chronic hepatitis B 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 2026-06-05. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Thymosin beta-4 is a separate 43-residue peptide that binds actin and participates in cell migration; it shares no sequence similarity with thymosin alpha-1 despite the common family name. Other preparative materials, such as thymosin fraction 5 and thymopoietin, contain distinct mixtures or peptides. The shared thymosin label reflects the tissue of origin used in early purification, not a common structural core. Treating these molecules as interchangeable is a frequent source of confusion in laboratory reports and in popular summaries alike.
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 |
|---|---|---|
| Molecular mass | ≈3,108 Da | Synthetic 28-residue peptide |
| Amino acid count | 28 | N-terminal serine carries an acetyl group |
| Appearance | White to off-white powder | Lyophilized solid |
| Water solubility | Freely soluble | Dissolves in aqueous buffer |
| Common synonyms | Thymalfasin; Tα1 | Thymalfasin is the international nonproprietary name |
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Findings across trials are mixed; some report changes in selected immune markers, while others find no clear clinical benefit. Many studies are small and define outcomes differently, which limits comparison. Regulatory approval is confined to a few countries, and the compound is not an approved drug in the United States or most of Europe.
Overall evidence quality varies considerably. A large share of published reports come from single centers, rely on surrogate immunological markers, or lack adequate control groups. Systematic reviews have highlighted this heterogeneity as a barrier to pooling results. Open questions include which patients, if any, might benefit, what treatment duration is appropriate, and whether any effect is independent of standard care. The peptide is often described as an immune modulator rather than a therapy for one disease, which complicates confirmatory trial design.
Thymosin alpha 1 was identified in 1977 as a component of thymosin fraction 5, a heterogeneous preparation used in early studies of thymic function. Investigators purified the active material and determined its amino acid sequence, which enabled chemical synthesis. Work in the following decades concentrated on T-cell maturation and immune reconstitution in animals and small human cohorts. Early preparations varied in composition, so results from that period are difficult to compare with studies using defined synthetic peptide.
Clinical interest has centered on chronic viral hepatitis, on immune restoration in various conditions, and on use as an adjuvant intended to improve responses to vaccines. Trials have reported mixed results, and regulatory status differs sharply between countries; in some places it is a prescription product, while elsewhere it is sold without an approved therapeutic indication. Because published studies vary widely in design, population, and endpoints, comparisons across them are difficult and no single conclusion covers the whole literature.
Thymosin alpha 1 is a short peptide of 28 amino acid residues that derives from the amino terminal region of a larger precursor protein known as prothymosin alpha. The peptide carries an acetyl group on its first residue and contains no disulfide bonds or carbohydrate chains. Its sequence is highly conserved across mammalian species, which is one reason laboratories treat it as a molecule with a defined and reproducible structure rather than a variable tissue extract. The name follows an early naming convention for thymus-derived fractions and does not imply that the peptide acts as a hormone in the classical endocrine sense.
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 a synthetic peptide of 28 amino acids, corresponding to the N-terminal fragment of prothymosin alpha. Its sequence begins with acetylation at the N-terminus, a modification that affects stability and receptor interaction. The peptide is acidic, with a calculated isoelectric point near 4.2, and carries no disulfide bonds, so its secondary structure is largely flexible in solution. Molecular mass is approximately 3108 daltons. The native form was first isolated from bovine thymus tissue, while pharmaceutical material is produced by solid-phase peptide synthesis.
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 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.
=== Smell and taste === The unpleasant smell of diallyl disulfide is perceived through the transient receptor potential cation channel, member A1 (TRPA1). This ion channel had long been present not only in humans and animals, but even in fungi. Thus, Alliaceae plants have likely developed the diallyl disulfide-TRPA1 protection mechanism against predators at the early stages of the evolution.
=== Lima Group === With Castillo taking a more pro-Venezuela stance, many thought that Peru would leave the Lima Group, a consortium of countries with the goal of aiding the Venezuelan opposition. Starting 6 August 2021, Venezuelan and Cuban state media started claiming that Peru had left the Lima Group. While foreign media had announced Peru's exit, there was no word from the Peruvian government, which left many confused. Furthermore, Luis Arce, the President of Bolivia, celebrated Peru's supposed departure from the Lima Group. There was still no word from the Castillo Administration. However, Peru's departure from the Lima Group had been seemingly confirmed by Free Peru's General Secretary, Vladimir Cerrón. As a result, domestic media and Congress was left unsure on whether Peru had left the organization or not. Eventually, members of Congress sent forward a motion to confirm Peru's status in the Lima Group. After a while, Prime Minister Bellido confirmed that Peru had not left the Lima Group, claiming that the issue had not been formally discussed. However, Bellido also mentioned that the Foreign Ministry was evaluating Peru's status in the Lima Group. As of 20 September 2021, the permanent representative of Peru to the OAS has stated that the Lima Group "does not exist, because it has completed its cycle." Later, the Vice Foreign Minister pointed out "The Lima Group is a mechanism, it is not an international organization, and therefore mechanisms work when they need to work.
In 2023, LECO and Cal State LA worked in tandem to launch a new chemical analysis lab. The new lab would work with both undergraduate and graduate students within the Department of Chemistry and Biochemistry. Since 2025, the cement industry has been working to reduce carbon emissions and adopt more sustainable production methods. The LECO Corporation provides analytical instrumentation to support that transition. Its portfolio has included calorimeters, thermogravimetric analyzers, and combustion analyzers that measure factors such as calorific value, moisture, ash, carbon, sulfur, and loss on ignition in fuels and raw materials. This helps cement producers evaluate alternative inputs, monitor performance, and improve operational efficiency while reducing environmental impact. Research was also conducted at Oxford by scholars within the Department of Materials which tested the LECO process of testing solar cells and silicon materials.
Sean Kinney said about the new album and the fans' mixed reactions about the band moving on after Staley's death: Look, it's a big move to fucking stand up and move on. Some people, the music connected with them so strongly, their opinions, how they feel about it ... It's amazing that they have such a connection but they seem to act like it happened to them. This happened to us and Layne's family, not them. This is actually our lives. If we're okay with it, why can't you be? This happened to us, this didn't happen to you. But this album isn't about that, it's a bigger universal point. We're all going to fucking die, we're all going to lose somebody, and it fucking hurts. How do you move on? This record is us moving on, and hurting. That, to me, is a victory. I already feel like I've won. Sometimes people ask us, 'Wouldn't Layne have been pissed off that we did this?' And I tell them it would have been the opposite: he would have been pissed off that it took us so long to do this. We're not doing this for money; there is no money in the music business anymore. Jerry and I funded the whole album, and we spent lots of our own money, because we believe in this. And one of the reasons I'm doing this is so more light is turned on to something where the light was turned off. And Cantrell added: "We've toured around the world, we've lost some friends, we buried a dear friend, and somebody that you just can't fucking replace, and then we've chosen by circumstance to get together again.
==== Mid-1990s ==== FARC military activity increased throughout the bulk of the 1990s as the group continued to grow in wealth from both kidnapping and drug-related activities, while drug crops rapidly spread throughout the countryside. The guerrillas protected many of the coca growers from eradication campaigns and allowed them to grow and commercialize coca in exchange for a "tax" in either money or crops. In this context, FARC had managed to recruit and train more fighters, beginning to use them in concentrated attacks. This led to a series of high-profile raids and attacks against Colombian state bases and patrols, mostly in the southeast of Colombia but also affecting other areas. In mid-1996, a civic protest movement made up of an estimated 200,000 coca growers from Putumayo and part of Cauca began marching against the Colombian government to reject its drug war policies, including fumigations and the declaration of special security zones in some departments. Different analysts have stressed that the movement itself fundamentally originated on its own, but at the same time, FARC heavily encouraged the marchers and actively promoted their demands both peacefully and through threats of force. Additionally, in 1997 and 1998, town councilmen in dozens of municipalities in the south of the country were threatened, killed, kidnapped, or forced to resign or exile themselves to department capitals by the FARC and the ELN.
Sources: en.wikipedia.org
=== Genetic population structure === The population sizes of P. phalangioides are influenced greatly by the presence of human-made buildings since these spiders prefer warmer habitats indoors. The large number of buildings in the world has favoured P. phalangioides, though populations tend to be relatively small, widely dispersed, and greatly isolated from one another. This small size combined with low mobility of populations results in an increased importance placed on the role of genetic drift, more specifically the founder effect, on population structure. Although some gene flow does exist between populations, its importance has been insignificant when compared to that of geographical isolation-driven genetic drift. As a result, most P. phalangioides individuals of the same population that live in the same geographical region will have a very low degree of genetic variation (intrapopulation differentiation). On the other hand, this genetic drift results in significant interpopulation differentiation.
The harvesting, processing, and consuming of seafoods are ancient practices with archaeological evidence dating back well into the Paleolithic. Findings in a sea cave at Pinnacle Point in South Africa indicate Homo sapiens (modern humans) harvested marine life as early as 165,000 years ago, while the Neanderthals, an extinct human species contemporary with early Homo sapiens, appear to have been eating seafood at sites along the Mediterranean coast beginning around the same time. Isotopic analysis of the skeletal remains of Tianyuan man, a 40,000-year-old anatomically modern human from eastern Asia, has shown that he regularly consumed freshwater fish. Archaeology features such as shell middens, discarded fish bones, and cave paintings show that sea foods were important for survival and consumed in significant quantities. During this period, most people lived a hunter-gatherer lifestyle and were, of necessity, constantly on the move. However, early examples of permanent settlements (though not necessarily permanently occupied), such as those at Lepenski Vir, were almost always associated with fishing as a major source of food. The ancient river Nile was full of fish; fresh and dried fish were a staple food for much of the population. The Egyptians had implements and methods for fishing and these are illustrated in tomb scenes, drawings, and papyrus documents. Some representations hint at fishing being pursued as a pastime.
Such machines are used for freezing oocytes, skin, blood products, embryo, sperm, stem cells, and general tissue preservation in hospitals, veterinary practices, and research labs. The number of live births from 'slow frozen' embryos is some 300,000 to 400,000 or 20% of the estimated 3 million in vitro fertilized births. Dr Christopher Chen, Australia, reported the world’s first pregnancy using slow-frozen oocytes from a British controlled-rate freezer in 1986. Cryosurgery (intended and controlled tissue destruction by ice formation) was carried out by James Arnott in 1845 in an operation on a patient with cancer.
==== MeSH D13.444.735 – rna ==== MeSH D13.444.735.130 – rna, algal MeSH D13.444.735.150 – rna, antisense MeSH D13.444.735.150.319 – micrornas MeSH D13.444.735.150.640 – oligoribonucleotides, antisense MeSH D13.444.735.150.700 – rna, small interfering MeSH D13.444.735.300 – rna, archaeal MeSH D13.444.735.473 – rna, bacterial MeSH D13.444.735.476 – rna, chloroplast MeSH D13.444.735.480 – rna, complementary MeSH D13.444.735.490 – rna, double-stranded MeSH D13.444.735.500 – rna, fungal MeSH D13.444.735.520 – rna, helminth MeSH D13.444.735.544 – rna, messenger MeSH D13.444.735.544.355 – codon MeSH D13.444.735.544.355.225 – codon, initiator MeSH D13.444.735.544.355.250 – codon, terminator MeSH D13.444.735.544.355.250.235 – codon, nonsense MeSH D13.444.735.544.500 – rna caps MeSH D13.444.735.544.500.710 – rna cap analogs MeSH D13.444.735.544.527 – rna, messenger, stored MeSH D13.444.735.544.550 – rna splice sites MeSH D13.444.735.544.875 – untranslated regions MeSH D13.444.735.544.875.880 – 3' untranslated regions MeSH D13.444.735.544.875.885 – 5' untranslated regions MeSH D13.444.735.615 – rna, neoplasm MeSH D13.444.735.628 – rna, nuclear MeSH D13.444.735.628.806 – rna, heterogeneous nuclear MeSH D13.444.735.628.818 – rna, small nuclear MeSH D13.444.735.628.818.800 – rna, small nucleolar MeSH D13.444.735.635 – rna, plant MeSH D13.444.735.635.575 – rna, chloroplast MeSH D13.444.735.640 – rna precursors MeSH D13.444.735.650 – rna, protozoan MeSH D13.444.735.686 – rna, ribosomal MeSH D13.444.735.686.650 – rna, ribosomal, 5s MeSH D13.444.735.686.660 – rna, ribosomal, 5.8s MeSH D13.444.735.686.670 – rna, ribosomal, 16s MeSH D13.444.735.686.675 – rna, ribosomal, 18s MeSH D13.444.735.686.680 – rna, ribosomal, 23s MeSH D13.444.735.686.690 – rna, ribosomal, 28s MeSH D13.444.735.686.845 – rna, ribosomal, self-splicing MeSH D13.444.735.721 – rna, satellite MeSH D13.444.735.721.250 – cucumber mosaic virus satellite MeSH D13.444.735.757 – rna, transfer MeSH D13.444.735.757.286 – anticodon MeSH D13.444.735.757.700 – rna, transfer, amino acid-specific MeSH D13.444.735.757.700.050 – rna, transfer, ala MeSH D13.444.735.757.700.075 – rna, transfer, arg MeSH D13.444.735.757.700.085 – rna, transfer, asn MeSH D13.444.735.757.700.090 – rna, transfer, asp MeSH D13.444.735.757.700.200 – rna, transfer, cys MeSH D13.444.735.757.700.400 – rna, transfer, gln MeSH D13.444.735.757.700.410 – rna, transfer, glu MeSH D13.444.735.757.700.420 – rna, transfer, gly MeSH D13.444.735.757.700.450 – rna, transfer, his MeSH D13.444.735.757.700.480 – rna, transfer, ile MeSH D13.444.735.757.700.500 – rna, transfer, leu MeSH D13.444.735.757.700.510 – rna, transfer, lys MeSH D13.444.735.757.700.525 – rna, transfer, met MeSH D13.444.735.757.700.650 – rna, transfer, phe MeSH D13.444.735.757.700.660 – rna, transfer, pro MeSH D13.444.735.757.700.700 – rna, transfer, ser MeSH D13.444.735.757.700.725 – rna, transfer, thr MeSH D13.444.735.757.700.740 – rna, transfer, trp MeSH D13.444.735.757.700.750 – rna, transfer, tyr MeSH D13.444.735.757.700.900 – rna, transfer, val MeSH D13.444.735.757.715 – rna, transfer, amino acyl MeSH D13.444.735.790 – rna, untranslated MeSH D13.444.735.790.099 – micrornas MeSH D13.444.735.790.149 – regulatory sequences, ribonucleic acid MeSH D13.444.735.790.199 – rna, catalytic MeSH D13.444.735.790.400 – rna, guide MeSH D13.444.735.790.530 – rna, small cytoplasmic MeSH D13.444.735.790.537 – rna, small interfering MeSH D13.444.735.790.545 – rna, small nuclear MeSH D13.444.735.790.545.800 – rna, small nucleolar MeSH D13.444.735.790.560 – rna, spliced leader MeSH D13.444.735.790.878 – untranslated regions MeSH D13.444.735.790.878.880 – 3' untranslated regions MeSH D13.444.735.790.878.885 – 5' untranslated regions MeSH D13.444.735.828 – rna, viral
Sources: en.wikipedia.org
Unlike a traditional incandescent lamp, an LED will light only when voltage is applied in the forward direction of the diode. No current flows and no light is emitted if voltage is applied in the reverse direction. If the reverse voltage exceeds the breakdown voltage, which is typically about five volts, a large current flows and the LED will be damaged. If the reverse current is sufficiently limited to avoid damage, the reverse-conducting LED is a useful noise diode. By definition, the energy band gap of any diode is higher when reverse-biased than when forward-biased. Because the band gap energy determines the wavelength of the light emitted, the color cannot be the same when reverse-biased. The reverse breakdown voltage is sufficiently high that the emitted wavelength cannot be similar enough to still be visible. Though dual-LED packages exist that contain a different color LED in each direction, it is not expected that any single LED element can emit visible light when reverse-biased. It is not known if any zener diode could exist that emits light only in reverse-bias mode. Uniquely, this type of LED would conduct when connected backwards.
For services to Animal Health and voluntary service to Sport. Madeleine Clare Hinch, MBE. For services to Hockey. Elaine Hinchliffe-Dale (Elaine Dale). Director, Special Educational Needs and Disabilities Support, City College Norwich. For services to Further Education. Dr. Elizabeth Janine Hogben. Lately Secretary, Prime Minister's Council for Science and Technology, Government Office for Science. For services to Science in Government. Lady (Patricia Ann) Hopkins. For services to Architecture. Carol Wai Wing Hui. Lately Board Member, British Tourist Authority. For services to Tourism. Mahboob Hussain, JP. For services to the community in Buckinghamshire. Elizabeth Louise Hutton. Chief Executive Officer, Kicks Count. For services to Education and Prevention of Stillbirths. Alasdair Bruce Jackson. Chief Executive, Recycling Lives Charity. For services to the Rehabilitation of Offenders. Kerry Joanne Jackson. Chief Executive, St Gemma's Hospice. For services to Palliative and End of Life Care. Salim Hassanali Moledina Janmohamed. For charitable and voluntary services to Faith Communities. Peter Jefferies. Team Leader, Ministry of Defence. For services to Defence. Timothy Nigel Jenkins. Lately District Judge, Brentford County Court. For services to the Administration of Justice. Peter Sinclair Jensen. Lately Chair of Trustees, Home of Horseracing Trust and Chair, British Sporting Arts Trust. For Charitable Service. Dr. Christopher Paul Johnson. Forensic Pathologist, Home Office. For services to Criminal Justice. Christopher Jolly. Publisher, Jolly Phonics.
Microscopic analysis is an important activity of the pathologist and the laboratory technologist. They have many different stains at their disposal (GRAM, MGG, Grocott, Ziehl–Neelsen, etc.). Immunofluorescence, cytochemistry, the immunocytochemistry, and FISH are also used in order make a correct diagnosis. Pathologists may review samples such as pleural, peritoneal, synovial, or pericardial fluids to characterize them as "normal", tumoral, inflammatory, or even infectious. Microscopic examination can also determine the causal infectious agent – often a bacterium, mould, yeast, parasite, or (rarely) virus.
After a physician ensures that the patient voluntarily chooses to receive treatment through a consent form, treatment planning can begin. The patient must show current addiction to an opioid, using accepted medical criteria such as those listed in the DSM-5 and have evidence that he or she became addicted at least 1 year before admission for treatment. Before administration of treatment, a clinical evaluation is required asking about drug use history, co-occurring disorders, and impact of substance use on life, along with providing information about the treatment goals and guidelines. A medical evaluation is also given in the form of a urinalysis test, a review of past and current health history, and a test for certain conditions which are known to be prevalent in addict populations, such as HIV, hepatitis, and tuberculosis. The medication is monitored by nursing staff and is prescribed by a physician. As of 2013, due to the strict changes in receiving prescription pain medication as well as decreases in non-medical prescription use, the requirements to be accepted into methadone clinics have changed in areas such as New York State.
== Veterinary uses == A number of veterinary medicine teaching hospitals are participating in a long-term clinical study examining the effect of rapamycin on the longevity of dogs. A clinical trial led by NC State College of Veterinary Medicine (HALT), run at a number of veterinary hospitals across the US, found that rapamycin reverses the effects of hypertrophic cardiomyopathy in cats. In March 2025, the US Food and Drug Administration announced conditional approval of sirolimus delayed-release tablets (Felycin-CA1) for the management of ventricular hypertrophy in cats with subclinical hypertrophic cardiomyopathy. This is the first product approved for use in cats with hypertrophic cardiomyopathy for any indication. Cardiomyopathy is a disease of the heart muscle. Hypertrophic cardiomyopathy in cats causes thickening of the heart's left ventricle. It is the most common heart disease in cats and is one of the most common causes of death in cats. While the cause is unknown in most cases, hypertrophic cardiomyopathy is associated with a genetic mutation in certain breeds, such as Maine Coons, Ragdolls, and Persians. Hypertrophic cardiomyopathy is a progressive disease. Cats in the subclinical phase have thickening of their heart wall but do not show clinical symptoms of the disease yet. Cats may live for years in the subclinical phase, while others may progress to congestive heart failure, arterial thromboembolism, or sudden death.
Sources: en.wikipedia.org
It is a chain of 28 amino acids, with an acetyl group attached to the first serine residue. The synthetic version replicates this sequence. Its molecular mass is about 3,108 daltons.
It is usually described as an immunomodulatory peptide rather than a classic hormone. It acts on immune cells through receptor pathways. No single endocrine organ target defines its function.
Several countries, including Italy and China, allow it for specific indications. The FDA has not approved it as a drug in the United States. Availability depends on local regulation.
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.