The short version of TB-500 fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-07-24 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.
TB-500 is a catalogue name applied to a synthetic peptide related to thymosin beta-4, an actin-binding protein found in most mammalian cells. Suppliers do not use the label consistently: some describe it as the full 43-residue protein, others as a short fragment from the actin-binding region, and others as a related tetrapeptide. Because the name is commercial rather than chemical, two products sold under it may not contain the same molecule. This naming ambiguity is the first point to check in any description of the material.
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.
Thymosin beta-4 itself is a natural peptide of 43 residues found in many cell types and body fluids. Its best-characterised function is binding and sequestering actin monomers, which influences cytoskeletal dynamics. The sequence most often associated with TB-500, LKKTETQ, corresponds to part of that actin-binding region. A different fragment, Ac-SDKP, is also derived from the same parent peptide and is studied in its own right, which is one reason discussions of thymosin fragments can become confusing. The two are structurally distinct and are not interchangeable.
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.
| 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 |
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.
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 seven-amino-acid peptide with the sequence LKKTETQ, corresponding to residues 17 through 23 of the protein thymosin beta-4. The N-terminus is typically acetylated in the described form, giving a monoisotopic mass near 888.5 Da and an average mass of about 889 Da. The designation TB-500 is a catalogue label rather than a formal chemical name, and the same sequence appears in the literature under several alternative abbreviations. It is handled as a research reagent rather than a pharmaceutical product.
Thymosin beta-4 is a 43-residue actin-binding protein found in most mammalian cell types, where it participates in cytoskeletal regulation and cell migration. TB-500 represents only a short fragment of that protein and does not include the remaining residues. Whether the isolated fragment reproduces the full range of activities reported for the intact protein remains an open question. Researchers commonly treat the two as related but distinct entities when comparing results.
Proposed activity centers on actin sequestration and on the movement of cells during repair processes. In cell culture and animal models, the fragment has been associated with migration, tube formation, and tissue remodeling. These observations are frequently described as preliminary, because most published work uses rodent or in vitro systems rather than controlled human trials. Whether the short fragment reproduces the effects of the full protein remains an open question, and the relationship between dose, route, and measured outcome is not well characterized.
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.
A parallelized version of pyrosequencing was developed by 454 Life Sciences, which has since been acquired by Roche Diagnostics. The method amplifies DNA inside water droplets in an oil solution (emulsion PCR), with each droplet containing a single DNA template attached to a single primer-coated bead that then forms a clonal colony. The sequencing machine contains many picoliter-volume wells each containing a single bead and sequencing enzymes. Pyrosequencing uses luciferase to generate light for detection of the individual nucleotides added to the nascent DNA, and the combined data are used to generate sequence reads. This technology provides intermediate read length and price per base compared to Sanger sequencing on one end and Solexa and SOLiD on the other.
The productive output of the Matrix is based upon this repeated cycle of destruction and recreation, to keep the human minds which power it in a stable structure because not every human accepts the simulated reality and if enough of them accumulate, it could cause a catastrophic system crash of the Matrix and subsequent extinction of both humanity and the Machines. The Oracle is as much part of that self-perpetuating design as the Architect and the prophecy of the One is designed to ensure it runs smoothly each time. The Architect warns of the annihilation of all human life in and out of the Matrix if he does not enter the Source door to reload the Matrix, but unlike his predecessors, Neo does not enter the door to the Source; he chooses not to believe the Architect's dire warnings of consequences and to save Trinity instead. Returning to the Matrix, he catches Trinity as she falls from an upper-story window of a power plant. She dies of a gunshot wound to the heart that she sustains during the fall, but Neo brings her back to life by reaching into her virtual body, removing the bullet and restarting her heart. Together, they exit the Matrix and return to the real world. Neo tells Morpheus that the prophecy was merely another system of control and that Zion's destruction is imminent. A group of sentinels begin to converge on their hovercraft, so Neo and the others are forced to abandon it and flee as it is destroyed.
Rosacea is a long-term skin condition that typically causes redness, visible blood vessels, and small bumps on the face. Medications with good evidence include topical metronidazole, ivermectin and azelaic acid.
Sources: en.wikipedia.org
Mizell led the league in strikeouts with 257, finished second in ERA to Tom Gorman (1.97 to 1.94), and tied for seventh in the league with 16 wins. With a record of 99–61, Houston won the pennant by 13.5 games over the San Antonio Missions.
small nucleolar RNA (snoRNA) A class of small non-coding RNA molecules whose primary function is to direct the post-transcriptional modification of other RNAs, mainly transfer RNAs (tRNA), small nuclear RNAs (snRNA), and especially ribosomal RNAs (rRNA) as a part of ribosome synthesis in the nucleolus. SnoRNAs contain antisense sequences that complement sequences within these target RNAs and guide ribonucleoprotein complexes to them, which can then catalyze specific nucleoside modifications, typically methylation or pseudouridylation.
14 Kevin Anderson at the Citi Open en route to the quarterfinals. Zverev's brief rankings drop in July meant that he needed to qualify for the US Open. He succeeded, but lost his opening round match to compatriot Philipp Kohlschreiber in five sets. Zverev won just one more main draw match the rest of the season and ended the year ranked No. 83 in the world. As the youngest player in the top 100, he was named the ATP Newcomer of the Year.
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.
No. Thymosin beta-4 is a 43-residue natural peptide, while TB-500 is a commercial label applied to a short synthetic fragment of it. The two differ in length, sequence coverage and how they are handled in the laboratory.