A practical reference on BDNF expression: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-10. Anything still debated is marked as such rather than presented as settled.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
| Property | Value | Notes |
|---|---|---|
| Solid storage temperature | -20 °C or below | Desiccated and protected from light |
| Solution storage temperature | -80 °C as single-use aliquots | Avoid repeated freeze-thaw cycles |
| Purity assessment method | RP-HPLC, around 214 nm | Reported as main-peak area percent |
| Identity confirmation method | ESI-MS or MALDI-TOF | Measured mass compared with calculated mass |
| Common synonyms | ACTH(4-10) analog; Met-Glu-His-Phe-Pro-Gly-Pro | Also written as Semaxum in some sources |
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
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.
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.
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.
Identity and purity are commonly assessed by reversed-phase high-performance liquid chromatography, with ultraviolet detection near 214 nanometers for the peptide backbone. Mass spectrometry, either electrospray or matrix-assisted laser desorption, confirms molecular mass and detects truncation or modification products. Amino acid analysis can verify composition. Because the sequence contains no strongly absorbing aromatic residue apart from phenylalanine, detection wavelengths are chosen carefully. Purity values above 95 percent are typical for research-grade material.
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
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。
Cartalax (Ala-Glu-Asp, T-31, AED) is a tripeptide derivative developed in Russia. It has anti-aging effects in vitro and in animal models, and has been sold in Russian-speaking countries as well as more broadly over the internet as a supposed treatment for conditions such as arthritis, though only limited studies in humans have been published.
2014: American paleoclimatologist and marine geologist Maureen Raymo became the first woman to be awarded the Wollaston Medal, the highest award of the Geological Society of London. 2014: American theoretical physicist Shirley Ann Jackson was awarded the National Medal of Science. Jackson had been the first African-American woman to receive a PhD from the Massachusetts Institute of Technology (MIT) during the early 1970s, and the first woman to chair the U.S. Nuclear Regulatory Commission. 2014: Australian paediatric neurologist Ingrid Scheffer is elected a Fellow of the Australian Academy of Science. She is credited with finding the first gene implicated in epilepsy. 2014: Iranian mathematician Maryam Mirzakhani became the first woman to receive the Fields Medal, for her work in "the dynamics and geometry of Riemann surfaces and their moduli spaces". 2015: The International Day of Women and Girls in Science is an annual observance adopted by the United Nations General Assembly to promote the full and equal access and participation of women in Science, Technology, Engineering and Mathematics (STEM) fields; the United Nations General Assembly passed resolution 70/212 on 22 December 2015, which proclaimed the 11th day of February as the annual commemoration of the observance. The resolution had been presented by Iraqi geneticist and activist Nisreen El-Hashemite. 2015: Chinese medical scientist Tu Youyou received the Nobel Prize in Physiology or Medicine, shared with William C.
27 December – The Met Office issues a yellow weather warning for rain over Hogmanay, starting on 30 December and lasting over the New Year. Public Health Scotland says health services in Scotland are under "acute pressure" following a surge in flu cases. Caledonian MacBrayne is forced to reduce the number of passengers allowed on the MV Isle of Mull to 45 per journey after failing a safety check. 29 December – Emergency services searching for keen wild swimmer Ian Napier, missing from the Scousburgh Bay area since 27 December, find a body in the sea near Shetland. 30 December – Edinburgh's Hogmanay celebrations are cancelled amid weather warnings for heavy rain, high winds and snow over the New Year. 2025 New Year Honours: Among those to be recognised in the New Year Honours are broadcaster Jackie Bird (MBE), footballer and broadcaster Alan Hansen (MBE) and Olympic swimmer Duncan Scott (OBE).
Sources: en.wikipedia.org
In July 2021, all family size limits as well as penalties for exceeding them were removed. Since abandoning population control restrictions, China has pursued pro-natalist policies in an attempt to boost the birth rate.
Clinical Allergology Clinical Chemistry Clinical Haematology Clinical Immunology and Blood Banking Clinical Microbiology Clinical Pharmacology Molecular Biology and Genetics Reproduction and Fertility Thrombosis and Haemostasis Toxicology The NPU terminology is supported by a joint committee (C-SC-NPU) of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and a subcommittee of the International Union of Pure and Applied Chemistry (IUPAC). The terminology is freely available for download in its generic version (in English [3]) and various language versions. The specific syntax and the references to international terminologies, classifications and nomenclatures make the terminology definitions language-independent.
Schröder (1993, 2002) reviewed the issue of CPA dosage and recommended a dosage of 200 to 300 mg/day for CPA as a monotherapy and a dosage of 100 to 200 mg/day for CPA in combined androgen blockade (that is, CPA in combination with surgical or medical castration). However, the combination of CPA with castration for prostate cancer has been found to significantly decrease overall survival compared to castration alone. Hence, the use of CPA as the antiandrogen component in combined androgen blockade would appear not to be advisable. When used by intramuscular injection to treat prostate cancer, CPA is used at a dosage of 300 mg once a week. The combination of CPA with an estrogen such as ethinylestradiol sulfonate or low-dose diethylstilbestrol has been used as a form of combined androgen blockade and as an alternative to the combination of CPA with surgical or medical castration.
==== β1-selectivity ==== Bisoprolol β1-selectivity is especially important in comparison to other nonselective beta blockers. The effects of the drug are limited to areas containing β1 adrenoreceptors, which are mainly the heart and part of the kidney. Bisoprolol, whilst β1 adrenoceptor selective can help patients to avoid certain side-effects associated with non-selective beta-blocker activity at additional adrenoceptors (α1 and β2), it does not signify its superiority in treating beta-blocker indicated cardiac conditions such as heart failure but could prove beneficial to patients with specific comorbidities. Bisoprolol has a higher degree of β1-selectivity compared to atenolol, metoprolol and betaxolol. With a selectivity ranging from being 11 to 15 times more selective for β1 over β2. However, nebivolol is approximately 3.5 times more β1-selective.
Sources: en.wikipedia.org
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.
A high main-peak percentage says little about identity, counter-ion content, or residual solvents. It also does not distinguish an isomer or a closely eluting analog. Mass confirmation and the accompanying documentation cover those gaps.
Salt form changes mass, solubility, and hygroscopicity, and acetate and trifluoroacetate salts behave differently in solution. Storage guidance still centers on -20 °C for powder and lower temperatures for solutions. The certificate should state which salt is present.
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.