This is a working overview of thymosin beta-4, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-09-26 and is reviewed periodically as new material appears.
The most frequently cited identity is a seven-residue fragment with the sequence LKKTETQ, taken from the actin-binding domain of the parent protein. A separate molecule, N-acetyl-seryl-aspartyl-lysyl-proline, often shortened to Ac-SDKP, derives from the same protein's N-terminal region and appears in overlapping literature. Reported molecular masses therefore differ between sources, and a mass value on its own does not establish which fragment is present. Confirmation requires a defined sequence rather than a single number.
Research interest in thymosin beta-4 fragments centres on actin sequestration, cell migration and tissue repair models. Most published work uses cultured cells or animal wound and cardiac preparations, and findings are generally described as preliminary. No fragment of this protein has been approved as a therapeutic product by major regulators. Reviews of the field note inconsistent dosing, delivery routes and outcome measures across studies, which complicates direct comparison. The material is best understood as a laboratory reagent with an active but unresolved research literature.
Regulatory status differs by country, but TB-500 is not an approved pharmaceutical in major jurisdictions. It is commonly sold as a research chemical for laboratory use, which places responsibility for identity and purity on the supplier and the laboratory. Published human data are limited, and most reports involve preclinical models or cell culture. Questions about whether the fragment mimics all actions of thymosin beta-4, and under which conditions, remain open. Independent verification of any material is therefore a practical requirement in research settings.
TB-500 is a synthetic heptapeptide with the sequence Ac-LKKTETQ. It corresponds to a short N-terminal region of thymosin beta-4, a 43-amino-acid protein found in many cell types. The fragment contains an actin-binding motif, which is one reason it appears in laboratory studies of cell migration and cytoskeletal dynamics. TB-500 is not the full-length protein and is produced as a research chemical rather than an approved therapeutic agent. Its molecular weight is approximately 889 Da.
Several names appear in scientific and commercial contexts for this peptide. The label TB-500 is informal and does not follow standard biochemical nomenclature. Research articles more often describe the compound as a thymosin beta-4 fragment, Tβ4 fragment, or by its sequence Ac-LKKTETQ. Confusing TB-500 with full-length thymosin beta-4 can lead to incorrect assumptions about activity because the fragment lacks the remaining residues of the parent protein. The relationship between fragment and parent protein remains an active area of study.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white lyophilized powder | Typical form for short synthetic peptides |
| Solubility class | Freely soluble in water and aqueous buffer | Dissolution aided by gentle mixing, not vigorous shaking |
| Typical storage temperature | −20 °C, desiccated | −80 °C used for long-term holding |
| Common analytical method | Reverse-phase HPLC with UV detection near 214 nm | Identity confirmed separately by mass spectrometry |
| Common synonyms | Thymosin beta-4 fragment; TB4 fragment | Naming varies between suppliers and publications |
The compound circulates in the literature as a research reagent rather than an approved therapeutic. Regulatory agencies in several countries have not authorized it for medical use, and sporting bodies list related thymosin beta-4 peptides among prohibited substances. Suppliers typically market it with a purity figure and a certificate of analysis, while peer-reviewed clinical reports remain sparse. Discussions therefore often separate laboratory findings from anecdotal reports, and reviewers tend to note the small size and methodological limits of the available studies.
TB-500 refers to a synthetic peptide fragment derived from the actin-binding region of thymosin beta-4, a protein present in most mammalian cells. The full protein contains forty-three amino acids, while the commonly sold fragment is a much shorter acetylated sequence, often cited as LKKTETQ. The fragment retains part of the actin-binding motif but lacks the remainder of the parent protein. Material sold under this name is usually lyophilized powder intended for laboratory research, and it is not a finished pharmaceutical product.
Thymosin beta-4 itself is a small, widely expressed protein that sequesters monomeric actin and participates in cell migration, angiogenesis, and tissue repair. Researchers have examined the shortened fragment as a possible mimic of some of these activities, reasoning that the actin-binding motif lies within the first few residues. Binding to monomeric actin has been observed in cell-free systems. Whether the fragment reproduces the broader effects of the full protein in living tissue remains an open question, and findings from animal models are frequently cited without a clear bridge to human physiology.
Discussion of TB-500 appears in several distinct literatures that rarely cite one another. Peer-reviewed studies usually describe in vitro assays or small animal experiments and are cautious about extrapolation. Veterinary and sports communities circulate anecdotal reports with limited methodological detail. Commercial listings add a third layer, often using the name interchangeably with thymosin beta-4 even though the two molecules differ in size and sequence. Regulatory status varies by country, and the compound is not a licensed medicine in most jurisdictions, so readers comparing sources should check which molecule and which purity each source actually describes.
TB-500 is a synthetic seven-residue peptide whose sequence, LKKTETQ, matches the N-terminal actin-binding region of thymosin beta-4. It is usually supplied in an N-terminally acetylated form, a modification that blocks the free amino terminus and can influence behavior in solution. In the research literature the same sequence appears under several names, including thymosin beta-4 fragment and shortened thymosin beta-4. Because it is a short peptide rather than the full 43-residue parent protein, its measured properties differ from those reported for thymosin beta-4 as a whole, and the two are not interchangeable in experimental design.
=== February === February 13, 2009: Netherlands The Dutch Statistics agency confirms the Netherlands are in recession since April 2008; with updated figures showing minor economic reductions in the 2nd and 3rd quarters of 2008, and a 0.9% reduction in the 4th quarter
In March 2021, Charles River announced the acquisition of Retrogenix for $48 million. In May 2021, Charles River announced the acquisition of Vigene Biosciences, a gene therapy contract development and manufacturing organization (CDMO), for $292.5 million. In October 2021, a Japanese subsidiary of Charles River was acquired by Jackson Laboratory for $63M. In April 2022, the company announced it would acquire Explora BioLabs. In January 2023, the business announced it would acquire SAMDI Tech, Inc.
=== Microscope === In this technique, a 2D position-sensitive detector is used to measure the spatial origin of the ions generated at the sample surface by the ion optics of the instruments. The resolution of the spatial information will depend on the magnification of the microscope, the quality of the ions optics and the sensitivity of the detector. A new region still needs to be scanned, but the number of positions drastically reduces. The limitation of this mode is the finite depth of vision present with all microscopes.
== External links == Images of fruit development from flowers at bioimages.Vanderbilt.edu (archived 18 February 2007) Fruit and seed dispersal images at bioimages.Vanderbilt.edu (archived 25 April 2017) Fruit Facts (Archived 2020-07-12 at the Wayback Machine from California Rare Fruit Growers, Inc.) Photo ID of Fruits (Archived 2021-01-09 at the Wayback Machine by Capt. Pawanexh Kohli) "Fruit" . Encyclopædia Britannica (11th ed.). 1911.
Marumiya has been selling furikake since 1927, and according to a 2021 The Nikkei survey, 11 of its products are among the top 20 value share about products in large bags. The product names include "Noritama", "Ajidoraku", "Soft Furikake", "Sukiyaki", and "Honkatsuo." Nagatanien sells furikake that is divided into individual servings. Its main products are "Furikake for Adult", "Furikake for Adult Mini", and "Anpanman Furikake." However, Nagatanien's market share is far behind that of Marumiya. Mishima Shokuhin's furikake products include "Yukari" and "Umeko," and four of the aforementioned top 20 products in large bags are "Yukari" and one is "Umeko.
Sources: en.wikipedia.org
In 1979 Zaffaroni was awarded the Chemical Pioneer Award by the American Institute of Chemists In 1995, he received the National Medal of Technology from President Bill Clinton for his contributions to the pharmaceutical and biotechnology industries. In 2004, he was one of the recipients of the Winthrop-Sears Medal from the Chemical Heritage Foundation and The Chemists’ Club, with George Rosenkranz. In 2005 he received the Bower Award for Business Leadership from the Franklin Institute for his creation of new biochemical processes and drug delivery technologies. In 2005 he was awarded the Gregory Pincus Award from the Worcester Foundation. In 2006, he received the Biotechnology Heritage Award, from the Biotechnology Industry Organization (BIO) and the Chemical Heritage Foundation.
=== Lipton Fusions === Lipton Fusions are a brand of lemonade-iced tea canned beverages. In April 28, 2025, Lipton Teas and Infusions created what's known as Lipton Fusions. They come in the following flavors:
When an allergen (pollen, dust) enters the body, the body produces immunoglobulin E antibodies, resulting in an antigen-antibody reaction. The antibodies are attached to mast cells, which release bioactive substances such as histamine and serotonin. Histamine causes expansion of blood vessels, resulting in allergic reactions such as low blood pressure, increased heart rate, skin itchiness, sneezing, runny nose, etc. Narirutin is said to prevent the release of histamine by the mast cells, reducing the allergic symptoms.
In 2010, the last of the prisons were turned over to the Iraqi government to run. An Associated Press article said Despite Abu Ghriab- or perhaps because of reforms in its wake- prisoners have more recently said they receive far better treatment in American custody than in Iraqi jails. In September 2010 Amnesty International warned in a report titled New Order, Same Abuses; Unlawful Detentions and Torture in Iraq that up to 30,000 prisoners, including many veterans of the US detention system, remain detained without rights in Iraq and are frequently tortured or abused. Furthermore, it describes a detention system that has not evolved since Saddam Hussein's regime, in which human rights abuses were endemic with arbitrary arrests and secret detention common and a lack of accountability throughout the security forces. Amnesty's Middle East and North Africa director, Malcolm Smart went on to say that "Iraq's security forces have been responsible for systematically violating detainees' rights and they have been permitted. US authorities, whose own record on detainees' rights has been so poor, have now handed over thousands of people detained by US forces to face this catalogue of illegality, violence and abuse, abdicating any responsibility for their human rights." On October 22, 2010 nearly 400,000 secret United States army field reports and war logs, detailing torture, summary executions and war crimes, were passed on to the British paper, the Guardian and several other international media organisations through the whistleblowing website WikiLeaks.
Donated blood is usually processed after collection to make it suitable for use in specific patient populations. Collected blood is then separated into blood components by centrifugation: red blood cells, plasma, and platelets. Plasma can be further processed to manufacture albumin protein, clotting factor concentrates, cryoprecipitate, fibrinogen concentrate, and immunoglobulins (antibodies). Red cells, plasma, and platelets can also be donated individually via a more complex process called apheresis. Different blood components require specific storage conditions: red blood cells are typically stored at 1–6 °C, platelets at 20–24 °C with continuous agitation, and plasma is stored frozen at −18 °C or lower to preserve clotting factors.
Sources: en.wikipedia.org
In June 2020, Health Canada approved the combination for people aged 12 years and older. In September 2021, the provinces Alberta and Saskatchewan announced they will join Ontario in funding the medication. They will determine coverage on a case-by-case basis using criteria that have not yet been announced.
1993/169) Combined Probation Areas (Kent) Order 1993 (S.I. 1993/173) Insurance Companies (Amendment) Regulations 1993 (S.I. 1993/174) Council Tax (Transitional Reduction Scheme) (England) Regulations 1993 (S.I. 1993/175) Motor Vehicles (Wearing of Seat Belts) Regulations 1993 (S.I. 1993/176) Loch Crinan Scallops Fishery Order 1993 (S.I. 1993/177) Local Government Act 1988 (Defined Activities) (Specified Periods) (Scotland) Amendment Regulations 1993 (S.I. 1993/178) Air Navigation (Dangerous Goods) (Fourth Amendment) Regulations 1992 S.I. 1993/179) City of London (Non-Domestic Rating Multiplier) Order 1993 (S.I. 1993/180) Sea Fish Licensing (Variation) Order 1993 (S.I. 1993/188) Spring Traps Approval (Variation) Order 1993 (S.I. 1993/189) New Severn Bridge (Restriction of Navigation) Regulations 1993 (S.I. 1993/190) Council Tax and Non-Domestic Rating (Demand Notices) (England) Regulations 1993 (S.I. 1993/191) Value Added Tax Act 1983 (Interest on Overpayments etc.) (Prescribed Rate) Order 1993 (S.I. 1993/192) Copyright (Certification of Licensing Scheme for Educational Recording of Broadcasts and Cable Programmes) (Educational Recording Agency Limited) (Amendment) Order 1993 (S.I. 1993/193) Local Government Finance Act 1992 (Commencement No. 7 and Amendment) Order 1993 (S.I. 1993/194) Council Tax (Reductions for Disabilities) (Amendment) Regulations 1993 (S.I. 1993/195) Council Tax (Administration and Enforcement) (Amendment) Regulations 1993 (S.I. 1993/196) Friendly Societies Act 1992 (Commencement No. 4) Order 1993 (S.I.
Animal studies indicate the amatoxins deplete hepatic glutathione; N-acetylcysteine serves as a glutathione precursor and may therefore prevent reduced glutathione levels and subsequent liver damage. None of the antidotes used have undergone prospective, randomized clinical trials, and only anecdotal support is available. Silibinin and N-acetylcysteine appear to be the therapies with the most potential benefit. Repeated doses of activated carbon may be helpful by absorbing any toxins that are returned to the gastrointestinal tract following enterohepatic circulation. Other methods of enhancing the elimination of the toxins have been trialed; techniques such as hemodialysis, hemoperfusion, plasmapheresis, and peritoneal dialysis have occasionally yielded success but overall do not appear to improve outcome. In patients developing liver failure, a liver transplant is often the only option to prevent death. Liver transplants have become a well-established option in amatoxin poisoning. This is a complicated issue, however, as transplants themselves may have significant complications and mortality; patients require long-term immunosuppression to maintain the transplant. That being the case, there has been a reassessment of criteria such as onset of symptoms, prothrombin time (PTT), serum bilirubin, and presence of encephalopathy for determining at what point a transplant becomes necessary for survival.
=== Sphingolipids === Like phospholipids, these fatty acid derivatives have a polar head and nonpolar tails. Unlike phospholipids, sphingolipids have a sphingosine backbone. Sphingolipids exist in eukaryotic cells and are particularly abundant in the central nervous system. For example, sphingomyelin is part of the myelin sheath of nerve fibers. Sphingolipids are formed from ceramides that consist of a fatty acid chain attached to the amino group of a sphingosine backbone. These ceramides are synthesized from the acylation of sphingosine. The biosynthetic pathway for sphingosine is found below:
Sources: en.wikipedia.org
TB-500 is a trade-style label for a synthetic peptide connected to thymosin beta-4. It is sold mainly through research-chemical channels and is not a single chemically defined product across suppliers.
Not necessarily. Some vendors use the name for the full 43-residue protein, while others apply it to a short actin-binding fragment or to a related tetrapeptide. The sequence should be confirmed from documentation rather than assumed from the label.
No thymosin beta-4 fragment holds marketing approval as a medicine in major jurisdictions. Material offered for sale is typically labelled for laboratory research only.
TB-500 is a synthetic heptapeptide corresponding to a fragment of thymosin beta-4. It is used in laboratory research and is not an approved drug.