heptapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-06-05. Anything still debated is marked as such rather than presented as settled.
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.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
| 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.
Later generations of the molecule include an N-acetylated form and an amidated form, both marketed online alongside the parent peptide. These variants differ in terminal chemistry and stability, and they are frequently discussed in the same breath even though they have not been compared in controlled trials. Supply outside formal healthcare systems comes largely from laboratories that synthesize peptides to order. Purity and identity of these materials vary widely, and no single body oversees the international trade.
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.
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
== Interactions == Co-administration with erythromycin, ketoconazole, azithromycin, fluoxetine, or cimetidine resulted in elevated blood plasma concentrations of desloratadine and its metabolite 3-hydroxydesloratadine in studies. However, no clinically relevant changes were observed.
=== 2000–2010: Further expansion === In 2001, Henry McKinnell became CEO, replacing William C. Steere, Jr. In 2002, The Bill & Melinda Gates Foundation purchased stock in Pfizer. In 2004, the company received approval for Lyrica (pregabalin), an anticonvulsant and anxiolytic medication used to treat epilepsy, neuropathic pain, fibromyalgia, restless leg syndrome, and generalized anxiety disorder. The United States patent on Lyrica was challenged by generic manufacturers and was upheld in 2014, extending the expiration date to 2018. In July 2006, Jeff Kindler was named CEO, replacing Henry McKinnell. On December 3, 2006, Pfizer ceased development of torcetrapib, a drug that increases production of HDL, which reduces LDL thought to be correlated to heart disease. During a Phase III clinical trial involving 15,000 patients, more deaths than expected occurred in the group that took the medicine, and the mortality rate of patients taking the combination of torcetrapib and Lipitor (82 deaths during the study) was 60% higher than those taking Lipitor alone (52 deaths during the study). Lipitor alone was not implicated in the results, but Pfizer lost nearly $1 billion developing the failed drug and its stock price dropped 11% on the day of the announcement. Between 2007 and 2010, Pfizer spent $3.3 million on investigations and legal fees and recovered about $5.1 million, and had another $5 million of pending recoveries from civil lawsuits against makers of counterfeit prescription drugs.
=== Taiwan === In October 2006, Taiwan banned ractopamine along with other beta-adrenergic agonists. In a 2012 climb-down, its legislature passed amendments to its Act Governing Food Sanitation, authorising government agencies to set safety standards for ractopamine. The Taiwanese Department of Health ultimately established an MRL of 10 ppb for ractopamine in beef on 31 July 2012. The American Institute in Taiwan, which represents US interests in Taiwan, states that these "and many other countries have determined that meat from animals fed ractopamine is safe for human consumption"; this is in the context of an ongoing trade dispute between Taiwan and the US on this subject, which threatened to prevent Taiwan's entry to the Trans-Pacific Partnership trade pact. In 2020, restrictions on imports of US pork with ractopamine were relaxed, leading to protests. A referendum took place on December 18, 2021, deciding whether to ban the import of pork with ractopamine, and the ban was rejected.
Sources: en.wikipedia.org
==== Other androgenic and antiandrogenic actions ==== A paradoxical effect occurs with certain prostate cancer cells which have genetic mutations in their ARs. These altered ARs can be activated, rather than inhibited, by CPA. In such cases, withdrawal of CPA may result in a reduction in cancer growth, rather than the reverse. This is known as antiandrogen withdrawal syndrome. CPA may also have a slight direct inhibitory effect on 5α-reductase, though the evidence for this is sparse and conflicting. Most studies however suggest that CPA does not produce important inhibition of 5α-reductase. The combination of birth control pills containing CPA with finasteride, a well-established, selective 5α-reductase inhibitor, has been found to result in significantly improved effectiveness in the treatment of hirsutism relative to CPA-containing birth control pills alone. In addition to its AR antagonistic activity and suppression of gonadal sex-hormone production, high-dose CPA has been found to suppress the levels of the adrenal androgen dehydroepiandrosterone sulfate (DHEA-S), which is due to exertion of negative feedback by CPA on adrenocorticotropic hormone (ACTH) secretion via the glucocorticoid activity of CPA.
{\displaystyle Q=\left[m_{\text{N}}\left({\ce {^{\mathit {A}}_{\mathit {Z}}X}}\right)-m_{\text{N}}\left({\ce {^{\mathit {A}}_{{\mathit {Z}}+1}X'}}\right)-m_{\text{e}}-m_{{\overline {\nu }}_{\text{e}}}\right]c^{2}}
== Advertising == In late 1986, Domino's was well known for its advertisements featuring a slapstick character called the Noid, created by Group 243 Inc. who hired Will Vinton Studios to produce the television commercials that featured the character. The character was designed to be the personification of any and all possible unsatisfactory experiences when having pizza delivered; as such, the catchphrase associated with the commercials was "Avoid the Noid". The ad campaign gained notoriety, however, in 1989, when a man named Kenneth Lamar Noid, believing the mascot to be an imitation of him, held two Domino's employees hostage in Chamblee, Georgia. The employees escaped while Noid ate a pizza he had ordered. Noid was eventually diagnosed with paranoid schizophrenia and acquitted due to insanity, and later committed suicide in 1995. Contrary to popular belief, Domino's has stated that the retirement of the Noid ad campaign was not a result of the hostage situation. The Noid was briefly brought back for a week in 2011 in an arcade-style game on the Domino's Facebook page. The person with the top score received a coupon for a free pizza. Owing to a glitch on the Domino's website, the company gave away nearly 11,000 free medium pizzas in March 2009. The company had planned the campaign for December 2008 but scrapped the idea and never promoted it.
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.
Reversed-phase high-performance liquid chromatography is the standard method, with detection in the ultraviolet range. Peak area percentage yields a purity figure for the main component. Mass spectrometry is normally run alongside to confirm molecular identity.