The short version of BDNF fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-10-27. Anything still debated is marked as such rather than presented as settled.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
| Property | Value | Notes |
|---|---|---|
| Primary research models | Rodent studies | Largest share of published data |
| Reported markers | BDNF and NGF expression | Measured mainly in animal tissue |
| Common administration | Intranasal | Matches the registered formulation |
| Blood residence time | Minutes | Rapid enzymatic degradation |
| Evidence quality | Small trials, limited replication | Noted repeatedly in reviews |
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.
== Solvation == Individual surfactant molecules that are in the system but are not part of a micelle are called "monomers". Micelles represent a molecular assembly, in which the individual components are thermodynamically in equilibrium with monomers of the same species in the surrounding medium. In water, the hydrophilic "heads" of surfactant molecules are always in contact with the solvent, regardless of whether the surfactants exist as monomers or as part of a micelle. However, the lipophilic "tails" of surfactant molecules have less contact with water when they are part of a micelle—this being the basis for the energetic drive for micelle formation. In a micelle, the hydrophobic tails of several surfactant molecules assemble into an oil-like core, the most stable form of which having no contact with water. By contrast, surfactant monomers are surrounded by water molecules that create a "cage" or solvation shell connected by hydrogen bonds. This water cage is similar to a clathrate and has an ice-like crystal structure and can be characterized according to the hydrophobic effect. The extent of lipid solubility is determined by the unfavorable entropy contribution due to the ordering of the water structure according to the hydrophobic effect. Micelles composed of ionic surfactants have an electrostatic attraction to the ions that surround them in solution, the latter known as counterions.
Xi has formulated the new concept for development, stressing the importance of high-quality development rather than "inflated growth". He has stated China has abandoned a growth-at-all-costs strategy which Xi refers to as "GDP heroism". Instead, Xi said other social issues such as environmental protection are important. Xi has made eradicating extreme poverty through targeted poverty alleviation a key goal. In 2015, he launched the battle against poverty. The campaign concluded by 2021, when Xi declared a "complete victory" over extreme poverty, saying nearly 100 million have been lifted out of poverty under his tenure, though some experts said China's poverty threshold was lower than that of the World Bank. In 2020, premier Li Keqiang, citing the National Bureau of Statistics (NBS) said that China still had 600 million people living with less than 1000 yuan ($140) a month, although The Economist said the methodology NBS used was flawed. When Xi took office in 2012, 58% of people in China were living on less than $8.30 per day, in 2022 this had fallen to 21%. At the 19th Party Congress in 2017, Xi stated the primary contradiction of China's conditions in the new era as "the contradiction between the people's ever-growing need for a better life and unbalanced and inadequate development." In this context, "unbalanced" refers to rural-urban inequalities, regional inequalities, inequalities between the rich and poor, and structural imbalances in the economy. "Inadequate" refers to household income share.
==== Decreasing mandatory tests ==== Expanded newborn screening is also opposed by among some health care providers, who are concerned that effective follow-up and treatment may not be available, that false positive screening tests may cause harm, and issues of informed consent. A recent study by Genetic Alliance and partners suggests that communication between health care providers and parents may be key in minimizing the potential harm when a false positive test occurs. The results from this study also reveal that parents found newborn screening to be a beneficial and necessary tool to prevent treatable diseases. To address the false positive issue, researchers from the University of Maryland, Baltimore and Genetic Alliance established a check-list to assist health care providers communicate with parents about a screen-positive result.
== Further reading == Kallweit MS, Kallweit NP, Kallweit U (29 November 2023). "Pharmacological Treatments of Sleep–Wake Disorders: Update 2023". Clinical and Translational Neuroscience. 7 (4): 42. doi:10.3390/ctn7040042. hdl:20.500.12512/242676. ISSN 2514-183X. Kornum BR, Breum AW, Mincikiewicz Z, Knudsen-Heier S (July 2026). "Therapeutic potential of targeting the orexin (hypocretin) system in sleep disorders". Nat Rev Endocrinol. doi:10.1038/s41574-026-01277-2. PMID 42533134.
== Side effects == Patients, physicians and researchers say usual, expected side effects include; temporary redness, pain and tenderness during injections and swelling and bruising at the injection sites. The more serious side effects include: immune system reactions which result in facial lumps and bumps known as granulomas, bothersome reactions which are very difficult for physicians to treat. According to Allergan, Juvéderm should not be used in patients with severe allergies, particularly those who have allergies to bacterial proteins or patients with a history of anaphylaxis, which is a potentially life-threatening hypersensitivity to some drugs and proteins.
Sources: en.wikipedia.org
==== African plate ==== Mount Etna (47) 37°45′N 15°00′E Hoggar hotspot (13) 23°18′N 5°36′E, w= 0.3 az= 046° ±12° Tibesti hotspot (40) 20°48′N 17°30′E, w= 0.2 az= 030° ±15° Jebel Marra/Darfur hotspot (6) 13°00′N 24°12′E, w= 0.5 az= 045° ±8° Afar hotspot (29, misplaced in map) 7°00′N 39°30′E, w= 0.2 az= 030° ±15° rate= 16 ±8 mm/yr Possibly related to the Afar triple junction, 30 Ma. Cameroon hotspot (17) 2°00′N 5°06′E, w= 0.3 az= 032° ±3° rate= 15 ±5 mm/yr Madeira hotspot (48) 32°36′N 17°18′W, w= 0.3 az= 055° ±15° rate= 8 ±3 mm/yr Canary hotspot (18) 28°12′N 18°00′W, w= 1 az= 094° ±8° rate= 20 ±4 mm/yr New England/Great Meteor hotspot (28) 29°24′N 29°12′W, w= 0.8 az= 040° ±10° Cape Verde hotspot (19) 16°00′N 24°00′W, w= 0.2 az= 060° ±30° Sierra Leone hotspot St. Helena hotspot (34) 16°30′S 9°30′W, w= 1 az= 078° ±5° rate= 20 ±3 mm/yr Gough hotspot (49), at 40°19' S 9°56' W. 40°18′S 10°00′W, w= 0.8 az= 079° ±5° rate= 18 ±3 mm/yr Tristan hotspot (42), at 37°07′ S 12°17′ W. 37°12′S 12°18′W Vema hotspot (Vema Seamount, 43), at 31°38' S 8°20' E. 32°06′S 6°18′W Related maybe to the Paraná and Etendeka traps (c. 132 Ma) through the Walvis Ridge. Discovery hotspot (50) (Discovery Seamounts) 43°00′S 2°42′W, w= 1 az= 068° ±3° Bouvet hotspot (51) 54°24′S 3°24′E Shona/Meteor hotspot (27) 51°24′S 1°00′W, w= 0.3 az= 074° ±6° Réunion hotspot (33) 21°12′S 55°42′E, w= 0.8 az= 047° ±10° rate= 40 ±10 mm/yr Possibly related to the Deccan Traps (main events: 68.5–66 Ma) Comoros hotspot (21) 11°30′S 43°18′E, w= 0.5 az=118 ±10° rate=35 ±10 mm/yr
Immunoglobulin G (IgG) antibodies are large heterodimeric molecules, approximately 150 kDa and are composed of two kinds of polypeptide chain, called the heavy (~50kDa) and the light chain (~25kDa). The two types of light chains are kappa (κ) and lambda (λ). By cleavage with enzyme papain, the Fab (fragment-antigen binding) part can be separated from the Fc (fragment crystallizable region) part of the molecule. The Fab fragments contain the variable domains, which consist of three antibody hypervariable amino acid domains responsible for the antibody specificity embedded into constant regions. The four known IgG subclasses are involved in antibody-dependent cellular cytotoxicity. Antibodies are a key component of the adaptive immune response, playing a central role in both in the recognition of foreign antigens and the stimulation of an immune response to them. The advent of monoclonal antibody technology has made it possible to raise antibodies against specific antigens presented on the surfaces of tumors. Monoclonal antibodies can be acquired in the immune system via passive immunity or active immunity. The advantage of active monoclonal antibody therapy is the fact that the immune system will produce antibodies long-term, with only a short-term drug administration to induce this response. However, the immune response to certain antigens may be inadequate, especially in the elderly. Additionally, adverse reactions from these antibodies may occur because of long-lasting response to antigens.
In addition to assessing the size of the pituitary tumor, physicians also look for damage to surrounding tissues, and perform tests to assess whether production of other pituitary hormones are normal. Depending on the size of the tumor, physicians may request an eye exam that includes the measurement of visual fields. In the rare cases that other causes of hyperprolactinaemia, such as surgery, medication usage, renal and hepatic diseases, and seizures, are ruled out and no evidence of existing adenomas, the hyperprolactinaemia is considered "idiopathic". When the cause of hyperprolactinaemia is concluded as idiopathic, standard of care is given to patients, and an MRI is expected to be repeated in 6–12 months. In diagnosing hyperprolactinaemia in men, some physical signs may indicate the onset of the condition. Increased prolactin can affect the inhibition of GnRH secretion, which is responsible for libido, and the release of FSH (Follicle-stimulating hormone), LH (Luteinizing hormone), and testosterone. FSH in men is responsible to stimulate sperm production and LH is responsible for the stimulation of testosterone; with the inhibition of GnRH, FSH, and LH, physical signs that show in men include reduced sex drive and infertility, these symptoms suggests the onset of hyperprolactinaemia. However, a high measurement of prolactin may also result from the presence of macroprolactin, otherwise known as 'big prolactin' or 'big-big prolactin', in the serum. Macroprolactin occurs when prolactin polymerizes together and can bind with IgG to form complexes.
Only a few troops were directly registered and the practice was soon discontinued with new "mixed" groups being encouraged to join the WOSM member organization of their country of residence. In 1955, only two such groups were still active, a troop in Iraq that disbanded that year, and the first group to be so registered, the International Troop 1 in Yokohama. The only remaining directly registered Troop is the International Boy Scouts, Troop 1 located in Yokohama, Japan. Temporary recognition was extended to Scouts in displaced persons camps after World War II. In 1947, at WOSM's 11th conference the "Displaced Persons Division" of WOSM's bureau was established to register and support Scouts in displaced person camps in Austria, Northern Italy, and Germany. These Scouts did not receive the right of WOSM membership but gained recognition as Scouts under WOSM's bureau until they took up residence in a country that had a recognized national Scout organization, which they could join. The D.P. Division was closed on 30 June 1950.
== Etymology of anesthesia == In ancient Greek texts, such as the Hippocratic Corpus and the dialogue Timaeus, the term ἀναισθησία (anaisthēsíā) is used, which translates to "without sensation". This term is derived from the prefix ἀν- (an-), meaning "without", and αἴσθησις (aisthēsis), which means "sensation". The concept of anaisthēsia is significant in understanding the historical foundations of anesthesia and its relevance in medical practices. In 1679, Steven Blankaart published Lexicon medicum graeco-latinum with the Latin term anaisthesia. In 1684, an English translation appeared titled A Physical Dictionary, with anesthesia defined as a "defect of sensation, as in paralytic and blasted persons". Subsequently, the term and variant spellings like anæsthesia are used in medical literature signifying "insensibility". In 1846, in a letter, Oliver Wendell Holmes proposed the term anesthesia to be used for the state induced by an agent and anesthetic for the agent itself. Holmes motivates this with earlier uses of anesthesia in medical literature to mean "insensibility", particularly to "objects of touch".
Sources: en.wikipedia.org
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.
The compound is registered as a medicine in Russia, so clinical work has concentrated there. Trials elsewhere are few and generally small. This geographic concentration is a recognized limitation in evidence reviews.
Some fraction may reach the central nervous system through olfactory pathways, and this is often cited as the rationale for the nasal route. The size of that fraction in humans is not well quantified. Blood concentrations after nasal dosing are low, which complicates measurement.
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.