Everything below concerns trifluoroacetate. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-05-31. Where a claim depends on a specific study, the study is described rather than over-claimed.
TB-500 is a synthetic peptide preparation marketed under a name derived from thymosin beta-4, a 43-residue actin-binding protein first isolated from thymus tissue. The full-length protein has a reported molecular mass near 4963 Da, while material sold as TB-500 is often described as a fragment containing the actin-binding motif LKKTETQ. Because suppliers use the name inconsistently, published sources sometimes refer to the same label as a fragment, a synthetic copy, or a related analog. This naming ambiguity complicates direct comparison of reports across studies.
Laboratory work on thymosin beta-4 describes binding to monomeric actin and effects on cell migration, angiogenesis, and inflammatory signaling in cultured cells. Animal models have examined skin, corneal, and cardiac repair after injury, with outcomes reported mainly in preclinical literature. Most of that evidence concerns the parent protein rather than preparations labelled TB-500, so extrapolation from animal findings to a specific commercial product remains uncertain. Whether the two behave identically in living systems has not been established in controlled human studies.
No major regulatory agency has approved TB-500 for therapeutic use, and it holds no pharmacopoeial monograph. The name appears on the World Anti-Doping Agency prohibited list within the class covering peptide hormones, growth factors, and related substances. Detection in doping control relies on mass spectrometric methods applied to urine, often after preparation steps that concentrate the analyte. Discussion of TB-500 therefore clusters in biochemistry, sports medicine, and anti-doping literature rather than in registered clinical trials.
The compound is most often distributed as a lyophilized powder, appearing white to off-white and forming a loose cake or fluffy solid. It is hygroscopic to some degree, so brief exposure to humid air can add water weight and complicate weighing. The peptide dissolves readily in water and in neutral aqueous buffers, and aqueous solubility is generally described as high, well above the concentrations used in typical assays. Some polar organic solvents are also usable, which matters when a concentrated stock is prepared before dilution into buffer.
Storage recommendations center on keeping the dry powder cold, dry, and dark. A freezer at -20 degrees Celsius or below is conventional, and desiccant is often included to limit moisture uptake. Once dissolved, the peptide is less stable, and solutions are typically kept frozen and thawed only once. Repeated freeze-thaw cycles are a common source of losses because they promote aggregation and adsorption to container surfaces. Working aliquots are therefore prepared in advance, and glass or low-binding plastic is usually preferred over ordinary laboratory plastic.
| Property | Value | Notes |
|---|---|---|
| Molecular mass | Approximately 4963 Da for full-length thymosin beta-4 | Value applies to the parent protein; fragment products may differ |
| Appearance | White to off-white lyophilized powder | Typical form of supplied synthetic peptide |
| Solubility | Freely soluble in water | Polar peptide; dissolves readily in aqueous buffer |
| Storage of dry powder | −20 °C, desiccated, protected from light | Standard laboratory practice for peptides |
| Typical detection method | Liquid chromatography–tandem mass spectrometry | Used in purity testing and anti-doping analysis |
Lyophilized TB-500 is hygroscopic and should be kept dry before use. The usual storage recommendation for the solid is -20 °C, protected from light and moisture. Once dissolved, the peptide is less stable, and repeated freeze-thaw cycles can promote aggregation or degradation. Laboratories often divide a reconstituted solution into single-use aliquots and store them at -80 °C. Exact stability limits depend on buffer, pH, and concentration, so published data do not define a single universal condition.
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.
Published research on the intact protein is substantial, covering actin regulation, cell migration, and wound models. Research using the heptapeptide fragment specifically is far smaller, and much of the circulating material originates in supplier documentation rather than peer-reviewed reports. Where fragment studies do exist, they often employ different sequences, chain lengths, or terminal modifications, which complicates direct comparison across papers. Readers encountering claims about TB-500 should therefore separate evidence about thymosin beta-4 from evidence about the fragment itself.
Discussion of the compound frequently appears alongside other short peptides described as fragments of larger proteins. That grouping is convenient but can be misleading, because fragment length, charge, and modification state determine how a peptide behaves in solution and in any experimental system. A seven-residue acetylated peptide and a full-length protein differ in mass by roughly an order of magnitude, and they cannot be assumed to share distribution or binding properties. Precision about which molecule is under discussion is the single most useful step when reading such material.
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.
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.
Ghana has a universal health care system, National Health Insurance Scheme (NHIS), which is strictly designated for Ghanaian nationals. Health care is variable throughout Ghana and in 2012, more than 12 million Ghanaian nationals were covered by the NHIS. Urban centres are served and contain most of the hospitals, clinics, and pharmacies. There are more than 200 hospitals, and Ghana is a destination for medical tourism. In 2010, there were 0.1 physicians per 1,000 people and as of 2011, 0.9 hospital beds per 1,000 people. In 2010, 5.2% of Ghana's GDP was spent on health. In 2020, the WHO announced Ghana became the second country in the WHO African Region to attain regulatory system "maturity level 3", the second-highest in the four-tiered WHO classification of National medicines regulatory systems. Life expectancy at birth in 2021 was 68.6 for a female and 63.7 for a male. In 2013, infant mortality was to 39 per 1,000 live births. Sources vary on life expectancy at birth; the World Health Organization (WHO) estimated 64 years for women and 62 years for men born in 2016. The fertility rate declined from 3.99 (2000) to 3.28 (2010) with 2.78 in urban region and 3.94 in rural region. The United Nations reports a fertility decline from 6.95 (1970) to 4.82 (2000) to 3.93 live births per woman in 2017. As of 2012, the HIV/AIDS prevalence was estimated at 1.40% among adults aged 15–49.
Luisa DiPietro is a faculty member at the University of Illinois at Chicago College of Dentistry. She is Director of the Center for Wound Repair and Tissue Regeneration and a Professor of Periodontics for the College. DiPietro's interests in wound healing focus on the effects of aging and inflammation on scarring during healing. She investigates critical differences in inflammation and angiogenesis between oral versus cutaneous wounds that ultimately result in rapid, nonscarring healing in mucosa. From 2010 to 2011, she served as the president of the Wound Healing Society. In 2015, she was named a University Scholar of the University of Illinois. DiPietro received her PhD in immunology and DDS from the University of Illinois at Chicago.
European Commission Regulation (EC) No 2073/2005 of November 15, 2005 European Committee for Standardization (CEN): Standard method for the detection of norovirus and hepatitis A virus in food products (shellfish, fruits and vegetables, surfaces and bottled water) CODEX Committee on Food Hygiene (CCFH): Guideline for the application of general principles of food hygiene for the control of viruses in food
Sources: en.wikipedia.org
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Three additional SeV proteins are also encoded by P/C mRNA. Two of these proteins V and W are products of RNA editing, at codon 317 of the mRNA -G residues are added co-transcriptionally, (+one G residue for V and +two G for W). The third -X protein is represented by 95 amino acids of the C terminal of the P protein and independently initiated by ribosomes. All these non-structural proteins have several functions, including the organization of viral RNA synthesis and helping the virus to infect rodent cells by escaping host innate immunity (see "Virus-induced immunosuppression" section above). It has also been found that C protein facilitates budding of virus-like particles and small amounts of C protein are associated with a viral capsid.
=== Myopathies === Inflammatory myopathies are caused by the immune system inappropriately attacking components of muscle, leading to signs of muscle inflammation. They may occur in conjunction with other immune disorders, such as systemic sclerosis, and include dermatomyositis, polymyositis, and inclusion body myositis.
Sources: en.wikipedia.org
Not necessarily. TB-500 is a commercial label that suppliers apply to synthetic peptides described as thymosin beta-4 or a fragment of it. Published research most often studies the full-length protein, so statements about one do not automatically transfer to the other.
No. No major regulatory authority lists an approved product under this name, and no pharmacopoeial monograph exists for it. Material sold under the label is therefore supplied outside approved pharmaceutical channels, which affects the quality documentation available.
It falls within a prohibited class covering peptide hormones and growth factors, based on presumed effects on tissue repair and blood vessel formation. Anti-doping laboratories have published mass spectrometry methods for detecting thymosin beta-4 related peptides in urine samples.
Short transit at ambient temperature is generally tolerated, but long-term storage at room temperature is not recommended. Heat, moisture, and light all accelerate degradation. Cold, dry, dark storage is the conventional choice.