The short version of thymalfasin fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-06-01. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| 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 |
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.
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.
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。
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。
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.
The IDF also said that it killed two Lebanese militants attempting to infiltrate the border and plant an explosive at an IDF post. Two Israeli soldiers were killed and nine others were injured in Hezbollah attacks in the vicinity of the Lebanese border. Three rockets launched by Hezbollah to Metula caused fires and damaged electric infrastructure. The IDF said that its jets struck more than a hundred Hezbollah rocket launchers and other Hezbollah sites in its heaviest air strikes since the Israel–Hezbollah conflict started in October 2023. An Israeli strike in al-Haniyeh wounded four people. The Lebanese National News Agency reported that Israeli airstrikes targeted Mahmoudieh, Ksar al-Aroush, and Birket Jabbour. On 20 September, an Israeli strike in the Dahieh suburb of Beirut killed Ibrahim Aqil, the acting commander of the elite Redwan Force and other personnel including Ahmad Mahmoud Wahabi, a senior commander of Hezbollah while they were in a meeting. At least 45 people were killed including Aqil, Wahabi, another 14 high-ranking Hezbollah militants, three children, and seven women, while 68 people were injured. Heavy rocket fire was reported afterward in northern Israel. Hezbollah claimed that its Katyusha rockets struck the IDF base in Meron. Hezbollah also said that it targeted Israeli airbases, intelligence bases, and a tank. On 21 September, the IDF claimed to have "almost completely dismantled" Hezbollah's military chain of command. The IDF claimed that it destroyed thousands of rocket launchers. Four people were wounded in Israeli strikes.
Since uranium and plutonium are nuclear weapons materials, there are proliferation concerns. Ordinarily (in spent nuclear fuel), plutonium is reactor-grade plutonium. In addition to plutonium-239, which is highly suitable for building nuclear weapons, it contains large amounts of undesirable contaminants: plutonium-240, plutonium-241, and plutonium-238. These isotopes are extremely difficult to separate, and more cost-effective ways of obtaining fissile material exist (e.g., uranium enrichment or dedicated plutonium production reactors). High-level waste is full of highly radioactive fission products, most of which are relatively short-lived. This is a concern since if the waste is stored, perhaps in deep geological storage, over many years the fission products decay, decreasing the radioactivity of the waste and making the plutonium easier to access. The undesirable contaminant Pu-240 decays faster than the Pu-239, and thus the quality of the bomb material increases with time (although its quantity decreases during that time as well). Thus, some have argued, as time passes, these deep storage areas have the potential to become "plutonium mines", from which material for nuclear weapons can be acquired with relatively little difficulty. Critics of the latter idea have pointed out the difficulty of recovering useful material from sealed deep storage areas makes other methods preferable. Specifically, high radioactivity and heat (80 °C in surrounding rock) greatly increase the difficulty of mining a storage area, and the enrichment methods required have high capital costs.
== History == In 2012, the Committee for Medicinal Products for Human Use (CHMP) of the EMA issued a positive opinion on the drug. Dapagliflozin was found effective in several studies in participants with type 2 diabetes. The main measure of effectiveness was the level of glycated haemoglobin (HbA1c), which indicates how well blood glucose is controlled. In two studies involving 840 participants with type 2 diabetes, dapagliflozin when used alone decreased HbA1c levels by 0.66% more than placebo (a dummy treatment) after 24 weeks. In four other studies involving 2,370 participants, adding dapagliflozin to other diabetes medicines decreased HbA1c levels by 0.54–0.68% more than adding placebo after 24 weeks. In a study involving 814 participants with type 2 diabetes, dapagliflozin used in combination with metformin was at least as effective as a sulphonylurea (another type of diabetes medicine) used with metformin. Both combinations reduced HbA1c levels by 0.52% after 52 weeks. A long-term study, involving over 17,000 participants with type 2 diabetes, looked at the effects of dapagliflozin on cardiovascular (heart and circulation) disease. The study indicated that dapagliflozin's effects were in line with those of other diabetes medicines that also work by blocking SGLT2. In two studies involving 1,648 participants with type 1 diabetes whose blood sugar was not controlled well enough on insulin alone, adding dapagliflozin 5 mg decreased HbA1c levels after 24 hours by 0.37% and by 0.42% more than adding placebo.
Sources: en.wikipedia.org
=== Alternative to autograft in long bone nonunions === In 2001, the Food and Drug Administration (FDA) approved rhBMP-7 (a.k.a. OP-1; Stryker Biotech) for a humanitarian device exemption as an alternative to autograft in long bone nonunions. In 2004, the humanitarian device exemption was extended as an alternative to autograft for posterolateral fusion. In 2002, rhBMP-2 (Infuse; Medtronic) was approved for anterior lumbar interbody fusions (ALIFs) with a lumbar fusion device. In 2008 it was approved to repair posterolateral lumbar pseudarthrosis, open tibia shaft fractures with intramedullary nail fixation. In these products, BMPs are delivered to the site of the fracture by being incorporated into a bone implant, and released gradually to allow bone formation, as the growth stimulation by BMPs must be localized and sustained for some weeks. The BMPs are eluted through a purified collagen matrix which is implanted in the site of the fracture. rhBMP-2 helps grow bone better than any other rhBMP so it is much more widely used clinically. There is "little debate or controversy" about the effectiveness of rhBMP-2 to grow bone to achieve spinal fusions, and Medtronic generates $700 million in annual sales from their product.
In addition it yielded interesting data in terms of who are the main downloaders of the AIDA program, and has also provided technical (computer) information which aided the release of a freeware upgrade to the software. A second study audited 2,437 separate downloads of the AIDA program. The Internet-based survey methodology was confirmed to be robust and reliable. Over a 7.5-month period (from mid-July 2000 to early March 2001) 2,437 responses were received. During the corresponding period 4,100 actual downloads of the software were independently logged via the same route at the AIDA Website — giving a response rate to this audit of 59.4%. Responses were received from participants in 61 countries — although over half of these (n 5 1,533; 62.9%) originated from the United States and United Kingdom. Of these responses 1,361 (55.8%) were received from people with diabetes and 303 (12.4%) from relatives of patients, with fewer responses from doctors, diabetes educators, students, nurses, pharmacists, and other end users. This study has confirmed the feasibility of using the Internet to survey, at no real cost, a large number of medical software downloaders / users. In addition, it yielded up-to-date and interesting data about who are the main downloaders of the AIDA program. A third study surveyed downloaders of a more recent release of the program (AIDA v4.3a). Over a 1-year period (from March 2001 to February 2002) in total 3,864 responses were received.
The three substrates of this enzyme are (S)-lactaldehyde, oxidised nicotinamide adenine dinucleotide (NAD+), and water. Its products are (S)-lactic acid, reduced NADH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (S)-lactaldehyde:NAD+ oxidoreductase. Other names in common use include L-lactaldehyde:NAD+ oxidoreductase, and nicotinamide adenine dinucleotide (NAD+)-linked dehydrogenase. This enzyme participates in pyruvate metabolism.
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.