The short version of heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-04-06 and is reviewed periodically as new material appears.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
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.
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.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
| 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 developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
Christianity does not require male circumcision, with covenant theology teaching that the Christian sacrament of baptism fulfills the Israelite practice of circumcision, both being signs and seals of the covenant of grace. Most mainstream Christian denominations currently maintain a neutral position on the practice of non-religious circumcision. Male circumcision is commonly practiced in many predominantly Christian countries and many Christian communities. In the Coptic Orthodox Church, the Ethiopian Orthodox Church and the Eritrean Orthodox Tewahedo Church male circumcision is an established practice, and require that their male members undergo circumcision, and it is seen as a rite of passage. While male circumcision is widely practiced by the Druze, the procedure is practiced as a cultural tradition, and has no religious significance in the Druze faith. There is no special date for this act in the Druze faith: male Druze infants are usually circumcised shortly after birth, however some remain uncircumcised until the age of ten or older. Some Druzes do not circumcise their male children, and refuse to observe this "common Muslim practice".
=== Common names === In the UK, to avoid being controlled by the Medicines Act, designer drugs such as mephedrone have been described as "plant food", despite the compounds having no history of being used for these purposes. In the US, similar descriptions ("bath salts" is the most common) have been used to describe mephedrone as well as methylone and methylenedioxypyrovalerone (MDPV). Combined with labeling that they are "not for human consumption," these descriptions are an attempt to skirt the Federal Analog Act which forbids drugs that are "substantially similar" to already classified drugs from being sold for human use. Synthetic cannabinoids are known under a variety of names including K2, Spice, Black Mamba, Bombay Blue, Genie, Zohai, Banana Cream Nuke, Krypton, and Lava Red. They are often called "synthetic marijuana," "herbal incense," or "herbal smoking blends" and often labeled "not for human consumption."
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Sources: en.wikipedia.org
is the absolute temperature). For accurate measurements of binding affinity, the curve of the thermogram must be sigmoidal. A steep sigmoidal curve signals a strong binding whereas a less steep sigmoidal curve points to a weaker binding. The profile of the curve is determined by the c-value, which is calculated using the equation:
In November 1993, sixteen months after Nickell's homicide, single mother Samantha Bisset and her four-year-old daughter Jazmine were murdered in their flat in Plumstead, London. The police detectives investigating the Bisset murders found the preponderance of similarities with the murder of Nickell very notable, and sat down to discuss this with the detectives from the Nickell murder. The Nickell detectives, who already had Stagg in custody at that time and thus had stopped looking for suspects, rejected – with "hostility" – the Bisset detectives' theory that the unknown murderer in the Bisset case was the true perpetrator in the Nickell case. The detective who later arrested Robert Napper for the Bisset murders also found the similarities convincing, and suggested Napper as a suspect in the murder of Rachel Nickell. In 1995, Napper was convicted for the Bisset murders. In July 2006, the Scotland Yard team interviewed him for two days at Broadmoor. Napper, 40 years old at that time, had been diagnosed as having paranoid schizophrenia and Asperger syndrome and had been held at the secure institution for more than ten years. On 28 November 2007, Napper was charged with Nickell's murder. He appeared at City of Westminster Magistrates' Court on 4 December 2007, where he was granted bail on condition he remained at Broadmoor psychiatric hospital until another hearing on 20 December 2007. On 24 January 2008, he pleaded not guilty to Nickell's murder and the trial started on 11 November 2008.
An umbrella review and a continuing education article differ as to whether it is effective in the treatment of AD. Atypical antipsychotics are modestly useful in reducing aggression and psychosis in people with AD, but their advantages are offset by serious adverse effects, such as stroke, movement difficulties, or cognitive decline. They are recommended in dementia only after first-line therapies such as behavior modification have failed, and due to the risk of adverse effects, they should be used for the shortest amount of time possible. Stopping antipsychotic use in this group of people appears to be safe.
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.
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.