A practical reference on Heptapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-06-30 and is reviewed periodically as new material appears.
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.
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.
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.
| 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. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
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.
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.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
In the course of the 1960s and 1970s, Cold War participants struggled to adjust to a new, more complicated pattern of international relations in which the world was no longer divided into two clearly opposed blocs. From the beginning of the post-war period with American help, Western Europe and Japan rapidly recovered from the destruction of World War II and sustained strong economic growth throughout the 1950s and 1960s, with per capita GDPs approaching those of the United States, while Eastern Bloc economies stagnated.
Have a diagnosable opioid use disorder, according to the DSM-5, Be actively addicted to opioids at the time of intake, and Have been addicted to opioids for at least one year before beginning treatment. In addition to these federal criteria, each state may have its own criteria individuals must meet. The US GAO also cited the cost of treatment and lack of health insurance coverage for MAT as barriers for many addicted to opioids. While methadone treatments are covered by Medicaid for low-income individuals, the extent of coverage depends on which state they are in and if the state has opted into Medicaid expansion under the Affordable Care Act. Buprenorphine, on the other hand, is not covered by Medicaid or, often, even by private health insurers. Because buprenorphine must typically be paid for out-of-pocket, lower-income individuals are often priced out of the lower-risk MAT. In some areas this creates major disparities along racial lines with the higher-risk treatment utilized by lower-income individuals - disproportionately represented by people of color - and the lower-risk treatment only accessible to higher-income individuals - disproportionately represented by whites. Other individual-level barriers may include transportation, especially for those who live in rural areas. The nearest Opioid Treatment Program (OTP) could be up to an hour away, and when daily methadone doses are required for treatment, this may interfere with the success of the MAT or the client's compliance in the program.
=== Differential diagnosis === While Gilbert syndrome is considered harmless, it is clinically important because it may give rise to a concern about a blood or liver condition, which could be more dangerous. However, these conditions have additional indicators:
In oxidative phosphorylation, the electrons removed from organic molecules in areas such as the citric acid cycle are transferred to oxygen and the energy released is used to make ATP. This is done in eukaryotes by a series of proteins in the membranes of mitochondria called the electron transport chain. In prokaryotes, these proteins are found in the cell's inner membrane. These proteins use the energy from reduced molecules like NADH to pump protons across a membrane.
=== Augmentation of Tumor Necrosis Factor === Injection of tuftsin intraperitoneally increases the formulation of TNF in serum and supernatants of cultured splenic and peritoneal adherent cells. This was also demonstrated in vitro using HL60 leukemia cells.
Sources: en.wikipedia.org
== Serious adverse events == Brentuximab vedotin was studied as monotherapy in 160 patients in two phase II trials. Across both trials, the most common adverse reactions (≥20%), regardless of causality, were chemotherapy-induced peripheral neuropathy (a progressive, enduring and often irreversible tingling numbness, intense pain, and hypersensitivity to cold, beginning in the hands and feet and sometimes involving the arms and legs), neutropenia (an immune system impairment), fatigue, nausea, anemia, upper respiratory tract infection, diarrhea, fever, rash, thrombocytopenia, cough and vomiting.
===== Response to stimuli ===== Serotonin is important in environmental response pathways, along with other neurotransmitters. Specifically, it has been found to be involved in auditory processing in social settings, as primary sensory systems are connected to social interactions. Serotonin is found in the IC structure of the midbrain, which processes specie specific and non-specific social interactions and vocalizations. It also receives acoustic projections that convey signals to auditory processing regions. Research has proposed that serotonin shapes the auditory information being received by the IC and therefore is influential in the responses to auditory stimuli. This can influence how an organism responds to the sounds of predatory or other impactful species in their environment, as serotonin uptake can influence aggression or social interaction.
== Life sciences specialties == Molecular toxicology Molecular pathology Blood transfusion science Cervical cytology Clinical biochemistry Clinical embryology Clinical immunology Clinical pharmacology and therapeutics Electron microscopy External quality assurance Haematology Haemostasis and thrombosis Histocompatibility and immunogenetics Histopathology and cytopathology Molecular genetics and cytogenetics Molecular biology and cell biology Microbiology including mycology Bacteriology Tropical diseases Phlebotomy Tissue banking/transplant Virology
It is considered particularly toxic in overdose, with a high rate of renal failure (which usually takes 2–5 days), rhabdomyolysis, coma, seizures and even status epilepticus. Some believe it to be less cardiotoxic than other TCAs in overdose, although reports of cardiotoxic overdoses have been made.
Sources: en.wikipedia.org
Experiments to date have supported the theory, with the half-lives of the confirmed nihonium isotopes increasing from milliseconds to seconds as neutrons are added and the island is approached. Nihonium has been calculated to have similar properties to its homologues boron, aluminium, gallium, indium, and thallium. All but boron are post-transition metals, and nihonium is expected to be a post-transition metal as well. It should also show several major differences from them; for example, nihonium should be more stable in the +1 oxidation state than the +3 state, like thallium, but in the +1 state nihonium should behave more like silver and astatine than thallium. Preliminary experiments have shown that elemental nihonium is not very volatile, and that it is less reactive than its lighter homologue thallium.
== Signs and symptoms == The hallmark of polymyositis is weakness and/or loss of muscle mass in the proximal musculature, as well as flexion of the neck and torso. These symptoms can be associated with marked pain in these areas as well. The hip extensors are often severely affected, leading to particular difficulty in climbing stairs and rising from a seated position. The skin involvement of dermatomyositis is absent in polymyositis. Dysphagia (difficulty swallowing) or other problems with esophageal motility occur in as many as 1/3 of patients. Low grade fever and enlarged lymph nodes may be present. Foot drop in one or both feet can be a symptom of advanced polymyositis and inclusion body myositis. The systemic involvement of polymyositis includes interstitial lung disease (ILD) and heart disease, such as heart failure and conduction abnormalities. Polymyositis tends to become evident in adulthood, presenting with bilateral proximal muscle weakness often noted in the upper legs due to early fatigue while walking. Sometimes the weakness presents itself as an inability to rise from a seated position without help or an inability to raise one's arms above one's head. The weakness is generally progressive, accompanied by lymphocytic inflammation (mainly cytotoxic T cells).
=== Depression === A 2016 Cochrane review concluded that for major depressive disorder, "Given the absence of high quality evidence and the inability to draw firm conclusions based on that evidence, the use of SAMe for the treatment of depression in adults should be investigated further.". A 2020 systematic review found that it performed significantly better than placebo, and had similar outcomes to other commonly used antidepressants (imipramine and escitalopram).
== See also == Upper Voltan Territorial Assembly election, 1957 List of French possessions and colonies French colonial empire French West Africa Heads of state of Burkina Faso Heads of government of Burkina Faso
=== Surgical removal === Epididymotomy is the placement of an incision into the epididymis and is sometimes considered a treatment option for acute suppurating epididymitis. Epididymectomy is the surgical removal of the epididymis, sometimes performed for post-vasectomy pain syndrome and for refractory cases of epididymitis. Epididymectomy is also performed for sterilization on some male animals of livestock species so they can be used to detect estrus in females ready for artificial insemination.
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 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.