Pro-Gly-Pro tail is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2025-09-02. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| 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 |
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.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
Otto Knut Olof Folin (April 4, 1867 – October 25, 1934) was a Swedish-born American chemist who is best known for his groundbreaking work at Harvard University on practical micromethods for the determination of the constituents of protein-free blood filtrates and the discovery of creatine phosphate in muscles.
== Function == Several lines of evidence suggest that PD-1 and its ligands negatively regulate immune responses. PD-1 knockout mice have been shown to develop lupus-like glomerulonephritis and dilated cardiomyopathy on the C57BL/6 and BALB/c backgrounds, respectively. In vitro, treatment of anti-CD3 stimulated T cells with PD-L1-Ig results in reduced T cell proliferation and IFN-γ secretion. IFN-γ is a key pro-inflammatory cytokine that promotes T cell inflammatory activity. Reduced T cell proliferation was also correlated with attenuated IL-2 secretion and together, these data suggest that PD-1 negatively regulates T cell responses. Experiments using PD-L1 transfected DCs and PD-1 expressing transgenic (Tg) CD4+ and CD8+ T cells suggest that CD8+ T cells are more susceptible to inhibition by PD-L1, although this could be dependent on the strength of TCR signaling. Consistent with a role in negatively regulating CD8+ T cell responses, using an LCMV viral vector model of chronic infection, Rafi Ahmed's group showed that the PD-1-PD-L1 interaction inhibits activation, expansion and acquisition of effector functions of virus specific CD8+ T cells, which can be reversed by blocking the PD-1-PD-L1 interaction. Expression of PD-L1 on tumor cells inhibits anti-tumor activity through engagement of PD-1 on effector T cells. Expression of PD-L1 on tumors is correlated with reduced survival in esophageal, pancreatic and other types of cancers, highlighting this pathway as a target for immunotherapy.
==== Papillary region ==== The papillary region is composed of loose areolar connective tissue. It is named for its finger-like projections called papillae, which extend toward the epidermis. The papillae provide the dermis with a "bumpy" surface that interdigitates with the epidermis, strengthening the connection between the two layers of skin. In the palms, fingers, soles, and toes, the influence of the papillae projecting into the epidermis forms contours in the skin's surface. These epidermal ridges occur in patterns (see: fingerprint) that are genetically and epigenetically determined and are therefore unique to the individual, making it possible to use fingerprints or footprints as a means of identification.
where aij is the number of atoms of element i in molecule j and b0i is the total number of atoms of element i, which is a constant, since the system is closed. If there are a total of k types of atoms in the system, then there will be k such equations. If ions are involved, an additional row is added to the aij matrix specifying the respective charge on each molecule which will sum to zero. This is a standard problem in optimisation, known as constrained minimisation. The most common method of solving it is using the method of Lagrange multipliers (although other methods may be used). Define:
The Battle of Binh Ba, also known as Operation Hammer, was a hard-fought, but one-sided, battle. Troops from the 5th Battalion, Royal Australian Regiment (5RAR) fought a PAVN/VC force in the village of Binh Ba, 5 kilometres (3.1 mi) north of Nui Dat in Phuoc Tuy Province resulting in 107 PAVN/VC killed and eight captured for the loss of one Australian killed.
Sources: en.wikipedia.org
=== Sense and sensitivity === In clinical microbiology labs, the quantitation of microbial burden is considered a routine function as it is associated with the severity and progression of the disease. To achieve a good quantitation a high sensitivity of the technique is needed. Whereas interfering substances represent a common problem to clinical chemistry or to PCR diagnostics, the degree of interference from host (for example, in tissue biopsies) or nonpathogen nucleic acids (for example, in stool) in metagenomics is a new twist. In addition, due to the relative size of the human genome in comparison with microbial genomes the interference can occur at low levels of contaminating material. Another challenge for clinical metagenomics in regards to sensitivity is the diagnosis of coinfections where there are present high-titer pathogens that can generate biased results as they may disproportionately soak up reads and make difficult to distinguish the less predominant pathogens. In addition to issues with interfering substances, specially in the diagnosis area, accurate quantitation and sensitivities are essential as a confusion in the results can affect to a third person, the patient. For these reason, practitioners currently have to be keenly aware of the index-swapping issues associated with Illumina sequencing which can lead to trace incorrectly barcoded samples. Since metagenomics has typically been used on patients for whom every other test to date has been negative, questions surrounding analytical sensitivity haven been less germane.
== Pharmacology == Nordazepam is a partial agonist at the GABAA receptor, which makes it less potent than other benzodiazepines, particularly in its amnesic and muscle-relaxing effects. Its elimination half-life is between 36 and 200 hours, with wide variation among individuals; factors such as age and sex are known to impact it. The variation of reported half-lives are attributed to differences in nordazepam metabolism and that of its metabolites as nordazepam is hydroxylated to active metabolites such as oxazepam, before finally being glucuronidated and excreted in the urine. This can be attributed to extremely variable hepatic and renal metabolic functions among individuals depending upon a number of factors (including age, ethnicity, disease, and current or previous use/abuse of other drugs/medicines).
== History == The efficacy of ceftolozane/tazobactam to treat complicated intra-abdominal infections (cIAI) in combination with metronidazole was established in a clinical trial with a total of 979 adults. Participants were randomly assigned to receive ceftolozane/tazobactam plus metronidazole or meropenem. Results showed ceftolozane/tazobactam plus metronidazole was effective for the treatment of cIAI. The efficacy of ceftolozane/tazobactam to treat complicated urinary tract infections (cUTI) was established in a clinical trial where 1,068 adults were randomly assigned to receive ceftolozane/tazobactam or levofloxacin. Ceftolozane/tazobactam demonstrated it was effective in treating cUTI. Ceftolozane/tazobactam was shown to be at least as effective as other antibiotics in curing infections in three main studies. One study involved 1,083 participants who mostly had kidney infection or in some cases a complicated urinary-tract infection. Ceftolozane/tazobactam successfully treated the infection in about 85% of the cases where it was given (288 of 340), compared with 75% (266 of 353) of those given another antibiotic called levofloxacin. The second study involved 993 participants with complicated intra-abdominal infections. Ceftolozane/tazobactam was compared with another antibiotic, meropenem. Both medicines cured 94% of participants (353 out of 375 given ceftolozane/tazobactam and 375 out of 399 given meropenem). The third study involved 726 participants who were using a ventilator and who had either hospital-acquired pneumonia or ventilator-associated pneumonia.
Therefore, the only option for GAHT may be self-administered medications (testosterone, oestrogen, anti-androgens,..etc.), without professional guidance. An examination of the use of self-medication found that people who self-medicated were more likely to experience adverse health effects from preexisting conditions such as high blood pressure as well as slower development of desired secondary sex characteristics. Transgender people seeking surgery may be informed they will need to take hormones for the rest of their life if they want to maintain the feminizing effects of oestrogen or the masculinizing effects of testosterone. Their dose of hormones will usually be reduced, but it should still be enough to produce the effects that they need and to keep them well, and to protect them against osteoporosis (thinning of the bones) as they get older. If they are still on hormone blockers, they will stop taking them altogether.
Sources: en.wikipedia.org
== Further reading == Habibi, N; Kamaly, N; Memic, A; Shafiee, H (2016). "Self-assembled peptide-based nanostructures: Smart nanomaterials toward targeted drug delivery". Nano Today. 11 (1): 41–60. doi:10.1016/j.nantod.2016.02.004. PMC 4834907. PMID 27103939.
=== Antiepileptics === Antiepileptics are rarely prescribed as an off-label treatment for anxiety disorders and post-traumatic stress disorders. There have been some suggestions that they may help with anxiety symptoms but there is generally a lack of research on its use. One antiepileptic, pregabalin, has been found to be better at treating GAD than a placebo, and comparable effects to benzodiazepines. It has also been shown be potentially efficient in treating social anxiety disorder. Gabapentin has been prescribed off-label for anxiety despite a lack of research evidence supporting such use, although some studies have indicated that it may relieve anxiety symptoms. The potential anxiolytic effect of tiagabine has been observed in some pre-clinical trials, but its effectiveness has not yet been proved. Similarly, there is a lack of research on valproate for the treatment of anxiety disorders.
The 2026 Iran war caused immediate volatility in energy markets, with Brent crude oil prices surging 10–13% to around $80–82 per barrel by 2 March 2026, and dropping back to near $70 by July, 2026. The conflict has caused the restriction of nearly all traffic through the Strait of Hormuz, leading to what the International Energy Agency has characterised as the "largest supply disruption in the history of the global oil market". The head of the IEA described the situation caused by the war as the "greatest global energy security challenge in history". Iran's closure of the Strait of Hormuz disrupted 20% of global oil supplies and significant liquefied natural gas (LNG) volumes. Analysts have forecast that prices could reach $100 per barrel if disruptions persisted, potentially adding 0.8% to global inflation. Even after Iran and the United States announced a ceasefire on 8 April, ship traffic through the Strait of Hormuz remained far below pre-war levels. Exports from the region have been typically going to Asian countries, with China, India, Japan, and South Korea accounting for 75% of oil and 59% of LNG exports. However, Singapore and Taiwan depend more on Qatari LNG, while Pakistan and Bangladesh are more price sensitive. Qatari state-owned oil and gas company QatarEnergy announced on 3 March that it was declaring Force Majeure on its contracts with buyers, and internal sources, according to Reuters, said that it would soon be shutting down gas liquefication, as LNG tankers could not leave the Gulf, and that restarting it would take weeks.
Contemporary global warming is driven by human activities, despite claims that it is not occurring, lacks strong scientific consensus, or that warming is mostly caused by non-human factors. No scientific body of national or international standing disagrees with the decades-old, near-complete scientific consensus on climate change. Global warming is primarily a result of the increase in atmospheric greenhouse gas concentrations (like CO2 and methane) via the burning of fossil fuels as well as other human activities such as deforestation, with secondary climate change feedback mechanisms (such as the melting of the polar ice increasing the Earth's absorption of sunlight) assisting to perpetuate the change. Global warming is not caused by the hole in the ozone layer. Ozone depletion is a separate problem caused by chlorofluorocarbons (CFCs) which have been released into the atmosphere. CFCs are strong greenhouse gases; however, the hole in the ozone layer is shrinking and in 2019 was the smallest it had been since 1982, while global warming continues. Cooling towers in power stations and other facilities do not emit smoke, harmful fumes, or radiation; they emit water vapor and do not contribute to climate change. Nuclear power is one of the safest sources of energy, resulting in orders of magnitude fewer deaths than conventional power sources per unit of energy produced. Extremely few people are killed or injured due to nuclear power on a yearly basis. (See also: Radiophobia) Earthquake strength (or magnitude) is not commonly measured using the Richter scale.
Mylodontidae is a family of extinct South American and North American ground sloths within the suborder Folivora of order Pilosa, living from around 23 million years ago (Mya) to 11,000 years ago. This family is most closely related to another family of extinct ground sloths, Scelidotheriidae, as well as to the extant arboreal two-toed sloths, family Choloepodidae; together these make up the superfamily Mylodontoidea. Phylogenetic analyses based on morphology uncovered the relationship between Mylodontidae and Scelidotheriidae; in fact, the latter was for a time considered a subfamily of mylodontids. However, molecular sequence comparisons were needed for the correct placement of Choloepodidae. These studies have been carried out using mitochondrial DNA sequences as well as with collagen amino acid sequences. The latter results indicate that Choloepodidae is closer to Mylodontidae than Scelidotheriidae is. The only other living sloth family, Bradypodidae (three-toed sloths), belongs to a different sloth radiation, Megatherioidea. The mylodontoids form one of three major radiations of sloths. The discovery of their fossils in caverns associated with human occupation lead some early researchers to theorize that the early humans built corrals when they could procure a young ground sloth, to raise the animal to butchering size. However, radiocarbon dates do not support simultaneous occupation of the site by humans and sloths. Subfossil remains like coproliths, fur and skin have been discovered in some quantities.
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.
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.