If you have been reading about Thymalfasin 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.
Last reviewed on 2025-08-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
The molecule consists of 28 amino acid residues with an acetyl group attached to the N-terminal serine. Its sequence is acidic overall, with several glutamic and aspartic acid residues distributed along the chain and no cysteine, so disulfide bridges do not form. The peptide carries a net negative charge at physiological pH. Because the N-terminus is blocked, the intact molecule resists degradation by many aminopeptidases, which contributes to its stability in biological fluids.
The peptide is generated in cells by cleavage of prothymosin alpha, a larger acidic protein encoded by the PTMA gene. Prothymosin alpha is expressed in many tissues, not only in the thymus, and its functions include nuclear roles in chromatin-related processes. The 28-residue fragment corresponds to the N-terminal portion of that precursor. How the cleavage occurs and how the fragment's concentration is regulated remain open questions; circulating amounts are small and difficult to measure reliably with routine assays.
Thymosin alpha-1 is a synthetic peptide of 28 amino acid residues that corresponds to a naturally occurring fragment first isolated from thymus tissue. Its chain is acetylated at the amino terminus, a modification that shields the peptide from rapid cleavage by aminopeptidases. The molecule carries a net negative charge at physiological pH and dissolves freely in water. Researchers classify it as an immune-modulating agent rather than a classical hormone, because it acts on several cell types of both the innate and the adaptive immune system.
The peptide was identified during work in the 1970s on thymosin fraction 5, a partially purified extract of calf thymus. Investigators separated that mixture and characterized individual components, one of which they named thymosin alpha-1. The same compound later received the international nonproprietary name thymalfasin. Commercial material is produced by solid-phase peptide synthesis rather than by extraction, so synthetic and natural forms share an identical sequence. Naming conventions vary across the literature, and readers should distinguish the alpha-1 peptide from other thymosins that have unrelated sequences and functions.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Acetylated peptide | N-terminal acetyl group blocks aminopeptidase attack |
| Residue count | 28 amino acids | Matches the N-terminus of prothymosin alpha |
| Molecular mass | About 3,108 Da | Value for the free, unmodified peptide |
| Isoelectric point | Approximately 4.2 | Acidic; net negative charge at neutral pH |
| Encoding gene | PTMA | Human gene for the precursor protein |
Thymosin alpha-1 is a synthetic peptide of 28 amino acids whose sequence matches the amino-terminal region of prothymosin alpha. The chain is acetylated at its first residue and contains one disulfide bridge between two cysteine residues, which folds the molecule into a compact loop. Its molecular formula, C129H215N33O55, corresponds to a monoisotopic mass of roughly 3,106 daltons. Material used in laboratories is made by solid-phase synthesis rather than isolated from animal tissue.
Early work on thymic extracts in the 1960s described a heat-stable acidic fraction containing many polypeptides. Separation of that mixture yielded individual components, and thymosin alpha-1 was named as one of them on the basis of assays for T-cell activity. The first preparations came from calf thymus, while subsequent research and clinical material has been chemically synthesized. Nomenclature in older papers is inconsistent, and the same peptide sometimes appears under different designations, which complicates literature searches.
Most published studies on thymosin alpha-1 report changes in immune measurements rather than clinical outcomes, and findings differ across designs and populations. Whether the peptide signals through one defined receptor or through several less specific interactions remains an open question. Its reported circulation half-life of a few hours complicates comparison of dosing schedules across trials. Mechanistic claims are frequently drawn from isolated cell cultures, and how far those results extend to whole organisms is unresolved.
Within the immune system, the peptide acts on several cell types rather than a single target. Reported activities include promotion of T-cell maturation, enhancement of natural killer cell activity, and modulation of cytokine production by dendritic cells and macrophages. Some of these effects appear to operate through toll-like receptor signaling, though the precise receptor-level mechanism remains debated. Whether the observed immune changes translate into clinical benefit is a separate question and depends on the indication studied.
The peptide was described in the 1970s as a component of thymic extracts, and early research focused on restoring immune function in immunodeficiency states. A synthetic version entered clinical development in the 1980s and is approved as a drug in several countries for conditions such as chronic hepatitis B and certain immunodeficiencies. Approval status varies widely by jurisdiction, and in the United States it is not an approved therapeutic. Regulatory and clinical positions differ, so statements about efficacy should be tied to specific indications and studies.
Thymosin alpha 1 is approved as a medicine in several countries, including Italy and China, for indications such as chronic hepatitis B and as an immune adjuvant. It is not approved by the United States Food and Drug Administration as a therapeutic product. In research settings the peptide appears in studies of sepsis, vaccine response, and oncology support, often with mixed or inconclusive results. The evidence base is uneven, and reviews note that many trials were small. Regulatory status therefore differs widely between jurisdictions.
Thymosin alpha 1 is a synthetic 28-amino-acid peptide first isolated in 1966 from thymosin fraction 5, a bovine thymus extract. Its chain begins with an acetylated serine residue and ends with asparagine. The native peptide carries a molecular mass near 3,108 daltons. Researchers classify it as an immunomodulatory agent rather than a hormone with a single endocrine target. Early work framed it as a thymus-derived factor that supports T-cell maturation. The synthetic form used in research and clinical products matches the natural sequence.
Immune signaling studies link thymosin alpha 1 to Toll-like receptor pathways, particularly TLR2 and TLR9, on dendritic cells and other antigen-presenting cells. Activation of these receptors promotes maturation of T cells and increases natural killer cell activity. The peptide shifts cytokine output toward a T helper 1 profile, raising interferon gamma and interleukin 2 while modulating interleukin 10. Whether these effects translate into clinical benefit for any specific disease remains a subject of debate. Reported outcomes vary across trials and populations.
For centuries, the Danes and Saxons had regarded each other as kindred peoples, sharing the same belief in the Germanic pantheon and frequently intermarrying, especially among the elite. Thus, the defeated Saxon warleader Widukind sought refuge with his father-in-law, Danish king Sigfred. The Royal Frankish Annals mentions that Widukind received substantial aid from Sigfred, though the exact nature of this aid is not explicitly stated. However, the chronicles do note that Sigfred and Charlemagne brokered a peace agreement some years later, indicating that Sigfred, upon hearing Widukind's plea, may have mustered his army and joined the war on the side of the Saxons. In response to the Danes' involvement in the war, Charlemagne seems to have recruited the Obotrites by promising them the Saxon portion of Holstein. This alliance with Charlemagne shifted the balance of power in the region. In 782, after another defeat of the Saxons, Charlemagne ordered the mass execution of 4,500 Saxons, an atrocity that became known as the Massacre of Verden. Following this brutal act, Charlemagne was nicknamed the "Butcher of Saxons" or "Saxonslaughterer." In 796, despite Saxony being fully under Frankish rule, the Saxons rose once more, supported by the Danes. The rebellion was triggered by the forced conscription of Saxons for the Frankish wars against the Avars. Moreover, Charlemagne, in alliance with the Obotrites, planned to subjugate the Danes, now led by King Gudfred Sigfredson. However, Gudfred struck first.
==== Other sensory methods ==== There are a variety of other chemical sensors for measuring glucose. Given the importance of glucose analysis in the life sciences, numerous optical probes have also been developed for saccharides based on the use of boronic acids, which are particularly useful for intracellular sensory applications where other (optical) methods are not or only conditionally usable. In addition to the organic boronic acid derivatives, which often bind highly specifically to the 1,2-diol groups of sugars, there are also other probe concepts classified by functional mechanisms which use selective glucose-binding proteins (e.g. concanavalin A) as a receptor. Furthermore, methods were developed which indirectly detect the glucose concentration via the concentration of metabolized products, e.g. by the consumption of oxygen using fluorescence-optical sensors. Finally, there are enzyme-based concepts that use the intrinsic absorbance or fluorescence of (fluorescence-labeled) enzymes as reporters.
Stupor: absence of psycho-motor activity; not actively relating to the environment Catalepsy: passive induction of a posture held against gravity Waxy flexibility: maintaining positions imposed by the examiner Mutism: minimal or absent verbal response (not due to aphasia) Negativism: resistance or lack of response to instructions or external stimuli Posturing: spontaneous and active maintenance of a posture against gravity Mannerisms: odd or exaggerated caricatures of normal actions Stereotypy: repetitive, abnormally frequent, non-goal-directed movements Agitation: excessive activity not influenced by external stimuli Grimacing: sustained facial expression Echolalia: mimicking another's speech Echopraxia: mimicking another's movements Other disorders (additional code 293.89 [F06.1] to indicate the presence of the co-morbid catatonia):
Sources: en.wikipedia.org
Given the importance of the Kucha region in the transmission of Buddhism into China and the evidence we have about the movement of translators such as Kumarajiva, it is reasonable to suggest that the art (and possibly the artists) of Kizil influenced the early art of the Mogao Cave complex near Dunhuang, further east along the Silk Road. The earliest of the extant Dunhuang caves (dating from the beginning of the fifth century) show distinctly "Central Asian" features in their painting, stylistically similar to what we find at Kizil. Among the subjects depicted at Kizil and Mogao in strikingly similar fashion is that of the "Cosmological Buddha", whose robe displays images connected with the phenomenal world.
Automated synthesis systems find new applications with a development of new robotic platforms. Possible applications include: uncontrolled synthesis, time-dependent synthesis, radiosynthesis, synthesis in demanding conditions (low temperatures, presence of specific atmosphere like CO, H2, N2, high pressure or under vacuum) or whenever the same or similar workflow needs to be applied multiple times with the aim to: optimize reactions, synthesize many derivatives in small scale, perform reactions of iterative homologations or radiosynthesis. Automated synthesis workflows are needed both in academic research and a wide array of industrial R&D settings (pharmaceuticals, agrochemicals, fine & specialty chemicals, renewables & energy research, catalysts, polymers, ceramics & abrasives, porous materials, nanomaterials, biomaterials, lubricants, paints & coatings, home care, personal care, nutrition, forensics).
Enteroglucagon is a proglucagon-derived peptide or enteroendocrine cells derived peptide in the small intestine. Preproglucagon undergoes post translational modification to release glucagon-like peptides (GLP-1 and GLP-2) and other molecules derived from L-cells of intestine. GLP-1 is derived from a class of intestinal hormones called incretin and the molecule exists in two forms GLP-1(7-37) and GLP-1(7-36) amide. GLP-1 form of incretin starts circulating in response to a high blood glucose level. Incretin effect is a negative feedback loop between glucose and insulin level, it promotes insulin release from beta cells of pancreas islet and suppresses glucagon when the glucose level is high. In vertebrate mammals, GLP-2 sequences are highly conversed in the intestine. The molecule functions as a part of adaptive response, such that contributes intestinal growth, proliferation effect, intestinal dilation (increases the mucosal blood flow) and reduces the chance of apoptosis.
Sources: en.wikipedia.org
13. Ir Med J. 2026 Sep 28;119(8):160. Non-Arteritic Anterior Ischaemic Optic Neuropathy Associated with Semaglutide use. Kearney M, Smyth NM, Hassan HSA, Khan MS. PRESENTATION: Non-arteritic ischaemic optic neuropathy (NAION) is a common cause of acute, painless monocular visual disturbance in older adults. This case discusses a woman in her 70s with vascular risk factors who presented with a three-day history of progressive left sided visual disturbance. Examination demonstrated a left relative afferent pupillary defect and inferior quadrantopia. DIAGNOSIS: Haematological investigations and neuroimaging were unremarkable. Formal ophthalmological assessment demonstrated superior optic disc swelling with an inferior visual field defect, consistent with NAION. TREATMENT: The patient had been taking semaglutide, as prescribed, for the six months prior to presentation. This was identified as a potential contributory agent and was discontinued. Visual acuity partially improved following cessation of semaglutide. DISCUSSION: This case seeks to highlight a possible association between semaglutide use and NAION. Although causality remains unproven, it underscores the importance of pharmacovigilance when manging patients presenting with ophthalmological symptoms.
In bone, entire collagen triple helices lie in a parallel, staggered array. 40 nm gaps between the ends of the tropocollagen subunits (approximately equal to the gap region) probably serve as nucleation sites for the deposition of long, hard, fine crystals of the mineral component, which is hydroxylapatite (approximately) Ca10(OH)2(PO4)6. Type I collagen gives bone its tensile strength.
==== Ultrastructure and collagen synthesis ==== Collagen fibres coalesce into macroaggregates. After secretion from the cell, cleaved by procollagen N- and C-proteases, the tropocollagen molecules spontaneously assemble into insoluble fibrils. A collagen molecule is about 300 nm long and 1–2 nm wide, and the diameter of the fibrils that are formed can range from 50–500 nm. In tendons, the fibrils then assemble further to form fascicles, which are about 10 mm in length with a diameter of 50–300 μm, and finally into a tendon fibre with a diameter of 100–500 μm. The collagen in tendons are held together with proteoglycan (a compound consisting of a protein bonded to glycosaminoglycan groups, present especially in connective tissue) components including decorin and, in compressed regions of tendon, aggrecan, which are capable of binding to the collagen fibrils at specific locations. The proteoglycans are interwoven with the collagen fibrils – their glycosaminoglycan (GAG) side chains have multiple interactions with the surface of the fibrils – showing that the proteoglycans are important structurally in the interconnection of the fibrils. The major GAG components of the tendon are dermatan sulfate and chondroitin sulfate, which associate with collagen and are involved in the fibril assembly process during tendon development. Dermatan sulfate is thought to be responsible for forming associations between fibrils, while chondroitin sulfate is thought to be more involved with occupying volume between the fibrils to keep them separated and help withstand deformation.
Ehlers–Danlos syndrome, vascular type: In rare cases, specific heterozygous arginine-to-cysteine substitution mutations in COL1A1 that are also associated with vascular fragility and mimic COL3A1-vEDS Ehlers–Danlos syndrome, arthrochalasia type: It is caused by mutations in the COL1A1 gene. The mutations in the COL1A1 gene that cause this disorder instruct the cell to leave out a part of the pro-alpha1(I) chain that contains a segment used to attach one molecule to another. When this part of the protein is missing, the structure of type I collagen is compromised. Tissues that are rich in type I collagen, such as the skin, bones, and tendons, are affected by this change. Ehlers–Danlos type IV is most attributed to abnormalities in the reticular fibers (collagen Type III). Ehlers–Danlos syndrome, classical type: In rare cases, a mutation in the COL1A1 gene has been shown to cause the classical type of Ehlers–Danlos syndrome. This mutation substitutes the amino acid cysteine for the amino acid arginine at position 134 in the protein made by the gene. (The mutation can also be written as Arg134Cys.) The altered protein interacts abnormally with other collagen-building proteins, disrupting the structure of type I collagen fibrils and trapping collagen in the cell. Researchers believe that these changes in collagen cause the signs and symptoms of the disorder. Ehlers–Danlos type IV is most attributed to abnormalities in the reticular fibers (collagen Type III). Without the hydroxylation of lysine, by the enzyme lysyl hydroxylase, the final collagen structure cannot form.
Sources: pubmed.ncbi.nlm.nih.gov
Thymosin fraction 5 is a mixture of many peptides obtained from thymus tissue, while thymosin alpha 1 is a single defined 28-residue molecule. The two names appear together in older literature because the purified peptide was first obtained from that mixture.
The precursor, prothymosin alpha, is encoded by the PTMA gene in humans. The 28-residue peptide corresponds to the N-terminal segment released from that larger protein.
It is produced as a fragment of prothymosin alpha and is present in many tissues. Circulating concentrations are low, which makes routine measurement difficult.
It is a 28-residue synthetic peptide studied as an immune-modulating agent and approved as a drug in some countries. The sequence matches a naturally occurring fragment isolated from thymus tissue. It is not a hormone in the endocrine sense.