The short version of thymus extract fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-06-25 and is reviewed periodically as new material appears.
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.
The compound has been investigated as an adjunct in chronic viral hepatitis and as a vaccine adjuvant, with results that vary by study design and population. Regulators in some countries have approved a synthetic form for specific indications, while other agencies have not. Whether the peptide produces consistent clinical benefit across diverse patient groups is still an open question, and many trials have been small. Its status is therefore best described as investigational in many contexts and established only narrowly.
The name itself causes confusion, because several unrelated thymic peptides share the thymosin label. Thymosin beta-4, for example, is a different molecule with different functions. Naming conventions in the literature also mix descriptive research terms with assigned nonproprietary names, so a reader should confirm which entity a given paper addresses. Clarifying that point is usually the first step in interpreting any claim about this peptide.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic peptide, 28 residues | N-terminal fragment of prothymosin alpha |
| Molecular mass | About 3108 Da | Acetylated form |
| Isoelectric point | Near 4.2 | Acidic peptide |
| Appearance | White to off-white lyophilized powder | Common supplied form |
| Typical storage | -20 °C or below, dry | Solution stability is lower |
20世纪70年代，研究者从胸腺提取物中纯化出多种小肽，Tα1是其中被较早表征的一种。最初的制备依赖组织匀浆和层析步骤，产量低且成分复杂。随着固相肽合成技术成熟，实验室和工业界能够生产与天然序列一致的合成版本。合成肽的纯度可达95%以上，并可通过反相高效液相色谱和质谱进行鉴定。这一转变使研究不再依赖动物胸腺来源。
市售的胸腺素α1通常以冻干粉形式提供，溶解后用于注射。其氨基酸组成包括多个酸性残基，因此在中性pH下带负电荷。该肽可溶于水和生理盐水，但在有机溶剂中溶解度有限。储存条件通常为冻干状态下负20摄氏度，溶解后需冷藏并避免反复冻融。常见的同义词包括胸腺肽α1、thymalfasin和Tα1。
Lyophilized thymosin alpha 1 is typically stored refrigerated at 2 to 8 degrees Celsius and kept away from light. Reconstituted solutions are less stable and are usually used promptly after preparation. Repeated freeze-thaw cycles are avoided because they can promote aggregation and loss of activity. The peptide adsorbs to some plastic and glass surfaces, so a carrier protein is often added to dilute working solutions. Manufacturer instructions and published protocols both govern handling.
Identity and purity testing for thymosin alpha 1 relies mainly on reversed-phase high-performance liquid chromatography and mass spectrometry. Chromatography separates the parent peptide from truncated or modified variants, while mass spectrometry confirms the expected molecular mass. Amino acid analysis and peptide mapping provide additional sequence confirmation. Counterion content, water content, and residual solvents are measured separately as part of specification testing. No single method captures every attribute, so laboratories combine several techniques.
Thymosin alpha 1 is a short peptide first isolated from bovine thymus tissue in the early 1970s during fractionation work aimed at identifying factors that influence T cell development. It belongs to a family of acidic thymic peptides, and the original preparations contained several components that were later separated by chromatography. The compound is now produced synthetically rather than extracted from tissue, which removes batch variability tied to animal sourcing. Researchers describe it as an immunomodulatory peptide because laboratory studies show effects on several cell types of the innate and adaptive immune systems.
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.
In healthy individuals, the cortisol level should increase above 18–20 μg/dl within 60 minutes on a 250 mcg cosyntropin stimulation test. For standardization across laboratories, the Short Synacthen Test is preferably performed in the morning (between 8:00 AM and 10:00 AM) to account for the diurnal peak of cortisol secretion. Baseline cortisol is drawn at time 0, with follow‑up samples at 30 minutes (and optionally 60 minutes) after administration of 250 μg synthetic ACTH. An adequate response is generally defined as a peak serum cortisol ≥ 500–550 nmol/L (approximately 18–20 μg/dL) or an increment ≥ 200 nmol/L, thresholds that improve diagnostic accuracy for adrenal insufficiency. Interpretation for primary adrenal insufficiency, Addison's disease In Addison's disease, both the cortisol and aldosterone levels are low, and the cortisol will not rise during the cosyntropin stimulation test.
There are many diverse ways of monitoring enzyme levels through the use of enzyme inhibition. The general principle in many of these is the use the knowledge that many enzymes are driven by phosphate-releasing compounds such as adenosine triphosphate. Using radiolabelled 32P phosphate a fluorometric analysis can be used. Or unique polymers can be used to immobilize enzymes and act in an electrochemical biosensor. Overall, the benefits include a fast response time and little sample preparation. Some of the downsides include a lack of specificity in terms of being able to get readings of very small amounts of toxin and the rigidity of the assays in apply certain procedures to different toxins.
He suggests that hindsight criticism of the early publications should be mitigated by the then nascent state of radiochemistry: highlighting the prudence of Debierne's claims in the original papers, he notes that nobody can contend that Debierne's substance did not contain actinium. Debierne, who is now considered by the vast majority of historians as the discoverer, lost interest in the element and left the topic. Giesel, on the other hand, can rightfully be credited with the first preparation of radiochemically pure actinium and with the identification of its atomic number 89. The name actinium originates from the Ancient Greek aktis, aktinos (ακτίς, ακτίνος), meaning beam or ray. Its symbol Ac is also used in abbreviations of other compounds that have nothing to do with actinium, such as acetyl, acetate and sometimes acetaldehyde.
=== Legal status === In September 2025, the Committee for Medicinal Products for Human Use of the European Medicines Agency adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Kyinsu, intended for treatment of type 2 diabetes mellitus. The applicant for this medicinal product is Novo Nordisk A/S. Insulin icodec/semaglutide was authorized for medical use in the European Union in November 2025.
==== Teleostei ==== Order Anabantiformes Betta splendens, Siamese fighting fish (2018) Helostoma temminkii, Kissing gourami (2020) Order Anguilliformes Anguilla anguilla, European Eel (2012) Anguilla japonica, Japanese Eel (2022) Order Atheriniformes Atherinopsis californiensis, Jack silverside (2023) Order Beloniformes Oryzias latipes, medaka (2007) Order Callionymiformes Callionymus lyra, common dragonet (2020) Order Carangiformes Caranx ignobilis, Giant trevally (2022) Caranx melampygus, Bluefin trevally (2021) Pseudocaranx georgianus, New Zealand trevally (2021) Order Centrarchiformes Oplegnathus fasciatus, barred knifejaw (2019) Siniperca roulei (Slender Mandarinfish) (2025) Order Characiformes Astyanax jordani, Mexican cavefish (2014) Astyanax mexicanus, Mexican tetra (2021) Colossoma macropomum, Tambaqui (2021) Hasemania nana, Silvertip tetra (2013) Hyphessobrycon heterorhabdus, Flag tetra (2023) Petitella bleheri, Firehead tetra (2015) Psalidodon paranae, (2016) Order Cichliformes Oreochromis niloticus, Nile tilapia (2019) Maylandia zebra, Lake Malawi cichlid (2019) Order Clupeiformes Clupea harengus, Atlantic herring (2020) Coilia nasus, Japanese grenadier anchovy (2020) Sardina pilchardus, European pilchard (2019) Order Cypriniformes Anabarilius grahami, Kanglang fish (2018) Danio rerio, zebrafish (2007) Leuciscus baicalensis, Siberian dace (2014) Megalobrama amblycephala, Wuchang bream (2017) Metzia formosae, (2015) Opsarius caudiocellatus, (2022) Oxygymnocypris stewartii, (2019) Pseudobrama simoni (2020) Rhodeus ocellatus, Rosy bitterling (2020) Triplophysa bleekeri, Tibetan stone loach (2020) Order Cyprinodontiformes Fundulus catenatus, Northern studfish (2020) Fundulus olivaceus, Blackspotted topminnow (2020) Fundulus nottii, Bayou topminnow (2020) Fundulus xenicus, Diamond killifish (2020) Gambusia affinis, western mosquitofish (2020) Heterandria formosa, least killifish (2019) Micropoecilia picta, swamp guppy (2021) Xiphophorus maculatus, platyfish (2013) Nothobranchius furzeri, turquoise killifish (2015) Order Esociformes Esox lucius, northern pike (2014) Order Gadiformes Gadus macrocephalus, Pacific cod (2022) Gadus morhua, Atlantic cod (2011) Order Gasterosteiformes Gasterosteus aculeatus, three-spined stickleback (2006, 2012) Order Gobiiformes Oxyeleotris marmorata, marble goby (2020) Periophthalmus modestus, shuttles hoppfish or shuttles mudskipper (2022) Order Gymnotiformes Electrophorus electricus, electric eel (2014) Order Lampriformes Lampris incognitus, Smalleye Pacific Opah (2021) Order Osmeriformes Neosalanx tangkahkeii, Chinese icefish (2015) Protosalanx hyalocranius, clearhead icefish (2017) Order Osteoglossiformes Heterotis niloticus, African arowana (2020) Paramormyrops kingsleyae, mormyrid electric fish (2017) Scleropages formosus, Asian arowana (2016) Order Perciformes Centropyge bicolor, bicolor angelfish (2021) Chaetodon trifasciatus, melon butterflyfish (2020) Channa argus, northern snakehead (2017) Channa maculata, blotched snakehead (2021) Chelmon rostratus, copperband butterflyfish (2020) Chrysiptera cyanea, Sapphite damselfish (2024) Dissostichus mawsoni, Antarctic toothfish (2019) Eleginops maclovinus, Patagonian robalo (2019) Epinephelus moara, kelp grouper (2021) Larimichthys crocea, large yellow croaker (2014) Lutjanus campechanus, Northern red snapper (2020) Naso vlamingii, bignose unicornfish (2020) Parachaenichthys charcoti, Antarctic dragonfish (2017) Rachycentron canadum, Cobia (2024) Seriola dumerili, Greater amberjack (2017) Sillago sinica, chinese sillago (2018) Siniperca knerii, Big-Eye Mandarin Fish (2020) Sparus aurata, gilt-head bream (2018) Holacanthus passer, King Angelfish (2024) Oplegnathus fasciatus, Barred knifejaw (2024) Order Pleuronectiformes Microstomus kitt, Lemon sole (2025) Order Salmoniformes Salmo salar, Atlantic salmon (2016) Oncorhynchus mykiss, rainbow trout (2014) Oncorhynchus tshawytscha, Chinook salmon (2018) Salvelinus namaycush, Lake Trout (2021) Order Scorpaeniformes Sebastes schlegelii, Black rockfish (2018) Order Siluriformes Clarias batrachus, walking catfish (2018) Ictalurus punctatus, channel catfish (2016) Pangasianodon hypophthalmus, Iridescent shark catfish (2021) Silurus glanis, Wels catfish (2020) Order Spariformes Datnioides pulcher, Siamese tigerfish (2020) Datnioides undecimradiatus, Mekong tiger perch (2020) Order Syngnathiformes Syngnathus scovelli, Gulf pipefish (2016, 2023) Entelurus aequoreus, Snake pipefish (2024) Order Tetraodontiformes Diodon holocanthus, Long-spine porcupinefish (2020) Mola mola, ocean sunfish (2016) Takifugu rubripes, a puffer fish (2002) Tetraodon nigroviridis, a puffer fish (2004)
Sources: en.wikipedia.org
=== Nervous system repair === Spinal cord injuries are one of the most common traumas brought into veterinary hospitals. Spinal injuries occur in two ways after the trauma: the primary mechanical damage, and in secondary processes, like inflammation and scar formation, in the days following the trauma. These cells involved in the secondary damage response secrete factors that promote scar formation and inhibit cellular regeneration. Mesenchymal stem cells that are induced to a neural cell fate are loaded onto a porous scaffold and are then implanted at the site of injury. The cells and scaffold secrete factors that counteract those secreted by scar forming cells and promote neural regeneration. Eight weeks later, dogs treated with stem cells showed immense improvement over those treated with conventional therapies. Dogs treated with stem cells were able to occasionally support their own weight, which has not been seen in dogs undergoing conventional therapies. In a study to evaluate the treatment of experimentally induced MS in dogs using laser activated non-expanded adipose derived stem cells. The results showed amelioration of the clinical signs over time confirmed by the resolution of the previous lesions on MRI. Positive migration of the injected cells to the site of lesion, increased remyelination detected by Myelin Basic Proteins, positive differentiation into Olig2 positive oligodendrocytes, prevented the glial scar formation and restored axonal architecture. Treatments are also in clinical trials to repair and regenerate peripheral nerves.
=== Initial appearance === The first known documented instance of an attack by the Phylloxera in France was in the village of Pujaut in the department of Gard of the former province of Languedoc, in 1863. The wine makers there did not notice the aphids, just as the French colonists in America had not, but they noted the mysterious blight that was damaging their vines. The only description of the disease that was given by these wine growers was that it "reminded them distressingly of 'consumption'"(tuberculosis). The blight quickly spread throughout France, but it was several years before the cause of the disease was determined.
=== Human Diseases and Gene Mutations === Greenspan has conducted various research projects directly on the molecular bases of human diseases. A collaborative study with a group at Jefferson Medical College showed mutations in the COL7A1 gene, for type VII collagen, to be the basis of the disabling and fatal skin disease dystrophic epidermolysis bullosa These studies also led to elucidation of the complete intron-exon structure of COL7A1 which at the time had more exons than any previously described gene. His lab was the first to clone and characterize the α1 chain of type V collagen and was also key in the first demonstration that mutations in a type V collagen gene can cause the heritable connective tissue disorder classic Ehers-Danlos syndrome. Accompanying and following these studies, the Greenspan lab has performed studies on collagen V genes and on the biosynthesis of type V collagen and on the molecular mechanisms whereby mutations in type V collagen result in defects in mammalian tissues. Their studies have also shown autoimmunity against type V collagen to be involved in organ transplant rejection and atherosclerosis, and that induction of immune tolerance to type V collagen can help ameliorate atherosclerosis. The Greenspan lab was also the first to clone and characterize the α3 chain of type V collagen and showed the α3(V) chain to be important to the functioning of certain highly specialized cell types and to be important to tumor growth and survival times in breast cancer.
Beyond its store endeavors, Jollibee also ventured into media, notably partnering with GMA for the children's magazine show Chikiting Patrol, which aired from 1996 to 2002. In 1998, Jollibee would expand to North America with its first United States location in Daly City, California. Jollibee first entered Europe in 2018 with the opening of a branch in Milan, Italy.
Sources: en.wikipedia.org
== Pharmacology == GnRH antagonists competitively and reversibly bind to GnRH receptors in the pituitary gland, blocking the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary. In men, the reduction in LH subsequently leads to rapid suppression of testosterone production in the testes; in women it leads to suppression of estradiol and progesterone production from the ovaries. GnRH antagonists are able to abolish gonadal sex hormone production and to suppress sex hormone levels into the castrate range, or by approximately 95%. Unlike the GnRH agonists, which cause an initial stimulation of the hypothalamic–pituitary–gonadal axis (HPG axis) that leads to a surge in testosterone or estrogen levels, GnRH antagonists have an immediate onset of action and rapidly reduce sex hormone levels without an initial surge.
Bacteria and archaea also can use chemiosmosis to generate ATP. Cyanobacteria, green sulfur bacteria, and purple bacteria synthesize ATP by a process called photophosphorylation. These bacteria use the energy of light to create a proton gradient using a photosynthetic electron transport chain. Non-photosynthetic bacteria such as E. coli also contain ATP synthase. In fact, mitochondria and chloroplasts are the product of endosymbiosis and trace back to incorporated prokaryotes. This process is described in the endosymbiotic theory. The origin of the mitochondrion triggered the origin of eukaryotes, and the origin of the plastid the origin of the Archaeplastida, one of the major eukaryotic supergroups.
Roseanne says Darlene must first finish high school, but after learning David threatened to break up with her if she goes, she demands Darlene attend, giving Darlene an opportunity to become the writer Roseanne wanted to be. Darlene, who had decided not to attend, reveals her real reason for declining admission is because she fears failing, but finally agrees to go. At college, Darlene begins dating Jimmy while still seeing David, who initially accepts this arrangement in order to be with Darlene. When he later demands she choose between them, Darlene chooses Jimmy, though he later breaks off their relationship due to Darlene's inability to be close. Darlene realizes she still loves David and they reconcile. Darlene and David marry after Darlene becomes pregnant, giving birth to a daughter, Harris Conner-Healy. Harris is born three months premature and David and Darlene must decide whether or not to keep her on life support or allow nature to determine her fate. Harris proves strong enough to survive on her own. In the final episode of Season 9, it is revealed that Darlene was actually dating Mark, and Becky was with David, though Roseanne had written in her book that Darlene being with David made more sense. However, by the start of Season 10, which takes place twenty years later, this revelation has been retconned out of existence. In Season 10, Darlene is now a single mother of two children, teen daughter Harris and ten-year-old son Mark.
Sources: en.wikipedia.org
It corresponds to a fragment of the larger protein prothymosin alpha, which is present in many tissues. The isolated 28-amino-acid peptide was originally obtained from thymus preparations, and the pharmaceutical product is synthesized rather than extracted. The term therefore describes both a natural fragment and a manufactured drug substance.
Thymosin alpha-1 is a single defined 28-residue peptide, while the broader family includes unrelated peptides such as thymosin beta-4. The shared name reflects historical isolation from thymus tissue rather than a common structure. Confusion between the two is common in older literature.
No single pathway fully accounts for its reported effects. Several studies describe interaction with innate immune receptors and downstream cytokine changes, but the complete picture is not settled. Open questions remain about which effects occur at physiological concentrations.
It is usually classified as an immunomodulatory peptide rather than a classical hormone. It derives from the larger protein prothymosin alpha and acts mainly on immune cells. The thymosin label covers a group of distinct peptides, so the naming can be misleading.