Research material and lot documents
TB-500 benefits are described online for tissue repair, inflammation, flexibility and many other uses, yet FDA's 2026 review found no published article in which people received TB-500. The studies below involve three different substances, and each entry names the one it used. Source for the FDA statement: FDA briefing document for TB-500, May 15, 2026.
FDA's briefing document lists the conditions for which TB-500 is marketed online. They include promoting tissue repair and regeneration, healing damage to tendons, muscles, ligaments and bones, wound healing, reducing inflammation, increasing muscle growth, improving endurance, promoting hair growth and improving flexibility and mobility. The FDA list is longer than this. It records marketing claims and reports no findings. Source: FDA briefing document.
FDA adds that several websites use TB-500 and thymosin beta-4 as interchangeable names, and it states: "thymosin beta-4 and TB-500 are not the same substance."
The studies in this section used thymosin beta-4, the protein of 43 amino acids. None used TB-500.
A 1999 rat wound study reported more re-epithelialization and wound contraction with thymosin beta-4 than with saline, along with more collagen deposition and angiogenesis, and reported that it stimulated keratinocyte migration in a cell assay. Source: 1999 rat wound-healing study, PMID 10469335.
A 2004 mouse study reported that after coronary artery ligation, thymosin beta-4 treatment was followed by enhanced early myocyte survival and improved cardiac function. In culture it promoted the migration and survival of cardiomyocytes. Source: 2004 mouse cardiac study, PMID 15565145.
A 2010 Phase 2 trial in 73 patients with venous stasis ulcers reported a safety profile that was acceptable and comparable to placebo. The authors suggested that one tested concentration may accelerate wound healing, with complete healing within 3 months in about 25% of patients. Source: 2010 venous ulcer trial, PMID 20536470.
A 2015 Phase II trial in 72 people with moderate to severe dry eye reported no significant difference between groups on either primary endpoint, improvements in several secondary endpoints and no adverse events. Source: 2015 dry eye trial, PMID 26056426.
A 2003 study used thymosin beta-4, its fragments and synthetic peptides. The authors reported that a seven-amino-acid actin-binding motif was essential for angiogenic activity. In endothelial cell migration and chick aortic-arch sprouting assays the motif showed near-identical activity to the full protein, and peptides that lacked any part of the motif were inactive. Source: 2003 angiogenesis study, PMID 14500546.
FDA's briefing document lists this 2003 paper among studies of the non-acetylated heptapeptide LKKTETQ. It states that "the pharmacological profile of the non-acetylated heptapeptide LKKTETQ cannot be directly extrapolated to the N-acetylated heptapeptide TB-500." Source: FDA briefing document.
A 2010 review describes a short sequence containing LKKTETQ, "the central actin-binding domain (aa 17-23) plus 1 additional amino acid (Q)", as promoting angiogenesis, wound healing and cell migration. Source: 2010 review, PMID 20179146. A 1996 study mapped the actin-binding site of thymosin beta-4 with chemically synthesized full-length variants and reported a hexapeptide motif at residues 17 to 22 that takes part in actin binding. Source: 1996 actin-binding site study, PMID 8617195.
A 2024 study used rat samples, enzyme systems, human serum and cultured fibroblasts. The authors measured TB-500 and its metabolites and compared their activity in a fibroblast wound-healing assay. They reported no cytotoxicity for the parent peptide or the metabolites, and found that only the metabolite Ac-LKKTE showed significant wound-healing activity compared with the control. They concluded that wound-healing activity reported earlier for TB-500 may come from that metabolite instead of the parent peptide. Source: 2024 TB-500 metabolite study, PMID 38382158.
FDA reads the study the same way. Its briefing says TB-500 "appeared to be devoid of wound-healing properties in an in-vitro study" and that "FDA did not identify nonclinical in-vivo pharmacological studies assessing the potential for TB-500 (free base) or TB-500 acetate to promote wound healing." Source: FDA briefing document.
The horse studies of 2012 and 2013 measured TB-500 and its breakdown products in plasma and urine for doping control. They tested detection methods. Sources: 2012 horse doping-control paper, PMID 23084823 and 2013 horse plasma peptide-screening paper, PMID 23318763.
FDA searched the published medical literature and found no article in which TB-500 was given to humans. Its briefing states: "We did not find case reports in the published medical literature on the use of TB-500 in humans." It also states: "The nominator has not provided clinical evidence on the use of TB-500 in wound healing." Source: FDA briefing document.
TB-500 is often discussed together with BPC-157. Studies and questions about the combination are collected on the BPC-157 and TB-500 combination page. None of the studies above tested BPC-157.
The records read for this page include no study of TB-500 in tendon or muscle. FDA looked for studies of whether TB-500 promotes wound healing and found none in living animals. Source: FDA briefing document.
They describe the 43-residue protein in people with venous ulcers or dry eye. FDA keeps TB-500 as a separate substance with its own UNII record. Source: FDA UNII record for TB-500.
According to the authors, the metabolite Ac-LKKTE showed significant activity compared with the control. The parent peptide did not.
The supplier's category page that lists TB-500 is Curo's recovery and regenerative research category.