If you have been reading about ACTH(4-10) 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 2025-08-14. Numbers and descriptions here follow the published literature rather than marketing material.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular weight | ~813.9 Da (free heptapeptide) | N-acetylated form is about 42 Da heavier |
| Residue count | 7 (heptapeptide) | Four residues from ACTH(4-10), three added |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility class | Freely soluble in water | Also dissolves in DMSO and polar organic solvents |
| Related parent fragment | ACTH(4-10) | Parent motif is Met-Glu-His-Phe |
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.
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.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
== Epidemiology == Each year, more than 2.5 million people in the United States develop pressure ulcers. In acute care settings in the United States, the incidence of bedsores is 0.4% to 38%; within long-term care it is 2.2% to 23.9%, and in home care, it is 0% to 17%. Similarly, there is wide variation in prevalence: 10% to 18% in acute care, 2.3% to 28% in long-term care, and 0% to 29% in home care. There is a much higher rate of bedsores in intensive care units because of immunocompromised individuals, with 8% to 40% of those in the ICU developing bedsores. However, pressure ulcer prevalence is highly dependent on the methodology used to collect the data. Using the European Pressure Ulcer Advisory Panel (EPUAP) methodology there are similar figures for pressure ulcers in acutely sick people in the hospital. There are differences across countries, but using this methodology, pressure ulcer prevalence in Europe was consistently high, from 8.3% (Italy) to 22.9% (Sweden). A recent study in Jordan also showed a figure in this range. Some research shows differences in pressure-ulcer detection among white and black residents in nursing homes.
== Preparation of platelet poor plasma == Within 1 hour of blood collection, centrifuge capped citrate (blue top) tube for 15 minutes Using a plastic transfer pipet, remove the top 3/4 of plasma and place it in a plastic centrifuge tube with cap. Centrifuge the plasma (in the plastic centrifuge tube) for another 15 minutes. Using a plastic transfer pipet, remove the top 3/4 into a plastic tube. Do not disturb the plasma in the bottom of the spun tube, where any residual platelets will be. Aliquots with visible red cells or hemolysis (pink plasma) are not acceptable. Freeze plasma immediately. Samples for most laboratory assays should be frozen within 4 hours of collection.
Honey use and production has a long and varied history, with its beginnings in prehistoric times. Several cave paintings in Cuevas de la Araña in Spain depict humans foraging for honey at least 8,000 years ago. While Apis mellifera is an Old World insect, large-scale meliponiculture of New World stingless bees has been practiced by Mayans since pre-Columbian times.
Before drying to make copra, raw coconut meat is 47% water, 33% fat, 15% carbohydrates, and 3% protein (table). In a reference amount of 100 grams (3.5 oz), raw coconut flesh supplies 354 calories of food energy, and is a rich source (20% or more of the Daily Value, DV) of manganese (65% DV), with various other dietary minerals in moderate amounts (10–18% DV; table). It is a poor source of vitamins. Raw coconut meat has a high content of saturated fatty acids (89% of total fats), with lauric acid as the main saturated fat (15% of total; USDA source in table).
Troponin C binds to calcium ions (Ca2+) to produce a conformational change in TnI Troponin T binds to tropomyosin, interlocking them to form a troponin-tropomyosin complex with thin filaments Troponin I binds to actin in thin myofilaments to hold the actin-tropomyosin complex in place. It inhibits the ATPase activise of actomyosin. Inside the cardiac troponin complex, the strongest interaction between molecules is the cTnI–TnC binary complex, especially in the presence of Ca2+ (KA = 1.5 × 10−8 M−1). TnC, forming a complex with cTnI, changes the conformation of cTnI molecule and shields part of its surface. According to the latest data cTnI is released in the blood stream of the patient in the form of binary complex with TnC or ternary complex with cTnT and TnC. cTnI-TnC complex formation plays an important positive role in improving the stability of cTnI molecule. cTnI, which is extremely unstable in its free form, demonstrates significantly better stability in complex with TnC or in ternary cTnI-cTnT-TnC complex. It has been demonstrated that stability of cTnI in native complex is significantly better than stability of the purified form of the protein or the stability of cTnI in artificial troponin complexes combined from purified proteins.
Sources: en.wikipedia.org
The colonization of Tahiti occurred in a time of rivalry for resources of the Pacific by colonizing European nations including the French and the British. It was also a time of rivalry and fighting between the people of Tahiti and neighbouring islands. It is unclear which is the first European ship to arrive at the island of Tahiti but it is often recognised as being HMS Dolphin captained by British Captain Samuel Wallis on 18 June 1767. He met a welcoming party of Tahitians who traded with him. Cultural differences leading to grave communication errors that resulted in a battle in Matavai Bay between three hundred war canoes and HMS Dolphin which fired on the war canoes with muskets, quarterdeck guns and then cannons. The Tahitian chief Obera (Purea) ordered peace offerings from her people after this battle and Wallis and the Tahitians departed on amicable terms when he left on 27 July 1767. A few months later the French arrived on 2 April 1768 with the ships Boudeuse and Etoile captained by Louis-Antoine de Bougainville.
Maximum temperatures rather than minimum temperatures influence the weight of hatchlings unless the minimum temperature exceeds the tolerance limit. In later hatchlings warmer weather and decreased food availability promotes more rapid development resulting in a smaller body size compared to earlier hatchlings. The heaviest hatchlings come from colder habitats. Increased population density also results in decreased adult size as well as slower development.
In 2022, the INCB said, regarding state legalization, “The Board has repeatedly expressed its concern that these developments may be inconsistent with the country’s legal obligations as a party to the three international drug conventions." Since then, over 20 other US states have legalized non-medical cannabis use. In 2013, Uruguay legalized cannabis, with the law taking effect in April 2014, making it the first country to do so. The INCB condemned the move and stated that Uruguay "knowingly decided to break the universally agreed and internationally endorsed legal provisions". The statement continued: "Cannabis is not only addictive but may also affect some fundamental brain functions, IQ potential, and academic and job performance and impair driving skills. Smoking cannabis is more carcinogenic than smoking tobacco." In 2018, Canada legalized cannabis, with the law taking effect that October. In "A Framework for the Legalization and Regulation of Cannabis in Canada", it was acknowledged that "Canada is one of more than 185 Parties to three United Nations drug control conventions" and said: "...
== Isotope vs. nuclide == A nuclide is a species of an atom with a specific number of protons and neutrons in the nucleus, for example, carbon-13 with 6 protons and 7 neutrons. Thus the terms are roughly the same, but the nuclide concept (referring to individual nuclear species) emphasizes nuclear properties over chemical properties, whereas the isotope concept (grouping all atoms of each element) emphasizes chemical over nuclear. The neutron number greatly affects nuclear properties, but its effect on chemical properties is negligible for most elements. Even for the lightest elements, whose ratio of neutron number to atomic number varies the most between isotopes, it usually has only a small effect although it matters in some circumstances (for hydrogen, the lightest element, the isotope effect is large enough to affect biology strongly). The term isotopes (originally also isotopic elements, now sometimes isotopic nuclides) is intended to imply comparison (like synonyms or isomers). For example, the nuclides 126C, 136C, 146C are isotopes (nuclides with the same atomic number but different mass numbers), but 4018Ar, 4019K, 4020Ca are isobars (nuclides with the same mass number). As the older and better-known term, isotope is however still used in some contexts where nuclide might be more appropriate, such as in nuclear technology and nuclear medicine.
Sources: en.wikipedia.org
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.
Semax is a synthetic analog of the ACTH(4-10) fragment rather than a copy of the full hormone. Truncation plus the added tail removes the steroidogenic portion of ACTH. That distinction explains why it is studied for nervous-system effects instead of adrenal stimulation.
It is registered as a prescription product in Russia and has been used there clinically, chiefly by the intranasal route. No approval exists in the United States or the European Union. Availability elsewhere typically falls under research-chemical distribution, with varying purity documentation.
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.