Thymosin fraction 5 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 2026-02-07. 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.
Several factors accelerate degradation: alkaline pH, elevated temperature, exposure to oxidants, and the presence of residual moisture. Deamidation of asparagine residues and oxidation of methionine are the most commonly reported degradation routes. Because the peptide lacks disulfide bonds, it does not undergo the thiol-related aggregation seen in some other biologics, but physical aggregation can still occur at high concentration. Stability data are product-specific, and extrapolating shelf life between formulations is not reliable.
Lyophilized thymosin alpha-1 is generally stored at or below minus twenty degrees Celsius, protected from moisture and light. Short-term handling at ambient temperature is possible for dry powder, but reconstituted solutions degrade faster and are usually kept at two to eight degrees Celsius with a defined expiry of days rather than weeks. Repeated freeze-thaw cycles should be avoided because they promote aggregation and loss of potency. Exact limits depend on the formulation and should follow the supplier's documentation.
Identity and purity are normally assessed by reversed-phase high-performance liquid chromatography, which separates the peptide from related impurities and truncation products. Mass spectrometry confirms molecular mass and detects modifications such as deamidation or oxidation. Amino acid analysis and peptide mapping provide additional sequence-level confirmation. For research material, a certificate of analysis typically reports these results together with water content and counter-ion identity, since the lyophilized powder is often supplied as an acetate or trifluoroacetate salt.
| 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 |
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.
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 activity of this peptide is generally described as immunomodulatory rather than directly antimicrobial. Experimental work links it to signaling through certain Toll-like receptors on dendritic cells and to downstream maturation of antigen-presenting cells. Reported effects include expansion of T cell subsets, shifts in cytokine profiles, and increased natural killer cell activity. These observations come largely from cell culture and animal models, and the precise receptor-level events in humans remain incompletely characterized.
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.
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.
=== Stable vs radioactive isotopes === All isotopes of an element have the same number of protons with varying numbers of neutrons. Hydrogen has three naturally occurring isotopes: 1H, 2H and 3H; called protium (H), deuterium (D) and tritium (T), respectively. Both 1H and 2H are stable, while 3H is unstable and beta-decays to 3He. While there are some important applications of 3H in geochemistry (such as its use as an ocean circulation tracer) these will not be discussed further here.
The plant would be capable of converting natural gas into a liquid form that can be trucked to consumers. The project will create between 700 and 2,800 jobs in the region. In May 2019, Minister McNaughton announced that the Ontario government "committed up to $63.7 million" to Southwestern Integrated Fibre Technology (SWIFT) with support from other levels of government. The not-for-profit, publicly-funded SWIFT project to develop a regional fibre optic network, has been one of the key initiatives of the Western Ontario Wardens' Caucus (WOWC) representing upper-tier municipalities in southern Ontario from Dufferin to Windsor. Through SWIFT, federal, provincial and local municipalities "subsidize the construction of an open-access, high-speed broadband network in Southwestern Ontario, Caledon and the Niagara Region." In December 2025, Ford and Niagara Falls mayor Jim Diodati announced a new tourism strategy for the city, including expanded transportation and entertainment offerings such as new "attractions, gaming, wine and restaurants, and arts and culture." In early 2026, Ford announced plans to build a new 2-million square foot convention centre in Toronto, replacing the Metro Toronto Convention Centre. He later also announced plans to take control of the Billy Bishop Toronto City Airport to expand its runway and allow jets at the island airport, a suggestion immediately supported by the Toronto Port Authority. Expansion remains opposed by local Councillors, local community associations and the "NoJetsTo" and "Parks Not Planes" advocacy groups.
=== General and cited references === National Burn Repository 2012 Report (PDF). Dataset Version 8.0. Chicago: American Burn Association. 2012. Archived from the original (PDF) on 3 March 2016. Retrieved 20 April 2013.
== Epidemiology == Asymptomatic subclinical infection may help spread these diseases, particularly Staphylococcus aureus, Campylobacter, Salmonella, Shigella, Enterobacter, Vibrio cholerae, and Yersinia. For example, as of 1984 it was estimated that in the United States, 200,000 people were asymptomatic carriers of Salmonella.
Other methods of preservation include the storage of specimens in spirit. Such wet specimens have special value in physiological and anatomical study, apart from providing better quality of DNA for molecular studies. Freeze drying of specimens is another technique that has the advantage of preserving stomach contents and anatomy, although it tends to shrink, making it less reliable for morphometrics.
Sources: en.wikipedia.org
There is a link between cognitive deficit and diabetes; studies have shown that diabetic individuals are at a greater risk of cognitive decline, and have a greater rate of decline compared to those without the disease. Diabetes increases the risk of dementia, and the earlier that one is diagnosed with diabetes, the higher the risk becomes. The condition also predisposes to falls in the elderly, especially those treated with insulin.
While working at St Mary's Hospital, London in 1928, Alexander Fleming, a Scottish physician, was investigating the variation of growth in cultures of S. aureus, trying to replicate research from Trinity College Dublin. He spent the summer break with his family at his country home The Dhoon at Barton Mills, Suffolk. Before leaving his laboratory at the end of July, he inoculated several culture plates with S. aureus. He kept the plates aside on one corner of the table away from direct sunlight and to make space for his research student, Stuart Craddock, to work in his absence. He returned to his laboratory on 3 September. As he and Daniel Merlin Pryce, his former research student, examined the culture plates, they found one with an open lid and the culture contaminated with a blue-green mould. In the contaminated plate the bacteria around the mould did not grow, while those farther away grew normally, meaning that the mould killed the bacteria. Fleming photographed the culture and took a sample of the mould for identification. Fleming resumed his vacation and returned to St Mary's that month. He collected the original mould and grew it in culture plates. After four days he found that the plates developed large colonies of the mould. He repeated the experiment with the same bacteria-killing results. He concluded that the mould was releasing a substance that was inhibiting bacterial growth. On testing against different bacteria, he found that the mould could kill only certain Gram-positive bacteria.
=== Two-step mechanism – autocatalysis model === In 1997, Finke and Watzky proposed a new kinetic model for the nucleation and growth of nanoparticles. This 2-step model suggested that constant slow nucleation (occurring far from supersaturation) is followed by autocatalytic growth where dispersity of nanoparticles is largely determined. This F-W (Finke-Watzky) 2-step model provides a firmer mechanistic basis for the design of nanoparticles with a focus on size, shape, and dispersity control. The model was later expanded to a 3-step and two 4-step models between 2004 and 2008. Here, an additional step was included to account for small particle aggregation, where two smaller particles could aggregate to form a larger particle. Next, a fourth step (another autocatalytic step) was added to account for a small particle agglomerating with a larger particle. Finally in 2014, an alternative fourth step was considered that accounted for a atomistic surface growth on a large particle.
For example, a reactivity ratio that is less than one for component 1 indicates that this component reacts with the other type of monomer more readily. Given this information, which is available for a multitude of monomer combinations in the "Wiley Database of Polymer Properties", the Mayo-Lewis equation can be used to predict the composition of the polymer product for all initial mole fractions of monomer. This equation is derived using the Markov model, which only considers the last segment added as affecting the kinetics of the next addition; the Penultimate Model considers the second-to-last segment as well, but is more complicated than is required for most systems. When both reactivity ratios are less than one, there is an azeotropic point in the Mayo-Lewis plot. At this point, the mole fraction of monomer equals the composition of the component in the polymer. There are several ways to synthesize random copolymers. The most common synthesis method is free radical polymerization; this is especially useful when the desired properties rely on the composition of the copolymer rather than the molecular weight, since free radical polymerization produces relatively disperse polymer chains. Free radical polymerization is less expensive than other methods, and produces high-molecular weight polymer quickly. Several methods offer better control over dispersity. Anionic polymerization can be used to create random copolymers, but with several caveats: if carbanions of the two components do not have the same stability, only one of the species will add to the other.
Sources: en.wikipedia.org
=== Others === Untitled submarine game: one of Valve's earliest game ideas was for a submarine game, with Valve co-founder Mike Harrington seeing an opportunity to create "fantastic underwater visuals and gameplay". It is unknown whether it ever advanced beyond the conceptual stage. Prospero: a third-person exploration game with a science fantasy theme. The project was in development at the same time as Half-Life. Prospero's development team transitioned to work on Half-Life, which had gained more traction. Untitled role-playing game (I): a fantasy, action role-playing game about fairies that was in a prototype phase and cancelled prior to Left 4 Dead's release. The Crossing: a first-person shooter developed in collaboration with Arkane Studios. The project was announced in 2007 and put on hold in May 2009. Stars of Blood: a space pirate game. In November 2012, Newell revealed the project's name and confirmed that it was no longer in development. Left 4 Dead 3: an open-world sequel to Left 4 Dead 2 that was set in Morocco. It was cancelled when it became clear that the Source 2 engine was not yet ready to support full-scale game development. Hot Dog: another attempt at creating a Left 4 Dead game, codenamed so that fans would not recognize it if its name were leaked. Untitled role-playing game (II): a fantasy RPG that was inspired by The Elder Scrolls, Dark Souls, and Monster Hunter series. It was at one point resurrected as a single-player RPG about the Dota 2 character Axe before it was shelved again.
=== Mental changes === The psychological effects of feminizing hormone therapy are harder to define than physical changes. Because hormone therapy is usually the first physical step taken to transition, the act of beginning it has a significant psychological effect, which is difficult to distinguish from hormonally induced changes. Changes in mood and well-being occur with hormone therapy in transgender women. Side effects of hormone therapy have the ability to significantly impact sexual functioning, either directly or indirectly through the various side effects, such as cerebrovascular disorders, obesity, and mood fluctuations. Some transgender women report a significant reduction in libido, depending on the dosage of antiandrogens. The effects of long-term hormonal regimens have not been conclusively studied and are difficult to estimate because research on the long-term use of hormonal therapy has not been noted. One study found that sex drive returned to baseline after three years of hormone therapy. It is possible to approximate outcomes of these therapies on transgender people based on their observed effect in cisgender men and women. Firstly, if one is to decrease testosterone in feminizing gender transition, it is likely that sexual desire and arousal would be inhibited; alternatively, if high doses of estrogen negatively impact sexual desire, which has been found in some research with cisgender women, it is hypothesized that combining androgens with high levels of estrogen would intensify this outcome.
The Socialist Republic of Bosnia and Herzegovina (SR Bosnia and Herzegovina; SR BiH), commonly referred to as Socialist Bosnia or simply Bosnia, was one of the six constituent republics forming the Socialist Federal Republic of Yugoslavia. It was a predecessor of the modern-day Bosnia and Herzegovina, existing between 1945 and 1992, under a number of different formal names, including Democratic Bosnia and Herzegovina (1943–1945), Federal State of Bosnia and Herzegovina (1945–1946), and People's Republic of Bosnia and Herzegovina (1946–1963). Within Yugoslavia, Bosnia and Herzegovina was a unique federal unit with no dominant ethnic group, as was the case in other constituent states, all of which were also nation states of Yugoslavia's South Slavic ethnic groups. It was administered under strict terms of sanctioned consociationalism, known locally as "ethnic key" or "national key" (Serbo-Croatian: etnički/nacionalni ključ), based on the balance of political representation of 3 largest ethnic groups (Bosnian Muslims, Croats and Serbs). Sarajevo served as the capital city throughout its existence and remained the capital following independence. The Socialist Republic was dissolved in 1990 when it abandoned its socialist institutions and adopted liberal ones, as the Republic of Bosnia and Herzegovina which declared independence from Yugoslavia in 1992. The Government of Bosnia and Herzegovina was, up to 20 December 1990, in sole control of the League of Communists of Bosnia and Herzegovina, the Bosnian branch of League of Communists of Yugoslavia.
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.
Dry lyophilized powder tolerates short ambient exposure during handling and shipping. Long-term room-temperature storage is not recommended because moisture uptake and slow degradation can occur over months. Storage at minus twenty degrees Celsius is the common practice for extended periods.