If you have been reading about thymosin alpha-1 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.
Updated 2025-12-27. Numbers and descriptions here follow the published literature rather than marketing material.
Thymosin alpha-1 is a synthetic 28-amino-acid peptide whose sequence was first identified in extracts of bovine thymus tissue during the 1970s. The chain carries an acetyl group on its N-terminal serine. Its acidic residue content is high, which produces strong water solubility and an isoelectric point well below neutrality. Material supplied for laboratory and clinical use is manufactured by solid-phase peptide synthesis rather than purified from animal tissue. Different salt forms, such as the acetate, alter the counter-ion content without changing the peptide backbone.
Whether the free 28-residue peptide circulates in human tissue remains debated. The best-documented human source is prothymosin alpha, a larger acidic protein that carries the sequence at its N-terminus. Reports of measurable peptide levels in serum and lymphoid tissue exist, yet some of that signal may come from cross-reacting fragments or from the parent protein. Most reviews therefore treat prothymosin alpha as the established human molecule and describe independent circulation of the small peptide as an unresolved question.
Immunological studies connect the peptide to multiple parts of the immune response. It has been reported to engage Toll-like receptor signaling, to promote dendritic cell maturation, and to influence the balance of T helper cell subsets. Changes in natural killer cell activity and in cytokine release appear in cell culture and animal models. These observations describe broad immunomodulatory behavior rather than a single defined receptor target, and the primary molecular interaction has not been settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Amino acid length | 28 residues | Single chain with an acetylated N-terminus |
| Molecular mass | Approximately 3,108 Da | Small shifts occur with counter-ion and water content |
| Isoelectric point | Around 3.5 | Low value follows from the many acidic residues |
| Parent molecule | N-terminal region of prothymosin alpha | Free circulating form in humans is not firmly established |
| Common synonyms | Thymalfasin; T alpha 1 | Older literature also uses the full spelled-out form |
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or chemically modified byproducts. Mass spectrometry confirms the expected molecular mass and can indicate acetylation state or sequence errors. Amino acid analysis and peptide mapping supply complementary sequence-level information, while endotoxin testing is relevant for preparations intended for cell or animal work. Purity figures reported by suppliers refer to the method used and are not directly comparable across laboratories unless conditions are stated.
Lyophilized material is typically treated as a hygroscopic solid that should be brought to room temperature before the container is opened, which limits condensation on the powder. Reconstitution is commonly done with sterile water or a buffered diluent, and gentle mixing is preferred over vigorous agitation to reduce foaming and surface adsorption. Because peptides can bind to plastic and glass, diluents containing a small amount of carrier protein are sometimes used in laboratory work. Working solutions are generally aliquoted and prepared fresh rather than subjected to repeated freezing and thawing.
Stability depends on temperature, pH, and the number of freeze-thaw events the sample has experienced. Freeze-dried material is commonly held at -20 °C or colder, while reconstituted liquid is kept cold and used within a short window. Extreme pH and prolonged light exposure can promote deamidation, oxidation, or aggregation, particularly at asparagine and methionine positions. Adsorption to container walls can lower the measured concentration of a dilute solution even when the peptide molecules themselves remain intact.
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。
胸腺素α1（thymosin alpha 1，Tα1）是一种由28个氨基酸组成的酸性肽，N端被乙酰化，分子量约为3108道尔顿。该肽最早从牛胸腺组织提取物中分离，属于胸腺素组分5的一个成分。其序列在不同哺乳动物中高度保守，提示其具有基本的生物学功能。名称中的“α1”指其在电泳中的迁移位置，并非表示亚型编号。它既存在于胸腺，也存在于脾脏和淋巴结等免疫组织。
===== Other names in the Western world ===== In the last decades, two new important terminologies emerged. Both are commonly used in the Western world in neoshamanic, recreative or pharmaceutical contexts to address ayahuasca-like substances created without the traditional botanical species, due to it being expensive and/or hard to find in these countries. These concepts are surrounded by some controversies involving ethnobotany, patents, commodification and biopiracy:
They found increases in plasma oxytocin following a social interaction were correlated with faster wound healing. They hypothesized this was due to oxytocin reducing inflammation, thus allowing the wound to heal more quickly. This study provides preliminary evidence that positive social interactions may directly influence aspects of health. According to a study published in 2014, silencing of oxytocin receptor interneurons in the medial prefrontal cortex (mPFC) of female mice resulted in loss of social interest in male mice during the sexually receptive phase of the estrous cycle. Oxytocin evokes feelings of contentment, reductions in anxiety, and feelings of calmness and security when in the company of the mate. This suggests oxytocin may be important for the inhibition of the brain regions associated with behavioral control, fear, and anxiety, thus allowing orgasm to occur. Research has also demonstrated that oxytocin can decrease anxiety and protect against stress, particularly in combination with social support. It is found that endocannabinoid signaling mediates oxytocin-driven social reward. During a 2008 study, a lack of oxytocin in mice was associated with abnormalities in emotional behavior. Another study conducted in 2014 saw similar results with a variation in the oxytocin receptor connected with dopamine transport and how levels of oxytocin are dependent on the levels of dopamine transporter levels.
The IdMOC plate consists of multiple inner wells within a large interconnecting chamber. Multiple cell types are first individually seeded in the inner wells and, when required, are flooded with an overlying medium to facilitate well-to-well communication. Test material can be added to the overlying medium and both media and cells can be analyzed individually. Plating of hepatocytes with other organ-specific cells allows evaluation of drug metabolism and organotoxicity. The IdMOC system has numerous applications in drug development, such as the evaluation of drug metabolism and toxicity. It can simultaneously evaluate the toxic potential of a drug on cells from multiple organs and evaluate drug stability, distribution, metabolite formation, and efficacy. By modeling multiple-organ interactions, IdMOC can examine the pharmacological effects of a drug and its metabolites on target and off-target organs as well as evaluate drug-drug interactions by measuring cytochrome P450 (CYP) induction or inhibition in hepatocytes. IdMOC can also be used for routine and high throughput screening of drugs with desirable ADME or ADME-Tox properties. In vitro toxicity screening using hepatocytes in conjunction with other primary cells such as cardiomyocytes (cardiotoxicity model), kidney proximal tubule epithelial cells (nephrotoxicity model), astrocytes (neurotoxicity model), endothelial cells (vascular toxicity model), and airway epithelial cells (pulmonary toxicity model) is invaluable to the drug design and discovery process. The IdMOC was patented by Dr. Albert P. Li in 2004.
=== 2019 revision of the SI === The definition of the dalton was not affected by the 2019 revision of the SI, that is, 1 Da in the SI is still 1/12 of the mass of a carbon-12 atom, a quantity that must be determined experimentally in terms of SI units. However, the definition of a mole was changed to be the amount of substance consisting of exactly 6.02214076×1023 entities, and the definition of the kilogram was changed as well. As a consequence, the molar mass constant (Mu) remains close to but no longer exactly 1 g/mol, meaning that the mass in grams of one mole of any substance remains nearly but no longer exactly numerically equal to the average mass of an entity in daltons, although the relative standard uncertainty of 4.5×10−10 at the time of the redefinition is insignificant for all practical purposes. Letting ent denote one entity, the smallest amount of any substance (retaining its chemical properties), one mole is an aggregate of an Avogadro number of entities, i.e. 1 mol = N0 ent ≈ (g/Da) ent. This means that the appropriate atomic-scale unit for molar mass is dalton per entity (Da/ent), equal to the constant Mu, very nearly equal to 1 g/mol. For Da/ent to be exactly equal to g/mol, the dalton would need to be redefined exactly in terms of the (fixed-h) kilogram and the Avogadro number so that 1 Da = (1/N0) g, satisfying the relationships N0 = g/Da and 1 mol = N0 ent = (g/Da) ent, thus conforming to the original mole concept—that the Avogadro number is the gram-to-dalton mass unit ratio.
Sources: en.wikipedia.org
=== Doping in sport === SARMs including enobosarm may be and have been used by athletes to assist in training and increase physical stamina and fitness, potentially producing effects similar to anabolic steroids. For this reason, SARMs were banned by the World Anti-Doping Agency in January 2008, despite no drugs from this class yet being in clinical use, and blood tests for all known SARMs have been developed. There are a variety of known cases of doping in sports with enobosarm by professional athletes.
The aforementioned hydrodynamic and hydrostatic instruments may be employed in a variety of ways, or modes of operation, in order to address the particular separation needs of the scientist. Many modes of operation have been devised to take advantage of the strengths and potentialities of the countercurrent chromatography technique. Generally, the following modes may be performed with commercially available instruments.
== Directed glycosylations == Multiple chemical approaches exist to encourage selectivity of α- and β-glycosidic bonds. The highly substrate specific nature of the selectivity and the overall activity of the pyranoside can provide major synthetic difficulties. The overall specificity of the glycosylation can be improved by utilizing approaches which take into account the relative transition states that the anomeric carbon can undergo during a typical glycosylation. Most notably, recognition and incorporation of Felkin-Ahn-Eisenstein models into rationale chemical design can generally provide reliable results provided the transformation can undergo this type of conformational control in the transition state. Fluorine directed glycosylations represent an encouraging handle for both B selectivity and introduction of a non-natural biomimetic C2 functionality on the carbohydrate. One innovative example provided by Bucher et al. provides a way to utilize a fluoro oxonium ion and the trichloroacetimidate to encourage B stereoselectivity through the gauche effect. This reasonable stereoselectivity is clear through visualization of the Felkin-Ahn models of the possible chair forms. This method represents an encouraging way to selectivity incorporate B-ethyl, isopropyl and other glycosides with typical trichloroacetimidate chemistry.
== How it works == Pyrolysis is the thermal decomposition of materials in an inert atmosphere or a vacuum. The sample is put into direct contact with a platinum wire, or placed in a quartz sample tube, and rapidly heated to 600–1000 °C. Depending on the application even higher temperatures are used. Three different heating techniques are used in actual pyrolyzers: Isothermal furnace, inductive heating (Curie Point filament), and resistive heating using platinum filaments. Large molecules cleave at their weakest bonds, producing smaller, more volatile fragments. These fragments can be separated by gas chromatography. Pyrolysis GC chromatograms are typically complex because a wide range of different decomposition products is formed. The data can either be used as fingerprint to prove material identity or the GC/MS data is used to identify individual fragments to obtain structural information. To increase the volatility of polar fragments, various methylating reagents can be added to a sample before pyrolysis. Besides the usage of dedicated pyrolyzers, pyrolysis GC of solid and liquid samples can be performed directly inside programmable temperature vaporizer (PTV) injectors that provide quick heating (up to 60 °C/s) and high maximum temperatures of 600-650 °C. This is sufficient for many pyrolysis applications. The main advantage is that no dedicated instrument has to be purchased and pyrolysis can be performed as part of routine GC analysis. In this case quartz GC inlet liners can be used.
==== Animal restraint ==== Large ranches and farms will generally use a squeeze chute to contain animals during branding. Livestock response to freeze branding is often so muted that ranchers report one leg restraint as being more than enough. Horse freeze branding is often accomplished with no more restraint than a twitch. This is a very different scenario from hot branding, where animals are often tied by all four legs to the bars of their squeeze chute to prevent the flight response from causing a misbrand.
Sources: en.wikipedia.org
It is usually described as an immunomodulatory peptide rather than a classic circulating hormone. No endocrine gland is known to release it as a primary secretory product, and its measured presence in blood is not firmly established.
Prothymosin alpha is a much larger acidic protein, roughly 111 to 113 residues long, and the thymosin alpha-1 sequence matches its N-terminal region. The small peptide is therefore best understood as a fragment of that parent protein rather than a separate gene product.
Trials and clinical reports have examined chronic hepatitis B and C, use as a vaccine adjuvant, and supportive treatment in some immunodeficiency and oncology settings. Results vary by indication, and regulatory approval differs between countries.
Its sequence corresponds to the amino-terminal portion of prothymosin alpha, a larger protein present in many cell types. The isolated 28-residue peptide is a fragment of that protein rather than a separately encoded molecule, and laboratory material is produced by synthesis.