# TB-500

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- Published: 2026-08-28
- Author: Best Health IQ
- Summary: A synthetic analog of Thymosin Beta-4 that promotes systemic healing through actin regulation and angiogenesis.
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\*\*Recovery & Repair · Moderate Evidence · Research Only\*\* ### TB-500 (S2.3) — Thymosin Beta-4 (synthetic fragment) A synthetic analog of Thymosin Beta-4 that promotes systemic healing through actin regulation and angiogenesis. \*\*Prohibited in competition.\*\* This compound is on the WADA Prohibited List (class \\\[S0 / S2.3 / S2\\\]), banned at all times, both in and out of competition. Athletes subject to WADA or USADA testing should not use it. ### Description TB-500 is a synthetic peptide corresponding to the actin-binding domain (amino acids 17–23) of Thymosin Beta-4 (TB4), a naturally occurring 43-amino acid peptide found in virtually all human cells. Thymosin Beta-4 is one of the most abundant intracellular peptides in mammals and is the primary G-actin sequestering peptide in cells. Whether the fragment reproduces the activity of full-length Thymosin Beta-4 has not been established. FDA has identified no human exposure data for the fragment, and evidence generated with full-length Tβ4 does not transfer to it. Unlike BPC-157, which has primarily local healing effects at the injection site, TB-500 provides systemic healing effects throughout the body, making it particularly valuable for widespread injuries, systemic inflammation, or tissues that are difficult to inject directly (such as tendons deep within joints or cardiac tissue). TB-500 has demonstrated remarkable healing effects in animal models of cardiac injury, tendon damage, corneal wounds, and neurological injury. It is commonly combined with BPC-157 for comprehensive tissue repair. ### Key Characteristics - \*\*Molecular Formula:\*\* C36H66N10O13 - \*\*Molecular Weight:\*\* 847 Da (LKKTETQ); listed in Key Characteristics as 4963.5 Da - \*\*Half-Life:\*\* ~24–36 hours - \*\*Administration Routes:\*\* Subcutaneous injection, Intramuscular injection - \*\*Typical Dose:\*\* 2–5 mg - \*\*Frequency:\*\* 2x per week (loading), 1x per week (maintenance) ### Investigated Benefits - Systemic tissue repair and healing - Reduced inflammation throughout body - Improved flexibility and range of motion - Accelerated muscle recovery - Cardiovascular tissue repair \\\* Benefits based on preclinical/animal research unless otherwise noted. “TB-500” is not a standardised identity. Most material sold under the name is the 7-residue fragment LKKTETQ (~847 Da); some is N-terminally acetylated (~889 Da). Full-length Thymosin Beta-4 is a different molecule at 43 amino acids and ~4,963 Da. Figures for one should not be applied to the other. ### Mechanism of Action “A synthetic analog of Thymosin Beta-4 that promotes systemic healing through actin regulation and angiogenesis.” TB-500’s primary mechanism involves sequestration of G-actin (monomeric actin) through its LKKTET actin-binding motif. By regulating the balance between G-actin and F-actin (filamentous actin), TB-500 controls cell migration, proliferation, and differentiation — all critical processes in tissue repair. Specifically, it promotes the migration of keratinocytes, endothelial cells, and fibroblasts into wound sites, accelerating wound closure. TB-500 also upregulates VEGF (vascular endothelial growth factor) and its receptor VEGFR2, promoting angiogenesis (new blood vessel formation) that is essential for tissue repair and regeneration. It reduces the expression of pro-inflammatory cytokines (IL-1β, TNF-α) and promotes the transition from the inflammatory to the proliferative phase of wound healing. In cardiac tissue, TB-500 has demonstrated the ability to activate cardiac progenitor cells and promote cardiomyocyte regeneration after ischemic injury — a property unique among peptides studied for cardiac repair. ### Dosing Protocol - \*\*Typical Dose:\*\* 2–5 mg - \*\*Frequency:\*\* 2x per week (loading), 1x per week (maintenance) - \*\*Cycle Length:\*\* 4–8 weeks loading, then maintenance - \*\*Administration:\*\* Subcutaneous injection \*\*Protocol Notes:\*\* Loading phase: 2–5 mg twice weekly for 4–6 weeks. Maintenance: 2 mg once weekly. Can be combined with BPC-157 for synergistic effects. ### Reconstitution Guide Add 2 mL bacteriostatic water to 10 mg vial → 5 mg/mL For 2.5 mg dose: draw 0.5 mL (50 units on U-100 syringe) ### Storage Information Lyophilized: refrigerate. Reconstituted: refrigerate and use within 30 days. ### Quality & Sourcing Standards When sourcing TB-500 for research purposes, the following quality benchmarks should be verified before use. - \*\*Purity:\*\* \>98% (verified by HPLC) - \*\*Certificate of Analysis (COA):\*\* Must be provided by supplier - \*\*Endotoxin Testing:\*\* \<0.1 EU/mg (prevents bacterial contamination) - \*\*GMP Compliance:\*\* Manufactured in cGMP-certified facility - \*\*Third-Party Testing:\*\* Independent lab verification preferred ### Competition Status TB-500 is prohibited by WADA under class S2.3 (growth factors and growth-factor modulators), at all times, both in and out of competition. ### Regulatory Status FDA placed TB-500 in Category 2 (significant safety risks) in September 2023. It is not FDA-approved and is not a lawful dietary ingredient. FDA has identified no human exposure data for the fragment. ### Unresolved Safety Questions TB-500 upregulates VEGF and VEGFR2. That pro-angiogenic mechanism carries the same unresolved tumour-promotion questions as other angiogenic agents, and has not been studied for that risk in humans. ### Research Highlights 1. Demonstrated cardiac repair in myocardial infarction models 2. Human trials exist for full-length Thymosin Beta-4 (e.g. RGN-259 in ophthalmology), but none for the TB-500 fragment 3. Improved wound healing in Phase II trials ### Evidence Level \*\*Moderate Evidence\*\* Multiple animal studies and/or early human trials. Reasonable confidence in mechanism, but human data is limited. ### Compatible Peptides Peptides commonly used alongside TB-500 for synergistic effects. - \*\*BPC-157\*\* (Recovery & Repair): A synthetic pentadecapeptide derived from gastric juice with extraordinary tissue healing properties across multiple organ systems. - \*\*CJC-1295 No DAC\*\* (Hormone & GH): A short-acting GHRH analog that produces physiological GH pulses when combined with a GHRP like Ipamorelin. - \*\*Ipamorelin\*\* (Hormone & GH): The most selective GHRP available, stimulating GH release with minimal cortisol or prolactin elevation. ### Protocols Featuring TB-500 - \*\*The Wolverine Stack:\*\* Maximum tissue repair and recovery - \*\*Complete Recovery Stack:\*\* Comprehensive recovery from surgery or major injury ### Quick Reference - \*\*Category:\*\* Recovery & Repair - \*\*Status:\*\* Research Only - \*\*Dose:\*\* 2–5 mg - \*\*Frequency:\*\* 2x per week (loading), 1x per week (maintenance) - \*\*Cycle:\*\* 4–8 weeks loading, then maintenance ### FDA Disclaimer The statements made within this website have not been evaluated by the US Food and Drug Administration. The products and information provided are not intended to diagnose, treat, cure, or prevent any disease. This website is intended for educational and research purposes only. Many peptides described on this site are not approved by the FDA for human therapeutic use and are classified as research chemicals. Nothing on this site constitutes medical advice.