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Semax Background And Mechanism — Complete Guide

By Editorial Desk · published 2025-12-31 · last reviewed 2026-02-14 · Data

A practical reference on synthetic heptapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.

Reviewed 2026-02-14. Anything still debated is marked as such rather than presented as settled.

Semax Background And Mechanism

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.

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.

Semax Origin and Molecular Structure

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.

Semax at a glance

PropertyValueNotes
Molecular formulaC37H51N9O10SCalculated for the free peptide
Molar mass813.9 g/molAnhydrous free base
Peptide classSynthetic heptapeptideACTH(4-10) analogue
Parent fragmentACTH(4-10)Adrenocorticotropic hormone segment
Developmental originInstitute of Molecular Genetics, MoscowWork began in the 1980s

Chemical Identity and Research Background

Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.

Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.

Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.

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Background from the literature

==== Mechanism of action ==== Xanomeline modulates certain dopaminergic and glutamatergic circuits in the brain that can provide therapeutic benefits in patients suffering from neuropsychiatric and neurological diseases such as schizophrenia and Alzheimer's disease through stimulation primarily of central M1 and M4 muscarinic receptor subtypes. Muscarinic M1 and M4 receptors have been shown in preclinical studies to be expressed in areas important for dopamine and glutamate neural circuit regulation (e.g. frontal cortex and dorsal and ventral striatum). Xanomeline has shown antipsychotic-like effects in various preclinical behavioral models, such as attenuation of amphetamine-induced locomotor hyperactivity, effects that are dependent on M1 and M4 receptor activation.

=== Radiation therapy === Radiation therapy is the most frequently used treatment for hypersomatotropic cats. Radiation therapy is expensive, limited in availability, cost, frequent anaesthetic, and the unpredictable outcomes for hormonal control. The resolution or improvement of neurological signs is the most consistent effect. Improvement diabetes symptoms is less consistent. One study found an average of 5 weeks for improvement to glycaemic control with all cats seeing an improvement within 20 weeks. The same study found 6 of the 14 cats to achieve diabetic remission within 6 months with an average of 3.6 months. Diabetic remission may occur as late as a year after radiotherapy. Improvement of diabetic symptoms occurs in roughly 70-80% of cases, diabetic remission occurs in roughly 50%. The physical acromegalic changes often persistent or have only slight improvement. High IGF-1 levels have been reported in cats following radiation therapy. Of note is that in several of those cases the patient had good control of diabetic symptoms or was in remission. Radiation therapy is tolerated by the majority of cats. Side effects such as ischaemic brain necrosis and hearing loss are rare and proper fractionation protocol can prevent these effects from occurring; hypopituitarism has not been reported in cats, despite being a common adverse effect in humans. Survival times for cats after radiation therapy has been reported to be up to 5 years.

Periodontal pocket formation Gingival ulceration and suppuration Destruction of the alveolar bone and periodontal ligament Tooth mobility, drifting and eventual loss Because bone loss makes its first appearance in the advanced lesion, it is equated with periodontitis, while the first three lesions are classified as gingivitis in levels of increasing severity. The advanced lesion is no longer localized to the area around the gingival sulcus but spreads apically as well as laterally around a tooth and perhaps even deep into the gum tissue papilla. There is a dense infiltrate of plasma cells, other lymphocytes and macrophages. The clusters of perivascular plasma cells still appears from the established lesion. Bone is resorbed, producing scarring and fibrous change.

A 2018 research study conducted in Poland with the recruitment of ten healthy volunteers who ate 300 grams per head (about twice the normal dose) of fried T. equestre in a single meal reported no consequences or alterations. However, a 2020 systematic review highlighted several studies indicating elevated plasma creatine kinase (CK) pro-inflammatory activities, in addition to its effect on other liver function biomarkers, underlining a cause for concern and suggests "not to harvest and consume this species". The same 2020 study registered the same level of plasma CK using different edible mushrooms. For example the same level obtained by T. equestre was also obtained by Boletus edulis.

In the United States, cream soda is often vanilla-flavored and is either clear or colored a light golden brown or pink. Red, orange, and blue colored variants of the plain soda are also made. Popular brands include:

Sources: en.wikipedia.org

Reference notes

== External links == Jane Higdon, "Vitamin A", Micronutrient Information Center, Linus Pauling Institute, Oregon State University NIH Office of Dietary Supplements – Vitamin A Vitamin A Deficiency at the Merck Manual of Diagnosis and Therapy

=== Legal status === In July 2024, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Vevizye, intended for the treatment of dry eye disease. The applicant for this medicinal product is Novaliq GmbH. Vevizye was authorized for medical use in the European Union in September 2024.

Aagenaes syndrome Acroangiodermatitis (acroangiodermatitis of Mali, Mali acroangiodermatitis, Pseudo-Kaposi's sarcoma) Acrocyanosis Acute hemorrhagic edema of infancy (acute hemorrhagic edema of childhood, Finkelstein's disease, infantile postinfectious iris-like purpura and edema, medallion-like purpura, purpura en cocarde avec oedema, Seidlmayer syndrome) Arterial insufficiency ulcer (ischemic ulcer) Arteriosclerosis obliterans Bier spots Blueberry muffin baby Bonnet–Dechaume–Blanc syndrome (Wyburn–Mason syndrome) Bullous lymphedema Bullous small vessel vasculitis (bullous variant of small vessel vasculitis) Calciphylaxis Caput succedaneum Cholesterol embolus (warfarin blue toe syndrome) Cobb syndrome Corona phlebectatica Cryofibrinogenemic purpura Cryoglobulinemic purpura Cryoglobulinemic vasculitis Cutaneous small-vessel vasculitis (cutaneous leukocytoclastic angiitis, cutaneous leukocytoclastic vasculitis, cutaneous necrotizing venulitis, hypersensitivity angiitis) Deep venous thrombosis Disseminated intravascular coagulation Doucas and Kapetanakis pigmented purpura Drug-induced purpura Drug-induced thrombocytopenic purpura Eczematid-like purpura of Doucas and Kapetanakis Epidemic dropsy Erythema elevatum diutinum Erythromelalgia (acromelalgia, erythermalgia) Factitial lymphedema (hysterical edema) Fibrinolysis syndrome (defibrinating syndrome, hypofibrinogenemia) Food-induced purpura Generalized essential telangiectasia (general essential telangiectasia) Giant-cell arteritis Gougerot–Blum syndrome (pigmented purpuric lichenoid dermatitis, pigmented purpuric lichenoid dermatitis of Gougerot and Blum) Granulomatosis with polyangiitis Harlequin color change Hematopoietic ulcer Hennekam syndrome (Hennekam lymphangiectasia-lymphedema syndrome, intestinal lymphagiectasia-lymphedema-mental retardation syndrome) Henoch–Schönlein purpura (anaphylactoid purpura, purpura rheumatica, Schönlein–Henoch purpura) Hereditary hemorrhagic telangiectasia (Osler's disease, Osler–Weber–Rendu disease) Idiopathic thrombocytopenic purpura (autoimmune thrombocytopenic purpura, Werlhof's disease) IgA vasculitis Kawasaki's disease (mucocutaneous lymph node syndrome) Levamisole-induced vasculitis Lichen aureus (lichen purpuricus) Livedo racemosa Livedo reticularis Livedoid dermatitis (embolia cutis medicamentosa, Nicolau syndrome) Livedoid vasculopathy (atrophie blanche, livedo reticularis with summer ulceration, livedoid vasculitis, PURPLE syndrome, segmental hyalinizing vasculitis) Lymphedema praecox Lymphedema–distichiasis syndrome Maffucci syndrome Majocchi's disease (purpura annularis telangiectodes, purpura annularis telangiectodes of Majocchi) Malignant atrophic papulosis (Degos' disease) Marshall–White syndrome Meige lymphedema Microscopic polyangiitis (microscopic polyarteritis, microscopic polyarteritis nodosa) Mondor's disease (Mondor's syndrome of superficial thrombophlebitis) Neuropathic ulcer (mal perforans) Njolstad syndrome Nonne–Milroy–Meige syndrome (hereditary lymphedema, Milroy disease) Obstructive purpura Orthostatic purpura (stasis purpura) Painful bruising syndrome (autoerythrocyte sensitization, Gardner–Diamond syndrome, psychogenic purpura) Parkes Weber syndrome Paroxysmal hand hematoma (Achenbach syndrome) Paroxysmal nocturnal hemoglobinuria Polyarteritis nodosa (panarteritis nodosa, periarteritis nodosa) Postcardiotomy syndrome Perinatal gangrene of the buttock Pigmentary purpuric eruptions (progressive pigmentary dermatosis, progressive pigmenting purpura, purpura pigmentosa chronica) Postinflammatory lymphedema Postmastectomy lymphangiosarcoma (Stewart–Treves syndrome) Purpura fulminans (purpura gangrenosa) Purpura secondary to clotting disorders Purpuric agave dermatitis Raynaud phenomenon Raynaud's disease (primary Raynaud's phenomenon) Reactive angioendotheliomatosis Schamberg's disease (progressive pigmentary dermatosis of Schamberg, purpura pigmentosa progressiva, Schamberg's purpura) Secondary lymphedema Septic thrombophlebitis Sinusoidal hemangioma Sneddon's syndrome (idiopathic livedo reticularis with cerebrovascular accidents) Solar purpura (actinic purpura, senile purpura) Stasis dermatitis (congestion eczema, gravitational dermatitis, gravitational eczema, stasis eczema, varicose eczema) Superficial thrombophlebitis Takayasu arteritis (aortic arch syndrome, pulseless disease) Temporal arteritis (cranial arteritis, Horton's disease) Thromboangiitis obliterans (Buerger's disease) Thrombotic thrombocytopenic purpura (Moschcowitz syndrome) Traumatic purpura Trousseau's syndrome Unilateral nevoid telangiectasia (nevoid telangiectasia) Urticarial vasculitis (chronic urticaria as a manifestation of venulitis, hypocomplementemic urticarial vasculitis syndrome, hypocomplementemic vasculitis, unusual lupus-like syndrome) Venous insufficiency ulceration Waldenström hyperglobulinemic purpura (purpura hyperglobulinemica) Waldenström macroglobulinemia Yellow nail syndrome (primary lymphedema associated with yellow nails and pleural effusion)

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Sources: en.wikipedia.org

Reference notes

Transfer of sulfur-containing groups is covered by EC 2.8 and is subdivided into the subcategories of sulfurtransferases, sulfotransferases, and CoA-transferases, as well as enzymes that transfer alkylthio groups. A specific group of sulfotransferases are those that use PAPS as a sulfate group donor. Within this group is alcohol sulfotransferase which has a broad targeting capacity. Due to this, alcohol sulfotransferase is also known by several other names including "hydroxysteroid sulfotransferase," "steroid sulfokinase," and "estrogen sulfotransferase." Decreases in its activity has been linked to human liver disease. This transferase acts via the following reaction: 3'-phosphoadenylyl sulfate + an alcohol

At 7:59 a.m., American Airlines Flight 11 took off from Logan International Airport in Boston. About fifteen minutes into the flight, five hijackers armed with boxcutters took over the plane, injuring at least three people and possibly killing one, before forcing their way into the cockpit. The terrorists also displayed an apparent explosive and sprayed mace into the cabin, to frighten the hostages into submission and further hinder resistance. Back at Logan, United Airlines Flight 175 took off at 8:14 a.m. Hundreds of miles southwest at Dulles International Airport, American Airlines Flight 77 left the runway at 8:20 a.m. Flight 175's journey proceeded normally for 28 minutes until 8:42 am, when a group of five hijacked the plane, murdering both pilots and stabbing several crew members before assuming control of the aircraft. These hijackers also used bomb threats to instill fear into the passengers and crew, also spraying "tear gas, pepper spray or another irritant" in the cabin to force passengers and flight attendants to the rear of the cabin. Concurrently, United Airlines Flight 93 departed from Newark International Airport in New Jersey; originally scheduled to pull away from the gate at 8:00 a.m., the plane was running 42 minutes late. At 8:46 a.m., Flight 11 was deliberately crashed into the north face of the World Trade Center's North Tower between the 93rd and 99th floors. The initial presumption by many was that it was an accident.

=== ELI immunization === Another approach to DNA vaccination is expression library immunization (ELI). Using this technique, potentially all the genes from a pathogen can be delivered at one time, which may be useful for pathogens that are difficult to attenuate or culture. ELI can be used to identify which genes induce a protective response. This has been tested with Mycoplasma pulmonis, a murine lung pathogen with a relatively small genome. Even partial expression libraries can induce protection from subsequent challenge.

These synthetic opioids have increased length and depth of satiating any opiate cravings and generate very strong analgesic effects due to their long metabolic half-life and strong receptor affinity at the mu-opioid receptor sites. Therefore, they impart much of the satiating and anti-addictive effects of methadone by suppressing drug cravings. It was only in 1947 that the drug was given the generic name "methadone" by the Council on Pharmacy and Chemistry of the American Medical Association. Since the patent rights of the I.G. Farbenkonzern and Farbwerke Hoechst were no longer protected, each pharmaceutical company interested in the formula could buy the rights for the commercial production of methadone for just one dollar (MOLL 1990). Methadone was introduced into the United States in 1947 by Eli Lilly and Company as an analgesic under the trade name Dolophine. An urban myth later arose that Nazi leader Adolf Hitler ordered the manufacture of methadone or that the brand name 'Dolophine' was named after him, probably based on the similarity of "doloph" with "Adolph". (The pejorative term "adolphine" would appear in the early 1970s.) However, the name "Dolophine" was a contraction of "Dolo" from the Latin word dolor (pain), and finis, the Latin word for "end". Therefore, Dolophine literally means "pain end". Methadone was studied as a treatment for opioid addiction at the Addiction Research Center of the Narcotics Farm in Lexington, Kentucky in the 1950s, and by Rockefeller University physicians Robert Dole and Marie Nyswander in the 1960s in New York City.

== Medical uses == Gallium (68Ga) gozetotide is a radioactive diagnostic agent indicated for positron emission tomography (PET) of prostate-specific membrane antigen (PSMA)-positive lesions in men with prostate cancer. Ga 68 PSMA-11 injections are used for PET imaging of prostate-specific membrane antigen (PSMA) positive lesions in males with prostate cancer. It can be given for the patients with suspected metastasis, and the candidates with initial definitive therapy.

Sources: en.wikipedia.org

Frequently asked questions

What is semax derived from?

Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.

Is semax approved as a medicine?

It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.

Why is much of the research published in Russian?

The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.

What is semax derived from?

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.

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