A practical reference on heptapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-12-20. Anything still debated is marked as such rather than presented as settled.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | ACTH(4-7) analogue |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Free N terminus, unmodified side chains |
| Molecular weight | 813.9 Da | Free base; salt forms differ |
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility | Freely soluble in water | Hydrophilic; polar solvents preferred |
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
== As a drug target == Inhibitors of MTHFR and antisense knockdown of the expression of the enzyme have been proposed as treatments for cancer. The active form of folate, L-methylfolate, may be appropriate to target for conditions affected by MTHFR polymorphisms.
The third case studied here is alpha-methylfentanyl. This group contains a substitution similar to the 3-methylfentanyl that was examined in the previous example on the previous image in this series (Fentanyl Synthesis p4.png), but it is on the phenethyl chain as opposed to being implanted on the piperidine ring. We then mark the two stereocenters, one on the C-4 carbon just as on fentanyl itself, and the other on the C-α (alpha carbon). To analogize these stereocenters we chose N-(1-hydroxyethyl)-4-hydroxypiperidine. When we draw out all potential stereoisomers, we see that the C-4 stereocenter is super-imposable, eliminating it as a true stereocenter. This leaves only 2 R/S assignments that follow the orientation of the stereocenter at the C-α (alpha carbon) position for the real α-methylfentanyl. These are labeled 7S and 7R, a reflection of the stereocenter in the piperidine derivative we used being at C-7 position. It is interesting that the C-4 stereocenter, which has no chiral activity in fentanyl (1st example), activiates it in 3-methylfentanyl with an on-the-ring addition, and loses it again in α-methylfentanyl with an off-the-ring addition. The fourth case studied here is ohmfentanyl. Ohmfentanyl has three potential stereocenters, which are best analogized by another piperidine derivative: N-(1-hydroxyethyl)-3-methyl-4-hydroxypiperidine. This uses a similar structure to analogize the three potential stereocenters in ohmfentanyl, namely the 4-C, the 3-C, and the β-C (beta carbon). These three stereocenters are analogized in the C-4, C-3, and C-7 respectively.
gene Any segment or set of segments of a nucleic acid molecule that contains the information necessary to produce a functional RNA transcript in a controlled manner. In living organisms, genes are often considered the fundamental units of heredity and are typically encoded in DNA. A particular gene can have multiple different versions, or alleles, and a single gene can result in a gene product that influences many different phenotypes.
Halogenating or making other modifications at positions 1 or 2 on the morphine carbon skeleton. The methyl group that makes morphine into codeine can be removed or added back, or replaced with another functional group like ethyl and others to make codeine analogues of morphine-derived drugs and vice versa. Codeine analogues of morphine-based drugs often serve as prodrugs of the stronger drug, as in codeine and morphine, hydrocodone and hydromorphone, oxycodone and oxymorphone, nicocodeine and nicomorphine, dihydrocodeine and dihydromorphine, etc. Saturating, opening, or other changes to the bond between positions 7 and 8, as well as adding, removing, or modifying functional groups to these positions; saturating, reducing, eliminating, or otherwise modifying the 7–8 bond and attaching a functional group at 14 yields hydromorphinol; the oxidation of the hydroxyl group to a carbonyl and changing the 7–8 bond to single from double changes codeine into oxycodone. Attachment, removal, or modification of functional groups to positions 3 or 6 (dihydrocodeine and related, hydrocodone, nicomorphine); in the case of moving the methyl functional group from position 3 to 6, codeine becomes heterocodeine, which is 72 times stronger, and therefore six times stronger than morphine Attachment of functional groups or other modification at position 14 (oxymorphone, oxycodone, naloxone) Modifications at positions 2, 4, 5, or 17, usually along with other changes to the molecule elsewhere on the morphine skeleton.
Sources: en.wikipedia.org
== Pharmacokinetics == A cross-over study in six healthy volunteers (median age 28 years) was conducted using single-dose pharmacokinetics of 5 mg clotiazepam drops, oral tablets, and sublingual tablets. The formulations had similar systemic availability. Compared with oral tablets, the sublingual route gave a lower peak concentration and a delayed peak time, while drops gave a greater maximum concentration with a similar peak time. The use of drops is suggested for a more marked initial effect and the sublingual route for easier administration, especially in the elderly.
The other elimination pathways are less important in the elimination of drugs, except in very specific cases, such as the respiratory tract for alcohol or anaesthetic gases. The case of mother's milk is of special importance. The liver and kidneys of newly born infants are relatively undeveloped and they are highly sensitive to a drug's toxic effects. For this reason it is important to know if a drug is likely to be eliminated from a woman's body if she is breast feeding in order to avoid this situation.
=== Africa === Fake antimalarial medication has been threatening efforts to control malaria in Africa, including the development of antimalarial resistance. Other medicines have been documented to be of dangerously poor quality. In October 2022, the deaths of at least 70 children in Gambia were linked to cough syrups manufactured in India, which had high levels of diethylene glycol and ethylene glycol. There were delays in government response, despite doctors pressing for this. In 2011, according to the World Health Organization (WHO), 64% of Nigeria's imported antimalarial medication drugs were fake. By 2023, the problem of substandard and falsified medicines had lessened somewhat since the peak. Nigeria is Africa's largest drugs market, and over 70% of its drugs are imported from India and China, considered the "biggest source of fakes." One response has been attempts to bolster domestic production of medicines, but challenges include insecurity and unstable electricity. There have been investments in technologies to increase detection and verification of poor-quality medicines. In 2018, Tramadol, a powerful and addictive opioid, became a major problem. A huge black market has emerged, and an increasing number of addicts overdose and die.
organometallic chemistry, compounds with metal-carbon bonds. This area touches on organic synthesis, which employs many organometallic catalysts and reagents. cluster chemistry, compounds with several metals bound together with metal–metal bonds or bridging ligands. bioinorganic chemistry, biomolecules that contain metals. This area touches on medicinal chemistry. materials chemistry and solid state chemistry, extended (i.e. polymeric) solids exhibiting properties not seen for simple molecules. Many practical themes are associated with these areas, including ceramics.
To counter the advances the pro-independence forces had made in South America, Spain prepared a second, large, expeditionary force in 1819. This force, however, never left Spain. Instead, it became the means by which liberals were finally able to reinstate a constitutional regime. On 1 January 1820, Rafael Riego, commander of the Asturias Battalion, headed a rebellion among the troops, demanding the return of the 1812 Constitution. His troops marched through the cities of Andalusia with the hope of extending the uprising to the civilian population, but locals were mostly indifferent. An uprising, however, did occur in Galicia in northern Spain, and from there it quickly spread throughout the country. On 7 March, the royal palace in Madrid was surrounded by soldiers under the command of General Francisco Ballesteros, and three days later, on 10 March, the besieged Ferdinand VII, now a virtual prisoner, agreed to restore the Constitution. Riego's Revolt had two significant effects on the war in the Americas. Militarily, the large numbers of reinforcements, which were especially needed to retake New Granada and defend the Viceroyalty of Peru, would never arrive. Furthermore, as the royalists' situation became more desperate in region after region, the army experienced wholesale defections of units to the Patriot side. Politically, the reinstitution of a liberal regime changed the terms under which the Spanish government sought to engage the insurgents.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.
It contains the 4-7 fragment of adrenocorticotropic hormone extended at the C terminus. That truncation removes the region associated with steroidogenic activity. The design intent was to keep neurotrophic properties while avoiding full hormonal effects.
No natural source of the intact heptapeptide is known. It is produced by solid-phase peptide synthesis. Some related ACTH fragments arise as hormone processing products, but the Pro-Gly-Pro extension is a designed addition rather than a natural sequence.
Registered medical products are most often 0.1% nasal drops. Research suppliers ship lyophilized powder, usually in milligram quantities, which is dissolved before use. The active peptide is the same in both cases; presentation and excipients differ.