If you have been reading about TB-500 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.
Last reviewed on 2026-05-28. Where a claim depends on a specific study, the study is described rather than over-claimed.
Animal work has examined the peptide in models of cardiac injury, skin wounding, and corneal repair, with reported outcomes covering cell migration, inflammatory cell influx, and tissue remodeling. Several of those experiments used the full-length protein or longer fragments instead of the seven-residue sequence, which makes direct comparison between reports difficult. Results are generally described as tissue-dependent, and effect sizes vary considerably across laboratories. Independent replication is uneven, so the overall picture is incomplete rather than settled.
Controlled human trials of the short fragment are scarce. Much of what appears in review articles is extrapolated from animal models or from studies of the parent protein, and literature searches return a larger body of cardiac and ophthalmic work on thymosin beta-4 than on the abbreviated peptide. Regulatory treatment differs by jurisdiction, and in several countries the material is handled as a research chemical rather than an approved therapeutic. Statements about human benefit should be read as provisional.
Literature and online discussion often conflate TB-500 with full-length thymosin beta-4, even though the two differ in size and are not interchangeable in analytical terms. The fragment is produced by solid-phase peptide synthesis, and the product is a defined seven-residue chain rather than a biological extract. Because the term is a trade-style label, two vendors may supply materials of the same nominal sequence but different counter-ion content, purity, or water content. Comparisons across studies are therefore difficult unless the exact sequence and purity are reported.
TB-500 is a research peptide whose sequence matches residues 17 to 23 of thymosin beta-4, a 43-residue protein present in most mammalian cells. The chain is seven amino acids long, written as LKKTETQ, and is normally supplied with an acetyl group on the N-terminus. Suppliers list it as a lyophilised powder under the code name TB-500, and the same sequence appears elsewhere in catalogues as the thymosin beta-4 actin-binding fragment. The label is commercial rather than systematic, so no single authority fixes exactly what TB-500 denotes.
Thymosin beta-4 was isolated from calf thymus in the early 1980s and later characterised as an abundant intracellular actin-sequestering protein. Interest in short synthetic fragments grew once the actin-binding motif had been mapped to the middle of the sequence. TB-500 came out of that line of work as a truncated analogue rather than a natural isolate, and it is now sold mainly to laboratories. Published studies on the fragment have been largely in vitro or in animal models, and controlled human trials remain sparse, so claims about effects in people rest on extrapolation.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Thymosin beta-4 fragment; TB4 fragment | Naming is inconsistent across suppliers and publications |
| Reported sequence | Ac-LKKTETQ | Corresponds to residues 17-23 of the parent protein |
| Frequently cited registry number | 77591-33-4 | Associated with full-length thymosin beta-4 rather than the fragment |
| Common supplied form | Freeze-dried solid | Often presented as an acetate or trifluoroacetate salt |
| Regulatory treatment | Varies by country | Frequently handled as a research chemical; not broadly approved as a therapeutic |
Interest in the fragment grew during the 1990s and 2000s, when it moved from laboratory work into sports and supplement markets. Anti-doping bodies added thymosin beta-4 fragments to prohibited lists, and a small number of adverse analytical findings have been reported in competition testing. Published controlled human trials remain scarce. Most mechanistic evidence comes from cell culture and animal models, and those studies examine endpoints such as cell migration, wound closure and inflammation markers. That evidence supports research interest but does not establish clinical benefit, and broad regenerative claims should be read as unverified.
TB-500 is a short synthetic peptide sold under a trade name rather than a systematic chemical name. Suppliers usually describe it as a fragment of thymosin beta-4 and ship it as a lyophilised powder intended for laboratory use. Because the label is commercial, the exact sequence attributed to it is not fully consistent across catalogues, and some listings present a seven-residue peptide while others describe related fragments of similar length. It is not an approved medicine in any major jurisdiction, and it is handled as a research chemical.
Identity and purity are normally assessed with reversed-phase high-performance liquid chromatography, paired with mass spectrometry to confirm molecular mass. A certificate of analysis reports a purity percentage, usually derived from chromatographic peak area, but that figure does not by itself prove a correct sequence or the absence of counterions. Independent verification may include amino acid analysis or peptide mapping. Batch-to-batch variation is a documented concern in the research chemical market, and the gap between a quoted purity value and actual peptide content can be substantial when the material is a salt or retains residual water.
Lyophilized peptide arrives as a dry cake that should stay sealed until use. Reconstitution is generally performed with sterile water or a buffered solution, and the resulting liquid should be handled gently to limit mechanical stress. Repeated freeze-thaw cycles are widely described as harmful to short peptides, so dividing a reconstituted batch into single-use portions is a common practice. Laboratories also record the solvent, concentration, and date of preparation on the vial label to keep later measurements traceable.
Dry powder is commonly held at minus twenty degrees Celsius, with some suppliers recommending lower temperatures for long-term archival storage. Once dissolved, solutions are typically kept cold and protected from light, since aqueous peptide solutions can lose integrity through hydrolysis or oxidation over time. Stability data specific to this fragment are limited in the public literature, and much of the guidance comes from general peptide handling practice rather than from controlled degradation studies. Users therefore treat stated shelf lives as approximate rather than fixed.
On-line mass spectrometry was develop to solve some of the limitations and problem that develop from off-line analysis, such as evaporation and chemical reactions of particles in the filters during long analysis time. On-line Mass spectrometry solves these problems through the collection and analysis of aerosol particles in real time. On-line instruments are very portable and allow for spatial variability to be examined. These portable instruments can be put on many different platforms such as boats, planes, and mobile platforms (e.g. car trailers). An example of this is in the picture at the beginning with the instrumentation attached to an aircraft. Like off-line, on-line mass spectrometry has many different type of instruments, which can be broken up into two types; instruments that measures the chemistry of the particle ensemble (bulk measurement) and those that measure the chemistry of individual particles (single-particle measurement). Thus based on analytical need different instrumentation is used in analysis of the aerosol particles.
These weight reduction treatments include the injection of HCG, a drug which has not been approved by the Food and Drug Administration as safe and effective in the treatment of obesity or weight control. There is no substantial evidence that HCG increases weight loss beyond that resulting from caloric restriction, that it causes a more attractive or "normal" distribution of fat, or that it decreases the hunger and discomfort associated with calorie-restrictive diets. There was a resurgence of interest in the "HCG diet" following promotion by Kevin Trudeau, who was banned from making HCG diet weight-loss claims by the U.S. Federal Trade Commission in 2008, and eventually jailed over such claims. A 1976 study in the American Journal of Clinical Nutrition concluded that HCG is not more effective as a weight-loss aid than dietary restriction alone. A 1995 meta analysis found that studies supporting HCG for weight loss were of poor methodological quality and concluded that "there is no scientific evidence that HCG is effective in the treatment of obesity; it does not bring about weight-loss or fat-redistribution, nor does it reduce hunger or induce a feeling of well-being". On November 15, 2016, the American Medical Association (AMA) passed policy that "The use of human chorionic gonadotropin (HCG) for weight loss is inappropriate."
After about four months, cerium-141, zirconium-95/niobium-95, and strontium-89 represent the largest share of radioactive material. After two to three years, cerium-144/praseodymium-144, ruthenium-106/rhodium-106, and promethium-147 are responsible for the bulk of the radioactivity. After a few years, the radiation is dominated by strontium-90 and caesium-137, whereas in the period between 10,000 and a million years it is technetium-99 that dominates.
Lobeglitazone (trade name Duvie, Chong Kun Dang) is an antidiabetic drug in the thiazolidinedione class of drugs. As an agonist for both PPARα and PPARγ, it works as an insulin sensitizer by binding to the PPAR receptors in fat cells and making the cells more responsive to insulin.
In July 2009, Sovershenno Sekretno wrote that before the war, the hospital was deployed near South Ossetia while smaller group of military doctors were deployed to Abkhazia and asked "does it mean that intensive hostilities were not planned there [in Abkhazia]?" The newspaper noted that General Alexey Maslov was fired from the post of Commander-in-Chief of the Russian Ground Forces several days before the full-scale invasion of Georgia and some changes were related to the preparation of the war against Georgia. It quoted an unnamed Russian General Staff member as having said that "Some prepared the operation, while others came to sit on the ready laurels". The newspaper also wrote that the Russian Air Force was covering up the loss of one Sukhoi Su-24. The newspaper concluded that Russia needed South Ossetia as bridgehead for offensive operations. In November 2011, Stanislav Sadalsky commented on Medvedev's statement to have halted NATO expansion in 2008 that this was an admission that it was Medevedev who started the war, which was prosecutable under the Criminal Code of Russia.
Sources: en.wikipedia.org
==== Shoulder disorders ==== A 2014 Cochrane review found insufficient evidence to determine whether electrotherapy was better than exercise at treating adhesive capsulitis. As of 2004, there is insufficient evidence to draw conclusions about any intervention for rotator cuff pathology, including electrotherapy; furthermore, methodological problems precluded drawing conclusions about the efficacy of any rehabilitation method for impingement syndrome.
=== 1940s === As President Franklin D. Roosevelt died and World War II concluded with the detonation of nuclear weapons over Japan in 1945, the stage was quickly set for the emergence of Cold War hostilities between the new superpowers in 1946. Musicians concertizing in the United States during this period were suddenly exposed to rapidly shifting diplomatic and political circumstances. In 1946 the US State Department assumed control of the cultural diplomacy initiatives in South America which were initiated in 1941 by President Roosevelt's Office of the Coordinator of Inter-American Affairs. At first, the State Department continued to encourage leading musicians to concertize and broadcast music in support of its Pan-Americanism policy in the region through its Office of International Broadcasting and Cultural Affairs. As a result, live radio broadcasts to South America by such musicians as Alfredo Antonini, Néstor Mesta Cháyres and John Serry Sr. on CBS's Viva América show continued into the first years of the Cold War era. As the decade came to a close, however, the focal point for American foreign policy shifted toward the superpower rivalry in Europe and such cultural broadcasting to South America was gradually eliminated.
Trump's cabinet choices were described by news media as valuing personal loyalty over relevant experience, and for having a range of conflicting ideologies and "eclectic personalities". It was also described as the wealthiest administration in modern history, with over 13 billionaires chosen to take government posts. He nominated or appointed 23 former Fox News employees to his administration. Notably, Trump's nomination of Scott Bessent as Secretary of the Treasury made Bessent the highest ranking openly LGBTQ person to serve in the United States government. In March 2026, The Wall Street Journal reported that Trump was planning to fire Kristi Noem after a Senate Judiciary Committee hearing during which she was criticised for her actions during her term of office, including her handling of the killings of Renée Good and Alex Pretti, inappropriate relations with her advisor, Corey Lewandowski, and mismanagement of funds. On March 5, Trump announced her reassignment to a new position, "Special Envoy for The Shield of the Americas", and announced Oklahoma senator, Markwayne Mullin as her successor as the secretary of homeland security. Noem is the first Cabinet official to be removed from her post during Trump's second presidency.
=== Latest history === In April 2022, the business announced it would acquire Sierra Oncology Inc. for $1.9 billion ($55 per share). In May 2022, GSK announced it would acquire Affinivax and its phase II 24-valent pneumococcal vaccine candidate for up to $3.3 billion, strengthening its vaccine business. On 16 May 2022, the company changed its name from GlaxoSmithKline to GSK. In April 2023, GSK announced it would acquire Bellus Health Inc. for $2 billion. In February 2024, the company acquired Aiolos Bio for over $1 billion, adding to its existing asthma business through AIO-001, a long-acting monoclonal antibody that targets the thymic stromal lymphopoietin cytokine. In May 2024, GSK sold off its 4.2% shareholding in Haleon for $1.58 billion. In July 2024, GSK moved its headquarters from Brentford to New Oxford Street in central London. As of 2025, capital investments in the company via its American Depository Receipts in New York were outpacing those via the company's primary listing in London. Mounting speculation that GSK would be moving its primary share listing to the New York Stock Exchange, following similar speculation about rival AstraZeneca, has been met with denials from GSK's corporate executives. In September 2025, the company announced Emma Walmsley was stepping down as chief executive at the beginning of 2026. GSK has appointed Luke Miels as her replacement, who has been the company's chief commercial officer since 2017.
== Biosynthesis == The production of bottromycin by S. bottropensis and S. scabies, as well as the production of a bottromycin analog termed bottromycin D, has been studied. It was independently confirmed in 2012 by multiple groups that bottromycin is produced as a ribosomal peptide natural product that it subsequently post-translationally modified. Before this, it was unclear whether bottromycin was produced by nonribosomal peptide synthetase machinery (NRPS). The presence of amino acids other than the 20 proteinogenic amino acids is often a feature of NRPS products because NRPS machinery can directly incorporate other amino acids, among other chemical building blocks. Ribosomal peptide synthesis, which is the same machinery that produces all proteins found in the cell, is limited to the 20 proteinogenic amino acids. However, bottromycin was found to be a highly modified ribosomal peptide by a combination of genome mining and gene deletion studies. In ribosomal peptide synthesis, the final product results from modifications to a linear peptide starting material translated by the ribosome from an mRNA transcript. In S. scabies the precursor peptide, termed BtmD, is a 44-amino acid peptide. The precursor peptide is termed BmbC in S. bottropensis. The amino acids forming the bottromycin core are residues 2-9 in BtmD: Gly-Pro-Val-Val-Val-Phe-Asp-Cys. In bottromycin D, the sequence is Gly-Pro-Ala-Val-Val-Phe-Asp-Cys, and the precursor peptide is termed BstA. BstA shares high sequence homology with BtmD in the follower peptide region.
Sources: en.wikipedia.org
The history of sertraline dates to the early 1970s when Pfizer chemist Reinhard Sarges invented a novel series of psychoactive compounds, including lometraline, based on the structures of the neuroleptics thiothixene and pinoxepin. Further work on these compounds led to tametraline, a norepinephrine and weaker dopamine reuptake inhibitor. Development of tametraline was soon stopped because of undesired stimulant effects observed in animals. A few years later, in 1977, pharmacologist Kenneth Koe, after comparing the structural features of a variety of reuptake inhibitors, became interested in the tametraline series. He asked another Pfizer chemist, Willard Welch, to synthesize some previously unexplored tametraline derivatives. Welch generated several potent norepinephrine and triple reuptake inhibitors, but to the surprise of the scientists, one representative of the generally inactive cis-analogs was a serotonin reuptake inhibitor. Welch then prepared stereoisomers of this compound, which were tested in vivo by animal behavioral scientist Albert Weissman. The most potent and selective (+)-isomer was taken into further development and eventually named sertraline. Weissman and Koe recalled that the group did not set up to produce an antidepressant of the SSRI type—in that sense their inquiry was not "very goal driven", and the invention of the sertraline molecule was serendipitous. According to Welch, they worked outside the mainstream at Pfizer, and even "did not have a formal project team".
The New York Times wrote that Biden's "weak filters make him capable of blurting out pretty much anything". According to The New York Times, Biden often embellishes elements of his life or exaggerates, a trait also noted by The New Yorker in 2014. For instance, he has claimed to have been more active in the civil rights movement than he actually was, and has falsely recalled being an excellent student who earned three college degrees. The Times wrote, "Mr. Biden's folksiness can veer into folklore, with dates that don't quite add up and details that are exaggerated or wrong, the factual edges shaved off to make them more powerful for audiences."
People receiving eptifibatide are typically seriously ill and most of them are concomitantly treated with other drugs known to have the potential to cause significant side effects. Therefore, not all side effects listed as follows may be attributable to eptifibatide treatment alone: The major adverse event in the PURSUIT study was severe bleeding. Bleeding occurred as well at sites of clinical intervention (local sites) as at other sites (systemically) like urogenital bleeds. Sometimes, these events were severe enough to require transfusion of blood or plasma concentrates to stop bleeding and counteract anemia. Severe bleeds occurred in 4.4 and 4.7% of patients respectively depending on the infusion rate (0.5 μg/kg/min vs. 0.75 μg/kg/min). A few cases of death due to severe bleeding events attributable to drug therapy were reported. No cases of hemorrhagic stroke were seen. Thrombocytopenia of unknown origin (allergic reaction?) was also noticed in 0.2% of patients. Additionally, hypotension was seen frequently (6%). Cardiovascular failure was also frequent (2%) as were serious arrhythmias (ventricular fibrillation 1.5%, atrial fibrillation 6%). Severe allergic (anaphylactic) reactions occurred in almost 0.2% of patients. These reactions can be life-threatening and may be due to the peptide character of eptifibatide. Other side effects were rare and mild in nature and may not be connected to eptifibatide therapy.
Myxofibrosarcoma (MFS), although a rare type of tumor, is one of the most common soft tissue sarcomas, i.e., cancerous tumors, that develop in the soft tissues of elderly individuals. Initially considered to be a type of histiocytoma termed fibrous histiocytoma or myxoid variant of malignant fibrous histiocytoma, Angervall et al. termed this tumor myxofibrosarcoma in 1977. In 2020, the World Health Organization reclassified MFS as a separate and distinct tumor in the category of malignant fibroblastic and myofibroblastic tumors. MFS tumors are often treated by surgical resection. However, these tumors have high recurrence rates at the sites of their resections. Local recurrences followed by surgical resections may be repeated multiple times but during these cycles MFS tumors often progress from a lower grade to a higher more aggressive grade, metastasize, and become life-threatening. An uncommon variant of the MFS tumors termed epithelioid myxofibrosarcoma is even more likely to follow an aggressive, recurrent, metastasizing, and life-threatening course than the more common form of the MFS tumors.
== Design == The bag is typically partially folded when it is placed in a microwave, and inflates as a result of steam pressure from the heated kernels. Microwave popcorn bags are designed to avoid popped-kernel scorching, an undesirable effect that takes place when popped kernels are heated above 300 °F (150 °C). A susceptor—usually a metalized film laminated onto the paper of the bag—absorbs microwaves and concentrates heat at the film interface, thus ensuring a heat distribution focused on the hard-to-heat flavor coating so that the unpopped kernels are evenly coated prior to popping, thereby ensuring even flavor throughout the product. Some popcorn is flawed and will not pop because of possible damage to the shell, which allows the steam to escape. These unpopped kernels are known as "old men" or "grandpas". An early susceptor popcorn bag design was patented by The American Company General Mills in 1981 (US Patent #4,267,420).
Sources: en.wikipedia.org
The leading proposal involves sequestration of monomeric actin, which would alter cytoskeletal turnover and cell movement. The actin-binding motif shared with the parent protein is central to that idea. Direct confirmation in whole organisms remains limited.
Very few controlled human studies focus on the seven-residue sequence itself. Most clinical data concern the full-length protein in cardiac or ophthalmic settings. Conclusions drawn for one form should not be assumed to transfer to the other.
Detection normally relies on reversed-phase liquid chromatography paired with mass spectrometry. Chromatographic retention time establishes the expected elution window, and the mass spectrum confirms the molecular ion. Immunoassays exist but can cross-react with related peptides.
No. Thymosin beta-4 is a 43-residue protein, while TB-500 matches only residues 17 to 23 of that chain. The two are related but differ in size, and a method that identifies one does not automatically identify the other.