If you have been reading about BDNF expression and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-01-13. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Purity assay | RP-HPLC, UV 214 nm | Typical research grade 95 percent or higher |
| Mass confirmation | ESI-MS or MALDI-TOF | Compared with theoretical value |
| Main degradation route | Methionine oxidation | Sulfoxide formation in solution |
| Powder storage | -20 °C, desiccated | Amber vial, minimal headspace |
| Working solution | Sterile water or saline | Prepare fresh; avoid repeated thawing |
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.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
Mahathir's administration committed to retaining good relations with China, but promised to review all Belt and Road Initiative projects in Malaysia that were initiated by the previous government. He characterised these as "unequal treaties". His government suspended work on the East Coast Rail Link, which recommenced after terms had been renegotiated. Mahathir cancelled approximately $2.8 billion worth of deals with China Petroleum Pipeline Bureau altogether, citing high repayment costs. On 13 February 2020, Mahathir spoke with Chinese president Xi Jinping to express solidarity and discuss cooperation in response to the COVID-19 outbreak. Prior to this, Mahathir had expressed his hopes that 2020, the 'Year of Culture and Tourism' between Malaysia and China, would further strengthen the ties and friendship between the two nations.
Tulips (Tulipa) also have a long cultural tradition, particularly in the Islamic world. The Persian word for tulips, lâleh (لاله), was borrowed into Turkish and Arabic as lale. In Arabic letters, lale is written with the same letters as Allah, and is used to denote God symbolically. Tulips became widely used in decorative motifs on tiles, fabrics, and ceramics in Islamic art and the Ottoman Empire in particular, and were revered in poetry, such as that of Omar Khayam in the twelfth century. Tulips were an essential part of the gardens of Persia, having been cultivated from the Steppes. As the Seljuks – Oghuz-Turkic leaders originated from the steppes – moved to Persia, and then west, they took tulips with them to Turkey, where many escaped cultivation and became naturalised. Today there are a number of places in Turkey called Laleli (‘with tulips’). Tulips first appeared in the decorative arts in Turkey in the thirteenth century and flourished under the Ottomans, in particular in the royal palaces, and was adopted by the Osmans as their symbol. Further species were collected from Persia and the spreading Ottoman Empire saw to it that tulip culture also spread. By the sixteenth century it was a national symbol, hence the designation "Tulip era", by which time they were becoming of economic importance.
Scans conducted during the studies showed that Sharrock's brain exhibited a heightened connection between the conscious and sub-conscious parts of her brain, which may aid easier memory recall – in particular for events that took place earlier in life. In December 2017, a man named Joey DeGrandis was verified as having HSAM by James McGaugh and subsequently featured in an article in Time magazine. DeGrandis also reports having poor short-term memory, indicating that HSAM does not necessarily improve one's short-term memory abilities. A 63-year-old man, anonymised as "The Amazing Memory Man" (MM) was featured in a paper by Neuropsychology in March 2018, where it is reported that he "appreciates that his memory for personally experienced life events and general knowledge are both exceptional, whereas his imaging the future is only average" (after scoring 123 on Episodic, 123 on Semantic, 112 on Spatial, and 91 on Future remembering memory types, all with a mean of 100). In October 2018, it was reported that teenager Tyler Hickenbottom, who is an identical twin, had the condition, which allowed him to "remember every day of his life like it was yesterday". Tim Rogers, an American video game developer and journalist, claims to experience the condition in several of his published works. John Romero, a video game developer and co-founder of id Software, has often said he has hyperthymesia, including in his 2023 autobiography, Doom Guy: Life in First Person. In 2024, Emily Nash, an 18-year-old high school student with HSAM, was featured in a CTV W5 story.
==== 1500–1599 ==== Local Authorities' Traffic Orders (Procedure) (England and Wales) (Amendment) Regulations 1993 (S.I. 1993/1500) A4074 Trunk Road (Crowmarsh Bypass) (Detrunking) Order 1993 (S.I. 1993/1501) Education (School Information)(England) Regulations 1993 (S.I. 1993/1502) Education (School Performance Information) (England) Regulations 1993 (S.I. 1993/1503) Non-Domestic Rating Contributions (Wales) (Amendment) Regulations 1993 (S.I. 1993/1505) Non-Domestic Rating (Demand Notices) (Wales) (Amendment) Regulations 1993 (S.I. 1993/1506) Value Added Tax (Supply of Services) Order 1993 (S.I. 1993/1507) Rent Act 1977 (Forms etc.) (Welsh Forms and Particulars) Regulations 1993 (S.I. 1993/1511) Non-Domestic Rating Act 1993 (Commencement No. 2) Order 1993 (S.I. 1993/1512) Food Protection (Emergency Prohibitions) (Paralytic Shellfish Poisoning) (No.5) Order 1993 (S.I. 1993/1515) Charging Orders (Residential Accommodation) (Scotland) Order 1993 (S.I. 1993/1516) Financial Assistance for Environmental Purposes (No. 2) Order 1993 (S.I. 1993/1518) Egg Products Regulations 1993 (S.I. 1993/1520) Gas (Meters) (Amendment) Regulations 1993 (S.I. 1993/1521) Northern Ireland (Emergency and Prevention of Terrorism Provisions) (Continuance) Order 1993 (S.I. 1993/1522) Food Protection (Emergency Prohibitions) (Paralytic Shellfish Poisoning) (No.6) Order 1993 (S.I. 1993/1523) Education (School Inspection) (Wales) Regulations 1993 (S.I. 1993/1529) Cosmetic Products (Safety) (Amendment)Regulations 1993 (S.I. 1993/1539) Income-related Benefits Schemes (Miscellaneous Amendments) (No.
In 1843, lithium carbonate was used to treat bladder and kidney stones. In 1859, some doctors recommended the compound for a number of ailments, including gout, urinary calculi, rheumatism, mania, depression, and headache. In 1948, John Cade discovered the anti-manic effects of lithium ions. This finding led to lithium carbonate's use as a psychiatric medication to treat mania, the elevated phase of bipolar disorder. Mogens Schou and others continued Cade's research. They found that lithium is effective against both mania and depression, and has preventative effects. Lithium is also unique among medications in that it has anti-suicide properties in people with bipolar disorder or recurrent depression. It has been shown to dramatically reduce the risk of suicide by 87% in clinical trials. In addition to its effects on suicide, lithium also reduces the risk of death from all causes in people with mood disorders. Prescription lithium carbonate from a pharmacy is suitable for use as medicine in humans but industrial lithium carbonate is not since it may contain unsafe levels of toxic heavy metals or other toxicants. After ingestion, lithium carbonate is dissociated into pharmacologically active lithium ions (Li+) and (non-therapeutic) carbonate, with 300 mg of lithium carbonate containing approximately 8 mEq (8 mmol) of lithium ion. The usual dosage of lithium is 600-900 mg/day for the maintenance treatment of bipolar disorder.
Sources: en.wikipedia.org
Raleigh ( RAH-lee) is the capital city of the U.S. state of North Carolina. It is the second-most populous city in the state (after Charlotte), tenth most populous city in the Southeast, the largest city in the Research Triangle area, and the 39th-most populous city in the U.S. Known as the "City of Oaks" for its oak-lined streets, Raleigh covers 148.54 square miles (384.7 km2) and had a population of 467,665 at the 2020 census. It is the county seat of Wake County and is named after Sir Walter Raleigh, who founded the lost Roanoke Colony. Raleigh is home to North Carolina State University and is part of the Research Triangle, which includes Durham (home to Duke University and North Carolina Central University) and Chapel Hill (home to the University of North Carolina at Chapel Hill). The Research Triangle area, centered around Research Triangle Park, has a population of over 2.37 million people. The Raleigh–Cary metropolitan statistical area alone has an estimated population of 1.51 million. Raleigh lies primarily in Wake County, with a small portion of the city extending into Durham County. Nearby suburbs include Apex, Cary, Clayton, Fuquay-Varina, Garner, Holly Springs, Knightdale, Morrisville, Rolesville, Wake Forest, Wendell, and Zebulon. Raleigh is an early example in the United States of a planned city. Following the American Revolutionary War when the U.S. gained independence, the area was chosen as the site of the state capital in 1788 and incorporated in 1792 as such.
=== Criteria === There are three sets of criteria for the clinical diagnoses of the spectrum of Alzheimer's disease: the 2013 fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5); the National Institute on Aging-Alzheimer's Association (NIA-AA) definition as revised in 2011; and the International Working Group criteria as revised in 2010. Eight intellectual domains are most commonly impaired in AD—memory, language, perceptual skills, attention, motor skills, orientation, problem solving and executive functional abilities, as listed in the fourth text revision of the DSM (DSM-IV-TR). The DSM-5 defines criteria for probable or possible AD for both major and mild neurocognitive disorders. Major or mild neurocognitive disorder must be present along with at least one cognitive deficit for a diagnosis of either probable or possible AD. For major neurocognitive disorder due to AD, probable Alzheimer's disease can be diagnosed if the individual has genetic evidence of AD or if two or more acquired cognitive deficits, and a functional disability that is not from another disorder, are present. Otherwise, possible AD can be diagnosed as the diagnosis follows an atypical route. For mild neurocognitive disorder due to AD, probable Alzheimer's disease can be diagnosed if there is genetic evidence, whereas possible AD can be met if all of the following are present: no genetic evidence, decline in both learning and memory, two or more cognitive deficits, and a functional disability not from another disorder.
== Mosaic Diagnostics, formerly Great Plains Laboratory == William Shaw's laboratory is known for performing nonstandard tests which have been used by alternative medicine practitioners to support discredited diagnoses. Great Plains Laboratory's urine mycotoxin test is not validated nor recommended for diagnosing any condition. In May 2020, early in the COVID-19 pandemic, Great Plains marketed unproven antibody tests.
Proenkephalin (PENK), formerly known as proenkephalin A (since proenkephalin B was renamed prodynorphin), is an endogenous opioid polypeptide hormone which, via proteolyic cleavage, produces the enkephalin peptides met-enkephalin, and to a lesser extent, leu-enkephalin. Upon cleavage, each proenkephalin peptide results in the generation of four copies of Met-enkephalin, two extended copies of met-enkephalin, and one copy of leu-enkephalin. Contrarily, Leu-enkephalin is predominantly synthesized from prodynorphin, which produces three copies of it per cleavage, and no copies of Met-enkephalin. Other endogenous opioid peptides produced by proenkephalin include adrenorphin, amidorphin, BAM-18, BAM-20P, BAM-22P, peptide B, peptide E, and peptide F. The following table lists the peptides that are derived from cleavage of the proenkephalin protein.
== Lead optimization phase == The objective of this drug discovery phase is to synthesize lead compounds, new analogs with improved potency, reduced off-target activities, and physiochemical/metabolic properties suggestive of reasonable in vivo pharmacokinetics. This optimization is accomplished through chemical modification of the hit structure, with modifications chosen by employing knowledge of the structure–activity relationship (SAR) as well as structure-based design if structural information about the target is available. Lead optimization is concerned with experimental testing and confirmation of the compound based on animal efficacy models and ADMET (in vitro and in situ) tools that may be followed by target identification and target validation.
Sources: en.wikipedia.org
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.
The main chemical risks are methionine oxidation and backbone hydrolysis in solution. Moisture and repeated temperature cycling accelerate both processes. Dry powder held cold and desiccated is considerably more stable than any reconstituted preparation.
It holds a medicine registration in Russia, where it has been used clinically for decades. In most other countries it is treated as a research chemical. That split explains the uneven distribution of clinical literature.
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.