melanocortin signalling 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 2025-08-03. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
| 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 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.
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 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
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 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. 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.
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.
== Research == More than 160 faculty members at the University of Texas Health Science Center at San Antonio are actively involved in biomedical and clinical research and educational activities that range from the molecular genetics of aging to issues of health care for the elderly population. Research at the Barshop Institute spans the continuum from basic discovery science to translational and clinical research aimed at extending healthspan and improving quality of life in older adults. Investigators study the fundamental biological processes that drive aging—including cellular senescence, mitochondrial dysfunction, metabolism, inflammation, genomic instability, and impaired tissue regeneration—and apply these discoveries to develop strategies for preventing or treating age-related diseases. Major areas of investigation include Alzheimer's disease and related dementias, cardiovascular disease, type 2 diabetes and metabolic disorders, cancer, frailty, sarcopenia, osteoporosis, and age-associated liver disease. Through the integration of laboratory research, animal models, clinical trials, and population-based studies, Barshop Institute scientists are advancing new therapeutic approaches that target the underlying mechanisms of aging to delay the onset of chronic disease, preserve physical and cognitive function, and promote healthy longevity.
1942: Native American aerospace engineer Mary Golda Ross became employed at Lockheed Aircraft Corporation, where she provided troubleshooting for military aircraft. She went on to work for NASA, developing operational requirements, flight plans, and a Planetary Flight Handbook for spacecraft missions such as the Apollo program. 1943: British geologist Eileen Guppy was promoted to the rank of assistant geologist, therefore becoming the first female geology graduate appointed to the scientific staff of the British Geological Survey. 1943: American geologist and crystallographer Elizabeth A. Wood became the first female to be hired as a member of the technical staff (MTS) at Bell Telephone Laboratories in Murray Hill, New Jersey. 1944: Indian chemist Asima Chatterjee became the first Indian woman to receive a doctorate of science, completing her studies at the University of Calcutta. She went on to establish the Department of Chemistry at Lady Brabourne College. 1945: American physicists and mathematicians Frances Spence, Ruth Teitelbaum, Marlyn Meltzer, Betty Holberton, Jean Bartik and Kathleen Antonelli programmed the electronic general-purpose computer ENIAC, becoming some of the world's first computer programmers.
Highland Council announces that Inverness's Hogmanay celebration will not take place in 2024–25 due to capacity and rising costs. 23 August – Edinburgh City Council votes to introduce a temporary fireworks ban around Bonfire Night in the city's Niddrie, Balerno, Seafield and Calton Hill districts, becoming the first Scottish council to implement such a ban. 25 August – BBC Scotland News reports that Scotland's local authorities are to divert money used to restore nature projects to pay for wage increases. 26 August – ASLEF suspends planned strike action for ScotRail drivers following a new pay offer, and will ballot its members on the offer. The Scottish Government confirms it will suspend the Connecting Scotland programme which provides iPads and laptops to people who are "digitally excluded" in order to pay for council pay rises. 28 August – Justice Secretary Angela Constance confirms that around 470 prisoners have been released under emergency provisions to release prisoners early from their sentences. 30 August – Cheyenne Naeb, an American philosophy student at the University of Dundee, who pushed a female member of railway staff in front of a stationary train at Glasgow Queen Street railway station in February 2023 after missing his train, is sentenced to 20 months in prison at Glasgow Sheriff Court. During a closed-door session at the SNP Party Conference, leader John Swinney tells delegates the party's losses at the election occurred because it spent too much time focusing on the "process of independence".
Sources: en.wikipedia.org
The series begins with a streamer (WayneRadioTV) playing a mod of Half-Life with VR support and intelligent AI characters. He begins a Let's Play, roleplaying as Gordon Freeman. Freeman is walking through the Black Mesa Research Facility and encounters Benry (Socpens), an antagonistic security guard who demands he provide a passport for identification, and begins to follow and taunt him. Freeman also comes across three eccentric scientists: Tommy Coolatta (Baaulp), who is childlike and book smart, Dr. Harold Coomer (Hollow_tones), who is friendly and the subject of frequent glitches, and Dr. Bubby (MasterGir), who is cranky and acts rude towards Freeman. Freeman and the scientists experiment on a crystal of unknown origin, which goes awry and triggers a resonance cascade. Freeman, the scientists, and Benry, collectively called "the science team", make their way through the damaged facility while fighting alien creatures and members of the US military, including an obstinate Marine named Forzen (Socpens). During the journey, Coomer accidentally noclips out of the map, causing him to suspect he may be in a video game. Freeman is betrayed by Bubby and Benry, leading him to be captured by the government soldiers deployed to clean up the incident. The soldiers cut off his arm and throw him into a trash compactor. A delirious Freeman comes to and makes his way to an abandoned section of Black Mesa where he rejoins Tommy. He then encounters Coomer, who attempts to use Freeman as a way to escape the video game using several clones of himself.
Through modulation of liver protein synthesis, conjugated oral estrogen increases the risk of blood clots, increases circulating levels of a variety of binding proteins including thyroid binding globulin (TBG), cortisol binding globulin (CBG), sex hormone binding globulin (SHBG), growth hormone binding protein (GHBP), insulin-like growth factor-binding proteins (IGFBPs), and copper binding protein (CBP), suppresses growth hormone (GH)-mediated insulin-like growth factor 1 (IGF-1) production, and produces positive blood lipid changes, among a variety of other effects. In contrast to oral estradiol, transdermal estradiol has relatively minimal impact on liver protein synthesis. As an example, a study found that 1 mg/day oral estradiol significantly increased SHBG levels by 45%, while 50 μg/day transdermal estradiol increased SHBG levels non-significantly by only 12%. In the circulation, approximately 38% of estradiol is reversibly bound to SHBG and 60% is reversibly bound to albumin in women under normal physiological circumstances, with 2 to 3% of total estradiol circulating free or unbound at any given time. Only estradiol that is free or unbound is able to be enter target cells and hence is biologically active. The increase in SHBG levels with oral estradiol (e.g., +50%) can result in a clinically meaningful increase in the fractions of sex hormones like estradiol and testosterone that are bound to SHBG, whereas this is not the case with typical clinical dosages of transdermal estradiol.
=== Labeling === For US food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value. For vitamin B6 labeling purposes 100% of the Daily Value was 2.0 mg, but as of May 27, 2016, it was revised to 1.7 mg to bring it into agreement with the adult RDA. A table of the old and new adult daily values is provided at Reference Daily Intake.
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.
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.