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 2026-02-03 and is reviewed periodically as new material appears.
Identity and purity are checked with chromatographic and mass spectrometric methods. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities, while mass spectrometry confirms the expected molecular mass. A certificate of analysis may report a purity percentage, but the laboratory should still verify the material independently. Common quality concerns include truncated sequences, deamidation, oxidation, and residual solvents from synthesis. Because TB-500 is short, some impurities can differ from the target by only a few mass units.
Reconstitution practices affect downstream measurements. The dry powder is typically dissolved in sterile water or a suitable aqueous buffer, then mixed gently rather than vortexed at high speed. Visible particles or cloudiness suggest incomplete dissolution or contamination and should be investigated. For long-term storage, aliquots should be labeled with concentration, solvent, and date. Open questions include how different buffers alter peptide conformation and whether specific container materials adsorb the peptide. Those variables can change apparent concentration in assays even when the chemical identity is correct.
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 |
|---|---|---|
| Storage temperature (dry) | -20 °C | Protected from light and moisture |
| Storage temperature (solution) | -80 °C | Single-use aliquots recommended |
| Identity assay | LC-MS or MALDI-TOF | Confirms mass near 889 Da |
| Purity assay | RP-HPLC | Reports main peak percentage |
| Common impurities | Truncated peptides, deamidated forms | Arise from synthesis or storage |
Reconstitution of a lyophilized peptide is normally done with sterile water or a suitable buffer under aseptic conditions. Adding solvent down the vial wall and allowing gentle dissolution instead of vigorous vortexing reduces the chance of aggregation, which can lower the effective concentration of the resulting solution. Concentrated stocks are usually diluted into working buffer shortly before use. Because no standard preparation protocol exists for TB-500 specifically, laboratories adapt general peptide handling practice, and reported results may reflect differing preparation choices.
Dry peptide powder is commonly kept at −20 °C in a desiccated container away from light, a practice that limits moisture uptake and oxidation. Once dissolved, solutions are generally held at 2–8 °C for short periods or frozen at −20 °C or lower for longer storage, with repeated freeze-thaw cycles avoided. Hydrolysis and oxidation are the main degradation routes for peptides in solution, and both accelerate at higher temperature or extreme pH. Published stability data specific to TB-500 are limited, so shelf life should be treated as uncertain.
Identity and purity checks for peptide material typically combine reversed-phase high-performance liquid chromatography with mass measurement, since retention time alone cannot confirm a sequence. Mass measurement verifies the expected molecular mass within instrument tolerance, while chromatographic peak area provides a purity estimate. Anti-doping analysis of urine uses related but more sensitive workflows, sometimes after solid-phase extraction. For research material, batch documentation, certificate content, and independent testing are common points of scrutiny, because supply chains outside pharmaceutical regulation vary widely in the paperwork they provide.
The seven-residue chain carries several polar and charged side chains, so it dissolves readily in water and in aqueous buffers near neutral pH. No cysteine is present, so disulphide formation is not a concern and reducing agents are unnecessary. Dilute ammonium hydroxide or acetonitrile-water mixtures are sometimes used for stock solutions when initial dissolution is slow. Strongly alkaline conditions and prolonged contact with oxidising agents are avoided because they can modify lysine-containing stretches, and haze in solution usually signals incomplete dissolution or aggregated material.
Identity and purity are checked with reversed-phase high-performance liquid chromatography, which separates the target sequence from truncated or deletion analogues, and with mass spectrometry, which confirms the expected molecular mass. Amino acid analysis and peptide mapping give orthogonal confirmation but are used less often outside specialist laboratories. Counter-ion content varies: material purified on trifluoroacetic acid gradients retains trifluoroacetate, and ion exchange can convert the salt form. Residual water and solvent are measured by Karl Fischer titration or thermogravimetric analysis, and any purity figure should be read together with the method used to obtain it.
=== Other treatments === Other treatments include anabolic steroids, medical grade honey, negative pressure wound therapy, phototherapy, pressure relieving devices, reconstructive surgery, support surfaces, ultrasound and topical phenytoin. There is little or no evidence to support or refute the benefits of most of these treatments compared to each other and placebo. It is not clear if electrical stimulation is an effective treatment for pressure ulcers. In addition, the benefit of using systemic or topical antibiotics in the management of pressure ulcer is still unclear. When selecting treatments, consideration should be given to patients' quality of life as well as the interventions' ease of use, reliability, and cost. The benefits of nutritional interventions with various compositions for pressure ulcer treatment are uncertain.
==== History ==== Kelp tea is thought to have been drunk from quite a long time ago because "the Japanese have incorporated kelp and seaweed into their diets for 1,500 years". It is said that, in 951, Kūya made a statue of the Ekādaśamukha to cure an epidemic that was spreading in the capital and went around the city giving oo-buku-cha to the sick. Tea using kelp already existed in Edo period (1603–1868) at the latest, and people in these days drank it by pouring boiling water over chopped kelp.
28 September The 15-year-old girl killed in Croydon, South London the previous day is named locally as Elianne Andam. Police are given an extra 24 hours to question the 17-year-old suspect. The landmark Sycamore Gap Tree, beside Hadrian's Wall in Northumberland, is illegally felled. A 16-year-old boy is subsequently arrested on suspicion of criminal damage. 29 September A school bus carrying 58 people overturns between junction 4 and 5 of the M53 motorway, killing a 15-year-old girl and the driver. A major incident is declared by North West Ambulance Service and Liverpool's Alder Hey Children's Hospital. Dozens of others are treated for injuries, and several are hospitalised. A 17-year-old boy appears in court charged with the murder of Elianne Andam, and is remanded in youth detention to appear before the Old Bailey on 3 October. A second person – a man in his 60s – is arrested in correction with the cutting-down of the world-famous Sycamore Gap Tree. The 16-year-old boy arrested over the incident the previous day is released on bail. In an interview with The Sun, Prime Minister Rishi Sunak reinforces his pro-motorist stance, saying he wants to stop "hare-brained" road calming and safety schemes – including 20 mph zones and low-traffic neighbourhoods – putting an end to what he refers to as a "war on motorists".
Sources: en.wikipedia.org
Emission of gaseous and volatile alkanes such as ethane, pentane, and hexane by plants has also been documented at low levels, though they are not generally considered to be a major component of biogenic air pollution. Edible vegetable oils also typically contain small fractions of biogenic alkanes with a wide spectrum of carbon numbers, mainly 8 to 35, usually peaking in the low to upper 20s, with concentrations up to dozens of milligrams per kilogram (parts per million by weight) and sometimes over a hundred for the total alkane fraction. Alkanes are important as pheromones, chemical messenger materials, on which insects depend for communication. 7-methyltricosane and 9-methyltricosane are active for ladybird beetles (Adalia bipunctata). The emerald ash borer (Agrilus planipennis Fairmaire) responds to 9-methylpentacosane. Female Asian long-horned beetles Anoplophora glabripennis, which are very damaging, secrete 2-methyldocosane. Waggle-dancing honey bees produce and release two alkanes, tricosane and pentacosane.
== Structure-activity relationship == Spironolactone and Eplerenone competitively block the binding of aldosterone to the mineralocorticoid receptor and hindering the reabsorption of sodium and chloride ions. The activity of mineralocorticoid antagonists is dependent on the presence of a y-lactone ring on the C-17 position. The C-7 position is also important for activity as substituents there sterically hinder the interaction of C-7-unsubstituted agonists such as aldosterone.
21 June – Harry Watson, artist and poet (born 1965). 24 June – Garry Ahern, sports broadcaster (Radio New Zealand) (born 1949). 26 June Takutai Tarsh Kemp, politician, MP for Tāmaki Makaurau (since 2023) (born 1975) Robbie Stuart, rugby union player (Hawke's Bay, national team) and coach (Hawke's Bay) (born 1948).
Sources: en.wikipedia.org
The dry powder is normally kept at -20 °C, protected from light and moisture. Reconstituted solutions are often divided into aliquots and stored at -80 °C to reduce freeze-thaw damage.
Reverse-phase HPLC assesses purity, and mass spectrometry confirms molecular mass. The combination helps distinguish the target peptide from truncated or modified impurities.
Buffer composition, pH, adsorption to containers, and freeze-thaw history can all affect the amount of intact peptide in solution. These factors may change results even when the starting material is chemically correct.
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.