medical advances presented better treatment options, prescribed opiate use began to decline. Meanwhile, opium smoking remained popular among Chinese immigrant laborers, thousands of whom had arrived during the California gold rush. The public face of opiate use began to change, from affluent white Americans, to "Chinese, gamblers, and prostitutes". During this period, states and municipalities began enacting laws banning or regulating certain drugs. In Pennsylvania, an anti-morphine law was passed in 1860. In 1875, San Francisco enacted an anti-opium ordinance, vigorously enforced, imposing stiff fines and jail for visiting opium dens. The rationale held that "many women and young girls, as well as young men of a respectable family, were being induced to visit the Chinese opium-smoking dens, where they were ruined morally and otherwise." The law catered to resentment towards the Chinese laborer population who were being accused of taking jobs; other uses of opiates or other drugs were unaffected. Similar laws were enacted in other states and cities. The federal government became involved, selectively raising the import tariff on the smoking grade of opium.
== S == SAII – Solvent-assisted ionization inlet SELDI – Surface-enhanced laser desorption/ionization SESI – Secondary electrospray ionization SHRIMP – Sensitive high-resolution ion microprobe SIFT – Selected ion flow tube SILAC – Stable isotope labelling by amino acids in cell culture SIM – Selected ion monitoring SIMS – Secondary ion mass spectrometry SIR – Selected ion recording SNMS – Secondary neutral mass spectrometry SRM – Selected reaction monitoring SWIFT – Stored waveform inverse Fourier transform SID – Surface-induced dissociation SIR – Surface-induced reaction SI – Surface ionization SORI – Sustained off-resonance irradiation
== Further reading == "New Guidelines Seek to Provide Clarity on Food Expiration Dates". All Things Considered. U.S.: NPR. 17 February 2017. Includes a list of the many terms used in the United States food industry. Anonymous, "Cold Chain Management", 2003, 2006 Anonymous, Protecting Perishable Foods During Transport by Truck Archived 2014-05-16 at the Wayback Machine, USDA Handbook 669, 1995 Kilcast, D., Subramamiam, P., Food and Beverage Stability and Shelf Life, Woodhead Publishing, 2011, ISBN 978-1-84569-701-3 Labuza, T. P., Szybist, L., Open dating of Foods, Food and Nutrition Press, 2001; other edition: Wiley-Blackwell, 2004, ISBN 0-917678-53-2 Man, C. M., Jones. A. A., Shelf-Life Evaluation of Foods, ISBN 0-8342-1782-1 Robertson, G.L., Food Packaging and Shelf Life: A Practical Guide, CRC Press, 2010, ISBN 978-1-4200-7844-2 Steele, R., Understanding and Measuring the Shelf-Life of Food, Woodhead Publishing, 2004, ISBN 1-85573-732-9 Weenen, H., Cadwallader, K., Freshness and Shelf Life of Foods, ACS, 2002, ISBN 0-8412-3801-4
=== Codeine === Codeine is a prescription opiate used to treat mild to moderate pain. It is available as a tablet and cough syrup. A 2013 study on the concoction of codeine with alcohol or soda, also known as "purple drank," reported that codeine is most widely used in a recreational way by men, Native Americans and Hispanics, urban students, and LGBT persons. The study also noted that all people who used "purple drank" reported using alcohol within the past month, and roughly 10 percent of cannabis users reported abusing "purple drank".
Sources: en.wikipedia.org
== Further reading == T. A. Dineen; M. A. Zajac; A. G. Myers (2006). "Efficient Transamidation of Primary Carboxamides by in situ Activation with N,N-Dialkylformamide Dimethyl Acetals". J. Am. Chem. Soc. 128 (50): 16406–16409. Bibcode:2006JAChS.12816406D. doi:10.1021/ja066728i. PMID 17165798.
Level 1: COMP (exons 10–15) and MATN3 (exon 2) Level 2: COMP (exons 8 & 9 and 16–19) Level 3: COL9A1 (exon 8), COL9A2 and COL9A3 (exon 3) All those genes are involved in the production of the extracellular matrix (ECM). The role of COMP gene remains unclear. It is a noncollagenous protein of the ECM. Mutations in this gene can cause the pseudoachondroplasia (PSACH). It should play a role in the structural integrity of cartilage by its interaction with other extracellular matrix proteins and can be part of the interaction of the chondrocytes with the matrix and it is also a potent suppressor of apoptosis in chondrocytes. Another role is maintaining a vascular smooth muscle cells contractile under physiological or pathological stimuli. Since 2003, the European Skeletal Dysplasia Network has used an online system to diagnose cases referred to the network before mutation analysis to study the mutations causing PSACH or MED. COL9A1, COL9A2, COL9A3 are genes coding for collagen type IX, that is a component of hyaline cartilage. MATN3 protein may play a role in the formation of the extracellular filamentous networks and in the development and homeostasis of cartilage and bone. In the recessive form, the DTDST gene, also known as SLC26A2, is mutated in almost 90% of the patients, causing diastrophic dysplasia. It is a sulfate transporter, transmembrane glycoprotein implicated in several chondrodysplasias. It is important for sulfation of proteoglycans and matrix organization.
=== Bethlem myopathy 2 === (Collagen XII gene) See Bethlem myopathy 2 Clinical synopsis on OMIM: 616471 In Bethlem myopathy 2, there is phenotypic variability. In one family, the only notable finding on T1-weighted MR images (used to detect fatty infiltration) was atrophy of the rectus femoris muscles of the thigh, with the degree of atrophy matching the severity of the disease, but no fatty infiltration. In another family, only the more severely affected older patient showed significant abnormality, by having symmetrical fatty atrophy of the femoral quadriceps of the thigh, the adductor and medial gastrocnemius muscles of the calf; as well as asymmetrical fatty atrophy of the adductor longus of the thigh. No muscle hypertrophy was reported and the muscles of the patients without fatty atrophy appeared normal. Bethlem myopathy 2 also differs by including the possibility of scapula winging, pectus excavatum, stooped posture, kyphosis (hunchback), micrognathia, retrognathia, and a high-arched palate. Childhood muscle weakness improves in teen years, but muscle weakness returns by the third decade of life.
207Pb(48Ca,xn)255−xNo (x=2) The measurement of the 2n excitation function for this reaction was reported in 2001 by Yuri Oganessian and co-workers at the FLNR. The reaction was used in 2004–5 to study the spectroscopy of 253No.
=== Mechanism of Action === In humans, uric acid is the final step in the catabolic pathway of purines. Rasburicase catalyzes enzymatic oxidation of poorly soluble uric acid into an inactive and more soluble metabolite allantoin with carbon dioxide and hydrogen peroxide as byproducts in the chemical reaction.
Sources: en.wikipedia.org
In the ensuing power struggle for control over the province, General Wang Zuanxu made a deal with Liu that he would return the Ya'an and Xichang regions to Xikang as well as subsidize the Xikang government with 360,000 yuan per year in exchange for Liu's support. This deal went through, and the central government even agreed to fund a highway from Sichuan to Xikang. On 28 November, 1938, the Executive Yuan ratified the establishment of Xikang Province, which was officially inaugurated on 1 January, 1939. Liu Wenhui became the governor of Xikang. In exchange, Wang Zuanxu was able to become the acting chairman of Sichuan Province, although he failed to secure control and was later usurped by Chiang Kai-shek himself. Liu Wenhui's provincial government was highly nepotistic, made up mostly of personal connections, secretaries, and subordinate officers. Only one politician in the new government, Ye Xiufeng, was a Chiang loyalist: he was subsequently outmaneuvered by Liu and dismissed within two years. Although the Tibetan population were hopeful that the establishment of the province would entail increased representation, Liu only appointed one Tibetan, a monk, to the governing board. This was justified by the national government as a prioritization of national stability over minority rights, ensuring that the Xikang government remained Han-centric and Han-dominant. In addition, the wartime situation meant that by cooperating with the central government, Liu Wenhui would be able to maintain his rule over Xikang.
production of the drug(s) or device(s) being evaluated staff salaries for the designers and administrators of the trial payments to the contract research organization, the site management organization (if used) and any outside consultants payments to local researchers and their staff for their time and effort in recruiting test subjects and collecting data for the sponsor the cost of study materials and the charges incurred to ship them communication with the local researchers, including on-site monitoring by the CRO before and (in some cases) multiple times during the study one or more investigator training meetings expense incurred by the local researchers, such as pharmacy fees, IRB fees and postage any payments to subjects enrolled in the trial the expense of treating a test subject who develops a medical condition caused by the study drug These expenses are incurred over several years. In the US, sponsors may receive a 50 percent tax credit for clinical trials conducted on drugs being developed for the treatment of orphan diseases. National health agencies, such as the US National Institutes of Health, offer grants to investigators who design clinical trials that attempt to answer research questions of interest to the agency. In these cases, the investigator who writes the grant and administers the study acts as the sponsor, and coordinates data collection from any other sites. These other sites may or may not be paid for participating in the study, depending on the amount of the grant and the amount of effort expected from them.
== Potential issues == While there is good evidence for the efficacy of opioid rotation as a treatment approach in general, there is less evidence for what particular opioid analgesics are most suitable, and in practice the choice of opioid drugs used depends on many factors such as patient characteristics, prescriber preferences and safety. One issue with opioid rotation is that an opioid therapy failure poorly predicts whether other opioids would be effective. In certain situations, multiple switches may be required before pain therapy is optimized. In addition, recent studies explore which opioid drugs are most effective in implementing in an opioid rotation, but have so far found no difference in efficacy between opioid drugs like methadone and fentanyl in cancer patients. Diversion of prescribed opioid drugs for illicit recreational use is also a particular concern in this field, as the drugs which are most effective for relieving suffering in palliative care also tend to be those most sought after by drug abusers. The choice of what opioid drug to use in which patient thus tends to be a balance between many different factors that must be considered, and the need for opioid rotation in chronic pain patients makes it advantageous for a wide range of different opioid drugs to be available, even though they may be broadly equivalent in action when used in shorter term treatment. Additionally, newer studies may explore which patient populations can benefit the most from opioid rotation and which populations can have their pain managed by other means.
Ripasudil had no effect on respiratory or neurological function. Although no carcinogenicity studies were performed on the drug, developers believed it to be non-carcinogenic due to its rapid elimination and therefore lack of accumulation in tissue, as well as the lack of inflammatory response in the eye post-administration.
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
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.