This is a working overview of neurotrophic factor, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-08-11 and is reviewed periodically as new material appears.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
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.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | ACTH(4-7) analogue |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Free N terminus, unmodified side chains |
| Molecular weight | 813.9 Da | Free base; salt forms differ |
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility | Freely soluble in water | Hydrophilic; polar solvents preferred |
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.
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.
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
Robert Boyle was the first to show in 1660 that vacuum is lethal to small animals. An experiment indicates that plants are able to survive in a low pressure environment (1.5 kPa) for about 30 minutes. Cold or oxygen-rich atmospheres can sustain life at pressures much lower than atmospheric, as long as the density of oxygen is similar to that of standard sea-level atmosphere. The colder air temperatures found at altitudes of up to 3 km generally compensate for the lower pressures there. Above this altitude, oxygen enrichment is necessary to prevent altitude sickness in humans that did not undergo prior acclimatization, and spacesuits are necessary to prevent ebullism above 19 km. Most spacesuits use only 20 kPa (150 Torr) of pure oxygen. This pressure is high enough to prevent ebullism, but decompression sickness and gas embolisms can still occur if decompression rates are not managed. Rapid decompression can be much more dangerous than vacuum exposure itself. Even if the victim does not hold his or her breath, venting through the windpipe may be too slow to prevent the fatal rupture of the delicate alveoli of the lungs. Eardrums and sinuses may be ruptured by rapid decompression, soft tissues may bruise and seep blood, and the stress of shock will accelerate oxygen consumption leading to hypoxia. Injuries caused by rapid decompression are called barotrauma. A pressure drop of 13 kPa (100 Torr), which produces no symptoms if it is gradual, may be fatal if it occurs suddenly.
Following the Christianization of the Roman Empire in late antiquity, vegetarianism practically disappeared from Europe, as it did elsewhere, except in India. Several orders of monks in medieval Europe restricted or banned the consumption of meat for ascetic reasons, but none of them eschewed fish. Moreover, the medieval definition of "fish" included such animals as seals, porpoises, dolphins, barnacle geese, puffins, and beavers. Vegetarianism re-emerged during the Renaissance, becoming more widespread in the 19th and 20th centuries. In 1847, the first Vegetarian Society was founded in the United Kingdom; Germany, the Netherlands, and other countries followed. In 1886, the vegetarian colony Nueva Germania was founded in Paraguay, though its vegetarian aspect would prove short-lived. The International Vegetarian Union, an association of the national societies, was founded in 1908. In the Western world, the popularity of vegetarianism grew during the 20th century as a result of nutritional, ethical, and—more recently—environmental and economic concerns. Virchand Gandhi was the official delegate representing Jainism at the first World's Parliament of Religions in Chicago in 1893. He was one of the first historical figures to defend Jain vegetarianism on a global stage to a Western audience. Gandhi systematically dismantled the contemporary Western assumption that vegetarianism led to physical weakness, successfully reframing the Jain diet in the West as a highly rational, scientifically grounded, and compassionate lifestyle.
=== Pregnancy, lactation, and early childhood === The U.S. Recommended Dietary Allowance (RDA) for pregnancy is 2.6 micrograms per day (μg/d), for lactation 2.8 μg/d. Determination of these values was based on an RDA of 2.4 μg/d for non-pregnant women, plus what will be transferred to the fetus during pregnancy and what will be delivered in breast milk. However, looking at the same scientific evidence, the European Food Safety Authority (EFSA) sets adequate intake (AI) at 4.5 μg/d for pregnancy and 5.0 μg/d for lactation. Low maternal vitamin B12, defined as serum concentration less than 148 pmol/L, increases the risk of miscarriage, preterm birth and newborn low birth weight. During pregnancy the placenta concentrates B12, so that newborn infants have a higher serum concentration than their mothers. As it is recently absorbed vitamin content that more effectively reaches the placenta, the vitamin consumed by the mother-to-be is more important than that contained in her liver tissue. Women who consume little animal-sourced food, or who are vegetarian or vegan, are at higher risk of becoming vitamin depleted during pregnancy than those who consume more animal products. This depletion can lead to anemia, and also an increased risk that their breastfed infants become vitamin deficient. Vitamin B12 is not one of the supplements recommended by the World Health Organization for healthy women who are pregnant, however, vitamin B12 is often suggested during pregnancy in a multivitamin along with folic acid especially for pregnant mothers who follow a vegetarian or vegan diet.
Tunable metamaterials allow arbitrary adjustments to frequency changes in the refractive index. A tunable metamaterial expands beyond the bandwidth limitations in left-handed materials by constructing various types of metamaterials.
Sources: en.wikipedia.org
=== Lifestyle and diet === Drinking enough water may help to keep skin hydrated, especially in individuals who are chronically dehydrated. A poor diet lacking vitamins can lead to skin problems, such as scurvy, pellagra, and numerous subclinical skin pathologies that have not been studied in detail. Lack of sleep has been shown to make conditions like atopic dermatitis, eczema and psoriasis worse, and these conditions have in turn been shown to reduce sleep quality.
== Awards and honours == 1995: Max-Bergmann-Medal of the MBK Society 2004: Josef Rudinger Award of the European Peptide Society 2011: Doctor honoris causa, University of Cergy-Pontoise, Paris 2018: Akabori Memorial Lecture Award of the Japanese Peptide Society 2020: Ernesto Scoffone Award of the Italian Peptide Society
In 2011, Antonio Lombatti noted several of these visual impossibilities in the body, such as the right footprint wrongly depicted in the shroud, and the locks of hair printed at the same height as the face, as if they were a solid structure, instead of resting on the ground. Lombatti further commented that the pressure from the body lying on the sheet should have caused the back image to be darker than the front image, which does not happen in the depiction of the shroud. The way the blood flows in rivulets from the head without mixing with the hair also struck him as more artistic than realistic. In 2018 an experimental Bloodstain Pattern Analysis (BPA) was performed to study the behaviour of blood flows from the wounds of a crucified person, and to compare this to the evidence on the Turin Shroud. The comparison between different tests demonstrated that the blood patterns on the forearms and on the back of the hand are not connected, and would have had to occur at different times, as a result of a very specific sequence of movements. In addition, the rivulets on the front of the image are not consistent with the lines on the lumbar area, even supposing there might have been different episodes of bleeding at different times. These inconsistencies suggest that the Turin linen was an artistic or didactic representation, rather than an authentic burial shroud.
Elderly people – due to impaired intestinal absorption – and children, premenopausal women, and pregnant women whose diets are low in animal foods are all at increased risk. Deficiency is especially harmful in pregnancy, childhood, and older adults. It can lead to neuropathy, megaloblastic anemia, and pernicious anemia, causing symptoms including fatigue, paresthesia, depression, cognitive decline, ataxia, and even irreversible nerve damage. In infants, untreated deficiency may result in neurological impairment and anemia. Maternal deficiency increases the risk of miscarriage, neural tube defects, and delayed development in offspring. Folate levels may modify the presentation of symptoms and disease course.
He attended college at University of California, Santa Cruz, for two years before transferring to New York University (NYU)'s Tisch School of the Arts, where he graduated in 2000. While at NYU, writer Murray Miller was his roommate.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.
It contains the 4-7 fragment of adrenocorticotropic hormone extended at the C terminus. That truncation removes the region associated with steroidogenic activity. The design intent was to keep neurotrophic properties while avoiding full hormonal effects.
No natural source of the intact heptapeptide is known. It is produced by solid-phase peptide synthesis. Some related ACTH fragments arise as hormone processing products, but the Pro-Gly-Pro extension is a designed addition rather than a natural sequence.
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.