thymosin beta-4 raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-03-31 and is reviewed periodically as new material appears.
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 28-residue peptide first isolated from thymus tissue in the 1970s. It corresponds to the N-terminal portion of thymosin beta-4, from which it is cleaved in vivo. The peptide carries an acetyl group at its N-terminus, a modification that affects its charge and stability. Synthetic material produced by solid-phase peptide synthesis is chemically identical to the natural fragment and is the form used in research and clinical studies.
Laboratory work indicates that the peptide acts on cells of both the innate and adaptive immune systems. Reported effects include signalling through Toll-like receptors on dendritic cells, enhanced T-cell maturation, and increased natural killer cell activity. These actions are described largely from cell-culture and animal experiments, and the precise receptor-level events remain incompletely defined. Studies in humans have generally measured immune markers rather than a single defined molecular target. The resulting picture remains partly descriptive.
| Property | Value | Notes |
|---|---|---|
| Molecular mass | About 3.1 kDa | 28 residues, N-terminally acetylated |
| Appearance | White to off-white powder | Lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in aqueous buffers |
| Storage temperature | 2 to 8 °C | Protect from light and moisture |
| Common synonyms | Thymalfasin; Tα1 | Same peptide sequence |
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.
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.
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.
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。
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。
== Early life == Kevin Darnell Hart was born in Philadelphia on July 6, 1979, to Nancy Hart (died 2007) and Henry Robert Witherspoon (died 2022). He has an older brother named Robert. He was raised in a single-parent household by his mother, who worked as a systems analyst for the Office of Student Registration and Financial Services at the University of Pennsylvania. His father was a cocaine addict who was in and out of jail throughout most of Hart's childhood, prompting Hart to use humor as a way to cope with his troubled family life. His relationship with his father improved after his father recovered from his addiction. He would also later talk about his mother in his stand-up routine, portraying her as a loving yet intimidating woman. As a teenager, Hart had aspirations of becoming a basketball player. He was a participant at the La Salle basketball camp with future National Basketball Association hall of famer Kobe Bryant and future political commentator and activist Marc Lamont Hill. After graduating from George Washington High School, Hart briefly attended the Community College of Philadelphia before dropping out and moving to New York City. He spent some time working as a shoe salesman.
Hoyle, F.; Wickramasinghe, N.C. (1979). "Biochemical chromophores and the interstellar extinction at ultraviolet wavelengths". Astrophysics and Space Science. 65 (1): 241–244. Bibcode:1979Ap&SS..65..241H. doi:10.1007/BF00643503. S2CID 120184918. Hoyle, F.; Wickramasinghe, N.C.; Al-Mufti, S.; et al. (1982). "Infrared spectroscopy over the 2.9-3.9 μm waveband in biochemistry and astronomy". Astrophysics and Space Science. 83 (1–3): 405–409. Bibcode:1999Ap&SS.268..161H. doi:10.1023/A:1002417307802. Hoyle, F.; Wickramasinghe, N.C.; Al-Mufti, S. (1982). "Organo-siliceous biomolecules and the infrared spectrum of the Trapezium nebula". Astrophysics and Space Science. 86 (1): 63–69. Bibcode:1982Ap&SS..86...63H. doi:10.1007/BF00651830. S2CID 120249547. Hoyle, F.; Wickramasinghe, N.C. (1983). "Bacterial life in space". Nature. 306 (5942): 420. Bibcode:1983Natur.306..420H. doi:10.1038/306420a0. PMID 6646221. Hoyle, F. and Wickramasinghe, N.C., 1986. The case for life as a cosmic phenomenon, Nature 322, 509-511 Hoyle, F. and Wickramasinghe, N.C., 1990. Influenza – evidence against contagion, Journal of the Royal Society of Medicine 83. 258-261 Napier, W.M.; Wickramasinghe, J.T; Wickramasinghe, N.C. (2007). "The origin of life in comets". International Journal of Astrobiology. 6 (4): 321–323. Bibcode:2007IJAsB...6..321N. doi:10.1017/S1473550407003941. S2CID 121008660. Rauf, K.; Wickramasinghe, C. (2010). "Evidence for biodegradation products in the interstellar medium". International Journal of Astrobiology. 9 (1): 29–34. Bibcode:2010IJAsB...9...29R. doi:10.1017/S1473550409990334.
== Insulin production == In 1940, during World War II, she and her husband, Victor Saxl, fled to Shanghai, China. In Shanghai, a year later, Saxl was diagnosed with Type 1 diabetes. When the Japanese attacked Pearl Harbor in 1941 the Japanese occupation of China was tightened, and soon all the pharmacies in Shanghai were closed. Saxl had no legal access to insulin. It was possible to buy insulin on the black market using one-ounce gold bars for payment. But that was not the safest option; one of Eva's friends died from using the black market insulin. Eventually, Victor and Eva decided to get insulin another—highly unconventional—way: make it themselves. The book "Beckman's Internal Medicine" described the methods that Frederick Banting and Charles Best first used to extract insulin from the pancreases of dogs, calves, and cows in 1921. A Chinese chemist lent them a small laboratory in the basement of a municipal building, where they attempted to extract insulin from pancreata of water buffaloes. After much work, they finally produced a brown-coloured insulin. The insulin was tested on rabbits starved for twenty-four hours and then divided into two groups. One group was injected with the extracted mix, and the other with Eva's insulin. Without equipment to test the rabbits’ urine or blood, the best way Victor could test the potency of the insulin was to see if the rabbits experienced the same hypoglycaemic shock as the other rabbits.
Sources: en.wikipedia.org
== Death and race continuation == On March 27, 2012, True failed to return after heading out for a run in the Gila Wilderness, part of the Gila National Forest in southwestern New Mexico. He departed from the Wilderness Lodge in Gila, saying he was going for a 12-mile (19 km) run. A subsequent mountain rescue effort involved three aircraft and at least nine search and rescue teams in off-road vehicles and on horseback, looking across 200,000 acres (81,000 ha) of high desert. Searchers included ultra-runners such as Scott Jurek, Kyle Skaggs, Timothy Olson, and many athletes and friends who had participated in the 51 mile Copper Canyon Ultra Marathon. On March 31, True was found dead with his legs dangling in a stream. The local sheriff said there were "no obvious signs of trauma", although True had scrapes and abrasions on his hands, arms, and knees, suggesting a fall. His remains were removed by horseback. Because of difficult terrain and remote location, the recovery was not completed until April 1. An autopsy was inconclusive with respect to the actual cause of death, revealing, however, that True was suffering from idiopathic cardiomyopathy, which had caused the left ventricle of his heart to become enlarged.
==== 2010s ==== In 2012, Starbucks had annual Frappuccino sales of over US$2 billion. In August 2012, the largest Starbucks in the US opened at the University of Alabama's Ferguson Centre. On June 25, 2013, Starbucks began to post calorie counts on menus for drinks and pastries in all of its U.S. stores. In July 2013, more than 10% of in-store purchases were made on customers' mobile devices via the Starbucks app. The company once again utilized the mobile platform when it launched the "Tweet-a-Coffee" promotion in October 2013. On this occasion, the promotion also involved Twitter and customers were able to purchase a US$5 gift card for a friend by entering both "@tweetacoffee" and the friend's handle in a tweet. Research firm Keyhole monitored the progress of the campaign; a December 2013 media article reported that 27,000 people had participated and US$180,000 of purchases had been made to date. In January 2014, as part of a change in compact direction, Starbucks management transitioned from a singular brand worldwide to focusing on locally relevant design for each store. In May 2014, Starbucks announced ongoing losses in the Australian market, which resulted in all remaining stores being sold to the Withers Group. In July 2017, Starbucks acquired the remaining 50% stake in its Chinese venture from long-term joint venture partners Uni-President Enterprises Corporation (UPEC) and President Chain Store Corporation (PCSC) for US$1.3 billion.
Relaxin family peptide hormones in humans are represented by seven members: three relaxin-like (RLN) and four insulin-like (INSL) peptides: RLN1, RLN2, RNL3, INSL3, INSL4, INSL5, INSL6. This subdivision into two classes (RLN and INSL) is based primarily on early findings, and does not reflect the evolutionary origins or physiological differences between peptides. For example, it is known that the genes coding for RLN3 and INSL5 arose from one ancestral gene, and INSL3 shares origin with RLN2 and its multiple duplicates: RLN1, INSL4, INSL6.
Sources: en.wikipedia.org
Buprenorphine/naloxone is used for the treatment of opioid use disorder. Long-term outcomes are generally better with use of buprenorphine/naloxone than attempts at stopping opioid use altogether. This includes a lower risk of overdose with medication use. Due to the high binding affinity and low activation at the opioid receptor, cravings and withdrawal for opioids are decreased while preventing a person from getting high and relapsing on another opioid. The combination of the two medications is preferred over buprenorphine alone for maintenance treatment due to the presence of naloxone in the formulation, which is believed to help discourage intravenous use. However, the belief that the addition of naloxone provides this benefit has been called into question, and posters on drug-related online forums have stated that they were able to attain a high by injecting preparations of buprenorphine despite being combined with naloxone. Buprenorphine/naloxone is effective for treating opioid dependence and serves as a recommended first-line medication according to the U.S. National Institute on Drug Abuse. The medication is an effective maintenance therapy for opioid dependence and has generally similar efficacy to methadone. Both treatments — buprenorphine/naloxone and methadone — are substantially more effective than abstinence-based treatment. As of October 2023 prescribers no longer need a Drug Addiction Treatment Act (DATA 2000) waiver to prescribe buprenorphine/naloxone for opioid dependence.
In September 2024, the US FDA approved pembrolizumab with pemetrexed and platinum chemotherapy as first-line treatment of unresectable advanced or metastatic malignant pleural mesothelioma. In March 2025, the US FDA granted traditional approval to pembrolizumab with trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy for the first-line treatment of adults with locally advanced unresectable or metastatic HER2-positive gastric or gastroesophageal junction adenocarcinoma whose tumors express PD-L1 (CPS ≥1). Pembrolizumab previously received accelerated approval for this indication in May 2021. Efficacy was evaluated in KEYNOTE-811 (NCT03615326), a multicenter, randomized, double-blind, placebo-controlled trial enrolling 698 participants with HER2-positive advanced gastric or GEJ adenocarcinoma not previously treated with systemic therapy for metastatic disease. Among the 698 participants, 594 (85%) had tumors expressing PD-L1 with a CPS ≥1 using the PD-L1 IHC 22C3 pharmDx kit. Participants were randomized (1:1) to pembrolizumab 200 mg or placebo, in combination with trastuzumab and either fluorouracil plus cisplatin or capecitabine plus oxaliplatin. In June 2025, the US FDA approved neoadjuvant and adjuvant pembrolizumab for resectable locally advanced head and neck squamous cell carcinoma.
=== Market === The global instant coffee market was valued at US$34.16 Billion in 2026. In 2025, Asia-Pacific accounted for 39% of the instant coffee market, Europe 28%, North America 24% and Middle East and Africa 9%. A 2014 article said that as a percentage of coffee sold, instant coffee accounted for 1% of the market in Italy, 4% in France, 7% in the US, and 77% in the UK. The high proportion in the UK was attributed to coffee, a novelty to a tea-drinking nation, being introduced in the form of instant coffee by US troops in Britain during World War II.
== Controversies == Following a shortage that led a court to delay an execution in California, a company spokesman for Hospira, the sole American manufacturer of the drug, objected to the use of thiopental in lethal injection. "Hospira manufactures this product because it improves or saves lives, and the company markets it solely for use as indicated on the product labeling. The drug is not indicated for capital punishment and Hospira does not support its use in this procedure." On January 21, 2011, the company announced that it would stop production of sodium thiopental from its plant in Italy, because it could not provide Italian authorities with guarantees that exported doses would not be used in executions. According to a company spokesperson, Italy was the only viable place where it could produce the drug, leaving the US without a supplier. In October 2015 the US Food and Drug Administration (FDA) confiscated an overseas shipment of thiopental destined for the states of Arizona and Texas. The FDA said in a statement, "Courts have concluded that sodium thiopental for the injection in humans is an unapproved drug and may not be imported into the country".
Sources: en.wikipedia.org
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.
The name traces back to thymosin fraction 5, a crude thymus extract examined in the 1970s. Individual peptides in that mixture were labeled with Greek letters, and alpha-1 was one of them. The international nonproprietary name thymalfasin was assigned later.
No. Thymosin beta-4 contains 43 residues and binds actin, while thymosin alpha-1 contains 28 residues and acts on immune cells. The two sit in a historical naming group but share no sequence similarity, and they are not substitutes for one another.
It corresponds to the first 28 amino acids of thymosin beta-4, a larger protein found in many tissues. The fragment is acetylated at its N-terminus and is produced synthetically for research and pharmaceutical use. Synthetic and natural forms share the same sequence.