A practical reference on thymalfasin: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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 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 short peptide of 28 amino acid residues first described in the 1970s as a component of thymic extracts. Its N-terminal residue carries an acetyl group, and the sequence is highly conserved across mammalian species. The peptide is not encoded as a standalone gene product; it is released by proteolytic cleavage from the N-terminus of prothymosin alpha, a larger acidic nuclear protein. That precursor relationship places it within a broader family of thymic and immune-associated peptides that have been studied for decades.
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.
| 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 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.
Biologically, the peptide is studied mainly in the context of immune cell development and regulation. It is produced in the thymus and in several other tissues, and it appears to influence the maturation and activity of T cells and other immune populations. Laboratory work describes effects on cytokine production, on the balance between T cell subsets, and on the function of dendritic cells. Much of this evidence comes from cell culture and animal models, so the extent to which the same pathways operate in humans remains an open question.
Recommended storage for the dry powder is a freezer near minus twenty degrees Celsius, kept desiccated and away from light. Once dissolved, the peptide is less stable and is usually held at two to eight degrees Celsius for short intervals or frozen for longer storage. Stability studies focus on the acetylated terminus and the disulfide linkage because those features define the intact molecule. Common degradation routes include cysteine oxidation, deamidation of asparagine or glutamine side chains, and slow formation of higher-molecular-weight species.
Identity and purity are usually checked by reverse-phase high-performance liquid chromatography, which separates the intact chain from truncated products, together with mass spectrometry for confirmation of the expected mass. Peptide mapping after enzymatic digestion and amino acid analysis add sequence-level evidence. Release testing also covers water content, residual solvents, and counter-ions, all of which influence measured mass and stability. Related-peptide limits are commonly expressed as a percentage of total peak area, with individual unspecified impurities held below a lower threshold.
=== Activity === This enzyme participates in 8 metabolic pathways: alanine and aspartate metabolism, methionine metabolism, valine, leucine and isoleucine degradation, tyrosine metabolism, phenylalanine metabolism, tryptophan metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, and alkaloid biosynthesis. It employs one cofactor, flavin adenine dinucleotide (FAD). The enzyme binds to FAD in the first step of the catalytic process, thereby reducing FAD to FADH2. The FAD is regenerated from FADH2 by oxidation as a result of O2 being reduced to H2O2. The mechanism proceeds via oxidative deamination of the L-amino acid, which affords an imino acid intermediate. Following hydrolysis of the intermediate, the enzyme successfully affords the 2-oxo acid, as shown in Scheme 1.
The concentrations of species containing reagent A are constrained by a condition of mass-balance, that is, the total (or analytical) concentration, which is the sum of all species' concentrations, must be constant. There is one mass-balance equation for each reagent of the type
=== Application === Among these four moisture conditions of aggregates, saturated surface dry is the condition that has the most applications in laboratory experiments, research, and studies, especially those related to water absorption, composition ratio, or shrinkage tests in materials like concrete. For many related experiments, a saturated surface dry condition is a premise that must be realized before the experiment. In saturated surface dry conditions, the aggregate's water content is in a relatively stable and static situation where its environment would not affect it. Therefore, in experiments and tests where aggregates are in saturated surface dry condition, there would be fewer disrupting factors than in the other three conditions.
Monitoring a person's health over time after treatment. This includes keeping track of the health of people who participate in a clinical study or clinical trial for a period of time, both during the study and after the study ends. (NCI) Food and Drug Administration (FDA)
Sources: en.wikipedia.org
=== Books === Arai, M.N. (1997). A Functional Biology of Scyphozoa. London: Chapman & Hall [p. 316]. ISBN 0-412-45110-7. Ax, P. (1999). Das System der Metazoa I. Ein Lehrbuch der phylogenetischen Systematik. Gustav Fischer, Stuttgart-Jena: Gustav Fischer. ISBN 3-437-30803-3. Barnes, R.S.K., P. Calow, P. J. W. Olive, D. W. Golding & J. I. Spicer (2001). The invertebrates—a synthesis. Oxford: Blackwell. 3rd edition [chapter 3.4.2, p. 54]. ISBN 0-632-04761-5. Brusca, R.C., G.J. Brusca (2003). Invertebrates. Sunderland, Mass.: Sinauer Associates. 2nd edition [chapter 8, p. 219]. ISBN 0-87893-097-3. Dalby, A. (2003). Food in the Ancient World: from A to Z. London: Routledge. Moore, J.(2001). An Introduction to the Invertebrates. Cambridge: Cambridge University Press [chapter 4, p. 30]. ISBN 0-521-77914-6. Schäfer, W. (1997). Cnidaria, Nesseltiere. In Rieger, W. (ed.) Spezielle Zoologie. Teil 1. Einzeller und Wirbellose Tiere. Stuttgart-Jena: Gustav Fischer. Spektrum Akademischer Verl., Heidelberg, 2004. ISBN 3-8274-1482-2. Werner, B. 4. Stamm Cnidaria. In: V. Gruner (ed.) Lehrbuch der speziellen Zoologie. Begr. von Kaestner. 2 Bde. Stuttgart-Jena: Gustav Fischer, Stuttgart-Jena. 1954, 1980, 1984, Spektrum Akad. Verl., Heidelberg-Berlin, 1993. 5th edition. ISBN 3-334-60474-8.
The following day, Foreign Minister Sihasak Phuangketkeow was named as Bhumjaithai's second candidate for prime minister as a backup. On 25 December, Pheu Thai announced its list of 500 candidates to contest every House seat. Anutin ruled out any coalition between Bhumjaithai and parties seeking to amend Article 112 on lèse-majesté following statements by Natthaphong that the People's Party would never vote for Anutin to become prime minister again. On 26 December, the Democrat Party announced its three candidates for prime minister: party leader Abhisit Vejjajiva, Korn Chatikavanij, and Karndee Leopairote, at its headquarters in Bangkok. Palang Pracharath Party leader Prawit Wongsuwon announced his intention to retire from politics after withdrawing as one of the party's three prime ministerial candidates. His withdrawal as a prime ministerial candidate was joined by deputy party leader Thirachai Phuvanatnaranubala, who also announced his withdrawal from politics. On 28 December, representatives from 52 political parties registered their parties' lists of prime ministerial and party-list candidates.
Radioactive waste comes from a number of sources. In countries with nuclear power plants, nuclear armament, or nuclear fuel treatment plants, the majority of waste originates from the nuclear fuel cycle and nuclear weapons reprocessing. Other sources include medical and industrial wastes, as well as naturally occurring radioactive materials (NORM) that can be concentrated as a result of the processing or consumption of coal, oil, and gas, and some minerals, as discussed below.
Feltenstein then took control of Thomas's care, even though he did not have admitting rights at St. Vincent's. The hospital's senior brain specialist, C. G. Gutierrez-Mahoney, was not called to examine Thomas until the afternoon of 6 November, some 36 hours after Thomas's admission. Caitlin, having flown from Britain, arrived at the hospital the following morning, by which time a tracheotomy had been performed. Her first words are reported to have been, "Is the bloody man dead yet?" Permitted to see Thomas for a short time, she returned, drunk, in the afternoon and made threats to John Brinnin. Feltenstein had her put into a straitjacket and committed to the River Crest Sanitarium. It is now believed that Thomas had been suffering from bronchitis, pneumonia, emphysema and asthma before his admission to St Vincent's. In their 2004 paper, Death by Neglect, D. N. Thomas and former GP Principal Simon Barton disclose that Thomas was found to have pneumonia when he was admitted to hospital in a coma. Doctors took three hours to restore his breathing, using artificial respiration and oxygen.
== Biology and genetics == S. boulardii was originally described as a species distinct from S. cerevisiae based on phenotypic traits, including the inability to ferment galactose, a reported lack of sporulation under standard laboratory conditions, and increased tolerance to human body temperature, gastric acidity, and digestive enzymes compared with many S. cerevisiae strains. Subsequent molecular and genomic analyses, however, have shown that S. boulardii falls within the genetic diversity of S. cerevisiae, forming a distinct clade most closely related to wine-associated strains. Like other S. cerevisiae strains, S. boulardii possesses 16 nuclear chromosomes and a 2-micron plasmid, and is diploid, carrying genetic determinants for both mating types (MATa and MATα). However, the MATa locus in S. boulardii contains mutations predicted to impair mating and sporulation, which may account for its reduced or absent sporulation phenotype under laboratory conditions. S. boulardii shares with other S. cerevisiae strains the production of secreted proteins reported to interfere with certain bacterial pathogens and their toxins, including a 63-kDa phosphatase (Pho8) that reduces Escherichia coli endotoxin activity and a 54-kDa serine protease (Ysp3) capable of degrading Clostridioides difficile toxins A and B. An additional, as-yet-unidentified protein of approximately 120 kDa has been reported to inhibit cholera toxin–induced increases in intracellular cyclic AMP (cAMP).
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 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.