A practical reference on aliquot: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-11-16 and is reviewed periodically as new material appears.
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.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White lyophilized powder | Typical for synthetic peptides |
| Solubility | Freely soluble in water | Also soluble in saline |
| Storage temperature | -20 C or below | Protect from repeated freeze-thaw |
| Analytical method | Reverse-phase HPLC | Confirms purity and identity |
| Common synonym | ACTH(4-10) analog | Reflects structural origin |
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.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
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.
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.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Helene Langevin is an American medical scientist who served as the Director of the National Center for Complementary and Integrative Health (NCCIH) at the National Institutes of Health (NIH) between November 2018 and November 2025. She was a professor in the University of Vermont College of Medicine's Department of Neurological Sciences. She is best known for characterizing certain cellular and mechanical effects of acupuncture. She was also a Professor in Residence of Medicine at Harvard Medical School, Brigham and Women's Hospital. Prior to working at NIH, Langevin was the Director of the Osher Center for Integrative Medicine, jointly owned by Brigham and Women's Hospital and Harvard Medical School. Langevin was the principal investigator of studies funded by the National Institutes of Health. The Boston Globe describes her as a "celebrity" in the world of acupuncture.
== Growth conditions == Limnospira platensis has been found in environments with high concentrations of carbonate and bicarbonate. It can also be found in high salt concentrations because of its alkali and salt tolerance. The temperature optimum for this organism is around 35 °C. Based on environmental conditions, culture medium often has a pH between 9–10, inorganic salts, and a high bicarbonate concentration.
=== Thyrotropin-releasing hormone stimulation test === Thyrotropin-releasing hormone (TRH) receptors are present in both the melanotropes of the pars intermedia and the corticotropes in the pars distalis. The administration of exogenous TRH causes an increase in ACTH and α-MSH in plasma of both normal horses and those with PPID. In both cases, plasma ACTH peaks 2–10 minutes after administration, before slowly dropping to normal levels over the course of an hour. PPID horses, however, show a much greater peak than normal horses, especially in the autumn. The test is relatively simple, involving one blood sample taken before TRH administration, and one 10 minutes or 30 minutes following TRH. TRH is currently not licensed for use in horses, and can cause various side effects, including yawning, flehmen, muscle trembling, and coughing. This test is thought to have greater sensitivity than other tests, but has drawbacks including cost, TRH availability, limited repeatability and lack of defined seasonal reference intervals. Due to a lack of seasonal references, it is only recommended for use from December until June.
== Diseases of other endocrine glands (249–259) == Note: for 249–259, the following fifth digit can be added: (250.x0) Diabetes mellitus type 2 (250.x1) Diabetes mellitus type 1 (250.x2) Diabetes mellitus type 2, uncontrolled (250.x3) Diabetes mellitus type 1, uncontrolled 249 Secondary diabetes mellitus 249.0 Secondary diabetes mellitus without mention of complication 249.1 Secondary diabetes mellitus with ketoacidosis 249.2 Secondary diabetes mellitus with hyperosmolarity 249.3 Secondary diabetes mellitus with other coma 249.4 Secondary diabetes mellitus with renal manifestations 249.5 Secondary diabetes mellitus with ophthalmic manifestations 249.6 Secondary diabetes mellitus with neurological manifestations 249.7 Secondary diabetes mellitus with peripheral circulatory disorders 249.8 Secondary diabetes mellitus with other specified manifestations 249.9 Secondary diabetes mellitus with unspecified complications 250 Diabetes mellitus 250.0 Diabetes mellitus without mention of complication 250.1 Diabetes with ketoacidosis 250.2 Diabetes with hyperosmolarity 250.3 Diabetes with other coma 250.4 Diabetes with renal manifestations 250.5 Diabetes with ophthalmic manifestations 250.6 Diabetes with neurological manifestations 250.7 Diabetes with peripheral circulatory disorders 250.8 Diabetes with other specified manifestations 250.9 Diabetes with unspecified complication 251 Other disorders of pancreatic internal secretion 251.2 Hypoglycemia, nondiabetic, unspec. 252 Disorders of parathyroid gland 252.0 Hyperparathyroidism, unspec.
Sources: en.wikipedia.org
=== Period 1: Initial transitional style === The first period consist in a short interval of transitional style, in which paintings remain subtil and rather nuanced, but blue pigments have started to appear. The Cave of the Devil C (Cave 198) and Cave of the Devil A (Cave 199), as well as the Cave with the Steps (Cave 110) and sometimes the Red-domed Cave A (Cave 67) are considered as the first period of this new style.
== Bibliography == Corson, D. R.; MacKenzie, K. R.; Segrè, E. (1940). "Artificially Radioactive Element 85". Physical Review. 58 (8): 672–678. Bibcode:1940PhRv...58..672C. doi:10.1103/PhysRev.58.672. (subscription required) Greenwood, N. N.; Earnshaw, A. (2002). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-7506-3365-9. Kugler, H. K.; Keller, C. (1985). 'At, Astatine', System No. 8a. Gmelin Handbook of Inorganic and Organometallic Chemistry. Vol. 8 (8th ed.). Springer-Verlag. ISBN 978-3-540-93516-2. Lavrukhina, Avgusta Konstantinovna; Pozdnyakov, Aleksandr Aleksandrovich (1970). Analytical Chemistry of Technetium, Promethium, Astatine, and Francium. Translated by R. Kondor. Ann Arbor–Humphrey Science Publishers. ISBN 978-0-250-39923-9. Scerri, Eric (2013). A Tale of Seven Elements. Oxford University Press, ISBN 9780195391312. Vértes, A.; Nagy, S.; Klencsár, Z. (2003). Handbook of Nuclear Chemistry. Vol. 4. Springer. ISBN 978-1-4020-1316-4. Zuckerman, J. J.; Hagen, A. P. (1989). Inorganic Reactions and Methods, Volume 3, The Formation of Bonds to Halogens (Part 1). John Wiley & Sons. ISBN 978-0-471-18656-4. Zuckerman, J. J.; Hagen, A. P. (1990). Inorganic Reactions and Methods, Volume 4, The Formation of Bonds to Halogens (Part 2). John Wiley & Sons. ISBN 978-0-471-18657-1.
=== Growth and proliferation === Intracrines such as fibroblast growth factor-2 (FGF2), vascular endothelial growth factor (VEGF), and insulin-like growth factor-1 (IGF-1) regulate cellular proliferation. In cancer, these factors often establish self-sustaining feed-forward loops, enhancing uncontrolled tumor growth. For example, VEGF's intracrine action is implicated in hematopoietic malignancies, while angiogenin has been identified in the nuclei of breast cancer cells, where it promotes proliferation.
Sources: en.wikipedia.org
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.
Peptidases degrade the compound within minutes in circulation. This short half-life is one reason nasal delivery is used, placing the substance close to the olfactory and trigeminal pathways.
No large multicenter trials have been published in English-language journals. The existing human evidence consists mainly of smaller studies conducted in Russia, which limits generalization.
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.